Move iris's text onto parley, with a glyph atlas

Two changes that only make sense together, because the atlas is what the
new layout feeds.

Parley replaces cosmic-text for layout and shaping, and its editing model
replaces the hand-written one. That is the larger win in edit.rs: parley
addresses text by byte offset into one string rather than by (line, index),
so `select_content`, `delete_between`, `insert_inner` and `newline` become
ordinary string operations, and `iter_layout_lines`, `index_x` and
`cursor_pos` -- which walked runs by hand to place the caret and the
selection boxes -- are deleted in favour of `Selection::geometry` and
`Cursor::geometry`. Those are bidi- and wrap-correct, which the hand-written
versions were not. The file loses about 130 lines and gains Home/End.

The atlas is what the TODO's "text resizing (per frame) is really slow" was
about. Every string used to be rasterised into its own RgbaImage and
uploaded as a whole texture whenever anything changed -- so a window resize
re-rasterised and re-uploaded every visible string. Now a glyph is
rasterised once per font, size and subpixel phase and shared by every string
containing it, and a resize re-emits quads without touching the GPU's copy.
The tabs example says so directly: its `views` counter, the number of
texture views bound, goes from 6 to 1.

Supporting pieces: a GLYPH primitive that samples a sub-rectangle and tints
it, since the existing texture primitive samples a whole texture; a Patch
texture update, because re-uploading a 4 MB page per glyph is what an atlas
exists to avoid; and GpuTextures now keeps its Textures, as a view cannot be
written through.

Two bugs found on the way. `primitives!`'s @count rule recursed with commas
while matching space-separated tokens, so it only terminated for exactly two
primitives -- adding a third hit the recursion limit. And Color had no
Default, which parley's Brush requires.

Drops cosmic-text and unicode-segmentation, and with them two nightly
feature gates that nothing uses any more: portable_simd (the old glyph
compositing) and gen_blocks (the deleted line iterator). Eleven gates left.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

iris/Cargo.lock

@@ -118,7 +118,7 @@ dependencies = [
  "clipboard-win",
  "image",
  "log",
- "objc2 0.6.3",
+ "objc2 0.6.4",
  "objc2-app-kit 0.3.2",
  "objc2-core-foundation",
  "objc2-core-graphics",
@@ -138,7 +138,7 @@ checksum = "0ae92a5119aa49cdbcf6b9f893fe4e1d98b04ccbf82ee0584ad948a44a734dea"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -318,7 +318,7 @@ checksum = "f9abbd1bc6865053c427f7198e6af43bfdedc55ab791faed4fbd361d789575ff"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -510,39 +510,6 @@ dependencies = [
  "memchr",
 ]
 
-[[package]]
-name = "core_maths"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "77745e017f5edba1a9c1d854f6f3a52dac8a12dd5af5d2f54aecf61e43d80d30"
-dependencies = [
- "libm",
-]
-
-[[package]]
-name = "cosmic-text"
-version = "0.16.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c4cadaea21e24c49c0c82116f2b465ae6a49d63c90e428b0f8d9ae1f638ac91f"
-dependencies = [
- "bitflags 2.10.0",
- "fontdb",
- "harfrust",
- "linebender_resource_handle",
- "log",
- "rangemap",
- "rustc-hash",
- "self_cell",
- "skrifa 0.39.0",
- "smol_str",
- "swash",
- "sys-locale",
- "unicode-bidi",
- "unicode-linebreak",
- "unicode-script",
- "unicode-segmentation",
-]
-
 [[package]]
 name = "crc32fast"
 version = "1.5.0"
@@ -602,7 +569,18 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "89a09f22a6c6069a18470eb92d2298acf25463f14256d24778e1230d789a2aec"
 dependencies = [
  "bitflags 2.10.0",
- "objc2 0.6.3",
+ "objc2 0.6.4",
+]
+
+[[package]]
+name = "displaydoc"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c6232dd377dcc64799954cbd3a9bb882e9cdc1308ccd87b1c098f1fb2eaf82a8"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 3.0.5",
 ]
 
 [[package]]
@@ -658,7 +636,7 @@ checksum = "44f23cf4b44bfce11a86ace86f8a73ffdec849c9fd00a386a53d278bd9e81fb3"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -715,7 +693,7 @@ checksum = "a0aca10fb742cb43f9e7bb8467c91aa9bcb8e3ffbc6a6f7389bb93ffc920577d"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -771,26 +749,34 @@ dependencies = [
 ]
 
 [[package]]
-name = "fontconfig-parser"
+name = "font-types"
-version = "0.5.8"
+version = "0.12.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bbc773e24e02d4ddd8395fd30dc147524273a83e54e0f312d986ea30de5f5646"
+checksum = "e64eb721ca85a34323425f4041adc5d82704d3782d5f8f03793bc012419dce23"
 dependencies = [
- "roxmltree",
+ "bytemuck",
 ]
 
 [[package]]
-name = "fontdb"
+name = "fontique"
-version = "0.23.0"
+version = "0.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "457e789b3d1202543297a350643cf459f836cade38934e7a4cf6a39e7cde2905"
+checksum = "6688bc1294fe7117d788937b6c53480169b29c566954af490830d4c09da9516a"
 dependencies = [
- "fontconfig-parser",
+ "hashbrown 0.17.1",
- "log",
+ "linebender_resource_handle",
  "memmap2",
- "slotmap",
+ "objc2 0.6.4",
- "tinyvec",
+ "objc2-core-foundation",
- "ttf-parser",
+ "objc2-core-text",
+ "objc2-foundation 0.3.2",
+ "parlance",
+ "read-fonts 0.41.0",
+ "roxmltree",
+ "smallvec",
+ "windows",
+ "windows-core",
+ "yeslogic-fontconfig-sys",
 ]
 
 [[package]]
@@ -811,7 +797,7 @@ checksum = "1a5c6c585bc94aaf2c7b51dd4c2ba22680844aba4c687be581871a6f518c5742"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -941,14 +927,13 @@ dependencies = [
 
 [[package]]
 name = "harfrust"
-version = "0.4.1"
+version = "0.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e0caaee032384c10dd597af4579c67dee16650d862a9ccbe1233ff1a379abc07"
+checksum = "c03d949a14aa089bbb282f7dd76a498a7f684428e4257202efc119ec010376f9"
 dependencies = [
  "bitflags 2.10.0",
  "bytemuck",
- "core_maths",
+ "read-fonts 0.41.0",
- "read-fonts 0.36.0",
  "smallvec",
 ]
 
@@ -972,6 +957,15 @@ dependencies = [
  "foldhash 0.2.0",
 ]
 
+[[package]]
+name = "hashbrown"
+version = "0.17.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed5909b6e89a2db4456e54cd5f673791d7eca6732202bbf2a9cc504fe2f9b84a"
+dependencies = [
+ "foldhash 0.2.0",
+]
+
 [[package]]
 name = "hermit-abi"
 version = "0.5.2"
@@ -984,6 +978,134 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dfa686283ad6dd069f105e5ab091b04c62850d3e4cf5d67debad1933f55023df"
 
+[[package]]
+name = "icu_collections"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fa68d21081c4a05d5a901a1c62add574c77048b6a1c67be3b50ce0b60d4ca513"
+dependencies = [
+ "displaydoc",
+ "potential_utf",
+ "utf8_iter",
+ "yoke",
+ "zerofrom",
+ "zerovec",
+]
+
+[[package]]
+name = "icu_locale_core"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d56e28588da92eee5c3201a6eff33fabdd49b62269c8938d4ff050ce4d900deb"
+dependencies = [
+ "displaydoc",
+ "litemap",
+ "serde",
+ "tinystr",
+ "writeable",
+ "zerovec",
+]
+
+[[package]]
+name = "icu_locale_fallback"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "251af8e57c9400e3eb58242fe5b8b1152b2a64fdf4cf632f923c38ccee6f2fa9"
+dependencies = [
+ "icu_locale_core",
+ "icu_locale_fallback_data",
+ "icu_provider",
+ "potential_utf",
+ "tinystr",
+ "zerovec",
+]
+
+[[package]]
+name = "icu_locale_fallback_data"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "decf2a22ec8fa68f1a0c1129a3f8583f8f8bc24e8b9ccbe98ead99f62a4dc3a8"
+
+[[package]]
+name = "icu_normalizer"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "12f9cf5f235641ed274641dd81c3f28d870e276763d0797aeeab72317b1c646f"
+dependencies = [
+ "icu_collections",
+ "icu_normalizer_data",
+ "icu_properties",
+ "icu_provider",
+ "smallvec",
+ "zerovec",
+]
+
+[[package]]
+name = "icu_normalizer_data"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1563da1ed3e0b3bf3d74c9b85917ac9c56464d2f57242270c09c9e752f8021a0"
+
+[[package]]
+name = "icu_properties"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7e7ca276ad3145661a65914e6daf131ca5120cd3dcee8f8f3214b8875184a148"
+dependencies = [
+ "displaydoc",
+ "icu_collections",
+ "icu_locale_core",
+ "icu_properties_data",
+ "icu_provider",
+ "zerotrie",
+ "zerovec",
+]
+
+[[package]]
+name = "icu_properties_data"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e590f038c1464a96894fd6d10127e90a8be4509f56ff7ecef851b15cee0b7caa"
+
+[[package]]
+name = "icu_provider"
+version = "2.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d27bbb9d3abbefac45d55f647c9de1d44aafcd1186eb91879afef17c396c3e73"
+dependencies = [
+ "displaydoc",
+ "icu_locale_core",
+ "serde",
+ "stable_deref_trait",
+ "writeable",
+ "yoke",
+ "zerofrom",
+ "zerotrie",
+ "zerovec",
+]
+
+[[package]]
+name = "icu_segmenter"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "82d07aafccd67af15d02512a6adf5896fbc5ed00f2e99b471d2efa14016db3db"
+dependencies = [
+ "icu_collections",
+ "icu_locale_fallback",
+ "icu_provider",
+ "icu_segmenter_data",
+ "potential_utf",
+ "smallvec",
+ "utf8_iter",
+ "zerovec",
+]
+
+[[package]]
+name = "icu_segmenter_data"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae293c039020f9ec10710af98d29ce6aa2051486638b49c9a6409f3b4a9e98ad"
+
 [[package]]
 name = "image"
 version = "0.25.9"
@@ -1042,7 +1164,7 @@ checksum = "c34819042dc3d3971c46c2190835914dfbe0c3c13f61449b2997f4e9722dfa60"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -1050,13 +1172,13 @@ name = "iris"
 version = "0.1.0"
 dependencies = [
  "arboard",
- "cosmic-text",
  "image",
  "iris-core",
  "iris-macro",
+ "parley",
  "pollster",
+ "swash",
  "tokio",
- "unicode-segmentation",
  "wgpu",
  "winit",
 ]
@@ -1066,9 +1188,10 @@ name = "iris-core"
 version = "0.1.0"
 dependencies = [
  "bytemuck",
- "cosmic-text",
  "fxhash",
  "image",
+ "parley",
+ "swash",
  "wgpu",
 ]
 
@@ -1078,7 +1201,7 @@ version = "0.1.0"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -1216,6 +1339,12 @@ version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "df1d3c3b53da64cf5760482273a98e575c651a67eec7f77df96b5b642de8f039"
 
+[[package]]
+name = "litemap"
+version = "0.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "47d9d19d1d6efa0109d2f65ff4c85cddd50bd572e5a00127ab10987290bcefae"
+
 [[package]]
 name = "litrs"
 version = "1.0.0"
@@ -1273,9 +1402,9 @@ checksum = "f52b00d39961fc5b2736ea853c9cc86238e165017a493d1d5c8eac6bdc4cc273"
 
 [[package]]
 name = "memmap2"
-version = "0.9.9"
+version = "0.9.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "744133e4a0e0a658e1374cf3bf8e415c4052a15a111acd372764c55b4177d490"
+checksum = "d1219ed1b7f229ee7104d281dd01d6802fe28bb6e95d292942c4daacdeb798c0"
 dependencies = [
  "libc",
 ]
@@ -1410,7 +1539,7 @@ checksum = "ed3955f1a9c7c0c15e092f9c887db08b1fc683305fdf6eb6684f22555355e202"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -1462,7 +1591,7 @@ dependencies = [
  "proc-macro-crate",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -1492,9 +1621,9 @@ dependencies = [
 
 [[package]]
 name = "objc2"
-version = "0.6.3"
+version = "0.6.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b7c2599ce0ec54857b29ce62166b0ed9b4f6f1a70ccc9a71165b6154caca8c05"
+checksum = "3a12a8ed07aefc768292f076dc3ac8c48f3781c8f2d5851dd3d98950e8c5a89f"
 dependencies = [
  "objc2-encode",
 ]
@@ -1522,7 +1651,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d49e936b501e5c5bf01fda3a9452ff86dc3ea98ad5f283e1455153142d97518c"
 dependencies = [
  "bitflags 2.10.0",
- "objc2 0.6.3",
+ "objc2 0.6.4",
  "objc2-core-graphics",
  "objc2-foundation 0.3.2",
 ]
@@ -1571,7 +1700,7 @@ checksum = "2a180dd8642fa45cdb7dd721cd4c11b1cadd4929ce112ebd8b9f5803cc79d536"
 dependencies = [
  "bitflags 2.10.0",
  "dispatch2",
- "objc2 0.6.3",
+ "objc2 0.6.4",
 ]
 
 [[package]]
@@ -1582,7 +1711,7 @@ checksum = "e022c9d066895efa1345f8e33e584b9f958da2fd4cd116792e15e07e4720a807"
 dependencies = [
  "bitflags 2.10.0",
  "dispatch2",
- "objc2 0.6.3",
+ "objc2 0.6.4",
  "objc2-core-foundation",
  "objc2-io-surface",
 ]
@@ -1611,6 +1740,16 @@ dependencies = [
  "objc2-foundation 0.2.2",
 ]
 
+[[package]]
+name = "objc2-core-text"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0cde0dfb48d25d2b4862161a4d5fcc0e3c24367869ad306b0c9ec0073bfed92d"
+dependencies = [
+ "bitflags 2.10.0",
+ "objc2-core-foundation",
+]
+
 [[package]]
 name = "objc2-encode"
 version = "4.1.0"
@@ -1637,7 +1776,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e3e0adef53c21f888deb4fa59fc59f7eb17404926ee8a6f59f5df0fd7f9f3272"
 dependencies = [
  "bitflags 2.10.0",
- "objc2 0.6.3",
+ "objc2 0.6.4",
  "objc2-core-foundation",
 ]
 
@@ -1648,7 +1787,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "180788110936d59bab6bd83b6060ffdfffb3b922ba1396b312ae795e1de9d81d"
 dependencies = [
  "bitflags 2.10.0",
- "objc2 0.6.3",
+ "objc2 0.6.4",
  "objc2-core-foundation",
 ]
 
@@ -1746,9 +1885,9 @@ dependencies = [
 
 [[package]]
 name = "once_cell"
-version = "1.21.3"
+version = "1.21.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
+checksum = "9f7c3e4beb33f85d45ae3e3a1792185706c8e16d043238c593331cc7cd313b50"
 
 [[package]]
 name = "orbclient"
@@ -1811,6 +1950,39 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "parlance"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b6937eda350acc1a5d05872c3cbf99fe78619c269096e2be3d4a350058639d5"
+
+[[package]]
+name = "parley"
+version = "0.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "22d2ff88bd3f7d68d1d9b09c7e6209f9a8e8c05088295140a2bcf2e9b17038c5"
+dependencies = [
+ "fontique",
+ "harfrust",
+ "hashbrown 0.17.1",
+ "icu_normalizer",
+ "icu_properties",
+ "icu_segmenter",
+ "linebender_resource_handle",
+ "parlance",
+ "parley_data",
+ "skrifa 0.44.0",
+]
+
+[[package]]
+name = "parley_data"
+version = "0.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1567535334d6ba2d3cde19221ba9a7bd0fabb3cbd99046ddfb10ae061cfcc889"
+dependencies = [
+ "icu_properties",
+]
+
 [[package]]
 name = "paste"
 version = "1.0.15"
@@ -1857,7 +2029,7 @@ checksum = "6e918e4ff8c4549eb882f14b3a4bc8c8bc93de829416eacf579f1207a8fbf861"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -1920,6 +2092,17 @@ dependencies = [
  "portable-atomic",
 ]
 
+[[package]]
+name = "potential_utf"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d83eb9bc6d8e5cf568e7a1101d60ee05e81ed50ea106026f3d18deeb046d7661"
+dependencies = [
+ "serde_core",
+ "writeable",
+ "zerovec",
+]
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.21"
@@ -1969,7 +2152,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "52717f9a02b6965224f95ca2a81e2e0c5c43baacd28ca057577988930b6c3d5b"
 dependencies = [
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -2007,9 +2190,9 @@ dependencies = [
 
 [[package]]
 name = "quote"
-version = "1.0.42"
+version = "1.0.47"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a338cc41d27e6cc6dce6cefc13a0729dfbb81c262b1f519331575dd80ef3067f"
+checksum = "1fbf4db142a473a8d80c26bbf18454ed458bf8d26c8219c331daecfdbd079001"
 dependencies = [
  "proc-macro2",
 ]
@@ -2055,12 +2238,6 @@ version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c3d6831663a5098ea164f89cff59c6284e95f4e3c76ce9848d4529f5ccca9bde"
 
-[[package]]
-name = "rangemap"
-version = "1.7.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "973443cf09a9c8656b574a866ab68dfa19f0867d0340648c7d2f6a71b8a8ea68"
-
 [[package]]
 name = "rav1e"
 version = "0.8.1"
@@ -2137,16 +2314,6 @@ dependencies = [
  "crossbeam-utils",
 ]
 
-[[package]]
-name = "read-fonts"
-version = "0.35.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6717cf23b488adf64b9d711329542ba34de147df262370221940dfabc2c91358"
-dependencies = [
- "bytemuck",
- "font-types",
-]
-
 [[package]]
 name = "read-fonts"
 version = "0.36.0"
@@ -2154,8 +2321,18 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5eaa2941a4c05443ee3a7b26ab076a553c343ad5995230cc2b1d3e993bdc6345"
 dependencies = [
  "bytemuck",
- "core_maths",
+ "font-types 0.10.1",
- "font-types",
+]
+
+[[package]]
+name = "read-fonts"
+version = "0.41.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "046a7d674daf459825b32f5062056d6882db0d2f5a479fbd76ccfc870ac18709"
+dependencies = [
+ "bytemuck",
+ "font-types 0.12.4",
+ "once_cell",
 ]
 
 [[package]]
@@ -2199,9 +2376,12 @@ checksum = "0c6a884d2998352bb4daf0183589aec883f16a6da1f4dde84d8e2e9a5409a1ce"
 
 [[package]]
 name = "roxmltree"
-version = "0.20.0"
+version = "0.21.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6c20b6793b5c2fa6553b250154b78d6d0db37e72700ae35fad9387a46f487c97"
+checksum = "f1964b10c76125c36f8afe190065a4bf9a87bf324842c05701330bba9f1cacbb"
+dependencies = [
+ "memchr",
+]
 
 [[package]]
 name = "rustc-hash"
@@ -2275,12 +2455,6 @@ dependencies = [
  "tiny-skia",
 ]
 
-[[package]]
-name = "self_cell"
-version = "1.2.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b12e76d157a900eb52e81bc6e9f3069344290341720e9178cde2407113ac8d89"
-
 [[package]]
 name = "serde"
 version = "1.0.228"
@@ -2308,7 +2482,7 @@ checksum = "d540f220d3187173da220f885ab66608367b6574e925011a9353e4badda91d79"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -2332,16 +2506,6 @@ dependencies = [
  "quote",
 ]
 
-[[package]]
-name = "skrifa"
-version = "0.37.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8c31071dedf532758ecf3fed987cdb4bd9509f900e026ab684b4ecb81ea49841"
-dependencies = [
- "bytemuck",
- "read-fonts 0.35.0",
-]
-
 [[package]]
 name = "skrifa"
 version = "0.39.0"
@@ -2352,6 +2516,16 @@ dependencies = [
  "read-fonts 0.36.0",
 ]
 
+[[package]]
+name = "skrifa"
+version = "0.44.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "819ab7d62b1d3e72d9d9dea5650bac30424f9111364bb94928dbf5ecad1baa68"
+dependencies = [
+ "bytemuck",
+ "read-fonts 0.41.0",
+]
+
 [[package]]
 name = "slab"
 version = "0.4.11"
@@ -2436,11 +2610,11 @@ checksum = "6637bab7722d379c8b41ba849228d680cc12d0a45ba1fa2b48f2a30577a06731"
 
 [[package]]
 name = "swash"
-version = "0.2.6"
+version = "0.2.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "47846491253e976bdd07d0f9cc24b7daf24720d11309302ccbbc6e6b6e53550a"
+checksum = "6c2499c2d826531388872b2268718aed907a39bd785ab0dcfe57fab26283f92e"
 dependencies = [
- "skrifa 0.37.0",
+ "skrifa 0.39.0",
  "yazi",
  "zeno",
 ]
@@ -2457,12 +2631,25 @@ dependencies = [
 ]
 
 [[package]]
-name = "sys-locale"
+name = "syn"
-version = "0.3.2"
+version = "3.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8eab9a99a024a169fe8a903cf9d4a3b3601109bcc13bd9e3c6fff259138626c4"
+checksum = "12df2e0110f65b775f769bb17ef989067a1d931b2eb822bd4346631eeada89f9"
 dependencies = [
- "libc",
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "synstructure"
+version = "0.13.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "728a70f3dbaf5bab7f0c4b1ac8d7ae5ea60a4b5549c8a5914361c99147a709d2"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -2500,7 +2687,7 @@ checksum = "4fee6c4efc90059e10f81e6d42c60a18f76588c3d74cb83a0b242a2b6c7504c1"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -2511,7 +2698,7 @@ checksum = "3ff15c8ecd7de3849db632e14d18d2571fa09dfc5ed93479bc4485c7a517c913"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -2554,20 +2741,16 @@ dependencies = [
 ]
 
 [[package]]
-name = "tinyvec"
+name = "tinystr"
-version = "1.10.0"
+version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bfa5fdc3bce6191a1dbc8c02d5c8bffcf557bafa17c124c5264a458f1b0613fa"
+checksum = "b1e27c91459209c2986af3dcf603a5a74a4368754ce37414f59acc971167f643"
 dependencies = [
- "tinyvec_macros",
+ "displaydoc",
+ "serde_core",
+ "zerovec",
 ]
 
-[[package]]
-name = "tinyvec_macros"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
-
 [[package]]
 name = "tokio"
 version = "1.49.0"
@@ -2639,15 +2822,6 @@ name = "ttf-parser"
 version = "0.25.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d2df906b07856748fa3f6e0ad0cbaa047052d4a7dd609e231c4f72cee8c36f31"
-dependencies = [
- "core_maths",
-]
-
-[[package]]
-name = "unicode-bidi"
-version = "0.3.18"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5c1cb5db39152898a79168971543b1cb5020dff7fe43c8dc468b0885f5e29df5"
 
 [[package]]
 name = "unicode-ident"
@@ -2655,18 +2829,6 @@ version = "1.0.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9312f7c4f6ff9069b165498234ce8be658059c6728633667c526e27dc2cf1df5"
 
-[[package]]
-name = "unicode-linebreak"
-version = "0.1.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3b09c83c3c29d37506a3e260c08c03743a6bb66a9cd432c6934ab501a190571f"
-
-[[package]]
-name = "unicode-script"
-version = "0.5.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "383ad40bb927465ec0ce7720e033cb4ca06912855fc35db31b5755d0de75b1ee"
-
 [[package]]
 name = "unicode-segmentation"
 version = "1.12.0"
@@ -2679,6 +2841,12 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b4ac048d71ede7ee76d585517add45da530660ef4390e49b098733c6e897f254"
 
+[[package]]
+name = "utf8_iter"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6c140620e7ffbb22c2dee59cafe6084a59b5ffc27a8859a5f0d494b5d52b6be"
+
 [[package]]
 name = "v_frame"
 version = "0.3.9"
@@ -2760,7 +2928,7 @@ dependencies = [
  "bumpalo",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
  "wasm-bindgen-shared",
 ]
 
@@ -3120,7 +3288,7 @@ checksum = "053e2e040ab57b9dc951b72c264860db7eb3b0200ba345b4e4c3b14f67855ddf"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -3131,7 +3299,7 @@ checksum = "3f316c4a2570ba26bbec722032c4099d8c8bc095efccdc15688708623367e358"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
 ]
 
 [[package]]
@@ -3493,6 +3661,12 @@ dependencies = [
  "wayland-protocols-wlr",
 ]
 
+[[package]]
+name = "writeable"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3ad82d2a33cdc9674dc7465672f271e096168fcdbe0f799d9e6db8c5892679dc"
+
 [[package]]
 name = "x11-dl"
 version = "2.21.0"
@@ -3568,6 +3742,40 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e01738255b5a16e78bbb83e7fbba0a1e7dd506905cfc53f4622d89015a03fbb5"
 
+[[package]]
+name = "yeslogic-fontconfig-sys"
+version = "6.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d8b8abf912b9a29ff112e1671c97c33636903d13a69712037190e6805af4f76"
+dependencies = [
+ "dlib",
+ "once_cell",
+ "pkg-config",
+]
+
+[[package]]
+name = "yoke"
+version = "0.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "709fe23a0424b6a435d82152b1bd3fdfb0833487d5fa90d05d42762a9891fef5"
+dependencies = [
+ "stable_deref_trait",
+ "yoke-derive",
+ "zerofrom",
+]
+
+[[package]]
+name = "yoke-derive"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "de844c262c8848816172cef550288e7dc6c7b7814b4ee56b3e1553f275f1858e"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.113",
+ "synstructure",
+]
+
 [[package]]
 name = "zeno"
 version = "0.3.3"
@@ -3591,7 +3799,63 @@ checksum = "d8a8d209fdf45cf5138cbb5a506f6b52522a25afccc534d1475dad8e31105c6a"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.113",
+]
+
+[[package]]
+name = "zerofrom"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ec05a11813ea801ff6d75110ad09cd0824ddba17dfe17128ea0d5f68e6c5272"
+dependencies = [
+ "zerofrom-derive",
+]
+
+[[package]]
+name = "zerofrom-derive"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "11532158c46691caf0f2593ea8358fed6bbf68a0315e80aae9bd41fbade684a1"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.113",
+ "synstructure",
+]
+
+[[package]]
+name = "zerotrie"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4ea269c3bd32f0a32c321907a2ae912ba6f4649bb0fc764a15627e99a7095a3f"
+dependencies = [
+ "displaydoc",
+ "yoke",
+ "zerofrom",
+ "zerovec",
+]
+
+[[package]]
+name = "zerovec"
+version = "0.11.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb0464e17806c1d976d5cba29399c7f08e516e279e2ba493f63123b5fca67dd8"
+dependencies = [
+ "serde",
+ "yoke",
+ "zerofrom",
+ "zerovec-derive",
+]
+
+[[package]]
+name = "zerovec-derive"
+version = "0.11.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34df6fc39dbd26ddc9c10e6a2984476e13acce22e64e4487636ef494369225da"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 3.0.5",
 ]
 
 [[package]]

iris/Cargo.toml

@@ -8,8 +8,8 @@ edition.workspace = true
 [dependencies]
 iris-core = { workspace = true }
 iris-macro = { workspace = true }
-cosmic-text = { workspace = true }
+parley = { workspace = true }
-unicode-segmentation = { workspace = true }
+swash = { workspace = true }
 winit = { workspace = true }
 arboard = { workspace = true, features = ["wayland-data-control"] }
 pollster = { workspace = true }
@@ -33,8 +33,8 @@ winit = "0.30.12"
 wgpu = "28.0.0"
 bytemuck = "1.23.1"
 image = "0.25.6"
-cosmic-text = "0.16.0"
+parley = "0.11.1"
-unicode-segmentation = "1.12.0"
+swash = "0.2.10"
 fxhash = "0.2.1"
 arboard = "3.6.1"
 iris-core = { path = "core" }

iris/core/Cargo.toml

@@ -7,5 +7,6 @@ edition.workspace = true
 wgpu = { workspace = true }
 bytemuck ={ workspace = true }
 image = { workspace = true }
-cosmic-text = { workspace = true }
+parley = { workspace = true }
+swash = { workspace = true }
 fxhash = { workspace = true }

iris/core/src/lib.rs

@@ -5,7 +5,6 @@
 #![feature(unboxed_closures)]
 #![feature(fn_traits)]
 #![feature(const_destruct)]
-#![feature(portable_simd)]
 #![feature(associated_type_defaults)]
 #![feature(unsize)]
 #![feature(coerce_unsized)]

iris/core/src/primitive/color.rs

@@ -10,6 +10,15 @@ pub struct Color<T> {
     pub a: T,
 }
 
+/// Required by parley's `Brush`, which every text style is generic over. Opaque
+/// black rather than transparent: a brush that was never set should be visible
+/// and obviously unstyled, not invisible.
+impl<T: ColorNum> Default for Color<T> {
+    fn default() -> Self {
+        Self::BLACK
+    }
+}
+
 impl<T: ColorNum> Color<T> {
     pub const BLACK: Self = Self::rgb(T::MIN, T::MIN, T::MIN);
     pub const WHITE: Self = Self::rgb(T::MAX, T::MAX, T::MAX);

iris/core/src/primitive/text.rs

@@ -1,60 +1,68 @@
-use crate::{Align, RegionAlign, TextureHandle, Textures, UiColor, util::Vec2};
+use crate::{Align, GlyphAtlas, GlyphKey, PlacedGlyph, RegionAlign, Textures, UiColor, util::Vec2};
-use cosmic_text::{
+use parley::{
-    Attrs, AttrsList, Buffer, CacheKey, Color, Family, FontSystem, Metrics, Placement, SwashCache,
+    Alignment, AlignmentOptions, FontContext, FontFamily, FontFamilyName, GenericFamily, Layout,
-    SwashContent,
+    LayoutContext, LineHeight, PositionedLayoutItem, StyleProperty,
+};
+use swash::{
+    FontRef,
+    scale::{Render, ScaleContext, Source, StrikeWith},
+    zeno::{Format, Vector},
 };
-use image::{DynamicImage, GenericImageView, RgbaImage};
-use std::simd::{Simd, num::SimdUint};
-
-/// TODO: properly wrap this
-pub mod text_lib {
-    pub use cosmic_text::*;
-}
 
+/// Everything text needs that outlives one string: the font collection, the
+/// layout scratch space, the glyph rasteriser and the atlas they fill.
 pub struct TextData {
-    pub font_system: FontSystem,
+    pub font_cx: FontContext,
-    pub swash_cache: SwashCache,
+    pub layout_cx: LayoutContext<UiColor>,
-    glyph_cache: Vec<(Placement, CacheKey, Color)>,
+    scale_cx: ScaleContext,
+    pub atlas: GlyphAtlas,
 }
 
 impl Default for TextData {
     fn default() -> Self {
         Self {
-            font_system: FontSystem::new(),
+            font_cx: FontContext::new(),
-            swash_cache: SwashCache::new(),
+            layout_cx: LayoutContext::new(),
-            glyph_cache: Default::default(),
+            scale_cx: ScaleContext::new(),
+            atlas: GlyphAtlas::default(),
         }
     }
 }
 
-#[derive(Clone, Copy)]
+/// Which family to ask for. Kept as an owned name rather than parley's
+/// borrowed `FontFamily<'_>` so that a widget can hold one without a lifetime.
+#[derive(Clone, PartialEq)]
+pub enum Family {
+    SansSerif,
+    Serif,
+    Monospace,
+    Named(String),
+}
+
+impl Family {
+    fn family(&self) -> FontFamily<'_> {
+        let name = match self {
+            Self::SansSerif => FontFamilyName::Generic(GenericFamily::SansSerif),
+            Self::Serif => FontFamilyName::Generic(GenericFamily::Serif),
+            Self::Monospace => FontFamilyName::Generic(GenericFamily::Monospace),
+            Self::Named(name) => FontFamilyName::Named(name.as_str().into()),
+        };
+        FontFamily::Single(name)
+    }
+}
+
+#[derive(Clone, PartialEq)]
 pub struct TextAttrs {
     pub color: UiColor,
     pub font_size: f32,
     pub line_height: f32,
-    pub family: Family<'static>,
+    pub family: Family,
     pub wrap: bool,
     /// inner alignment of text region (within where it's drawn)
     pub align: RegionAlign,
 }
 
-impl TextAttrs {
+pub const LINE_HEIGHT_MULT: f32 = 1.1;
-    pub fn apply(&self, font_system: &mut FontSystem, buf: &mut Buffer, width: Option<f32>) {
-        buf.set_metrics_and_size(
-            font_system,
-            Metrics::new(self.font_size, self.line_height),
-            width,
-            None,
-        );
-        let attrs = Attrs::new().family(self.family);
-        let list = AttrsList::new(&attrs);
-        for line in &mut buf.lines {
-            line.set_attrs_list(list.clone());
-        }
-    }
-}
-
-pub type TextBuffer = Buffer;
 
 impl Default for TextAttrs {
     fn default() -> Self {
@@ -70,122 +78,200 @@ impl Default for TextAttrs {
     }
 }
 
-pub const LINE_HEIGHT_MULT: f32 = 1.1;
+/// A string together with its laid-out form.
+///
+/// The text and the layout live in one place because parley's `Layout` borrows
+/// nothing but is only meaningful against the string it was built from: keeping
+/// them apart is how they get out of step.
+pub struct TextBuffer {
+    text: String,
+    layout: Layout<UiColor>,
+    /// What the current layout was built for, so `shape` can decline to redo
+    /// work that would come out the same.
+    shaped: Option<(TextAttrs, Option<f32>)>,
+}
 
-impl TextData {
+impl TextBuffer {
-    pub fn draw(
+    pub fn new(text: impl Into<String>) -> Self {
-        &mut self,
+        Self {
-        buffer: &mut TextBuffer,
+            text: text.into(),
-        attrs: &TextAttrs,
+            layout: Layout::new(),
-        textures: &mut Textures,
+            shaped: None,
-    ) -> RenderedText {
-        // TODO: either this or the layout stuff (or both) is super slow,
-        // should probably do texture packing and things if possible.
-        // very visible if you add just a couple of wrapping texts and resize window
-        // should also be timed to figure out exactly what points need to be sped up
-        // let mut pixels = HashMap::<_, [u8; 4]>::default();
-        let mut min_x = 0;
-        let mut min_y = 0;
-        let mut max_x = 0;
-        let mut max_y = 0;
-        let text_color = {
-            let c = attrs.color;
-            cosmic_text::Color::rgba(c.r, c.g, c.b, c.a)
-        };
-        let mut max_width = 0.0f32;
-        let mut height = 0.0;
-
-        for run in buffer.layout_runs() {
-            for glyph in run.glyphs.iter() {
-                let physical_glyph = glyph.physical((0., 0.), 1.0);
-
-                let glyph_color = match glyph.color_opt {
-                    Some(some) => some,
-                    None => text_color,
-                };
-
-                if let Some(img) = self
-                    .swash_cache
-                    .get_image(&mut self.font_system, physical_glyph.cache_key)
-                {
-                    let mut pos = img.placement;
-                    pos.left += physical_glyph.x;
-                    pos.top = physical_glyph.y + run.line_y as i32 - pos.top;
-                    min_x = min_x.min(pos.left);
-                    min_y = min_y.min(pos.top);
-                    max_x = max_x.max(pos.left + pos.width as i32);
-                    max_y = max_y.max(pos.top + pos.height as i32);
-                    self.glyph_cache
-                        .push((pos, physical_glyph.cache_key, glyph_color));
-                }
-            }
-            max_width = max_width.max(run.line_w);
-            height += run.line_height;
         }
-        let img_width = (max_x - min_x + 1) as u32;
+    }
-        let img_height = (max_y - min_y + 1) as u32;
-        let mut image = RgbaImage::new(img_width, img_height);
 
-        for (pos, key, color) in self.glyph_cache.drain(..) {
+    pub fn new_empty() -> Self {
-            let img = self
+        Self::new("")
-                .swash_cache
+    }
-                .get_image(&mut self.font_system, key)
-                .as_ref()
-                .unwrap();
-            let mut merge = |i, color: [u8; 4]| {
-                let i = i as i32;
-                let x = (i % pos.width as i32 + pos.left - min_x) as u32;
-                let y = (i / pos.width as i32 + pos.top - min_y) as u32;
-                let pixel = &mut image[(x, y)].0;
-                // TODO: no clue if proper alpha blending should be done
-                *pixel = Simd::from(color).saturating_add(Simd::from(*pixel)).into();
-            };
 
-            match img.content {
+    pub fn text(&self) -> &str {
-                SwashContent::Mask => {
+        &self.text
-                    for (i, a) in img.data.iter().enumerate() {
+    }
-                        let mut color = color.as_rgba();
+
-                        color[3] = ((color[3] as u32 * *a as u32) / u8::MAX as u32) as u8;
+    pub fn layout(&self) -> &Layout<UiColor> {
-                        merge(i, color);
+        &self.layout
-                    }
+    }
-                }
+
-                SwashContent::SubpixelMask => todo!("subpixel mask text rendering"),
+    pub fn is_empty(&self) -> bool {
-                SwashContent::Color => {
+        self.text.is_empty()
-                    let (colors, _) = img.data.as_chunks::<4>();
+    }
-                    for (i, color) in colors.iter().enumerate() {
+
-                        merge(i, *color);
+    pub fn set_text(&mut self, text: impl Into<String>) {
-                    }
+        let text = text.into();
-                }
+        if text != self.text {
-            }
+            self.text = text;
+            self.shaped = None;
         }
+    }
 
-        let max_dim = 8192;
+    /// Edit the string in place; invalidates the layout unconditionally, since
-        if image.width() > max_dim || image.height() > max_dim {
+    /// the caller is assumed to have changed something.
-            let width = image.width().min(max_dim);
+    pub fn edit(&mut self) -> &mut String {
-            let height = image.height().min(max_dim);
+        self.shaped = None;
-            eprintln!(
+        &mut self.text
-                "WARNING: image of size {:?} cropped to {:?} (texture too big)",
+    }
-                image.dimensions(),
-                (width, height)
-            );
-            image = image.view(0, 0, width, height).to_image();
-        }
 
-        RenderedText {
+    pub fn size(&self) -> Vec2 {
-            handle: textures.add(image),
+        Vec2::new(self.layout.width(), self.layout.height())
-            top_left_offset: Vec2::new(min_x as f32, min_y as f32),
+    }
-            size: Vec2::new(max_width, height),
+
+    /// Lay the text out, unless it is already laid out for these attributes and
+    /// this width.
+    pub fn shape(&mut self, data: &mut TextData, attrs: &TextAttrs, width: Option<f32>) {
+        if self.shaped.as_ref() == Some(&(attrs.clone(), width)) {
+            return;
         }
+        let mut builder = data
+            .layout_cx
+            .ranged_builder(&mut data.font_cx, &self.text, 1.0, true);
+        builder.push_default(StyleProperty::FontFamily(attrs.family.family()));
+        builder.push_default(StyleProperty::FontSize(attrs.font_size));
+        builder.push_default(StyleProperty::LineHeight(LineHeight::Absolute(
+            attrs.line_height,
+        )));
+        builder.push_default(StyleProperty::Brush(attrs.color));
+        builder.build_into(&mut self.layout, &self.text);
+        self.layout.break_all_lines(width);
+        self.layout
+            .align(Alignment::Start, AlignmentOptions::default());
+        self.shaped = Some((attrs.clone(), width));
     }
 }
 
-#[derive(Clone)]
+impl TextData {
-pub struct RenderedText {
+    /// Rasterise whatever of `buffer` is not in the atlas yet, and return where
-    pub handle: TextureHandle,
+    /// each glyph goes relative to the text's top-left.
-    pub top_left_offset: Vec2,
+    ///
-    pub size: Vec2,
+    /// Nothing is uploaded for a glyph already in the atlas, which is the point
+    /// of having one: a resize re-runs this and touches the GPU only if the new
+    /// width brought genuinely new glyphs into view.
+    pub fn place(&mut self, buffer: &TextBuffer, textures: &mut Textures) -> Vec<PlacedGlyph> {
+        let mut placed = Vec::new();
+        for line in buffer.layout.lines() {
+            for item in line.items() {
+                let PositionedLayoutItem::GlyphRun(run) = item else {
+                    continue;
+                };
+                let font = run.run().font();
+                let font_size = run.run().font_size();
+                let coords = run.run().normalized_coords();
+                let Some(font_ref) = FontRef::from_index(font.data.as_ref(), font.index as usize)
+                else {
+                    continue;
+                };
+                let coords_hash = hash_coords(coords);
+                // `font.data.id()` rather than the pointer, so the same font
+                // loaded twice is still one set of entries.
+                let font_id = font.data.id();
+
+                for glyph in run.positioned_glyphs() {
+                    let subpixel = ((glyph.x.fract() * 4.0).round() as i32).rem_euclid(4) as u8;
+                    let key = GlyphKey {
+                        font: font_id,
+                        glyph: glyph.id,
+                        size: (font_size * 16.0).round() as u32,
+                        subpixel,
+                        coords: coords_hash,
+                    };
+                    let entry = match self.atlas.get(&key) {
+                        Some(entry) => entry,
+                        None => {
+                            let mut scaler = self
+                                .scale_cx
+                                .builder(font_ref)
+                                .size(font_size)
+                                .hint(true)
+                                .normalized_coords(coords)
+                                .build();
+                            let image = Render::new(&[
+                                Source::ColorOutline(0),
+                                Source::ColorBitmap(StrikeWith::BestFit),
+                                Source::Outline,
+                            ])
+                            .format(Format::Alpha)
+                            .offset(Vector::new(subpixel as f32 / 4.0, 0.0))
+                            .render(&mut scaler, glyph.id as u16);
+                            match image {
+                                Some(image) => self.atlas.insert(key, &image, textures),
+                                None => {
+                                    self.atlas.insert_empty(key);
+                                    None
+                                }
+                            }
+                        }
+                    };
+                    let Some(entry) = entry else { continue };
+                    placed.push(PlacedGlyph {
+                        entry,
+                        offset: Vec2::new(
+                            glyph.x.floor() + entry.left as f32,
+                            glyph.y.floor() - entry.top as f32,
+                        ),
+                    });
+                }
+            }
+        }
+        placed
+    }
 }
 
-pub trait HasTextures {
+fn hash_coords(coords: &[i16]) -> u64 {
-    fn add_texture(&mut self, image: DynamicImage) -> TextureHandle;
+    // FxHash over the coordinates; they are short and change rarely.
+    let mut h: u64 = 0xcbf2_9ce4_8422_2325;
+    for c in coords {
+        h ^= *c as u16 as u64;
+        h = h.wrapping_mul(0x1000_0000_01b3);
+    }
+    h
+}
+
+/// A laid-out string, ready to draw: where each glyph goes, how big the whole
+/// thing is, and what colour to tint the atlas with.
+///
+/// Cheap to clone and to keep, which is the point -- a widget holds one across
+/// frames and re-emits its quads without going near the rasteriser.
+#[derive(Clone)]
+pub struct RenderedText {
+    pub glyphs: std::sync::Arc<Vec<PlacedGlyph>>,
+    pub size: Vec2,
+    pub color: UiColor,
+}
+
+impl TextData {
+    /// Lay out and place in one step, which is what a widget wants.
+    pub fn render(
+        &mut self,
+        buffer: &mut TextBuffer,
+        attrs: &TextAttrs,
+        width: Option<f32>,
+        textures: &mut Textures,
+    ) -> RenderedText {
+        buffer.shape(self, attrs, width);
+        let glyphs = self.place(buffer, textures);
+        RenderedText {
+            glyphs: std::sync::Arc::new(glyphs),
+            size: buffer.size(),
+            color: attrs.color,
+        }
+    }
 }

iris/core/src/primitive/texture.rs

@@ -29,14 +29,27 @@ pub struct Textures {
 pub enum TextureUpdate<'a> {
     Push(&'a DynamicImage),
     Set(u32, &'a DynamicImage),
+    /// Overwrite a rectangle of an existing texture, rather than replacing it.
+    /// The glyph atlas grows a glyph at a time, and re-uploading a whole atlas
+    /// per glyph is megabytes of copy for a few hundred bytes of change.
+    Patch(u32, PatchRect, &'a DynamicImage),
     Free(u32),
     PushFree,
     SetFree,
 }
 
+#[derive(Debug, Clone, Copy)]
+pub struct PatchRect {
+    pub x: u32,
+    pub y: u32,
+    pub width: u32,
+    pub height: u32,
+}
+
 enum Update {
     Push(u32),
     Set(u32),
+    Patch(u32, PatchRect),
     Free(u32),
 }
 
@@ -81,6 +94,19 @@ impl Textures {
         }
     }
 
+    /// The stored image for a handle, to be written into before `patch`.
+    pub fn image_mut(&mut self, handle: &TextureHandle) -> &mut DynamicImage {
+        self.images[handle.inner.view_idx as usize]
+            .as_mut()
+            .expect("texture was freed while still held")
+    }
+
+    /// Queue an upload of just `rect`, after writing it with `image_mut`.
+    pub fn patch(&mut self, handle: &TextureHandle, rect: PatchRect) {
+        self.updates
+            .push(Update::Patch(handle.inner.view_idx, rect));
+    }
+
     pub fn free(&mut self) {
         for idx in self.recv.try_iter() {
             self.images[idx as usize] = None;
@@ -99,6 +125,10 @@ impl Textures {
                 .as_ref()
                 .map(|img| TextureUpdate::Set(i, img))
                 .unwrap_or(TextureUpdate::SetFree),
+            Update::Patch(i, rect) => self.images[i as usize]
+                .as_ref()
+                .map(|img| TextureUpdate::Patch(i, rect, img))
+                .unwrap_or(TextureUpdate::SetFree),
             Update::Free(i) => TextureUpdate::Free(i),
         })
     }

iris/core/src/render/atlas.rs

@@ -0,0 +1,234 @@
+//! A glyph atlas: one texture holding many rasterised glyphs, so drawing text
+//! is a quad per glyph rather than a texture per string.
+//!
+//! What this replaces is why it exists. Text used to be rasterised into its own
+//! `RgbaImage` and uploaded as a whole texture, per text widget, every time
+//! anything about it changed -- so every window resize re-rasterised and
+//! re-uploaded every visible string, which is what the TODO meant by "resizing
+//! (per frame) is really slow". Here a glyph is rasterised once for a given
+//! font, size and subpixel offset and then reused by every string that contains
+//! it, and a resize re-emits quads without touching the GPU's copy at all.
+
+use crate::{
+    PatchRect, TextureHandle, Textures,
+    util::{HashMap, Vec2},
+};
+use image::RgbaImage;
+use swash::scale::image::{Content, Image};
+
+/// Side of one atlas page, in pixels. 1024 is 4 MB at RGBA8 -- enough for a
+/// few thousand glyphs at UI sizes, and small enough that a page nobody fills
+/// is not a big waste.
+const PAGE: u32 = 1024;
+
+/// Transparent margin kept around every glyph, so that sampling one cannot
+/// pick up its neighbour along a shared edge.
+const PAD: u32 = 1;
+
+/// Identifies a rasterised glyph. Anything that changes the pixels has to be in
+/// here, or two different glyphs share one entry and the wrong one is drawn.
+#[derive(Clone, Copy, PartialEq, Eq, Hash)]
+pub struct GlyphKey {
+    pub font: u64,
+    pub glyph: u32,
+    /// Font size in 1/16 px, so sizes that round to the same pixels share a
+    /// raster instead of filling the atlas with near-duplicates.
+    pub size: u32,
+    /// Horizontal subpixel phase, in 1/4 px.
+    pub subpixel: u8,
+    /// Hash of the variation coordinates; a variable font at two weights is two
+    /// different sets of pixels from one glyph id.
+    pub coords: u64,
+}
+
+#[derive(Clone, Copy)]
+pub struct GlyphEntry {
+    pub uv_min: [f32; 2],
+    pub uv_max: [f32; 2],
+    /// Offset from the glyph's pen position to the top-left of its pixels.
+    pub left: i32,
+    pub top: i32,
+    pub width: u32,
+    pub height: u32,
+    pub is_color: bool,
+    pub view_idx: u32,
+    pub sampler_idx: u32,
+}
+
+struct Page {
+    handle: TextureHandle,
+    /// Shelf packing: glyphs are placed left to right along a shelf whose
+    /// height is the tallest glyph on it, and a new shelf starts above when the
+    /// row runs out. Chosen over a real packer because glyphs at one size are
+    /// close to the same height, which is the case shelves are good at.
+    x: u32,
+    y: u32,
+    shelf_height: u32,
+}
+
+#[derive(Default)]
+pub struct GlyphAtlas {
+    pages: Vec<Page>,
+    /// `None` for a glyph that rasterised to nothing -- a space, say. Cached
+    /// too, so it is not re-rasterised on every layout.
+    entries: HashMap<GlyphKey, Option<GlyphEntry>>,
+}
+
+impl GlyphAtlas {
+    pub fn get(&self, key: &GlyphKey) -> Option<Option<GlyphEntry>> {
+        self.entries.get(key).copied()
+    }
+
+    /// Rasterised pixels in, a place in the atlas out. `None` means the glyph
+    /// has no pixels, which is a normal answer rather than a failure.
+    pub fn insert(
+        &mut self,
+        key: GlyphKey,
+        image: &Image,
+        textures: &mut Textures,
+    ) -> Option<GlyphEntry> {
+        let w = image.placement.width;
+        let h = image.placement.height;
+        if w == 0 || h == 0 {
+            self.entries.insert(key, None);
+            return None;
+        }
+        if w + PAD * 2 > PAGE || h + PAD * 2 > PAGE {
+            // A single glyph larger than a page. Refusing is better than
+            // silently drawing a cropped one; the caller draws nothing.
+            self.entries.insert(key, None);
+            return None;
+        }
+
+        let (page_idx, x, y) = self.allocate(w, h, textures);
+        let page = &self.pages[page_idx];
+
+        let img = textures.image_mut(&page.handle);
+        let rgba = img.as_mut_rgba8().expect("atlas page is rgba8");
+        write_glyph(rgba, image, x, y);
+
+        let handle = page.handle.clone();
+        let rect = PatchRect {
+            x,
+            y,
+            width: w,
+            height: h,
+        };
+        textures.patch(&handle, rect);
+
+        let page = &self.pages[page_idx];
+        let scale = 1.0 / PAGE as f32;
+        let entry = GlyphEntry {
+            uv_min: [x as f32 * scale, y as f32 * scale],
+            uv_max: [(x + w) as f32 * scale, (y + h) as f32 * scale],
+            left: image.placement.left,
+            top: image.placement.top,
+            width: w,
+            height: h,
+            is_color: matches!(image.content, Content::Color),
+            view_idx: page.handle.primitive().view_idx,
+            sampler_idx: page.handle.primitive().sampler_idx,
+        };
+        self.entries.insert(key, Some(entry));
+        Some(entry)
+    }
+
+    /// A free `w`x`h` spot, opening a shelf or a page as needed.
+    fn allocate(&mut self, w: u32, h: u32, textures: &mut Textures) -> (usize, u32, u32) {
+        let need_w = w + PAD;
+        let need_h = h + PAD;
+        if let Some(i) = self.pages.iter().position(|p| fits(p, need_w, need_h)) {
+            let page = &mut self.pages[i];
+            if page.x + need_w > PAGE {
+                page.y += page.shelf_height;
+                page.x = PAD;
+                page.shelf_height = 0;
+            }
+            let (x, y) = (page.x, page.y);
+            page.x += need_w;
+            page.shelf_height = page.shelf_height.max(need_h);
+            return (i, x, y);
+        }
+
+        let handle = textures.add(RgbaImage::new(PAGE, PAGE));
+        self.pages.push(Page {
+            handle,
+            x: PAD + w + PAD,
+            y: PAD,
+            shelf_height: h + PAD,
+        });
+        (self.pages.len() - 1, PAD, PAD)
+    }
+
+    /// Record that a glyph has no pixels, so it is not re-rasterised.
+    pub fn insert_empty(&mut self, key: GlyphKey) {
+        self.entries.insert(key, None);
+    }
+
+    pub fn page_count(&self) -> usize {
+        self.pages.len()
+    }
+
+    pub fn glyph_count(&self) -> usize {
+        self.entries.len()
+    }
+}
+
+fn fits(page: &Page, need_w: u32, need_h: u32) -> bool {
+    // On the current shelf, or on a new one above it.
+    (page.x + need_w <= PAGE && page.y + need_h <= PAGE)
+        || (need_w + PAD <= PAGE && page.y + page.shelf_height + need_h <= PAGE)
+}
+
+/// Copy one rasterised glyph into the page image at `(x, y)`.
+///
+/// A mask glyph keeps its coverage in alpha with the colour left to the shader,
+/// so one raster serves text of any colour; a colour glyph carries its own.
+fn write_glyph(page: &mut RgbaImage, image: &Image, x: u32, y: u32) {
+    let w = image.placement.width;
+    let h = image.placement.height;
+    match image.content {
+        Content::Mask => {
+            for row in 0..h {
+                for col in 0..w {
+                    let a = image.data[(row * w + col) as usize];
+                    page.put_pixel(x + col, y + row, image::Rgba([255, 255, 255, a]));
+                }
+            }
+        }
+        Content::Color => {
+            for row in 0..h {
+                for col in 0..w {
+                    let i = ((row * w + col) * 4) as usize;
+                    let px = [
+                        image.data[i],
+                        image.data[i + 1],
+                        image.data[i + 2],
+                        image.data[i + 3],
+                    ];
+                    page.put_pixel(x + col, y + row, image::Rgba(px));
+                }
+            }
+        }
+        Content::SubpixelMask => {
+            // Not asked for: `Format::Alpha` is what the renderer requests, so
+            // reaching here means the request changed and this needs writing.
+            // Drawn as a plain mask from the green channel rather than dropped,
+            // so the text is readable rather than absent.
+            for row in 0..h {
+                for col in 0..w {
+                    let i = ((row * w + col) * 4) as usize;
+                    let a = image.data[i + 1];
+                    page.put_pixel(x + col, y + row, image::Rgba([255, 255, 255, a]));
+                }
+            }
+        }
+    }
+}
+
+/// Where a glyph goes on screen, in pixels relative to the text's origin.
+#[derive(Clone, Copy)]
+pub struct PlacedGlyph {
+    pub entry: GlyphEntry,
+    pub offset: Vec2,
+}

iris/core/src/render/mod.rs

@@ -11,11 +11,13 @@ use wgpu::{
     *,
 };
 
+mod atlas;
 mod data;
 mod primitive;
 mod texture;
 mod util;
 
+pub use atlas::*;
 pub use data::{Mask, MaskIdx};
 pub use primitive::*;
 

iris/core/src/render/primitive.rs

@@ -93,7 +93,13 @@ macro_rules! primitives {
             }
         )*
     };
-    (@count $t1:tt $($t:tt)+) => { 1 + primitives!(@count $($t),+) };
+    // The recursion has to hand back the same shape it matches -- space
+    // separated, not comma separated. Written with `$($t),+` it re-entered
+    // with a comma as the first token and never terminated, which happened to
+    // work only because there were exactly two primitives: the first step left
+    // a single token, and a single token matches the base case whichever
+    // separator it was written with.
+    (@count $t1:tt $($t:tt)+) => { 1 + primitives!(@count $($t)+) };
     (@count $t:tt) => { 1 };
 }
 
@@ -201,6 +207,7 @@ impl PrimitiveHandle {
 primitives!(
     rects: RectPrimitive => 0,
     textures: TexturePrimitive => 1,
+    glyphs: GlyphPrimitive => 2,
 );
 
 #[repr(C)]
@@ -230,6 +237,28 @@ pub struct TexturePrimitive {
     pub sampler_idx: u32,
 }
 
+/// One glyph, drawn as a sub-rectangle of the glyph atlas.
+///
+/// Separate from `TexturePrimitive` because that one samples a whole texture:
+/// text needs many quads sharing one atlas, which is the whole point of having
+/// an atlas. `color` is the text colour and is multiplied by the atlas's alpha
+/// for an ordinary mask glyph; a colour glyph (emoji) carries its own colour
+/// and takes the atlas texel unchanged, which is what `IS_COLOR` selects.
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct GlyphPrimitive {
+    pub uv_min: [f32; 2],
+    pub uv_max: [f32; 2],
+    pub view_idx: u32,
+    pub sampler_idx: u32,
+    pub color: Color<u8>,
+    pub flags: u32,
+}
+
+impl GlyphPrimitive {
+    pub const IS_COLOR: u32 = 1;
+}
+
 pub struct PrimitiveVec<T> {
     vec: Vec<T>,
     free: Vec<usize>,

iris/core/src/render/shader.wgsl

@@ -1,5 +1,6 @@
 const RECT: u32 = 0u;
 const TEXTURE: u32 = 1u;
+const GLYPH: u32 = 2u;
 
 @group(0) @binding(0)
 var<uniform> window: WindowUniform;
@@ -7,6 +8,8 @@ var<uniform> window: WindowUniform;
 var<storage> rects: array<Rect>;
 @group(1) @binding(TEXTURE)
 var<storage> textures: array<TextureInfo>;
+@group(1) @binding(GLYPH)
+var<storage> glyphs: array<GlyphInfo>;
 
 struct Rect {
     color: u32,
@@ -20,6 +23,15 @@ struct TextureInfo {
     sampler_idx: u32,
 }
 
+struct GlyphInfo {
+    uv_min: vec2<f32>,
+    uv_max: vec2<f32>,
+    view_idx: u32,
+    sampler_idx: u32,
+    color: u32,
+    flags: u32,
+}
+
 struct Mask {
     x: UiSpan,
     y: UiSpan,
@@ -125,6 +137,9 @@ fn fs_main(
         case TEXTURE: {
             color = draw_texture(region, textures[i]);
         }
+        case GLYPH: {
+            color = draw_glyph(region, glyphs[i]);
+        }
         default: {
             color = vec4(1.0, 0.0, 1.0, 1.0);
         }
@@ -148,6 +163,17 @@ fn draw_texture(region: Region, info: TextureInfo) -> vec4<f32> {
     return textureSample(views[info.view_idx], samplers[info.sampler_idx], region.uv);
 }
 
+fn draw_glyph(region: Region, g: GlyphInfo) -> vec4<f32> {
+    let uv = mix(g.uv_min, g.uv_max, region.uv);
+    let texel = textureSample(views[g.view_idx], samplers[g.sampler_idx], uv);
+    if (g.flags & 1u) != 0u {
+        return texel;
+    }
+    var color = unpack4x8unorm(g.color);
+    color.a *= texel.a;
+    return color;
+}
+
 fn draw_rounded_rect(region: Region, rect: Rect) -> vec4<f32> {
     var color = unpack4x8unorm(rect.color);
 

iris/core/src/render/texture.rs

@@ -1,11 +1,15 @@
-use image::{DynamicImage, EncodableLayout};
+use image::{DynamicImage, EncodableLayout, GenericImageView};
 use wgpu::{util::DeviceExt, *};
 
-use crate::{TextureUpdate, Textures};
+use crate::{PatchRect, TextureUpdate, Textures};
 
 pub struct GpuTextures {
     device: Device,
     queue: Queue,
+    /// Kept alongside the views because a patch writes into the texture, and a
+    /// view cannot be written through. Parallel to `views`; `None` where the
+    /// slot is the shared null view.
+    textures: Vec<Option<Texture>>,
     views: Vec<TextureView>,
     view_count: usize,
     samplers: Vec<Sampler>,
@@ -21,6 +25,13 @@ impl GpuTextures {
             match update {
                 TextureUpdate::Push(image) => self.push(image),
                 TextureUpdate::Set(i, image) => self.set(i, image),
+                TextureUpdate::Patch(i, rect, image) => {
+                    // A patch changes texture contents, not the binding array,
+                    // so it must not report `changed` -- rebuilding the bind
+                    // group per glyph is the cost this exists to avoid.
+                    self.patch(i, rect, image);
+                    changed = false;
+                }
                 TextureUpdate::SetFree => self.view_count += 1,
                 TextureUpdate::Free(i) => self.free(i),
                 TextureUpdate::PushFree => self.push_free(),
@@ -30,24 +41,66 @@ impl GpuTextures {
     }
     fn set(&mut self, i: u32, image: &DynamicImage) {
         self.view_count += 1;
-        let view = self.create_view(image);
+        let (texture, view) = self.create(image);
+        self.textures[i as usize] = Some(texture);
         self.views[i as usize] = view;
     }
     fn free(&mut self, i: u32) {
         self.view_count -= 1;
+        self.textures[i as usize] = None;
         self.views[i as usize] = self.null_view.clone();
     }
     fn push(&mut self, image: &DynamicImage) {
         self.view_count += 1;
-        let view = self.create_view(image);
+        let (texture, view) = self.create(image);
+        self.textures.push(Some(texture));
         self.views.push(view);
     }
     fn push_free(&mut self) {
         self.view_count += 1;
+        self.textures.push(None);
         self.views.push(self.null_view.clone());
     }
 
-    fn create_view(&self, image: &DynamicImage) -> TextureView {
+    fn patch(&mut self, i: u32, rect: PatchRect, image: &DynamicImage) {
+        let Some(texture) = &self.textures[i as usize] else {
+            return;
+        };
+        if rect.width == 0 || rect.height == 0 {
+            return;
+        }
+        // Cropped rather than written straight from the atlas, because
+        // write_texture wants tightly packed rows and the atlas rows are as
+        // wide as the atlas. A glyph is small, so the copy is too.
+        let sub = image
+            .view(rect.x, rect.y, rect.width, rect.height)
+            .to_image();
+        self.queue.write_texture(
+            TexelCopyTextureInfo {
+                texture,
+                mip_level: 0,
+                origin: Origin3d {
+                    x: rect.x,
+                    y: rect.y,
+                    z: 0,
+                },
+                aspect: TextureAspect::All,
+            },
+            sub.as_bytes(),
+            TexelCopyBufferLayout {
+                offset: 0,
+                bytes_per_row: Some(rect.width * 4),
+                rows_per_image: Some(rect.height),
+            },
+            Extent3d {
+                width: rect.width,
+                height: rect.height,
+                depth_or_array_layers: 1,
+            },
+        );
+    }
+
+    fn create(&self, image: &DynamicImage) -> (Texture, TextureView) {
         let image = image.to_rgba8();
         let (width, height) = image.dimensions();
         let texture = self.device.create_texture_with_data(
@@ -63,13 +116,14 @@ impl GpuTextures {
                 sample_count: 1,
                 dimension: TextureDimension::D2,
                 format: TextureFormat::Rgba8Unorm,
-                usage: TextureUsages::TEXTURE_BINDING,
+                usage: TextureUsages::TEXTURE_BINDING | TextureUsages::COPY_DST,
                 view_formats: &[],
             },
             wgt::TextureDataOrder::MipMajor,
             image.as_bytes(),
         );
-        texture.create_view(&TextureViewDescriptor::default())
+        let view = texture.create_view(&TextureViewDescriptor::default());
+        (texture, view)
     }
 
     pub fn new(device: &Device, queue: &Queue) -> Self {
@@ -77,6 +131,7 @@ impl GpuTextures {
         Self {
             device: device.clone(),
             queue: queue.clone(),
+            textures: Vec::new(),
             views: Vec::new(),
             samplers: vec![default_sampler(device)],
             no_views: vec![null_view.clone()],

iris/core/src/ui/painter.rs

@@ -1,7 +1,7 @@
 use crate::{
     Axis, Len, RenderedText, Size, SizeCtx, StrongWidget, TextAttrs, TextBuffer, TextData,
-    TextureHandle, UiRegion, UiRenderState, UiRsc, Widget, WidgetId,
+    TextureHandle, UiRegion, UiRenderState, UiRsc, UiScalar, UiVec2, Widget, WidgetId,
-    render::{Mask, MaskIdx, Primitive, PrimitiveHandle, PrimitiveInst},
+    render::{GlyphPrimitive, Mask, MaskIdx, Primitive, PrimitiveHandle, PrimitiveInst},
     util::Vec2,
 };
 
@@ -90,10 +90,48 @@ impl<'a> Painter<'a> {
         self.primitive_at(handle.primitive(), region);
     }
 
-    /// returns (handle, offset from top left)
+    pub fn render_text(
-    pub fn render_text(&mut self, buffer: &mut TextBuffer, attrs: &TextAttrs) -> RenderedText {
+        &mut self,
+        buffer: &mut TextBuffer,
+        attrs: &TextAttrs,
+        width: Option<f32>,
+    ) -> RenderedText {
         let ui = self.rsc.ui_mut();
-        ui.text.draw(buffer, attrs, &mut ui.textures)
+        ui.text.render(buffer, attrs, width, &mut ui.textures)
+    }
+
+    /// Draw a laid-out string: one quad per glyph, all sampling the atlas.
+    ///
+    /// `origin` is where the text's top-left goes; every glyph is placed at an
+    /// absolute pixel offset from it, so re-drawing after a resize is this loop
+    /// and nothing else.
+    pub fn glyphs(&mut self, text: &RenderedText, origin: UiRegion) {
+        let flags_for = |is_color| {
+            if is_color {
+                GlyphPrimitive::IS_COLOR
+            } else {
+                0
+            }
+        };
+        for glyph in text.glyphs.iter() {
+            let mut region = origin;
+            region.x.end = region.x.start;
+            region.y.end = region.y.start;
+            let mut region = region.offset(UiVec2::abs(glyph.offset));
+            region.x.end = region.x.start + UiScalar::abs(glyph.entry.width as f32);
+            region.y.end = region.y.start + UiScalar::abs(glyph.entry.height as f32);
+            self.primitive_at(
+                GlyphPrimitive {
+                    uv_min: glyph.entry.uv_min,
+                    uv_max: glyph.entry.uv_max,
+                    view_idx: glyph.entry.view_idx,
+                    sampler_idx: glyph.entry.sampler_idx,
+                    color: text.color,
+                    flags: flags_for(glyph.entry.is_color),
+                },
+                region,
+            );
+        }
     }
 
     pub fn region(&self) -> UiRegion {

iris/core/src/ui/size.rs

@@ -76,8 +76,13 @@ impl SizeCtx<'_> {
         self.output_size
     }
 
-    pub fn draw_text(&mut self, buffer: &mut TextBuffer, attrs: &TextAttrs) -> RenderedText {
+    pub fn draw_text(
-        self.text.draw(buffer, attrs, self.textures)
+        &mut self,
+        buffer: &mut TextBuffer,
+        attrs: &TextAttrs,
+        width: Option<f32>,
+    ) -> RenderedText {
+        self.text.render(buffer, attrs, width, self.textures)
     }
 
     pub fn label(&self, id: WidgetId) -> &String {

iris/examples/tabs/main.rs

@@ -1,4 +1,3 @@
-use cosmic_text::Family;
 use std::{cell::RefCell, rc::Rc};
 use winit::event::WindowEvent;
 

iris/src/lib.rs

@@ -1,6 +1,5 @@
 #![feature(unboxed_closures)]
 #![feature(fn_traits)]
-#![feature(gen_blocks)]
 #![feature(associated_type_defaults)]
 #![feature(unsize)]
 #![feature(option_into_flat_iter)]

iris/src/widget/text/build.rs

@@ -1,5 +1,4 @@
 use crate::prelude::*;
-use cosmic_text::{Attrs, Family, Metrics};
 use std::marker::{PhantomData, Sized};
 
 pub struct TextBuilder<State, O = TextOutput, H: WidgetOption<State> = ()> {
@@ -20,7 +19,7 @@ impl<State, O, H: WidgetOption<State>> TextBuilder<State, O, H> {
         self.attrs.color = color;
         self
     }
-    pub fn family(mut self, family: Family<'static>) -> Self {
+    pub fn family(mut self, family: Family) -> Self {
         self.attrs.family = family;
         self
     }
@@ -82,19 +81,13 @@ impl<Rsc: UiRsc> TextBuilderOutput<Rsc> for TextOutput {
         state: &mut Rsc,
         builder: TextBuilder<Rsc, Self, H>,
     ) -> Self::Output {
-        let mut buf = TextBuffer::new_empty(Metrics::new(
+        let buf = TextBuffer::new(&builder.content);
-            builder.attrs.font_size,
-            builder.attrs.line_height,
-        ));
         let hint = builder.hint.get(state);
-        let font_system = &mut state.ui_mut().text.font_system;
-        buf.set_text(font_system, &builder.content, &Attrs::new(), SHAPING, None);
         let mut text = Text {
             content: builder.content.into(),
             view: TextView::new(buf, builder.attrs, hint),
         };
         text.content.changed = false;
-        builder.attrs.apply(font_system, &mut text.view.buf, None);
         text
     }
 }
@@ -110,19 +103,11 @@ impl<State: UiRsc> TextBuilderOutput<State> for TextEditOutput {
         state: &mut State,
         builder: TextBuilder<State, Self, H>,
     ) -> Self::Output {
-        let buf = TextBuffer::new_empty(Metrics::new(
+        let buf = TextBuffer::new(&builder.content);
-            builder.attrs.font_size,
+        TextEdit::new(
-            builder.attrs.line_height,
-        ));
-        let mut text = TextEdit::new(
             TextView::new(buf, builder.attrs, builder.hint.get(state)),
             builder.output.mode,
-        );
+        )
-        let font_system = &mut state.ui_mut().text.font_system;
-        text.buf
-            .set_text(font_system, &builder.content, &Attrs::new(), SHAPING, None);
-        builder.attrs.apply(font_system, &mut text.buf, None);
-        text
     }
 }
 

iris/src/widget/text/edit.rs

@@ -1,17 +1,35 @@
 use crate::prelude::*;
-use cosmic_text::{Affinity, Attrs, Cursor, FontSystem, LayoutRun, Motion};
+use iris_core::{TextData, UiColor};
+use parley::{Affinity, Layout, Selection};
 use std::ops::{Deref, DerefMut};
-use unicode_segmentation::UnicodeSegmentation;
 use winit::{
     event::KeyEvent,
     keyboard::{Key, NamedKey},
 };
 
+/// Which way a cursor movement goes. Named here rather than taken from the text
+/// stack so that the key handling below does not have to change when the stack
+/// does; the mapping onto parley lives in one place, in `apply_motion`.
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub enum Motion {
+    Left,
+    Right,
+    LeftWord,
+    RightWord,
+    Up,
+    Down,
+    LineStart,
+    LineEnd,
+}
+
 pub struct TextEdit {
     view: TextView,
-    selection: TextSelection,
+    /// `None` when the field is not focused -- which parley's `Selection` has no
-    history: Vec<(String, TextSelection)>,
+    /// way to say, since it always denotes some position in the text. A
-    double_hit: Option<Cursor>,
+    /// collapsed selection is a caret; an uncollapsed one is a span.
+    selection: Option<Selection>,
+    history: Vec<(String, Option<Selection>)>,
+    double_hit: Option<usize>,
     pub mode: EditMode,
 }
 
@@ -25,27 +43,19 @@ impl TextEdit {
     pub fn new(view: TextView, mode: EditMode) -> Self {
         Self {
             view,
-            selection: Default::default(),
+            selection: None,
             history: Default::default(),
             double_hit: None,
             mode,
         }
     }
-    pub fn select_content(&self, start: Cursor, end: Cursor) -> String {
+
-        let (start, end) = sort_cursors(start, end);
+    pub fn selected_text(&self) -> Option<String> {
-        let mut iter = self.buf.lines.iter().skip(start.line);
+        let sel = self.selection?;
-        let first = iter.next().unwrap();
+        if sel.is_collapsed() {
-        if start.line == end.line {
+            return None;
-            first.text()[start.index..end.index].to_string()
-        } else {
-            let mut str = first.text()[start.index..].to_string();
-            for _ in (start.line + 1)..end.line {
-                str = str + "\n" + iter.next().unwrap().text();
-            }
-            let last = iter.next().unwrap();
-            str = str + "\n" + &last.text()[..end.index];
-            str
         }
+        Some(self.buf.text()[sel.text_range()].to_string())
     }
 }
 
@@ -57,39 +67,29 @@ impl Widget for TextEdit {
         painter.layer = base;
         let region = self.region();
 
-        let size = vec2(1, self.attrs.line_height);
+        let Some(selection) = self.selection else {
-        match self.selection {
+            return;
-            TextSelection::None => (),
+        };
-            TextSelection::Pos(cursor) => {
+        let layout = self.view.buf.layout();
-                if let Some(offset) = cursor_pos(cursor, &self.buf) {
+
-                    painter.primitive_within(
+        // parley reports selection as boxes in layout space, so bidi and
-                        RectPrimitive::color(Color::WHITE),
+        // wrapped lines come out right without this code knowing about either.
-                        size.align(Align::TOP_LEFT).offset(offset).within(&region),
+        for (rect, _) in selection.geometry(layout) {
-                    );
+            let size = vec2(rect.width() as f32, rect.height() as f32);
-                }
+            let top_left = vec2(rect.x0 as f32, rect.y0 as f32);
-            }
+            painter.primitive_within(
-            TextSelection::Span { start, end } => {
+                RectPrimitive::color(Color::SKY),
-                let (start, end) = sort_cursors(start, end);
+                size.align(Align::TOP_LEFT).offset(top_left).within(&region),
-                for (l, x, width) in iter_layout_lines(start, end, &self.buf) {
+            );
-                    let top_left = vec2(x, self.attrs.line_height * l as f32);
-                    painter.primitive_within(
-                        RectPrimitive::color(Color::SKY),
-                        size.with_x(width)
-                            .align(Align::TOP_LEFT)
-                            .offset(top_left)
-                            .within(&region),
-                    );
-                }
-                if let Some(end_offset) = cursor_pos(end, &self.buf) {
-                    painter.primitive_within(
-                        RectPrimitive::color(Color::WHITE),
-                        size.align(Align::TOP_LEFT)
-                            .offset(end_offset)
-                            .within(&region),
-                    );
-                }
-            }
         }
+
+        let caret = selection.focus().geometry(layout, CARET_WIDTH);
+        let size = vec2(caret.width() as f32, caret.height() as f32);
+        let top_left = vec2(caret.x0 as f32, caret.y0 as f32);
+        painter.primitive_within(
+            RectPrimitive::color(Color::WHITE),
+            size.align(Align::TOP_LEFT).offset(top_left).within(&region),
+        );
     }
 
     fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
@@ -101,154 +101,79 @@ impl Widget for TextEdit {
     }
 }
 
-/// provides top left + width
+const CARET_WIDTH: f32 = 1.0;
-fn iter_layout_lines(
-    start: Cursor,
-    end: Cursor,
-    buf: &TextBuffer,
-) -> impl Iterator<Item = (usize, f32, f32)> {
-    gen move {
-        let mut iter = buf.layout_runs().enumerate();
-        for (i, line) in iter.by_ref() {
-            if line.line_i == start.line
-                && let Some(start_x) = index_x(&line, start.index)
-            {
-                if start.line == end.line
-                    && let Some(end_x) = index_x(&line, end.index)
-                {
-                    yield (i, start_x, end_x - start_x);
-                    return;
-                }
-                yield (i, start_x, line.line_w - start_x);
-                break;
-            }
-        }
-        for (i, line) in iter {
-            if line.line_i > end.line {
-                return;
-            }
-            if line.line_i == end.line
-                && let Some(end_x) = index_x(&line, end.index)
-            {
-                yield (i, 0.0, end_x);
-                return;
-            }
-            yield (i, 0.0, line.line_w);
-        }
-    }
-}
-
-/// copied & modified from fn found in Editor in cosmic_text
-/// returns x pos of a (non layout) index within an layout run
-fn index_x(run: &LayoutRun, index: usize) -> Option<f32> {
-    for glyph in run.glyphs.iter() {
-        if index == glyph.start {
-            return Some(glyph.x);
-        } else if index > glyph.start && index < glyph.end {
-            // Guess x offset based on characters
-            let mut before = 0;
-            let mut total = 0;
-
-            let cluster = &run.text[glyph.start..glyph.end];
-            for (i, _) in cluster.grapheme_indices(true) {
-                if glyph.start + i < index {
-                    before += 1;
-                }
-                total += 1;
-            }
-
-            let offset = glyph.w * (before as f32) / (total as f32);
-            return Some(glyph.x + offset);
-        }
-    }
-    None
-}
-
-/// returns top of line segment where cursor should visually select
-fn cursor_pos(cursor: Cursor, buf: &TextBuffer) -> Option<Vec2> {
-    let mut prev = None;
-    for run in buf
-        .layout_runs()
-        .skip_while(|r| r.line_i < cursor.line)
-        .take_while(|r| r.line_i == cursor.line)
-    {
-        prev = Some(vec2(run.line_w, run.line_top));
-        if let Some(pos) = index_x(&run, cursor.index) {
-            return Some(vec2(pos, run.line_top));
-        }
-    }
-    prev
-}
 
 pub struct TextEditCtx<'a> {
     pub text: &'a mut TextEdit,
-    pub font_system: &'a mut FontSystem,
+    pub data: &'a mut TextData,
 }
 
 impl<'a> TextEditCtx<'a> {
+    /// The layout, brought up to date with the text first.
+    ///
+    /// Every cursor movement and hit test goes through parley's layout, so an
+    /// edit that left it stale would move the caret against the previous text.
+    /// Shaping is skipped when nothing changed, so calling this freely is fine.
+    fn layout(&mut self) -> &Layout<UiColor> {
+        let attrs = self.text.view.attrs.clone();
+        let width = self.text.view.wrap_width();
+        self.text.view.buf.shape(self.data, &attrs, width);
+        self.text.view.buf.layout()
+    }
+
+    /// Keep the selection valid after the text underneath it changed.
+    fn refresh(&mut self) {
+        if let Some(sel) = self.text.selection {
+            let layout = self.layout();
+            self.text.selection = Some(sel.refresh(layout));
+        }
+    }
+
     pub fn take(&mut self) -> String {
-        let text = self
+        let text = self.text.view.buf.text().to_string();
-            .text
+        self.set("");
-            .buf
-            .lines
-            .drain(..)
-            .map(|l| l.into_text())
-            .collect::<Vec<_>>()
-            .join("\n");
-        self.text
-            .buf
-            .set_text(self.font_system, "", &Attrs::new(), SHAPING, None);
-        self.text.selection.clear();
         text
     }
 
     pub fn set(&mut self, text: &str) {
         let text = self.string(text);
-        self.text
+        self.text.view.buf.set_text(text);
-            .buf
+        self.text.view.buf.changed = true;
-            .set_text(self.font_system, &text, &Attrs::new(), SHAPING, None);
+        self.text.selection = None;
-        self.text.selection.clear();
     }
 
     pub fn motion(&mut self, motion: Motion, select: bool) {
-        if let TextSelection::Pos(cursor) = self.text.selection
+        let Some(sel) = self.text.selection else {
-            && let Some(new) = self.buf_motion(cursor, motion)
+            return;
-        {
+        };
-            if select {
+        let layout = self.layout();
-                self.text.selection = TextSelection::Span {
+        // Collapsing a span with an unshifted left/right puts the caret at the
-                    start: cursor,
+        // near end rather than moving one character from the focus, which is
-                    end: new,
+        // what every other editor does.
-                };
+        let sel = if !select && !sel.is_collapsed() {
-            } else {
+            match motion {
-                self.text.selection = TextSelection::Pos(new);
+                Motion::Left | Motion::LeftWord => {
-            }
+                    Selection::from(sel.text_range().start_cursor(layout))
-        } else if let TextSelection::Span { start, end } = self.text.selection {
-            if select {
-                if let Some(cursor) = self.buf_motion(end, motion) {
-                    self.text.selection = TextSelection::Span { start, end: cursor };
                 }
-            } else {
+                Motion::Right | Motion::RightWord => {
-                let (start, end) = sort_cursors(start, end);
+                    Selection::from(sel.text_range().end_cursor(layout))
-                let sel = &mut self.text.selection;
-                match motion {
-                    Motion::Left | Motion::LeftWord => *sel = TextSelection::Pos(start),
-                    Motion::Right | Motion::RightWord => *sel = TextSelection::Pos(end),
-                    _ => {
-                        if let Some(cursor) = self.buf_motion(end, motion) {
-                            self.text.selection = TextSelection::Pos(cursor);
-                        }
-                    }
                 }
+                _ => apply_motion(sel, layout, motion, false),
             }
-        }
+        } else {
+            apply_motion(sel, layout, motion, select)
+        };
+        self.text.selection = Some(sel);
     }
 
+    /// Replace the `len` characters before the caret. This is the IME's
+    /// preedit path: it re-sends the whole composition each time.
     pub fn replace(&mut self, len: usize, text: &str) {
         let text = self.string(text);
         for _ in 0..len {
-            self.delete(false);
+            self.backspace(false);
         }
-        self.insert_inner(&text, false);
+        self.insert_str(&text);
     }
 
     fn string(&self, text: &str) -> String {
@@ -261,202 +186,174 @@ impl<'a> TextEditCtx<'a> {
 
     pub fn insert(&mut self, text: &str) {
         let text = self.string(text);
-        let mut lines = text.split('\n');
+        self.insert_str(&text);
-        let Some(first) = lines.next() else {
+    }
+
+    fn insert_str(&mut self, text: &str) {
+        if text.is_empty() {
             return;
-        };
-        self.insert_inner(first, true);
-        for line in lines {
-            self.newline();
-            self.insert_inner(line, true);
         }
-    }
-
-    pub fn clear_span(&mut self) -> bool {
-        if let TextSelection::Span { start, end } = self.text.selection {
-            self.delete_between(start, end);
-            let (start, _) = sort_cursors(start, end);
-            self.text.selection = TextSelection::Pos(start);
-            true
-        } else {
-            false
-        }
-    }
-
-    pub fn delete_between(&mut self, start: Cursor, end: Cursor) {
-        let lines = &mut self.text.view.buf.lines;
-        let (start, end) = sort_cursors(start, end);
-        if start.line == end.line {
-            let line = &mut lines[start.line];
-            let text = line.text();
-            let text = text[..start.index].to_string() + &text[end.index..];
-            edit_line(line, text);
-        } else {
-            // start
-            let start_text = lines[start.line].text()[..start.index].to_string();
-            let end_text = &lines[end.line].text()[end.index..];
-            let text = start_text + end_text;
-            edit_line(&mut lines[start.line], text);
-        }
-        // between
-        let range = (start.line + 1)..=end.line;
-        if !range.is_empty() {
-            lines.splice(range, None);
-        }
-    }
-
-    fn insert_inner(&mut self, text: &str, mov: bool) {
         self.clear_span();
-        if let TextSelection::Pos(cursor) = &mut self.text.selection {
+        let at = match self.text.selection {
-            let line = &mut self.text.view.buf.lines[cursor.line];
+            Some(sel) => sel.focus().index(),
-            let mut line_text = line.text().to_string();
+            None => return,
-            line_text.insert_str(cursor.index, text);
+        };
-            edit_line(line, line_text);
+        let at = at.min(self.text.view.buf.text().len());
-            if mov {
+        self.text.view.buf.edit().insert_str(at, text);
-                for _ in 0..text.chars().count() {
+        self.text.view.buf.changed = true;
-                    self.motion(Motion::Right, false);
+        self.set_caret(at + text.len());
-                }
+    }
-            }
+
+    /// True when there was a span to remove.
+    pub fn clear_span(&mut self) -> bool {
+        let Some(sel) = self.text.selection else {
+            return false;
+        };
+        if sel.is_collapsed() {
+            return false;
         }
+        let range = sel.text_range();
+        self.text.view.buf.edit().replace_range(range.clone(), "");
+        self.text.view.buf.changed = true;
+        self.set_caret(range.start);
+        true
+    }
+
+    fn set_caret(&mut self, index: usize) {
+        let index = index.min(self.text.view.buf.text().len());
+        let layout = self.layout();
+        self.text.selection = Some(Selection::from_byte_index(
+            layout,
+            index,
+            Affinity::default(),
+        ));
     }
 
     pub fn newline(&mut self) {
-        if self.text.mode == EditMode::SingleLine {
+        if self.text.mode == EditMode::MultiLine {
-            return;
+            self.insert_str("\n");
-        }
-        self.clear_span();
-        if let TextSelection::Pos(cursor) = &mut self.text.selection {
-            let lines = &mut self.text.view.buf.lines;
-            let line = &mut lines[cursor.line];
-            let new = line.split_off(cursor.index);
-            cursor.line += 1;
-            lines.insert(cursor.line, new);
-            cursor.index = 0;
         }
     }
 
     pub fn backspace(&mut self, word: bool) {
-        if !self.clear_span()
+        if self.clear_span() {
-            && let TextSelection::Pos(cursor) = &mut self.text.selection
+            return;
-            && (cursor.index != 0 || cursor.line != 0)
-        {
-            self.motion(if word { Motion::LeftWord } else { Motion::Left }, false);
-            self.delete(word);
         }
+        let Some(sel) = self.text.selection else {
+            return;
+        };
+        let end = sel.focus().index();
+        if end == 0 {
+            return;
+        }
+        let layout = self.layout();
+        let start = if word {
+            sel.focus().previous_logical_word(layout).index()
+        } else {
+            sel.focus().previous_visual(layout).index()
+        };
+        self.delete_range(start, end);
     }
 
     pub fn delete(&mut self, word: bool) {
-        if !self.clear_span()
+        if self.clear_span() {
-            && let TextSelection::Pos(cursor) = &mut self.text.selection
+            return;
-        {
-            if word {
-                let start = *cursor;
-                if let Some(end) = self.buf_motion(start, Motion::RightWord) {
-                    self.delete_between(start, end);
-                }
-            } else {
-                let lines = &mut self.text.view.buf.lines;
-                let line = &mut lines[cursor.line];
-                if cursor.index == line.text().len() {
-                    if cursor.line == lines.len() - 1 {
-                        return;
-                    }
-                    let add = lines.remove(cursor.line + 1).into_text();
-                    let line = &mut lines[cursor.line];
-                    let mut cur = line.text().to_string();
-                    cur.push_str(&add);
-                    edit_line(line, cur);
-                } else {
-                    let mut text = line.text().to_string();
-                    text.remove(cursor.index);
-                    edit_line(line, text);
-                }
-            }
         }
+        let Some(sel) = self.text.selection else {
+            return;
+        };
+        let start = sel.focus().index();
+        if start >= self.text.view.buf.text().len() {
+            return;
+        }
+        let layout = self.layout();
+        let end = if word {
+            sel.focus().next_logical_word(layout).index()
+        } else {
+            sel.focus().next_visual(layout).index()
+        };
+        self.delete_range(start, end);
     }
 
-    fn buf_motion(&mut self, cursor: Cursor, motion: Motion) -> Option<Cursor> {
+    fn delete_range(&mut self, start: usize, end: usize) {
-        self.text
+        let len = self.text.view.buf.text().len();
-            .buf
+        let (start, end) = (start.min(end).min(len), start.max(end).min(len));
-            .cursor_motion(self.font_system, cursor, None, motion)
+        if start == end {
-            .map(|r| r.0)
+            return;
+        }
+        self.text.view.buf.edit().replace_range(start..end, "");
+        self.text.view.buf.changed = true;
+        self.set_caret(start);
     }
 
-    pub fn select_word_at(&mut self, cursor: Cursor) {
+    pub fn select_all(&mut self) {
-        if let (Some(start), Some(end)) = (
+        let len = self.text.view.buf.text().len();
-            self.buf_motion(cursor, Motion::LeftWord),
+        if len == 0 {
-            self.buf_motion(cursor, Motion::RightWord),
+            return;
-        ) {
-            self.text.selection = TextSelection::Span { start, end };
-        }
-    }
-
-    pub fn select_line_at(&mut self, cursor: Cursor) {
-        let end = self.text.buf.lines[cursor.line].text().len();
-        self.text.selection = TextSelection::Span {
-            start: Cursor::new(cursor.line, 0),
-            end: Cursor::new(cursor.line, end),
         }
+        let layout = self.layout();
+        let anchor = parley::Cursor::from_byte_index(layout, 0, Affinity::default());
+        let focus = parley::Cursor::from_byte_index(layout, len, Affinity::default());
+        self.text.selection = Some(Selection::new(anchor, focus));
     }
 
     pub fn select(&mut self, pos: Vec2, size: Vec2, drag: bool, recent: bool) {
         let pos = pos - self.text.region().top_left().to_abs(size);
-        let hit = self.text.buf.hit(pos.x, pos.y);
+        let prev_sel = self.text.selection;
-        let sel = &mut self.text.selection;
+        let prev_hit = self.text.double_hit;
-        match sel {
+
-            TextSelection::None => {
+        // The layout borrows `self`, so the whole decision is made in here and
-                if !drag && let Some(hit) = hit {
+        // only the answer escapes.
-                    *sel = TextSelection::Pos(hit)
+        let outcome = {
-                }
+            let layout = self.layout();
+            let inside =
+                pos.x >= 0.0 && pos.y >= 0.0 && pos.x <= layout.width() && pos.y <= layout.height();
+
+            if !inside {
+                if drag { None } else { Some((None, None)) }
+            } else if drag {
+                prev_sel.map(|sel| (Some(sel.extend_to_point(layout, pos.x, pos.y)), prev_hit))
+            } else {
+                let hit = Selection::from_point(layout, pos.x, pos.y);
+                let index = hit.focus().index();
+                // A second click in the same place takes the word and a third
+                // the line; `double_hit` is what remembers that the previous
+                // click had already grown to a word.
+                Some(if recent && prev_hit == Some(index) {
+                    (Some(Selection::line_from_point(layout, pos.x, pos.y)), None)
+                } else if recent && prev_sel.map(|s| s.focus().index()) == Some(index) {
+                    (
+                        Some(Selection::word_from_point(layout, pos.x, pos.y)),
+                        Some(index),
+                    )
+                } else {
+                    (Some(hit), None)
+                })
             }
-            TextSelection::Pos(pos) => match (hit, drag) {
+        };
-                (None, false) => *sel = TextSelection::None,
+
-                (None, true) => (),
+        if let Some((selection, double_hit)) = outcome {
-                (Some(hit), false) => {
+            self.text.selection = selection;
-                    if recent && hit == *pos {
+            self.text.double_hit = double_hit;
-                        self.text.double_hit = Some(hit);
-                        return self.select_word_at(hit);
-                    } else {
-                        *pos = hit
-                    }
-                }
-                (Some(end), true) => *sel = TextSelection::Span { start: *pos, end },
-            },
-            TextSelection::Span { start, end } => match (hit, drag) {
-                (None, false) => *sel = TextSelection::None,
-                (None, true) => *sel = TextSelection::Pos(*start),
-                (Some(hit), false) => {
-                    if recent
-                        && let Some(double) = self.text.double_hit
-                        && double == hit
-                    {
-                        return self.select_line_at(hit);
-                    } else {
-                        *sel = TextSelection::Pos(hit)
-                    }
-                }
-                (Some(hit), true) => *end = hit,
-            },
-        }
-        if let TextSelection::Span { start, end } = sel
-            && start == end
-        {
-            *sel = TextSelection::Pos(*start);
         }
     }
 
     pub fn deselect(&mut self) {
-        self.text.selection = TextSelection::None;
+        self.text.selection = None;
+        self.text.double_hit = None;
     }
 
     pub fn apply_event(&mut self, event: &KeyEvent, modifiers: &Modifiers) -> TextInputResult {
-        let old = (self.text.content(), self.text.selection);
+        let old = (self.text.view.buf.text().to_string(), self.text.selection);
         let mut undo = false;
         let res = self.apply_event_inner(event, modifiers, &mut undo);
-        if undo && let Some((old, selection)) = self.text.history.pop() {
+        if undo {
-            self.set(&old);
+            if let Some((old, selection)) = self.text.history.pop() {
-            self.text.selection = selection;
+                self.set(&old);
-        } else if self.text.content() != old.0 {
+                self.text.selection = selection;
+                self.refresh();
+            }
+        } else if self.text.view.buf.text() != old.0 {
             self.text.history.push(old);
         }
         res
@@ -481,21 +378,25 @@ impl<'a> TextEditCtx<'a> {
                     }
                 }
                 NamedKey::ArrowRight => {
-                    if modifiers.control {
+                    let motion = if modifiers.control {
-                        self.motion(Motion::RightWord, modifiers.shift)
+                        Motion::RightWord
                     } else {
-                        self.motion(Motion::Right, modifiers.shift)
+                        Motion::Right
-                    }
+                    };
+                    self.motion(motion, modifiers.shift);
                 }
                 NamedKey::ArrowLeft => {
-                    if modifiers.control {
+                    let motion = if modifiers.control {
-                        self.motion(Motion::LeftWord, modifiers.shift)
+                        Motion::LeftWord
                     } else {
-                        self.motion(Motion::Left, modifiers.shift)
+                        Motion::Left
-                    }
+                    };
+                    self.motion(motion, modifiers.shift);
                 }
                 NamedKey::ArrowUp => self.motion(Motion::Up, modifiers.shift),
                 NamedKey::ArrowDown => self.motion(Motion::Down, modifiers.shift),
+                NamedKey::Home => self.motion(Motion::LineStart, modifiers.shift),
+                NamedKey::End => self.motion(Motion::LineEnd, modifiers.shift),
                 NamedKey::Escape => {
                     self.deselect();
                     return TextInputResult::Unfocus;
@@ -507,34 +408,18 @@ impl<'a> TextEditCtx<'a> {
                     match text.as_str() {
                         "v" => return TextInputResult::Paste,
                         "c" => {
-                            if let TextSelection::Span { start, end } = self.text.selection {
+                            if let Some(content) = self.text.selected_text() {
-                                let content = self.text.select_content(start, end);
                                 return TextInputResult::Copy(content);
                             }
                         }
                         "x" => {
-                            if let TextSelection::Span { start, end } = self.text.selection {
+                            if let Some(content) = self.text.selected_text() {
-                                let content = self.text.select_content(start, end);
                                 self.clear_span();
                                 return TextInputResult::Copy(content);
                             }
                         }
-                        "a" => {
+                        "a" => self.select_all(),
-                            if !self.text.buf.lines[0].text().is_empty()
+                        "z" => *undo = true,
-                                || self.text.buf.lines.len() > 1
-                            {
-                                let lines = &self.text.buf.lines;
-                                let last_line = lines.len() - 1;
-                                let last_idx = lines[last_line].text().len();
-                                self.text.selection = TextSelection::Span {
-                                    start: Cursor::new(0, 0),
-                                    end: Cursor::new(last_line, last_idx),
-                                };
-                            }
-                        }
-                        "z" => {
-                            *undo = true;
-                        }
                         _ => self.insert(text),
                     }
                 } else {
@@ -547,6 +432,40 @@ impl<'a> TextEditCtx<'a> {
     }
 }
 
+fn apply_motion(
+    sel: Selection,
+    layout: &Layout<UiColor>,
+    motion: Motion,
+    extend: bool,
+) -> Selection {
+    match motion {
+        Motion::Left => sel.previous_visual(layout, extend),
+        Motion::Right => sel.next_visual(layout, extend),
+        Motion::LeftWord => sel.previous_visual_word(layout, extend),
+        Motion::RightWord => sel.next_visual_word(layout, extend),
+        Motion::Up => sel.previous_line(layout, extend),
+        Motion::Down => sel.next_line(layout, extend),
+        Motion::LineStart => sel.line_start(layout, extend),
+        Motion::LineEnd => sel.line_end(layout, extend),
+    }
+}
+
+/// The ends of a byte range as cursors, so collapsing a selection can put the
+/// caret at whichever end the movement asked for.
+trait RangeCursors {
+    fn start_cursor(&self, layout: &Layout<UiColor>) -> parley::Cursor;
+    fn end_cursor(&self, layout: &Layout<UiColor>) -> parley::Cursor;
+}
+
+impl RangeCursors for std::ops::Range<usize> {
+    fn start_cursor(&self, layout: &Layout<UiColor>) -> parley::Cursor {
+        parley::Cursor::from_byte_index(layout, self.start, Affinity::default())
+    }
+    fn end_cursor(&self, layout: &Layout<UiColor>) -> parley::Cursor {
+        parley::Cursor::from_byte_index(layout, self.end, Affinity::default())
+    }
+}
+
 #[derive(Default)]
 pub struct Modifiers {
     pub shift: bool,
@@ -569,33 +488,6 @@ pub enum TextInputResult {
     Paste,
 }
 
-#[derive(Debug, Default, Clone, Copy)]
-pub enum TextSelection {
-    #[default]
-    None,
-    Pos(Cursor),
-    Span {
-        start: Cursor,
-        end: Cursor,
-    },
-}
-
-impl TextSelection {
-    pub fn clear(&mut self) {
-        match self {
-            TextSelection::None => (),
-            TextSelection::Pos(cursor) => {
-                cursor.line = 0;
-                cursor.index = 0;
-                cursor.affinity = Affinity::default();
-            }
-            TextSelection::Span { start: _, end: _ } => {
-                *self = TextSelection::None;
-            }
-        }
-    }
-}
-
 impl TextInputResult {
     pub fn unfocus(&self) -> bool {
         matches!(self, TextInputResult::Unfocus)
@@ -625,7 +517,7 @@ impl<I: IdLike<Widget = TextEdit>> TextEditable for I {
         let ui = ui.ui_mut();
         TextEditCtx {
             text: ui.widgets.get_mut(self).unwrap(),
-            font_system: &mut ui.text.font_system,
+            data: &mut ui.text,
         }
     }
 }

iris/src/widget/text/mod.rs

@@ -6,11 +6,8 @@ pub use edit::*;
 use iris_core::util::MutDetect;
 
 use crate::prelude::*;
-use cosmic_text::{Attrs, BufferLine, Cursor, Metrics, Shaping};
 use std::ops::{Deref, DerefMut};
 
-pub const SHAPING: Shaping = Shaping::Advanced;
-
 pub struct Text {
     pub content: MutDetect<String>,
     view: TextView,
@@ -25,6 +22,18 @@ pub struct TextView {
     pub hint: Option<StrongWidget>,
 }
 
+impl TextView {
+    fn is_blank(&self) -> bool {
+        self.buf.is_empty()
+    }
+
+    /// The width the text was last laid out against, so an editor asking for
+    /// the layout gets the same wrapping the last draw used.
+    pub fn wrap_width(&self) -> Option<f32> {
+        self.width
+    }
+}
+
 impl TextView {
     pub fn new(buf: TextBuffer, attrs: TextAttrs, hint: Option<StrongWidget>) -> Self {
         Self {
@@ -45,15 +54,6 @@ impl TextView {
             .align(self.align)
     }
 
-    fn tex_region(&self, tex: &RenderedText) -> UiRegion {
-        let region = tex.size.align(self.align);
-        let dims = tex.handle.size();
-        let mut region = region.offset(tex.top_left_offset);
-        region.x.end = region.x.start + UiScalar::abs(dims.x);
-        region.y.end = region.y.start + UiScalar::abs(dims.y);
-        region
-    }
-
     fn render(&mut self, ctx: &mut SizeCtx) -> RenderedText {
         let width = if self.attrs.wrap {
             Some(ctx.px_size().x)
@@ -68,10 +68,7 @@ impl TextView {
             return tex.clone();
         }
         self.width = width;
-        let font_system = &mut ctx.text.font_system;
+        let tex = ctx.draw_text(&mut self.buf, &self.attrs, width);
-        self.attrs.apply(font_system, &mut self.buf, width);
-        self.buf.shape_until_scroll(font_system, false);
-        let tex = ctx.draw_text(&mut self.buf, &self.attrs);
         self.tex = Some(tex.clone());
         self.attrs.changed = false;
         self.buf.changed = false;
@@ -81,9 +78,8 @@ impl TextView {
         self.tex.as_ref()
     }
     pub fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
-        if let Some(hint) = &self.hint
+        if self.is_blank()
-            && let [line] = &self.buf.lines[..]
+            && let Some(hint) = &self.hint
-            && line.text().is_empty()
         {
             ctx.width(hint)
         } else {
@@ -91,9 +87,8 @@ impl TextView {
         }
     }
     pub fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len {
-        if let Some(hint) = &self.hint
+        if self.is_blank()
-            && let [line] = &self.buf.lines[..]
+            && let Some(hint) = &self.hint
-            && line.text().is_empty()
         {
             ctx.height(hint)
         } else {
@@ -102,47 +97,35 @@ impl TextView {
     }
     pub fn draw(&mut self, painter: &mut Painter) -> UiRegion {
         let tex = self.render(&mut painter.size_ctx());
-        let region = self.tex_region(&tex);
+        let region = tex.size.align(self.align);
-        if let Some(hint) = &self.hint
+        if self.is_blank()
-            && let [line] = &self.buf.lines[..]
+            && let Some(hint) = &self.hint
-            && line.text().is_empty()
         {
             painter.widget(hint);
         } else {
-            painter.texture_within(&tex.handle, region);
+            let within = region.within(&painter.region());
+            painter.glyphs(&tex, within);
         }
         region
     }
 
     pub fn content(&self) -> String {
-        self.buf
+        self.buf.text().to_string()
-            .lines
-            .iter()
-            .map(|l| l.text())
-            .collect::<Vec<_>>()
-            .join("\n")
     }
 }
 
 impl Text {
     pub fn new(content: impl Into<String>) -> Self {
-        let attrs = TextAttrs::default();
+        let content: String = content.into();
-        let buf = TextBuffer::new_empty(Metrics::new(attrs.font_size, attrs.line_height));
         Self {
-            content: content.into().into(),
+            view: TextView::new(TextBuffer::new(&content), TextAttrs::default(), None),
-            view: TextView::new(buf, attrs, None),
+            content: content.into(),
         }
     }
-    fn update_buf(&mut self, ctx: &mut SizeCtx) {
+    fn update_buf(&mut self, _ctx: &mut SizeCtx) {
         if self.content.changed {
             self.content.changed = false;
-            self.view.buf.set_text(
+            self.view.buf.set_text(self.content.as_str());
-                &mut ctx.text.font_system,
-                &self.content,
-                &Attrs::new().family(self.view.attrs.family),
-                SHAPING,
-                None,
-            );
         }
     }
 }
@@ -164,16 +147,6 @@ impl Widget for Text {
     }
 }
 
-pub fn sort_cursors(a: Cursor, b: Cursor) -> (Cursor, Cursor) {
-    let start = a.min(b);
-    let end = a.max(b);
-    (start, end)
-}
-
-pub fn edit_line(line: &mut BufferLine, text: String) {
-    line.set_text(text, line.ending(), line.attrs_list().clone());
-}
-
 impl Deref for Text {
     type Target = TextAttrs;