cursor finally working properly and removed from render_text

src/core/text_edit.rs

@@ -1,5 +1,6 @@
 use crate::prelude::*;
 use cosmic_text::{Attrs, Cursor, Family, FontSystem, Metrics, Motion, Shaping};
+use unicode_segmentation::UnicodeSegmentation;
 
 pub struct TextEdit {
     pub attrs: TextAttrs,
@@ -21,31 +22,60 @@ impl Widget for TextEdit {
         let font_system = &mut painter.text_data().font_system;
         self.buf.shape_until_scroll(font_system, false);
         self.attrs.apply(font_system, &mut self.buf);
-        let (handle, offset) = painter.render_text(
-            &mut self.buf,
-            &self.attrs,
-            &match self.cursor {
-                None => VisualCursor::None,
-                Some(cursor) => VisualCursor::Select {
-                    line: cursor.line as isize,
-                    col: cursor.index as isize,
-                },
-            },
-        );
+        let (handle, tex_offset) = painter.render_text(&mut self.buf, &self.attrs);
         let dims = handle.size();
-        self.size = offset.size(&handle);
-        let mut region = self.region();
-        region.top_left.offset += offset.top_left;
-        region.bot_right.offset = region.top_left.offset + dims;
-        painter.draw_texture_within(&handle, region);
+        self.size = tex_offset.size(&handle);
+        let region = self.region();
+        let mut tex_region = region;
+        tex_region.top_left.offset += tex_offset.top_left;
+        tex_region.bot_right.offset = tex_region.top_left.offset + dims;
+        painter.texture_within(&handle, tex_region);
+        if let Some(cursor) = &self.cursor
+            && let Some(pos) = cursor_pos(cursor, &self.buf)
+        {
+            let size = vec2(1, self.attrs.line_height);
+            let offset = vec2(pos, cursor.line as f32 * self.attrs.line_height);
+            painter.primitive_within(
+                RectPrimitive::color(Color::WHITE),
+                UiRegion::from_size_align(size, Align::TopLeft)
+                    .shifted(offset)
+                    .within(&region),
+            );
+        }
     }
 
     fn get_size(&mut self, ctx: &mut SizeCtx) -> Vec2 {
-        let (handle, offset) = ctx.draw_text(&mut self.buf, &self.attrs, &VisualCursor::None);
+        let (handle, offset) = ctx.draw_text(&mut self.buf, &self.attrs);
         offset.size(&handle)
     }
 }
 
+/// copied & modified from fn found in Editor in cosmic_text
+fn cursor_pos(cursor: &Cursor, buf: &TextBuffer) -> Option<f32> {
+    let run = buf.layout_runs().find(|r| r.line_i == cursor.line)?;
+    for glyph in run.glyphs.iter() {
+        if cursor.index == glyph.start {
+            return Some(glyph.x);
+        } else if cursor.index > glyph.start && cursor.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 < cursor.index {
+                    before += 1;
+                }
+                total += 1;
+            }
+
+            let offset = glyph.w * (before as f32) / (total as f32);
+            return Some(glyph.x + offset);
+        }
+    }
+    Some(run.line_w)
+}
+
 pub struct TextEditBuilder {
     pub content: String,
     pub attrs: TextAttrs,
@@ -112,26 +142,11 @@ impl<'a> TextEditCtx<'a> {
     }
 
     pub fn backspace(&mut self) {
-        if let Some(cursor) = &mut self.text.cursor {
-            if cursor.index == 0 {
-                if cursor.line == 0 {
-                    return;
-                }
-                let add = self.text.buf.lines.remove(cursor.line).into_text();
-                cursor.line -= 1;
-                let line = &mut self.text.buf.lines[cursor.line];
-                let mut cur = line.text().to_string();
-                cursor.index = cur.len();
-                cur.push_str(&add);
-                line.set_text(cur, line.ending(), line.attrs_list().clone());
-            } else {
-                let line = &mut self.text.buf.lines[cursor.line];
-                let mut text = line.text().to_string();
-                let idx = text.floor_char_boundary(cursor.index - 1);
-                text.remove(idx);
-                line.set_text(text, line.ending(), line.attrs_list().clone());
-                cursor.index = idx;
-            }
+        if let Some(cursor) = &mut self.text.cursor
+            && (cursor.index != 0 || cursor.line != 0)
+        {
+            self.motion(Motion::Left);
+            self.delete();
         }
     }
 
@@ -153,12 +168,6 @@ impl<'a> TextEditCtx<'a> {
                 line.set_text(text, line.ending(), line.attrs_list().clone());
             }
         }
-        if let Some(cursor) = self.text.cursor {
-            let line = &mut self.text.buf.lines[cursor.line];
-            let mut text = line.text().to_string();
-            text.remove(cursor.index);
-            line.set_text(text, line.ending(), line.attrs_list().clone());
-        }
     }
 
     pub fn select(&mut self, pos: Vec2, size: Vec2) {