cache text buf

src/core/text.rs

@@ -1,9 +1,9 @@
 use cosmic_text::{Attrs, Family, FontSystem, Metrics, Shaping};
 
-use crate::prelude::*;
+use crate::{prelude::*, util::MutDetect};
 
 pub struct Text {
-    pub content: String,
+    pub content: MutDetect<String>,
     pub attrs: TextAttrs,
     /// inner alignment of text region (within where its drawn)
     pub align: Align,
@@ -32,7 +32,7 @@ impl Text {
     pub fn new(content: impl Into<String>) -> Self {
         let attrs = TextAttrs::default();
         Self {
-            content: content.into(),
+            content: content.into().into(),
             buf: TextBuffer::new_empty(Metrics::new(attrs.font_size, attrs.line_height)),
             attrs,
             align: Align::Center,
@@ -49,6 +49,8 @@ impl Text {
             font_system,
             Metrics::new(self.attrs.font_size, self.attrs.line_height),
         );
+        if self.content.changed {
+            self.content.changed = false;
             self.buf.set_text(
                 font_system,
                 &self.content,
@@ -57,6 +59,7 @@ impl Text {
             );
         }
     }
+}
 
 impl Widget for Text {
     fn draw(&mut self, painter: &mut Painter) {

src/util/change.rs

@@ -0,0 +1,30 @@
+use std::ops::{Deref, DerefMut};
+
+pub struct MutDetect<T> {
+    inner: T,
+    pub changed: bool,
+}
+
+impl<T> Deref for MutDetect<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &self.inner
+    }
+}
+
+impl<T> DerefMut for MutDetect<T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.changed = true;
+        &mut self.inner
+    }
+}
+
+impl<T> From<T> for MutDetect<T> {
+    fn from(inner: T) -> Self {
+        MutDetect {
+            inner,
+            changed: true,
+        }
+    }
+}

src/util/mod.rs

@@ -1,9 +1,11 @@
 mod borrow;
+mod change;
 mod id;
 mod math;
 mod refcount;
 
 pub(crate) use borrow::*;
+pub use change::*;
 pub(crate) use id::*;
 pub(crate) use math::*;
 pub(crate) use refcount::*;