Implement present_with_damage for Web (#101)

src/web.rs

@@ -107,34 +107,10 @@ impl WebImpl {
     pub(crate) fn buffer_mut(&mut self) -> Result<BufferImpl, SoftBufferError> {
         Ok(BufferImpl { imp: self })
     }
-}
-
-pub struct BufferImpl<'a> {
-    imp: &'a mut WebImpl,
-}
-
-impl<'a> BufferImpl<'a> {
-    pub fn pixels(&self) -> &[u32] {
-        &self.imp.buffer
-    }
-
-    pub fn pixels_mut(&mut self) -> &mut [u32] {
-        &mut self.imp.buffer
-    }
 
-    pub fn age(&self) -> u8 {
-        if self.imp.buffer_presented {
-            1
-        } else {
-            0
-        }
-    }
-
-    /// Push the buffer to the canvas.
-    pub fn present(self) -> Result<(), SoftBufferError> {
+    fn present_with_damage(&mut self, damage: &[Rect]) -> Result<(), SoftBufferError> {
         // Create a bitmap from the buffer.
         let bitmap: Vec<_> = self
-            .imp
             .buffer
             .iter()
             .copied()
@@ -159,26 +135,86 @@ impl<'a> BufferImpl<'a> {
             let array = Uint8Array::new_with_length(bitmap.len() as u32);
             array.copy_from(&bitmap);
             let array = Uint8ClampedArray::new(&array);
-            ImageDataExt::new(array, self.imp.width)
+            ImageDataExt::new(array, self.width)
                 .map(JsValue::from)
                 .map(ImageData::unchecked_from_js)
         };
         #[cfg(not(target_feature = "atomics"))]
         let result =
-            ImageData::new_with_u8_clamped_array(wasm_bindgen::Clamped(&bitmap), self.imp.width);
+            ImageData::new_with_u8_clamped_array(wasm_bindgen::Clamped(&bitmap), self.width);
         // This should only throw an error if the buffer we pass's size is incorrect.
         let image_data = result.unwrap();
 
-        // This can only throw an error if `data` is detached, which is impossible.
-        self.imp.ctx.put_image_data(&image_data, 0.0, 0.0).unwrap();
+        for Rect {
+            x,
+            y,
+            width,
+            height,
+        } in damage
+        {
+            // This can only throw an error if `data` is detached, which is impossible.
+            self.ctx
+                .put_image_data_with_dirty_x_and_dirty_y_and_dirty_width_and_dirty_height(
+                    &image_data,
+                    (*x).into(),
+                    (*y).into(),
+                    (*x).into(),
+                    (*y).into(),
+                    (*width).into(),
+                    (*height).into(),
+                )
+                .unwrap();
+        }
 
-        self.imp.buffer_presented = true;
+        self.buffer_presented = true;
 
         Ok(())
     }
+}
+
+pub struct BufferImpl<'a> {
+    imp: &'a mut WebImpl,
+}
+
+impl<'a> BufferImpl<'a> {
+    pub fn pixels(&self) -> &[u32] {
+        &self.imp.buffer
+    }
+
+    pub fn pixels_mut(&mut self) -> &mut [u32] {
+        &mut self.imp.buffer
+    }
+
+    pub fn age(&self) -> u8 {
+        if self.imp.buffer_presented {
+            1
+        } else {
+            0
+        }
+    }
+
+    /// Push the buffer to the canvas.
+    pub fn present(self) -> Result<(), SoftBufferError> {
+        let (width, height) = (|| {
+            let width = i32::try_from(self.imp.width).ok()?;
+            let height = i32::try_from(self.imp.height).ok()?;
+            Some((width, height))
+        })()
+        .ok_or(SoftBufferError::SizeOutOfRange {
+            width: NonZeroU32::new(self.imp.width).unwrap(),
+            height: NonZeroU32::new(self.imp.height).unwrap(),
+        })?;
+
+        self.imp.present_with_damage(&[Rect {
+            x: 0,
+            y: 0,
+            width,
+            height,
+        }])
+    }
 
-    pub fn present_with_damage(self, _damage: &[Rect]) -> Result<(), SoftBufferError> {
-        self.present()
+    pub fn present_with_damage(self, damage: &[Rect]) -> Result<(), SoftBufferError> {
+        self.imp.present_with_damage(damage)
     }
 }