[web] Fix repaint logic for cullrect,transform changes (#22273)
diff --git a/lib/web_ui/lib/src/engine/html/picture.dart b/lib/web_ui/lib/src/engine/html/picture.dart
index a6d1867..6915010 100644
--- a/lib/web_ui/lib/src/engine/html/picture.dart
+++ b/lib/web_ui/lib/src/engine/html/picture.dart
@@ -91,6 +91,10 @@
final ui.Rect? localPaintBounds;
final int hints;
double _density = 1.0;
+ /// Cull rect changes and density changes due to transforms should
+ /// call applyPaint for picture when retain() or update() is called after
+ /// preroll is complete.
+ bool _requiresRepaint = false;
/// Cache for reusing elements such as images across picture updates.
CrossFrameCache<html.HtmlElement>? _elementCache =
@@ -114,16 +118,7 @@
? 1.0 : _computePixelDensity(_transform, paintWidth, paintHeight);
if (newDensity != _density) {
_density = newDensity;
- if (_canvas != null) {
- // If cull rect and density hasn't changed, this will only repaint.
- // If density doesn't match canvas, a new canvas will be created
- // and paint queued.
- //
- // Similar to preroll for transform where transform is updated, for
- // picture this means we need to repaint so pixelation doesn't occur
- // due to transform changing overall dpi.
- applyPaint(_canvas);
- }
+ _requiresRepaint = true;
}
_computeExactCullRects();
}
@@ -204,13 +199,14 @@
}
}
- bool _computeOptimalCullRect(PersistedPicture? oldSurface) {
+ void _computeOptimalCullRect(PersistedPicture? oldSurface) {
assert(_exactLocalCullRect != null);
if (oldSurface == null || !oldSurface.picture.recordingCanvas!.didDraw) {
// First useful paint.
_optimalLocalCullRect = _exactLocalCullRect;
- return true;
+ _requiresRepaint = true;
+ return;
}
assert(oldSurface._optimalLocalCullRect != null);
@@ -224,7 +220,10 @@
// The clip collapsed into a zero-sized rectangle. If it was already zero,
// no need to signal cull rect change.
_optimalLocalCullRect = ui.Rect.zero;
- return oldOptimalLocalCullRect != ui.Rect.zero;
+ if (oldOptimalLocalCullRect != ui.Rect.zero) {
+ _requiresRepaint = true;
+ }
+ return;
}
if (rectContainsOther(oldOptimalLocalCullRect!, _exactLocalCullRect!)) {
@@ -233,7 +232,7 @@
// a clip when it is scrolled out of the screen. In this case we do not
// repaint the picture. We just let it be shrunk by the outer clip.
_optimalLocalCullRect = oldOptimalLocalCullRect;
- return false;
+ return;
}
// The new cull rect contains area not covered by a previous rect. Perhaps
@@ -270,9 +269,8 @@
_predictTrend(bottomwardDelta, _exactLocalCullRect!.height),
).intersect(localPaintBounds!);
- final bool localCullRectChanged = _optimalLocalCullRect != newLocalCullRect;
+ _requiresRepaint = _optimalLocalCullRect != newLocalCullRect;
_optimalLocalCullRect = newLocalCullRect;
- return localCullRectChanged;
}
/// Predicts the delta a particular side of a clip rect will move given the
@@ -309,6 +307,7 @@
void _applyPaint(PersistedPicture? oldSurface) {
final EngineCanvas? oldCanvas = oldSurface?._canvas;
+ _requiresRepaint = false;
if (!picture.recordingCanvas!.didDraw || _optimalLocalCullRect!.isEmpty) {
// The picture is empty, or it has been completely clipped out. Skip
// painting. This removes all the setup work and scaffolding objects
@@ -540,6 +539,7 @@
@override
void build() {
_computeOptimalCullRect(null);
+ _requiresRepaint = true;
super.build();
}
@@ -556,15 +556,14 @@
_applyTranslate();
}
- final bool cullRectChangeRequiresRepaint =
- _computeOptimalCullRect(oldSurface);
+ _computeOptimalCullRect(oldSurface);
if (identical(picture, oldSurface.picture)) {
bool densityChanged =
(_canvas is BitmapCanvas &&
_density != (_canvas as BitmapCanvas)._density);
// The picture is the same. Attempt to avoid repaint.
- if (cullRectChangeRequiresRepaint || densityChanged) {
+ if (_requiresRepaint || densityChanged) {
// Cull rect changed such that a repaint is still necessary.
_applyPaint(oldSurface);
} else {
@@ -581,8 +580,8 @@
@override
void retain() {
super.retain();
- final bool cullRectChangeRequiresRepaint = _computeOptimalCullRect(this);
- if (cullRectChangeRequiresRepaint) {
+ _computeOptimalCullRect(this);
+ if (_requiresRepaint) {
_applyPaint(this);
}
}
