markNeedsCompositedLayerUpdate method Null safety
Mark this render object as having changed a property on its composited layer.
Render objects that have a composited layer have isRepaintBoundary equal to true may update the properties of that composited layer without repainting their children. If this render object is a repaint boundary but does not yet have a composited layer created for it, this method will instead mark the nearest repaint boundary parent as needing to be painted.
If this method is called on a render object that is not a repaint boundary or is a repaint boundary but hasn't been composited yet, it is equivalent to calling markNeedsPaint.
See also:
- RenderOpacity, which uses this method when its opacity is updated to update the layer opacity without repainting children.
Implementation
void markNeedsCompositedLayerUpdate() {
assert(!_debugDisposed);
assert(owner == null || !owner!.debugDoingPaint);
if (_needsCompositedLayerUpdate || _needsPaint) {
return;
}
_needsCompositedLayerUpdate = true;
// If this was not previously a repaint boundary it will not have
// a layer we can paint from.
if (isRepaintBoundary && _wasRepaintBoundary) {
// If we always have our own layer, then we can just repaint
// ourselves without involving any other nodes.
assert(_layerHandle.layer != null);
if (owner != null) {
owner!._nodesNeedingPaint.add(this);
owner!.requestVisualUpdate();
}
} else {
markNeedsPaint();
}
}