50 lines
1.2 KiB
Dart
50 lines
1.2 KiB
Dart
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import 'package:flutter/rendering.dart';
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import 'package:flutter/widgets.dart';
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// Applies a BlendMode to its child.
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class BlendMask extends SingleChildRenderObjectWidget {
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final BlendMode blendMode;
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final double opacity;
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const BlendMask({
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required this.blendMode,
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this.opacity = 1.0,
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super.key,
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super.child,
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});
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@override
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RenderObject createRenderObject(context) {
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return RenderBlendMask(blendMode, opacity);
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}
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@override
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void updateRenderObject(BuildContext context, RenderBlendMask renderObject) {
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renderObject.blendMode = blendMode;
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renderObject.opacity = opacity;
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}
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}
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class RenderBlendMask extends RenderProxyBox {
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BlendMode blendMode;
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double opacity;
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RenderBlendMask(this.blendMode, this.opacity);
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@override
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void paint(context, offset) {
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// Create a new layer and specify the blend mode and opacity to composite it with:
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context.canvas.saveLayer(
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offset & size,
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Paint()
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..blendMode = blendMode
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..color = Color.fromARGB((opacity * 255).round(), 255, 255, 255),
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);
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super.paint(context, offset);
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// Composite the layer back into the canvas using the blendmode:
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context.canvas.restore();
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}
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}
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