我知道如何使用 RepaintBoundary
将可见的小部件保存到图像中
我想要的是一种保存 widget
的方法用户看不到的 image
.
最佳答案
/// Creates an image from the given widget by first spinning up a element and render tree,
/// then waiting for the given [wait] amount of time and then creating an image via a [RepaintBoundary].
///
/// The final image will be of size [imageSize] and the the widget will be layout, ... with the given [logicalSize].
Future<Uint8List> createImageFromWidget(Widget widget, {Duration wait, Size logicalSize, Size imageSize}) async {
final RenderRepaintBoundary repaintBoundary = RenderRepaintBoundary();
logicalSize ??= ui.window.physicalSize / ui.window.devicePixelRatio;
imageSize ??= ui.window.physicalSize;
assert(logicalSize.aspectRatio == imageSize.aspectRatio);
final RenderView renderView = RenderView(
window: null,
child: RenderPositionedBox(alignment: Alignment.center, child: repaintBoundary),
configuration: ViewConfiguration(
size: logicalSize,
devicePixelRatio: 1.0,
),
);
final PipelineOwner pipelineOwner = PipelineOwner();
final BuildOwner buildOwner = BuildOwner();
pipelineOwner.rootNode = renderView;
renderView.prepareInitialFrame();
final RenderObjectToWidgetElement<RenderBox> rootElement = RenderObjectToWidgetAdapter<RenderBox>(
container: repaintBoundary,
child: widget,
).attachToRenderTree(buildOwner);
buildOwner.buildScope(rootElement);
if (wait != null) {
await Future.delayed(wait);
}
buildOwner.buildScope(rootElement);
buildOwner.finalizeTree();
pipelineOwner.flushLayout();
pipelineOwner.flushCompositingBits();
pipelineOwner.flushPaint();
final ui.Image image = await repaintBoundary.toImage(pixelRatio: imageSize.width / logicalSize.width);
final ByteData byteData = await image.toByteData(format: ui.ImageByteFormat.png);
return byteData.buffer.asUint8List();
}
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关于android - 是否可以将隐藏的小部件导出为图像?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/56911112/