本文整理汇总了C++中HTMLCanvasElement::Width方法的典型用法代码示例。如果您正苦于以下问题：C++ HTMLCanvasElement::Width方法的具体用法？C++ HTMLCanvasElement::Width怎么用？C++ HTMLCanvasElement::Width使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类HTMLCanvasElement的用法示例。
在下文中一共展示了HTMLCanvasElement::Width方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: GetSurfaceFromElement
/* static */ already_AddRefed<ImageBitmap>
ImageBitmap::CreateInternal(nsIGlobalObject* aGlobal, HTMLCanvasElement& aCanvasEl,
const Maybe<IntRect>& aCropRect, ErrorResult& aRv)
{
if (aCanvasEl.Width() == 0 || aCanvasEl.Height() == 0) {
aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
return nullptr;
}
RefPtr<SourceSurface> surface = GetSurfaceFromElement(aGlobal, aCanvasEl, aRv);
if (NS_WARN_IF(aRv.Failed())) {
return nullptr;
}
// Crop the source surface if needed.
RefPtr<SourceSurface> croppedSurface;
IntRect cropRect = aCropRect.valueOr(IntRect());
// If the HTMLCanvasElement's rendering context is WebGL, then the snapshot
// we got from the HTMLCanvasElement is a DataSourceSurface which is a copy
// of the rendering context. We handle cropping in this case.
if ((aCanvasEl.GetCurrentContextType() == CanvasContextType::WebGL1 ||
aCanvasEl.GetCurrentContextType() == CanvasContextType::WebGL2) &&
aCropRect.isSome()) {
// The _surface_ must be a DataSourceSurface.
MOZ_ASSERT(surface->GetType() == SurfaceType::DATA,
"The snapshot SourceSurface from WebGL rendering contest is not \
DataSourceSurface.");
RefPtr<DataSourceSurface> dataSurface = surface->GetDataSurface();
croppedSurface = CropAndCopyDataSourceSurface(dataSurface, cropRect);
cropRect.MoveTo(0, 0);
}