bool GraphicsContext::isCompatibleWithBuffer(ImageBuffer* buffer) const
{
AffineTransform localTransform = getCTM();
AffineTransform bufferTransform = buffer->context()->getCTM();
if (localTransform.xScale() != bufferTransform.xScale() || localTransform.yScale() != bufferTransform.yScale())
return false;
if (isAcceleratedContext() != buffer->context()->isAcceleratedContext())
return false;
return true;
}
bool GraphicsContext::isCompatibleWithBuffer(ImageBuffer& buffer) const
{
GraphicsContext& bufferContext = buffer.context();
return scalesMatch(getCTM(), bufferContext.getCTM()) && isAcceleratedContext() == bufferContext.isAcceleratedContext();
}
PassOwnPtr<ImageBuffer> GraphicsContext::createCompatibleBuffer(const IntSize& size) const
{
// Make the buffer larger if the context's transform is scaling it so we need a higher
// resolution than one pixel per unit. Also set up a corresponding scale factor on the
// graphics context.
AffineTransform transform = getCTM(DefinitelyIncludeDeviceScale);
IntSize scaledSize(static_cast<int>(ceil(size.width() * transform.xScale())), static_cast<int>(ceil(size.height() * transform.yScale())));
OwnPtr<ImageBuffer> buffer = ImageBuffer::create(scaledSize, 1, ColorSpaceDeviceRGB, isAcceleratedContext() ? Accelerated : Unaccelerated);
if (!buffer)
return nullptr;
buffer->context()->scale(FloatSize(static_cast<float>(scaledSize.width()) / size.width(),
static_cast<float>(scaledSize.height()) / size.height()));
return buffer.release();
}