bool AsyncPanZoomController::SampleContentTransformForFrame(const TimeStamp& aSampleTime,
const FrameMetrics& aFrame,
const gfx3DMatrix& aCurrentTransform,
gfx3DMatrix* aNewTransform) {
// The eventual return value of this function. The compositor needs to know
// whether or not to advance by a frame as soon as it can. For example, if a
// fling is happening, it has to keep compositing so that the animation is
// smooth. If an animation frame is requested, it is the compositor's
// responsibility to schedule a composite.
bool requestAnimationFrame = false;
// Scales on the root layer, on what's currently painted.
float rootScaleX = aCurrentTransform.GetXScale(),
rootScaleY = aCurrentTransform.GetYScale();
nsIntPoint metricsScrollOffset(0, 0);
nsIntPoint scrollOffset;
float localScaleX, localScaleY;
{
MonitorAutoLock mon(mMonitor);
// If a fling is currently happening, apply it now. We can pull the updated
// metrics afterwards.
requestAnimationFrame = requestAnimationFrame || DoFling(aSampleTime - mLastSampleTime);
// Current local transform; this is not what's painted but rather what PZC has
// transformed due to touches like panning or pinching. Eventually, the root
// layer transform will become this during runtime, but we must wait for Gecko
// to repaint.
localScaleX = mFrameMetrics.mResolution.width;
localScaleY = mFrameMetrics.mResolution.height;
if (aFrame.IsScrollable()) {
metricsScrollOffset = aFrame.mViewportScrollOffset;
}
scrollOffset = mFrameMetrics.mViewportScrollOffset;
}
nsIntPoint scrollCompensation(
(scrollOffset.x / rootScaleX - metricsScrollOffset.x) * localScaleX,
(scrollOffset.y / rootScaleY - metricsScrollOffset.y) * localScaleY);
ViewTransform treeTransform(-scrollCompensation, localScaleX, localScaleY);
*aNewTransform = gfx3DMatrix(treeTransform) * aCurrentTransform;
mLastSampleTime = aSampleTime;
return requestAnimationFrame;
}
void AsyncPanZoomController::GetContentTransformForFrame(const FrameMetrics& aFrame,
const gfx3DMatrix& aRootTransform,
const gfxSize& aWidgetSize,
gfx3DMatrix* aTreeTransform,
gfxPoint* aReverseViewTranslation) {
// Scales on the root layer, on what's currently painted.
float rootScaleX = aRootTransform.GetXScale(),
rootScaleY = aRootTransform.GetYScale();
// Current local transform; this is not what's painted but rather what PZC has
// transformed due to touches like panning or pinching. Eventually, the root
// layer transform will become this during runtime, but we must wait for Gecko
// to repaint.
float localScaleX = mFrameMetrics.mResolution.width,
localScaleY = mFrameMetrics.mResolution.height;
// Handle transformations for asynchronous panning and zooming. We determine the
// zoom used by Gecko from the transformation set on the root layer, and we
// determine the scroll offset used by Gecko from the frame metrics of the
// primary scrollable layer. We compare this to the desired zoom and scroll
// offset in the view transform we obtained from Java in order to compute the
// transformation we need to apply.
float tempScaleDiffX = rootScaleX * localScaleX;
float tempScaleDiffY = rootScaleY * localScaleY;
nsIntPoint metricsScrollOffset(0, 0);
if (aFrame.IsScrollable())
metricsScrollOffset = aFrame.mViewportScrollOffset;
nsIntPoint scrollCompensation(
mFrameMetrics.mViewportScrollOffset.x / rootScaleX - metricsScrollOffset.x,
mFrameMetrics.mViewportScrollOffset.y / rootScaleY - metricsScrollOffset.y);
ViewTransform treeTransform(-scrollCompensation, localScaleX, localScaleY);
*aTreeTransform = gfx3DMatrix(treeTransform);
float offsetX = mFrameMetrics.mViewportScrollOffset.x / tempScaleDiffX,
offsetY = mFrameMetrics.mViewportScrollOffset.y / tempScaleDiffY;
nsIntRect localContentRect = mFrameMetrics.mContentRect;
offsetX = NS_MAX((float)localContentRect.x,
NS_MIN(offsetX, (float)(localContentRect.XMost() - aWidgetSize.width)));
offsetY = NS_MAX((float)localContentRect.y,
NS_MIN(offsetY, (float)(localContentRect.YMost() - aWidgetSize.height)));
*aReverseViewTranslation = gfxPoint(offsetX - metricsScrollOffset.x,
offsetY - metricsScrollOffset.y);
}
