TEST_F(APZHitTestingTester, HitTestingRespectsScrollClip_Bug1257288) {
// Create the layer tree.
const char* layerTreeSyntax = "c(tt)";
// LayerID 0 12
nsIntRegion layerVisibleRegion[] = {
nsIntRegion(IntRect(0,0,200,200)),
nsIntRegion(IntRect(0,0,200,200)),
nsIntRegion(IntRect(0,0,200,100))
};
root = CreateLayerTree(layerTreeSyntax, layerVisibleRegion, nullptr, lm, layers);
// Add root scroll metadata to the first painted layer.
SetScrollableFrameMetrics(layers[1], FrameMetrics::START_SCROLL_ID, CSSRect(0,0,200,200));
// Add root and subframe scroll metadata to the second painted layer.
// Give the subframe metadata a scroll clip corresponding to the subframe's
// composition bounds.
// Importantly, give the layer a layer clip which leaks outside of the
// subframe's composition bounds.
ScrollMetadata rootMetadata = BuildScrollMetadata(
FrameMetrics::START_SCROLL_ID, CSSRect(0,0,200,200),
ParentLayerRect(0,0,200,200));
ScrollMetadata subframeMetadata = BuildScrollMetadata(
FrameMetrics::START_SCROLL_ID + 1, CSSRect(0,0,200,200),
ParentLayerRect(0,0,200,100));
subframeMetadata.SetScrollClip(Some(LayerClip(ParentLayerIntRect(0,0,200,100))));
layers[2]->SetScrollMetadata({subframeMetadata, rootMetadata});
layers[2]->SetClipRect(Some(ParentLayerIntRect(0,0,200,200)));
SetEventRegionsBasedOnBottommostMetrics(layers[2]);
// Build the hit testing tree.
ScopedLayerTreeRegistration registration(manager, 0, root, mcc);
manager->UpdateHitTestingTree(nullptr, root, false, 0, 0);
// Pan on a region that's inside layers[2]'s layer clip, but outside
// its subframe metadata's scroll clip.
Pan(manager, 120, 110);
// Test that the subframe hasn't scrolled.
EXPECT_EQ(CSSPoint(0,0), ApzcOf(layers[2], 0)->GetFrameMetrics().GetScrollOffset());
}
FrameMetrics GetPinchableFrameMetrics()
{
FrameMetrics fm;
fm.SetCompositionBounds(ParentLayerRect(200, 200, 100, 200));
fm.SetScrollableRect(CSSRect(0, 0, 980, 1000));
fm.SetScrollOffset(CSSPoint(300, 300));
fm.SetZoom(CSSToParentLayerScale2D(2.0, 2.0));
// APZC only allows zooming on the root scrollable frame.
fm.SetIsRootContent(true);
// the visible area of the document in CSS pixels is x=300 y=300 w=50 h=100
return fm;
}
TEST_F(APZCBasicTester, Overzoom) {
// the visible area of the document in CSS pixels is x=10 y=0 w=100 h=100
FrameMetrics fm;
fm.SetCompositionBounds(ParentLayerRect(0, 0, 100, 100));
fm.SetScrollableRect(CSSRect(0, 0, 125, 150));
fm.SetScrollOffset(CSSPoint(10, 0));
fm.SetZoom(CSSToParentLayerScale2D(1.0, 1.0));
fm.SetIsRootContent(true);
apzc->SetFrameMetrics(fm);
MakeApzcZoomable();
EXPECT_CALL(*mcc, RequestContentRepaint(_)).Times(1);
PinchWithPinchInputAndCheckStatus(apzc, ScreenIntPoint(50, 50), 0.5, true);
fm = apzc->GetFrameMetrics();
EXPECT_EQ(0.8f, fm.GetZoom().ToScaleFactor().scale);
// bug 936721 - PGO builds introduce rounding error so
// use a fuzzy match instead
EXPECT_LT(std::abs(fm.GetScrollOffset().x), 1e-5);
EXPECT_LT(std::abs(fm.GetScrollOffset().y), 1e-5);
}
void
SharedFrameMetricsHelper::FindFallbackContentFrameMetrics(ContainerLayer* aLayer,
ParentLayerRect& aCompositionBounds,
CSSToParentLayerScale& aZoom) {
if (!aLayer) {
return;
}
ContainerLayer* layer = aLayer;
const FrameMetrics* contentMetrics = &(layer->GetFrameMetrics());
// Walk up the layer tree until a valid composition bounds is found
while (layer && contentMetrics->mCompositionBounds.IsEmpty()) {
layer = layer->GetParent();
contentMetrics = layer ? &(layer->GetFrameMetrics()) : contentMetrics;
}
MOZ_ASSERT(!contentMetrics->mCompositionBounds.IsEmpty());
aCompositionBounds = ParentLayerRect(contentMetrics->mCompositionBounds);
aZoom = contentMetrics->GetZoomToParent(); // TODO(botond): double-check this
return;
}
void
ClientTiledThebesLayer::BeginPaint()
{
if (ClientManager()->IsRepeatTransaction()) {
return;
}
mPaintData.mLowPrecisionPaintCount = 0;
mPaintData.mPaintFinished = false;
mPaintData.mCompositionBounds.SetEmpty();
mPaintData.mCriticalDisplayPort.SetEmpty();
if (!GetBaseTransform().Is2D()) {
// Give up if there is a complex CSS transform on the layer. We might
// eventually support these but for now it's too complicated to handle
// given that it's a pretty rare scenario.
return;
}
// Get the metrics of the nearest scrollable layer and the nearest layer
// with a displayport.
ContainerLayer* scrollAncestor = nullptr;
ContainerLayer* displayPortAncestor = nullptr;
for (ContainerLayer* ancestor = GetParent(); ancestor; ancestor = ancestor->GetParent()) {
const FrameMetrics& metrics = ancestor->GetFrameMetrics();
if (!scrollAncestor && metrics.GetScrollId() != FrameMetrics::NULL_SCROLL_ID) {
scrollAncestor = ancestor;
}
if (!metrics.mDisplayPort.IsEmpty()) {
displayPortAncestor = ancestor;
// Any layer that has a displayport must be scrollable, so we can break
// here.
break;
}
}
if (!displayPortAncestor || !scrollAncestor) {
// No displayport or scroll ancestor, so we can't do progressive rendering.
#if defined(MOZ_WIDGET_ANDROID) || defined(MOZ_B2G)
// Both Android and b2g are guaranteed to have a displayport set, so this
// should never happen.
NS_WARNING("Tiled Thebes layer with no scrollable container ancestor");
#endif
return;
}
TILING_PRLOG(("TILING 0x%p: Found scrollAncestor 0x%p and displayPortAncestor 0x%p\n", this,
scrollAncestor, displayPortAncestor));
const FrameMetrics& scrollMetrics = scrollAncestor->GetFrameMetrics();
const FrameMetrics& displayportMetrics = displayPortAncestor->GetFrameMetrics();
// Calculate the transform required to convert ParentLayer space of our
// display port ancestor to the Layer space of this layer.
gfx3DMatrix transformToDisplayPort =
GetTransformToAncestorsParentLayer(this, displayPortAncestor);
mPaintData.mTransformDisplayPortToLayer = transformToDisplayPort.Inverse();
// Note that below we use GetZoomToParent() in a number of places. Because this
// code runs on the client side, the mTransformScale field of the FrameMetrics
// will not have been set. This can result in incorrect values being returned
// by GetZoomToParent() when we have CSS transforms set on some of these layers.
// This code should be audited and updated as part of fixing bug 993525.
// Compute the critical display port that applies to this layer in the
// LayoutDevice space of this layer.
ParentLayerRect criticalDisplayPort =
(displayportMetrics.mCriticalDisplayPort * displayportMetrics.GetZoomToParent())
+ displayportMetrics.mCompositionBounds.TopLeft();
mPaintData.mCriticalDisplayPort = RoundedOut(
ApplyParentLayerToLayerTransform(mPaintData.mTransformDisplayPortToLayer, criticalDisplayPort));
TILING_PRLOG_OBJ(("TILING 0x%p: Critical displayport %s\n", this, tmpstr.get()), mPaintData.mCriticalDisplayPort);
// Compute the viewport that applies to this layer in the LayoutDevice
// space of this layer.
ParentLayerRect viewport =
(displayportMetrics.mViewport * displayportMetrics.GetZoomToParent())
+ displayportMetrics.mCompositionBounds.TopLeft();
mPaintData.mViewport = ApplyParentLayerToLayerTransform(
mPaintData.mTransformDisplayPortToLayer, viewport);
TILING_PRLOG_OBJ(("TILING 0x%p: Viewport %s\n", this, tmpstr.get()), mPaintData.mViewport);
// Store the resolution from the displayport ancestor layer. Because this is Gecko-side,
// before any async transforms have occurred, we can use the zoom for this.
mPaintData.mResolution = displayportMetrics.GetZoomToParent();
TILING_PRLOG(("TILING 0x%p: Resolution %f\n", this, mPaintData.mResolution.scale));
// Store the applicable composition bounds in this layer's Layer units.
gfx3DMatrix transformToCompBounds =
GetTransformToAncestorsParentLayer(this, scrollAncestor);
mPaintData.mCompositionBounds = ApplyParentLayerToLayerTransform(
transformToCompBounds.Inverse(), ParentLayerRect(scrollMetrics.mCompositionBounds));
TILING_PRLOG_OBJ(("TILING 0x%p: Composition bounds %s\n", this, tmpstr.get()), mPaintData.mCompositionBounds);
// Calculate the scroll offset since the last transaction
mPaintData.mScrollOffset = displayportMetrics.GetScrollOffset() * displayportMetrics.GetZoomToParent();
TILING_PRLOG_OBJ(("TILING 0x%p: Scroll offset %s\n", this, tmpstr.get()), mPaintData.mScrollOffset);
}
TEST_F(APZCBasicTester, ComplexTransform) {
// This test assumes there is a page that gets rendered to
// two layers. In CSS pixels, the first layer is 50x50 and
// the second layer is 25x50. The widget scale factor is 3.0
// and the presShell resolution is 2.0. Therefore, these layers
// end up being 300x300 and 150x300 in layer pixels.
//
// The second (child) layer has an additional CSS transform that
// stretches it by 2.0 on the x-axis. Therefore, after applying
// CSS transforms, the two layers are the same size in screen
// pixels.
//
// The screen itself is 24x24 in screen pixels (therefore 4x4 in
// CSS pixels). The displayport is 1 extra CSS pixel on all
// sides.
RefPtr<TestAsyncPanZoomController> childApzc =
new TestAsyncPanZoomController(0, mcc, tm);
const char* layerTreeSyntax = "c(c)";
// LayerID 0 1
nsIntRegion layerVisibleRegion[] = {
nsIntRegion(IntRect(0, 0, 300, 300)),
nsIntRegion(IntRect(0, 0, 150, 300)),
};
Matrix4x4 transforms[] = {
Matrix4x4(),
Matrix4x4(),
};
transforms[0].PostScale(0.5f, 0.5f, 1.0f); // this results from the 2.0 resolution on the root layer
transforms[1].PostScale(2.0f, 1.0f, 1.0f); // this is the 2.0 x-axis CSS transform on the child layer
nsTArray<RefPtr<Layer> > layers;
RefPtr<LayerManager> lm;
RefPtr<Layer> root = CreateLayerTree(layerTreeSyntax, layerVisibleRegion, transforms, lm, layers);
ScrollMetadata metadata;
FrameMetrics& metrics = metadata.GetMetrics();
metrics.SetCompositionBounds(ParentLayerRect(0, 0, 24, 24));
metrics.SetDisplayPort(CSSRect(-1, -1, 6, 6));
metrics.SetScrollOffset(CSSPoint(10, 10));
metrics.SetScrollableRect(CSSRect(0, 0, 50, 50));
metrics.SetCumulativeResolution(LayoutDeviceToLayerScale2D(2, 2));
metrics.SetPresShellResolution(2.0f);
metrics.SetZoom(CSSToParentLayerScale2D(6, 6));
metrics.SetDevPixelsPerCSSPixel(CSSToLayoutDeviceScale(3));
metrics.SetScrollId(FrameMetrics::START_SCROLL_ID);
ScrollMetadata childMetadata = metadata;
FrameMetrics& childMetrics = childMetadata.GetMetrics();
childMetrics.SetScrollId(FrameMetrics::START_SCROLL_ID + 1);
layers[0]->SetScrollMetadata(metadata);
layers[1]->SetScrollMetadata(childMetadata);
ParentLayerPoint pointOut;
AsyncTransform viewTransformOut;
// Both the parent and child layer should behave exactly the same here, because
// the CSS transform on the child layer does not affect the SampleContentTransformForFrame code
// initial transform
apzc->SetFrameMetrics(metrics);
apzc->NotifyLayersUpdated(metadata, true, true);
apzc->SampleContentTransformForFrame(&viewTransformOut, pointOut);
EXPECT_EQ(AsyncTransform(LayerToParentLayerScale(1), ParentLayerPoint()), viewTransformOut);
EXPECT_EQ(ParentLayerPoint(60, 60), pointOut);
childApzc->SetFrameMetrics(childMetrics);
childApzc->NotifyLayersUpdated(childMetadata, true, true);
childApzc->SampleContentTransformForFrame(&viewTransformOut, pointOut);
EXPECT_EQ(AsyncTransform(LayerToParentLayerScale(1), ParentLayerPoint()), viewTransformOut);
EXPECT_EQ(ParentLayerPoint(60, 60), pointOut);
// do an async scroll by 5 pixels and check the transform
metrics.ScrollBy(CSSPoint(5, 0));
apzc->SetFrameMetrics(metrics);
apzc->SampleContentTransformForFrame(&viewTransformOut, pointOut);
EXPECT_EQ(AsyncTransform(LayerToParentLayerScale(1), ParentLayerPoint(-30, 0)), viewTransformOut);
EXPECT_EQ(ParentLayerPoint(90, 60), pointOut);
childMetrics.ScrollBy(CSSPoint(5, 0));
childApzc->SetFrameMetrics(childMetrics);
childApzc->SampleContentTransformForFrame(&viewTransformOut, pointOut);
EXPECT_EQ(AsyncTransform(LayerToParentLayerScale(1), ParentLayerPoint(-30, 0)), viewTransformOut);
EXPECT_EQ(ParentLayerPoint(90, 60), pointOut);
// do an async zoom of 1.5x and check the transform
metrics.ZoomBy(1.5f);
apzc->SetFrameMetrics(metrics);
apzc->SampleContentTransformForFrame(&viewTransformOut, pointOut);
EXPECT_EQ(AsyncTransform(LayerToParentLayerScale(1.5), ParentLayerPoint(-45, 0)), viewTransformOut);
EXPECT_EQ(ParentLayerPoint(135, 90), pointOut);
childMetrics.ZoomBy(1.5f);
childApzc->SetFrameMetrics(childMetrics);
childApzc->SampleContentTransformForFrame(&viewTransformOut, pointOut);
EXPECT_EQ(AsyncTransform(LayerToParentLayerScale(1.5), ParentLayerPoint(-45, 0)), viewTransformOut);
EXPECT_EQ(ParentLayerPoint(135, 90), pointOut);
childApzc->Destroy();
}
void
LayerManagerComposite::PostProcessLayers(Layer* aLayer,
nsIntRegion& aOpaqueRegion,
LayerIntRegion& aVisibleRegion,
const Maybe<ParentLayerIntRect>& aClipFromAncestors)
{
if (aLayer->Extend3DContext()) {
// For layers participating 3D rendering context, their visible
// region should be empty (invisible), so we pass through them
// without doing anything.
// Direct children of the establisher may have a clip, becaue the
// item containing it; ex. of nsHTMLScrollFrame, may give it one.
Maybe<ParentLayerIntRect> layerClip =
aLayer->AsHostLayer()->GetShadowClipRect();
Maybe<ParentLayerIntRect> ancestorClipForChildren =
IntersectMaybeRects(layerClip, aClipFromAncestors);
MOZ_ASSERT(!layerClip || !aLayer->Combines3DTransformWithAncestors(),
"Only direct children of the establisher could have a clip");
for (Layer* child = aLayer->GetLastChild();
child;
child = child->GetPrevSibling()) {
PostProcessLayers(child, aOpaqueRegion, aVisibleRegion,
ancestorClipForChildren);
}
return;
}
nsIntRegion localOpaque;
// Treat layers on the path to the root of the 3D rendering context as
// a giant layer if it is a leaf.
Matrix4x4 transform = GetAccTransformIn3DContext(aLayer);
Matrix transform2d;
Maybe<IntPoint> integerTranslation;
// If aLayer has a simple transform (only an integer translation) then we
// can easily convert aOpaqueRegion into pre-transform coordinates and include
// that region.
if (transform.Is2D(&transform2d)) {
if (transform2d.IsIntegerTranslation()) {
integerTranslation = Some(IntPoint::Truncate(transform2d.GetTranslation()));
localOpaque = aOpaqueRegion;
localOpaque.MoveBy(-*integerTranslation);
}
}
// Compute a clip that's the combination of our layer clip with the clip
// from our ancestors.
LayerComposite* composite = static_cast<LayerComposite*>(aLayer->AsHostLayer());
Maybe<ParentLayerIntRect> layerClip = composite->GetShadowClipRect();
MOZ_ASSERT(!layerClip || !aLayer->Combines3DTransformWithAncestors(),
"The layer with a clip should not participate "
"a 3D rendering context");
Maybe<ParentLayerIntRect> outsideClip =
IntersectMaybeRects(layerClip, aClipFromAncestors);
// Convert the combined clip into our pre-transform coordinate space, so
// that it can later be intersected with our visible region.
// If our transform is a perspective, there's no meaningful insideClip rect
// we can compute (it would need to be a cone).
Maybe<LayerIntRect> insideClip;
if (outsideClip && !transform.HasPerspectiveComponent()) {
Matrix4x4 inverse = transform;
if (inverse.Invert()) {
Maybe<LayerRect> insideClipFloat =
UntransformBy(ViewAs<ParentLayerToLayerMatrix4x4>(inverse),
ParentLayerRect(*outsideClip),
LayerRect::MaxIntRect());
if (insideClipFloat) {
insideClipFloat->RoundOut();
LayerIntRect insideClipInt;
if (insideClipFloat->ToIntRect(&insideClipInt)) {
insideClip = Some(insideClipInt);
}
}
}
}
Maybe<ParentLayerIntRect> ancestorClipForChildren;
if (insideClip) {
ancestorClipForChildren =
Some(ViewAs<ParentLayerPixel>(*insideClip, PixelCastJustification::MovingDownToChildren));
}
// Save the value of localOpaque, which currently stores the region obscured
// by siblings (and uncles and such), before our descendants contribute to it.
nsIntRegion obscured = localOpaque;
// Recurse on our descendants, in front-to-back order. In this process:
// - Occlusions are computed for them, and they contribute to localOpaque.
// - They recalculate their visible regions, taking ancestorClipForChildren
// into account, and accumulate them into descendantsVisibleRegion.
LayerIntRegion descendantsVisibleRegion;
bool hasPreserve3DChild = false;
for (Layer* child = aLayer->GetLastChild(); child; child = child->GetPrevSibling()) {
PostProcessLayers(child, localOpaque, descendantsVisibleRegion, ancestorClipForChildren);
if (child->Extend3DContext()) {
hasPreserve3DChild = true;
}
}
// Recalculate our visible region.
LayerIntRegion visible = composite->GetShadowVisibleRegion();
// If we have descendants, throw away the visible region stored on this
// layer, and use the region accumulated by our descendants instead.
if (aLayer->GetFirstChild() && !hasPreserve3DChild) {
visible = descendantsVisibleRegion;
}
// Subtract any areas that we know to be opaque.
if (!obscured.IsEmpty()) {
visible.SubOut(LayerIntRegion::FromUnknownRegion(obscured));
}
// Clip the visible region using the combined clip.
if (insideClip) {
visible.AndWith(*insideClip);
}
composite->SetShadowVisibleRegion(visible);
// Transform the newly calculated visible region into our parent's space,
// apply our clip to it (if any), and accumulate it into |aVisibleRegion|
// for the caller to use.
ParentLayerIntRegion visibleParentSpace = TransformBy(
ViewAs<LayerToParentLayerMatrix4x4>(transform), visible);
if (const Maybe<ParentLayerIntRect>& clipRect = composite->GetShadowClipRect()) {
visibleParentSpace.AndWith(*clipRect);
}
aVisibleRegion.OrWith(ViewAs<LayerPixel>(visibleParentSpace,
PixelCastJustification::MovingDownToChildren));
// If we have a simple transform, then we can add our opaque area into
// aOpaqueRegion.
if (integerTranslation &&
!aLayer->HasMaskLayers() &&
aLayer->IsOpaqueForVisibility()) {
if (aLayer->IsOpaque()) {
localOpaque.OrWith(composite->GetFullyRenderedRegion());
}
localOpaque.MoveBy(*integerTranslation);
if (layerClip) {
localOpaque.AndWith(layerClip->ToUnknownRect());
}
aOpaqueRegion.OrWith(localOpaque);
}
}
void
SimpleClientTiledThebesLayer::BeginPaint()
{
if (ClientManager()->IsRepeatTransaction()) {
return;
}
mPaintData.mLowPrecisionPaintCount = 0;
mPaintData.mPaintFinished = false;
// Get the metrics of the nearest scroll container.
ContainerLayer* scrollParent = nullptr;
for (ContainerLayer* parent = GetParent(); parent; parent = parent->GetParent()) {
const FrameMetrics& metrics = parent->GetFrameMetrics();
if (metrics.mScrollId != FrameMetrics::NULL_SCROLL_ID) {
scrollParent = parent;
break;
}
}
if (!scrollParent) {
// XXX I don't think this can happen, but if it does, warn and set the
// composition bounds to empty so that progressive updates are disabled.
NS_WARNING("Tiled Thebes layer with no scrollable container parent");
mPaintData.mCompositionBounds.SetEmpty();
return;
}
const FrameMetrics& metrics = scrollParent->GetFrameMetrics();
// Calculate the transform required to convert screen space into transformed
// layout device space.
gfx::Matrix4x4 effectiveTransform = GetEffectiveTransform();
for (ContainerLayer* parent = GetParent(); parent; parent = parent->GetParent()) {
if (parent->UseIntermediateSurface()) {
effectiveTransform = effectiveTransform * parent->GetEffectiveTransform();
}
}
gfx3DMatrix layoutToParentLayer;
gfx::To3DMatrix(effectiveTransform, layoutToParentLayer);
layoutToParentLayer.ScalePost(metrics.GetParentResolution().scale,
metrics.GetParentResolution().scale,
1.f);
mPaintData.mTransformParentLayerToLayout = layoutToParentLayer.Inverse();
// Compute the critical display port in layer space.
mPaintData.mLayoutCriticalDisplayPort.SetEmpty();
if (!metrics.mCriticalDisplayPort.IsEmpty()) {
// Convert the display port to screen space first so that we can transform
// it into layout device space.
const ParentLayerRect& criticalDisplayPort = metrics.mCriticalDisplayPort
* metrics.mDevPixelsPerCSSPixel
* metrics.GetParentResolution();
LayoutDeviceRect transformedCriticalDisplayPort =
ApplyParentLayerToLayoutTransform(mPaintData.mTransformParentLayerToLayout, criticalDisplayPort);
mPaintData.mLayoutCriticalDisplayPort =
LayoutDeviceIntRect::ToUntyped(RoundedOut(transformedCriticalDisplayPort));
}
// Calculate the frame resolution. Because this is Gecko-side, before any
// async transforms have occurred, we can use mZoom for this.
mPaintData.mResolution = metrics.mZoom;
// Calculate the scroll offset since the last transaction, and the
// composition bounds.
mPaintData.mCompositionBounds.SetEmpty();
mPaintData.mScrollOffset.MoveTo(0, 0);
Layer* primaryScrollable = ClientManager()->GetPrimaryScrollableLayer();
if (primaryScrollable) {
const FrameMetrics& metrics = primaryScrollable->AsContainerLayer()->GetFrameMetrics();
mPaintData.mScrollOffset = metrics.mScrollOffset * metrics.mZoom;
mPaintData.mCompositionBounds =
ApplyParentLayerToLayoutTransform(mPaintData.mTransformParentLayerToLayout,
ParentLayerRect(metrics.mCompositionBounds));
}
}
bool
SharedFrameMetricsHelper::UpdateFromCompositorFrameMetrics(
ContainerLayer* aLayer,
bool aHasPendingNewThebesContent,
bool aLowPrecision,
ParentLayerRect& aCompositionBounds,
CSSToParentLayerScale& aZoom)
{
MOZ_ASSERT(aLayer);
CompositorChild* compositor = CompositorChild::Get();
if (!compositor) {
FindFallbackContentFrameMetrics(aLayer, aCompositionBounds, aZoom);
return false;
}
const FrameMetrics& contentMetrics = aLayer->GetFrameMetrics();
FrameMetrics compositorMetrics;
if (!compositor->LookupCompositorFrameMetrics(contentMetrics.mScrollId,
compositorMetrics)) {
FindFallbackContentFrameMetrics(aLayer, aCompositionBounds, aZoom);
return false;
}
aCompositionBounds = ParentLayerRect(compositorMetrics.mCompositionBounds);
aZoom = compositorMetrics.GetZoomToParent();
// Reset the checkerboard risk flag when switching to low precision
// rendering.
if (aLowPrecision && !mLastProgressiveUpdateWasLowPrecision) {
// Skip low precision rendering until we're at risk of checkerboarding.
if (!mProgressiveUpdateWasInDanger) {
return true;
}
mProgressiveUpdateWasInDanger = false;
}
mLastProgressiveUpdateWasLowPrecision = aLowPrecision;
// Always abort updates if the resolution has changed. There's no use
// in drawing at the incorrect resolution.
if (!FuzzyEquals(compositorMetrics.GetZoom().scale, contentMetrics.GetZoom().scale)) {
return true;
}
// Never abort drawing if we can't be sure we've sent a more recent
// display-port. If we abort updating when we shouldn't, we can end up
// with blank regions on the screen and we open up the risk of entering
// an endless updating cycle.
if (fabsf(contentMetrics.GetScrollOffset().x - compositorMetrics.GetScrollOffset().x) <= 2 &&
fabsf(contentMetrics.GetScrollOffset().y - compositorMetrics.GetScrollOffset().y) <= 2 &&
fabsf(contentMetrics.mDisplayPort.x - compositorMetrics.mDisplayPort.x) <= 2 &&
fabsf(contentMetrics.mDisplayPort.y - compositorMetrics.mDisplayPort.y) <= 2 &&
fabsf(contentMetrics.mDisplayPort.width - compositorMetrics.mDisplayPort.width) <= 2 &&
fabsf(contentMetrics.mDisplayPort.height - compositorMetrics.mDisplayPort.height)) {
return false;
}
// When not a low precision pass and the page is in danger of checker boarding
// abort update.
if (!aLowPrecision && !mProgressiveUpdateWasInDanger) {
if (AboutToCheckerboard(contentMetrics, compositorMetrics)) {
mProgressiveUpdateWasInDanger = true;
return true;
}
}
// Abort drawing stale low-precision content if there's a more recent
// display-port in the pipeline.
if (aLowPrecision && !aHasPendingNewThebesContent) {
return true;
}
return false;
}
