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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "mozilla/layers/StackingContextHelper.h"
#include "mozilla/PresShell.h"
#include "mozilla/gfx/Point.h"
#include "mozilla/gfx/Matrix.h"
#include "UnitTransforms.h"
#include "nsDisplayList.h"
#include "mozilla/dom/BrowserChild.h"
#include "nsLayoutUtils.h"
#include "ActiveLayerTracker.h"
namespace mozilla {
namespace layers {
using namespace gfx;
StackingContextHelper::StackingContextHelper()
: mBuilder(nullptr),
mScale(1.0f, 1.0f),
mAffectsClipPositioning(false),
mDeferredTransformItem(nullptr),
mRasterizeLocally(false) {
// mOrigin remains at 0,0
}
static nsSize ComputeDesiredDisplaySizeForAnimation(nsIFrame* aContainerFrame) {
// Use the size of the nearest widget as the maximum size. This
// is important since it might be a popup that is bigger than the
// pres context's size.
nsPresContext* presContext = aContainerFrame->PresContext();
nsIWidget* widget = aContainerFrame->GetNearestWidget();
if (widget) {
return LayoutDevicePixel::ToAppUnits(widget->GetClientSize(),
presContext->AppUnitsPerDevPixel());
}
return presContext->GetVisibleArea().Size();
}
/* static */
MatrixScales ChooseScale(nsIFrame* aContainerFrame,
nsDisplayItem* aContainerItem,
const nsRect& aVisibleRect, float aXScale,
float aYScale, const Matrix& aTransform2d,
bool aCanDraw2D) {
MatrixScales scale;
// XXX Should we do something for 3D transforms?
if (aCanDraw2D && !aContainerFrame->Combines3DTransformWithAncestors() &&
!aContainerFrame->HasPerspective()) {
// If the container's transform is animated off main thread, fix a suitable
// scale size for animation
if (aContainerItem &&
aContainerItem->GetType() == DisplayItemType::TYPE_TRANSFORM &&
// FIXME: What we need is only transform, rotate, and scale, not
// translate, so it's be better to use a property set, instead of
// display item type here.
EffectCompositor::HasAnimationsForCompositor(
aContainerFrame, DisplayItemType::TYPE_TRANSFORM)) {
nsSize displaySize =
ComputeDesiredDisplaySizeForAnimation(aContainerFrame);
// compute scale using the animation on the container, taking ancestors in
// to account
nsSize scaledVisibleSize = nsSize(aVisibleRect.Width() * aXScale,
aVisibleRect.Height() * aYScale);
scale = nsLayoutUtils::ComputeSuitableScaleForAnimation(
aContainerFrame, scaledVisibleSize, displaySize);
// multiply by the scale inherited from ancestors--we use a uniform
// scale factor to prevent blurring when the layer is rotated.
float incomingScale = std::max(aXScale, aYScale);
scale = scale * ScaleFactor<UnknownUnits, UnknownUnits>(incomingScale);
} else {
// Scale factors are normalized to a power of 2 to reduce the number of
// resolution changes
scale = (aTransform2d * gfx::Matrix::Scaling(aXScale, aYScale))
.ScaleFactors();
// For frames with a changing scale transform round scale factors up to
// nearest power-of-2 boundary so that we don't keep having to redraw
// the content as it scales up and down. Rounding up to nearest
// power-of-2 boundary ensures we never scale up, only down --- avoiding
// jaggies. It also ensures we never scale down by more than a factor of
// 2, avoiding bad downscaling quality.
Matrix frameTransform;
if (ActiveLayerTracker::IsScaleSubjectToAnimation(aContainerFrame)) {
scale.xScale = gfxUtils::ClampToScaleFactor(scale.xScale);
scale.yScale = gfxUtils::ClampToScaleFactor(scale.yScale);
// Limit animated scale factors to not grow excessively beyond the
// display size.
nsSize maxScale(4, 4);
if (!aVisibleRect.IsEmpty()) {
nsSize displaySize =
ComputeDesiredDisplaySizeForAnimation(aContainerFrame);
maxScale = Max(maxScale, displaySize / aVisibleRect.Size());
}
if (scale.xScale > maxScale.width) {
scale.xScale = gfxUtils::ClampToScaleFactor(maxScale.width, true);
}
if (scale.yScale > maxScale.height) {
scale.yScale = gfxUtils::ClampToScaleFactor(maxScale.height, true);
}
} else {
// XXX Do we need to move nearly-integer values to integers here?
}
}
// If the scale factors are too small, just use 1.0. The content is being
// scaled out of sight anyway.
if (fabs(scale.xScale) < 1e-8 || fabs(scale.yScale) < 1e-8) {
scale = MatrixScales(1.0, 1.0);
}
} else {
scale = MatrixScales(1.0, 1.0);
}
// Prevent the scale from getting too large, to avoid excessive memory
// allocation. Usually memory allocation is limited by the visible region,
// which should be restricted to the display port. But at very large scales
// the visible region itself can become excessive due to rounding errors.
// Clamping the scale here prevents that.
return MatrixScales(std::min(scale.xScale, 32768.0f),
std::min(scale.yScale, 32768.0f));
}
StackingContextHelper::StackingContextHelper(
const StackingContextHelper& aParentSC, const ActiveScrolledRoot* aAsr,
nsIFrame* aContainerFrame, nsDisplayItem* aContainerItem,
wr::DisplayListBuilder& aBuilder, const wr::StackingContextParams& aParams,
const LayoutDeviceRect& aBounds)
: mBuilder(&aBuilder),
mScale(1.0f, 1.0f),
mDeferredTransformItem(aParams.mDeferredTransformItem),
mRasterizeLocally(aParams.mRasterizeLocally ||
aParentSC.mRasterizeLocally) {
MOZ_ASSERT(!aContainerItem || aContainerItem->CreatesStackingContextHelper());
mOrigin = aParentSC.mOrigin + aBounds.TopLeft();
// Compute scale for fallback rendering. We don't try to guess a scale for 3d
// transformed items
if (aParams.mBoundTransform) {
gfx::Matrix transform2d;
bool canDraw2D = aParams.mBoundTransform->CanDraw2D(&transform2d);
if (canDraw2D &&
aParams.reference_frame_kind != wr::WrReferenceFrameKind::Perspective &&
!aContainerFrame->Combines3DTransformWithAncestors()) {
mInheritedTransform = transform2d * aParentSC.mInheritedTransform;
int32_t apd = aContainerFrame->PresContext()->AppUnitsPerDevPixel();
nsRect r = LayoutDevicePixel::ToAppUnits(aBounds, apd);
mScale = ChooseScale(aContainerFrame, aContainerItem, r,
aParentSC.mScale.xScale, aParentSC.mScale.yScale,
transform2d,
/* aCanDraw2D = */ true);
} else {
mScale = gfx::MatrixScales(1.0f, 1.0f);
mInheritedTransform = gfx::Matrix::Scaling(1.f, 1.f);
}
if (aParams.mAnimated) {
mSnappingSurfaceTransform = gfx::Matrix::Scaling(mScale);
} else {
mSnappingSurfaceTransform =
transform2d * aParentSC.mSnappingSurfaceTransform;
}
} else if (aParams.reference_frame_kind ==
wr::WrReferenceFrameKind::Transform &&
aContainerItem &&
aContainerItem->GetType() == DisplayItemType::TYPE_ASYNC_ZOOM &&
aContainerItem->Frame()) {
float resolution = aContainerItem->Frame()->PresShell()->GetResolution();
gfx::Matrix transform = gfx::Matrix::Scaling(resolution, resolution);
mInheritedTransform = transform * aParentSC.mInheritedTransform;
mScale =
ScaleFactor<UnknownUnits, UnknownUnits>(resolution) * aParentSC.mScale;
MOZ_ASSERT(!aParams.mAnimated);
mSnappingSurfaceTransform = transform * aParentSC.mSnappingSurfaceTransform;
} else if (!aAsr && !aContainerFrame && !aContainerItem &&
aParams.mRootReferenceFrame) {
// this is the root stacking context helper
Scale2D resolution;
// If we are in a remote browser, then apply scaling from ancestor browsers
if (mozilla::dom::BrowserChild* browserChild =
mozilla::dom::BrowserChild::GetFrom(
aParams.mRootReferenceFrame->PresShell())) {
resolution = browserChild->GetEffectsInfo().mRasterScale;
}
gfx::Matrix transform =
gfx::Matrix::Scaling(resolution.xScale, resolution.yScale);
mInheritedTransform = transform * aParentSC.mInheritedTransform;
mScale = aParentSC.mScale * resolution;
MOZ_ASSERT(!aParams.mAnimated);
mSnappingSurfaceTransform = transform * aParentSC.mSnappingSurfaceTransform;
} else {
mInheritedTransform = aParentSC.mInheritedTransform;
mScale = aParentSC.mScale;
}
auto rasterSpace =
mRasterizeLocally
? wr::RasterSpace::Local(std::max(mScale.xScale, mScale.yScale))
: wr::RasterSpace::Screen();
MOZ_ASSERT(!aParams.clip.IsNone());
mReferenceFrameId = mBuilder->PushStackingContext(
aParams, wr::ToLayoutRect(aBounds), rasterSpace);
if (mReferenceFrameId) {
mSpaceAndClipChainHelper.emplace(aBuilder, mReferenceFrameId.ref());
}
mAffectsClipPositioning =
mReferenceFrameId.isSome() || (aBounds.TopLeft() != LayoutDevicePoint());
// If the parent stacking context has a deferred transform item, inherit it
// into this stacking context, as long as the ASR hasn't changed. Refer to
// the comments on StackingContextHelper::mDeferredTransformItem for an
// explanation of what goes in these fields.
if (aParentSC.mDeferredTransformItem &&
aAsr == aParentSC.mDeferredTransformItem->GetActiveScrolledRoot()) {
if (mDeferredTransformItem) {
// If we are deferring another transform, put the combined transform from
// all the ancestor deferred items into mDeferredAncestorTransform
mDeferredAncestorTransform = aParentSC.GetDeferredTransformMatrix();
} else {
// We are not deferring another transform, so we can just inherit the
// parent stacking context's deferred data without any modification.
mDeferredTransformItem = aParentSC.mDeferredTransformItem;
mDeferredAncestorTransform = aParentSC.mDeferredAncestorTransform;
}
}
}
StackingContextHelper::~StackingContextHelper() {
if (mBuilder) {
mSpaceAndClipChainHelper.reset();
mBuilder->PopStackingContext(mReferenceFrameId.isSome());
}
}
nsDisplayTransform* StackingContextHelper::GetDeferredTransformItem() const {
return mDeferredTransformItem;
}
Maybe<gfx::Matrix4x4> StackingContextHelper::GetDeferredTransformMatrix()
const {
if (mDeferredTransformItem) {
// See the comments on StackingContextHelper::mDeferredTransformItem for
// an explanation of what's stored in mDeferredTransformItem and
// mDeferredAncestorTransform. Here we need to return the combined transform
// transform from all the deferred ancestors, including
// mDeferredTransformItem.
gfx::Matrix4x4 result = mDeferredTransformItem->GetTransform().GetMatrix();
if (mDeferredAncestorTransform) {
result = result * *mDeferredAncestorTransform;
}
return Some(result);
} else {
return Nothing();
}
}
void StackingContextHelper::ClearDeferredTransformItem() const {
mDeferredTransformItem = nullptr;
}
void StackingContextHelper::RestoreDeferredTransformItem(
nsDisplayTransform* aItem) const {
mDeferredTransformItem = aItem;
}
} // namespace layers
} // namespace mozilla