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-rw-r--r--layout/base/MotionPathUtils.cpp428
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diff --git a/layout/base/MotionPathUtils.cpp b/layout/base/MotionPathUtils.cpp
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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
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/MotionPathUtils.h"
+
+#include "gfxPlatform.h"
+#include "mozilla/dom/SVGPathData.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/Matrix.h"
+#include "mozilla/layers/LayersMessages.h"
+#include "mozilla/RefPtr.h"
+#include "nsIFrame.h"
+#include "nsLayoutUtils.h"
+#include "nsStyleTransformMatrix.h"
+
+#include <math.h>
+
+namespace mozilla {
+
+using nsStyleTransformMatrix::TransformReferenceBox;
+
+RayReferenceData::RayReferenceData(const nsIFrame* aFrame) {
+ // FIXME: Bug 1581237: Should use view-box for the SVG context.
+ const nsIFrame* container = aFrame->GetContainingBlock();
+ if (!container) {
+ // If there is no parent frame, it's impossible to calculate the path
+ // length, so does the path.
+ return;
+ }
+
+ // The initial position is (0, 0) in |aFrame|, and we have to transform it
+ // into the space of |container|, so use GetOffsetsTo() to get the delta
+ // value.
+ // FIXME: Bug 1559232: The initial position will be adjusted by offset
+ // starting position.
+ // https://drafts.fxtf.org/motion-1/#offset-position-property
+ mInitialPosition = CSSPoint::FromAppUnits(aFrame->GetOffsetTo(container));
+ // FIXME: Bug 1581237: We should use <coord-box> as the box of its containing
+ // block. https://drafts.fxtf.org/motion-1/#valdef-offset-path-coord-box
+ mContainingBlockRect =
+ CSSRect::FromAppUnits(container->GetRectRelativeToSelf());
+ // We use the border-box size to calculate the reduced path length when using
+ // "contain" keyword.
+ // https://drafts.fxtf.org/motion-1/#valdef-ray-contain
+ //
+ // Note: Per the spec, border-box is treated as stroke-box in the SVG context,
+ // Also, SVGUtils::GetBBox() may cache the box via the frame property, so we
+ // have to do const-casting.
+ // https://drafts.csswg.org/css-box-4/#valdef-box-border-box
+ mBorderBoxSize = CSSSize::FromAppUnits(
+ nsLayoutUtils::ComputeGeometryBox(const_cast<nsIFrame*>(aFrame),
+ // StrokeBox and BorderBox are in the
+ // same switch case for CSS context.
+ StyleGeometryBox::StrokeBox)
+ .Size());
+}
+
+// The distance is measured between the initial position and the intersection of
+// the ray with the box
+// https://drafts.fxtf.org/motion-1/#size-sides
+static CSSCoord ComputeSides(const CSSPoint& aInitialPosition,
+ const CSSSize& aContainerSize,
+ const StyleAngle& aAngle) {
+ // Given an acute angle |theta| (i.e. |t|) of a right-angled triangle, the
+ // hypotenuse |h| is the side that connects the two acute angles. The side
+ // |b| adjacent to |theta| is the side of the triangle that connects |theta|
+ // to the right angle.
+ //
+ // e.g. if the angle |t| is 0 ~ 90 degrees, and b * tan(theta) <= b',
+ // h = b / cos(t):
+ // b*tan(t)
+ // (0, 0) #--------*-----*--# (aContainerSize.width, 0)
+ // | | / |
+ // | | / |
+ // | b h |
+ // | |t/ |
+ // | |/ |
+ // (aInitialPosition) *---b'---* (aContainerSize.width, aInitialPosition.y)
+ // | | |
+ // | | |
+ // | | |
+ // | | |
+ // | | |
+ // #-----------------# (aContainerSize.width,
+ // (0, aContainerSize.height) aContainerSize.height)
+ double theta = aAngle.ToRadians();
+ double sint = std::sin(theta);
+ double cost = std::cos(theta);
+
+ double b = cost >= 0 ? aInitialPosition.y.value
+ : aContainerSize.height - aInitialPosition.y.value;
+ double bPrime = sint >= 0 ? aContainerSize.width - aInitialPosition.x.value
+ : aInitialPosition.x.value;
+ sint = std::fabs(sint);
+ cost = std::fabs(cost);
+
+ // If |b * tan(theta)| is larger than |bPrime|, the intersection is
+ // on the other side, and |b'| is the opposite side of angle |theta| in this
+ // case.
+ //
+ // e.g. If b * tan(theta) > b', h = b' / sin(theta):
+ // *----*
+ // | |
+ // | /|
+ // b /t|
+ // |t/ |
+ // |/ |
+ // *-b'-*
+ if (b * sint > bPrime * cost) {
+ return bPrime / sint;
+ }
+ return b / cost;
+}
+
+static CSSCoord ComputeRayPathLength(const StyleRaySize aRaySizeType,
+ const StyleAngle& aAngle,
+ const RayReferenceData& aRayData) {
+ if (aRaySizeType == StyleRaySize::Sides) {
+ // If the initial position is not within the box, the distance is 0.
+ if (!aRayData.mContainingBlockRect.Contains(aRayData.mInitialPosition)) {
+ return 0.0;
+ }
+
+ return ComputeSides(aRayData.mInitialPosition,
+ aRayData.mContainingBlockRect.Size(), aAngle);
+ }
+
+ // left: the length between the initial point and the left side.
+ // right: the length between the initial point and the right side.
+ // top: the length between the initial point and the top side.
+ // bottom: the lenght between the initial point and the bottom side.
+ CSSCoord left = std::abs(aRayData.mInitialPosition.x);
+ CSSCoord right = std::abs(aRayData.mContainingBlockRect.width -
+ aRayData.mInitialPosition.x);
+ CSSCoord top = std::abs(aRayData.mInitialPosition.y);
+ CSSCoord bottom = std::abs(aRayData.mContainingBlockRect.height -
+ aRayData.mInitialPosition.y);
+
+ switch (aRaySizeType) {
+ case StyleRaySize::ClosestSide:
+ return std::min({left, right, top, bottom});
+
+ case StyleRaySize::FarthestSide:
+ return std::max({left, right, top, bottom});
+
+ case StyleRaySize::ClosestCorner:
+ case StyleRaySize::FarthestCorner: {
+ CSSCoord h = 0;
+ CSSCoord v = 0;
+ if (aRaySizeType == StyleRaySize::ClosestCorner) {
+ h = std::min(left, right);
+ v = std::min(top, bottom);
+ } else {
+ h = std::max(left, right);
+ v = std::max(top, bottom);
+ }
+ return sqrt(h.value * h.value + v.value * v.value);
+ }
+ default:
+ MOZ_ASSERT_UNREACHABLE("Unsupported ray size");
+ }
+
+ return 0.0;
+}
+
+static CSSCoord ComputeRayUsedDistance(const RayFunction& aRay,
+ const LengthPercentage& aDistance,
+ const CSSCoord& aPathLength,
+ const CSSSize& aBorderBoxSize) {
+ CSSCoord usedDistance = aDistance.ResolveToCSSPixels(aPathLength);
+ if (!aRay.contain) {
+ return usedDistance;
+ }
+
+ // The length of the offset path is reduced so that the element stays within
+ // the containing block even at offset-distance: 100%. Specifically, the
+ // path’s length is reduced by half the width or half the height of the
+ // element’s border box, whichever is larger, and floored at zero.
+ // https://drafts.fxtf.org/motion-1/#valdef-ray-contain
+ return std::max(
+ usedDistance -
+ std::max(aBorderBoxSize.width, aBorderBoxSize.height) / 2.0f,
+ 0.0f);
+}
+
+/* static */
+CSSPoint MotionPathUtils::ComputeAnchorPointAdjustment(const nsIFrame& aFrame) {
+ if (!aFrame.HasAnyStateBits(NS_FRAME_SVG_LAYOUT)) {
+ return {};
+ }
+
+ auto transformBox = aFrame.StyleDisplay()->mTransformBox;
+ if (transformBox == StyleGeometryBox::ViewBox ||
+ transformBox == StyleGeometryBox::BorderBox) {
+ return {};
+ }
+
+ if (aFrame.IsFrameOfType(nsIFrame::eSVGContainer)) {
+ nsRect boxRect = nsLayoutUtils::ComputeGeometryBox(
+ const_cast<nsIFrame*>(&aFrame), StyleGeometryBox::FillBox);
+ return CSSPoint::FromAppUnits(boxRect.TopLeft());
+ }
+ return CSSPoint::FromAppUnits(aFrame.GetPosition());
+}
+
+/* static */
+Maybe<ResolvedMotionPathData> MotionPathUtils::ResolveMotionPath(
+ const OffsetPathData& aPath, const LengthPercentage& aDistance,
+ const StyleOffsetRotate& aRotate, const StylePositionOrAuto& aAnchor,
+ const CSSPoint& aTransformOrigin, TransformReferenceBox& aRefBox,
+ const CSSPoint& aAnchorPointAdjustment) {
+ if (aPath.IsNone()) {
+ return Nothing();
+ }
+
+ // Compute the point and angle for creating the equivalent translate and
+ // rotate.
+ double directionAngle = 0.0;
+ gfx::Point point;
+ if (aPath.IsPath()) {
+ const auto& path = aPath.AsPath();
+ if (!path.mGfxPath) {
+ // Empty gfx::Path means it is path('') (i.e. empty path string).
+ return Nothing();
+ }
+
+ // Per the spec, we have to convert offset distance to pixels, with 100%
+ // being converted to total length. So here |gfxPath| is built with CSS
+ // pixel, and we calculate |pathLength| and |computedDistance| with CSS
+ // pixel as well.
+ gfx::Float pathLength = path.mGfxPath->ComputeLength();
+ gfx::Float usedDistance =
+ aDistance.ResolveToCSSPixels(CSSCoord(pathLength));
+ if (path.mIsClosedIntervals) {
+ // Per the spec, let used offset distance be equal to offset distance
+ // modulus the total length of the path. If the total length of the path
+ // is 0, used offset distance is also 0.
+ usedDistance = pathLength > 0.0 ? fmod(usedDistance, pathLength) : 0.0;
+ // We make sure |usedDistance| is 0.0 or a positive value.
+ // https://github.com/w3c/fxtf-drafts/issues/339
+ if (usedDistance < 0.0) {
+ usedDistance += pathLength;
+ }
+ } else {
+ // Per the spec, for unclosed interval, let used offset distance be equal
+ // to offset distance clamped by 0 and the total length of the path.
+ usedDistance = clamped(usedDistance, 0.0f, pathLength);
+ }
+ gfx::Point tangent;
+ point = path.mGfxPath->ComputePointAtLength(usedDistance, &tangent);
+ directionAngle = (double)atan2(tangent.y, tangent.x); // In Radian.
+ } else if (aPath.IsRay()) {
+ const auto& ray = aPath.AsRay();
+ MOZ_ASSERT(ray.mRay);
+
+ CSSCoord pathLength =
+ ComputeRayPathLength(ray.mRay->size, ray.mRay->angle, ray.mData);
+ CSSCoord usedDistance = ComputeRayUsedDistance(
+ *ray.mRay, aDistance, pathLength, ray.mData.mBorderBoxSize);
+
+ // 0deg pointing up and positive angles representing clockwise rotation.
+ directionAngle =
+ StyleAngle{ray.mRay->angle.ToDegrees() - 90.0f}.ToRadians();
+
+ point.x = usedDistance * cos(directionAngle);
+ point.y = usedDistance * sin(directionAngle);
+ } else {
+ MOZ_ASSERT_UNREACHABLE("Unsupported offset-path value");
+ return Nothing();
+ }
+
+ // If |rotate.auto_| is true, the element should be rotated by the angle of
+ // the direction (i.e. directional tangent vector) of the offset-path, and the
+ // computed value of <angle> is added to this.
+ // Otherwise, the element has a constant clockwise rotation transformation
+ // applied to it by the specified rotation angle. (i.e. Don't need to
+ // consider the direction of the path.)
+ gfx::Float angle = static_cast<gfx::Float>(
+ (aRotate.auto_ ? directionAngle : 0.0) + aRotate.angle.ToRadians());
+
+ // Compute the offset for motion path translate.
+ // Bug 1559232: the translate parameters will be adjusted more after we
+ // support offset-position.
+ // Per the spec, the default offset-anchor is `auto`, so initialize the anchor
+ // point to transform-origin.
+ CSSPoint anchorPoint(aTransformOrigin);
+ gfx::Point shift;
+ if (!aAnchor.IsAuto()) {
+ const auto& pos = aAnchor.AsPosition();
+ anchorPoint = nsStyleTransformMatrix::Convert2DPosition(
+ pos.horizontal, pos.vertical, aRefBox);
+ // We need this value to shift the origin from transform-origin to
+ // offset-anchor (and vice versa).
+ // See nsStyleTransformMatrix::ReadTransform for more details.
+ shift = (anchorPoint - aTransformOrigin).ToUnknownPoint();
+ }
+
+ anchorPoint += aAnchorPointAdjustment;
+
+ return Some(ResolvedMotionPathData{point - anchorPoint.ToUnknownPoint(),
+ angle, shift});
+}
+
+static OffsetPathData GenerateOffsetPathData(const nsIFrame* aFrame) {
+ const StyleOffsetPath& path = aFrame->StyleDisplay()->mOffsetPath;
+ switch (path.tag) {
+ case StyleOffsetPath::Tag::Path: {
+ const StyleSVGPathData& pathData = path.AsPath();
+ RefPtr<gfx::Path> gfxPath =
+ aFrame->GetProperty(nsIFrame::OffsetPathCache());
+ MOZ_ASSERT(
+ gfxPath || pathData._0.IsEmpty(),
+ "Should have a valid cached gfx::Path or an empty path string");
+ return OffsetPathData::Path(pathData, gfxPath.forget());
+ }
+ case StyleOffsetPath::Tag::Ray:
+ return OffsetPathData::Ray(path.AsRay(), RayReferenceData(aFrame));
+ case StyleOffsetPath::Tag::None:
+ return OffsetPathData::None();
+ default:
+ MOZ_ASSERT_UNREACHABLE("Unknown offset-path");
+ return OffsetPathData::None();
+ }
+}
+
+/* static*/
+Maybe<ResolvedMotionPathData> MotionPathUtils::ResolveMotionPath(
+ const nsIFrame* aFrame, TransformReferenceBox& aRefBox) {
+ MOZ_ASSERT(aFrame);
+
+ const nsStyleDisplay* display = aFrame->StyleDisplay();
+
+ // FIXME: It's possible to refactor the calculation of transform-origin, so we
+ // could calculate from the caller, and reuse the value in nsDisplayList.cpp.
+ CSSPoint transformOrigin = nsStyleTransformMatrix::Convert2DPosition(
+ display->mTransformOrigin.horizontal, display->mTransformOrigin.vertical,
+ aRefBox);
+
+ return ResolveMotionPath(GenerateOffsetPathData(aFrame),
+ display->mOffsetDistance, display->mOffsetRotate,
+ display->mOffsetAnchor, transformOrigin, aRefBox,
+ ComputeAnchorPointAdjustment(*aFrame));
+}
+
+static OffsetPathData GenerateOffsetPathData(
+ const StyleOffsetPath& aPath, const RayReferenceData& aRayReferenceData,
+ gfx::Path* aCachedMotionPath) {
+ switch (aPath.tag) {
+ case StyleOffsetPath::Tag::Path: {
+ const StyleSVGPathData& pathData = aPath.AsPath();
+ // If aCachedMotionPath is valid, we have a fixed path.
+ // This means we have pre-built it already and no need to update.
+ RefPtr<gfx::Path> path = aCachedMotionPath;
+ if (!path) {
+ RefPtr<gfx::PathBuilder> builder =
+ MotionPathUtils::GetCompositorPathBuilder();
+ path = MotionPathUtils::BuildPath(pathData, builder);
+ }
+ return OffsetPathData::Path(pathData, path.forget());
+ }
+ case StyleOffsetPath::Tag::Ray:
+ return OffsetPathData::Ray(aPath.AsRay(), aRayReferenceData);
+ case StyleOffsetPath::Tag::None:
+ default:
+ return OffsetPathData::None();
+ }
+}
+
+/* static */
+Maybe<ResolvedMotionPathData> MotionPathUtils::ResolveMotionPath(
+ const StyleOffsetPath* aPath, const StyleLengthPercentage* aDistance,
+ const StyleOffsetRotate* aRotate, const StylePositionOrAuto* aAnchor,
+ const Maybe<layers::MotionPathData>& aMotionPathData,
+ TransformReferenceBox& aRefBox, gfx::Path* aCachedMotionPath) {
+ if (!aPath) {
+ return Nothing();
+ }
+
+ MOZ_ASSERT(aMotionPathData);
+
+ auto zeroOffsetDistance = LengthPercentage::Zero();
+ auto autoOffsetRotate = StyleOffsetRotate{true, StyleAngle::Zero()};
+ auto autoOffsetAnchor = StylePositionOrAuto::Auto();
+ return ResolveMotionPath(
+ GenerateOffsetPathData(*aPath, aMotionPathData->rayReferenceData(),
+ aCachedMotionPath),
+ aDistance ? *aDistance : zeroOffsetDistance,
+ aRotate ? *aRotate : autoOffsetRotate,
+ aAnchor ? *aAnchor : autoOffsetAnchor, aMotionPathData->origin(), aRefBox,
+ aMotionPathData->anchorAdjustment());
+}
+
+/* static */
+StyleSVGPathData MotionPathUtils::NormalizeSVGPathData(
+ const StyleSVGPathData& aPath) {
+ StyleSVGPathData n;
+ Servo_SVGPathData_Normalize(&aPath, &n);
+ return n;
+}
+
+/* static */
+already_AddRefed<gfx::Path> MotionPathUtils::BuildPath(
+ const StyleSVGPathData& aPath, gfx::PathBuilder* aPathBuilder) {
+ if (!aPathBuilder) {
+ return nullptr;
+ }
+
+ const Span<const StylePathCommand>& path = aPath._0.AsSpan();
+ return SVGPathData::BuildPath(path, aPathBuilder, StyleStrokeLinecap::Butt,
+ 0.0);
+}
+
+/* static */
+already_AddRefed<gfx::PathBuilder> MotionPathUtils::GetCompositorPathBuilder() {
+ // FIXME: Perhaps we need a PathBuilder which is independent on the backend.
+ RefPtr<gfx::PathBuilder> builder =
+ gfxPlatform::Initialized()
+ ? gfxPlatform::GetPlatform()
+ ->ScreenReferenceDrawTarget()
+ ->CreatePathBuilder(gfx::FillRule::FILL_WINDING)
+ : gfx::Factory::CreateSimplePathBuilder();
+ return builder.forget();
+}
+
+} // namespace mozilla
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