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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/MotionPathUtils.h"
#include "gfxPlatform.h"
#include "mozilla/dom/SVGGeometryElement.h"
#include "mozilla/dom/SVGPathData.h"
#include "mozilla/dom/SVGViewportElement.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/gfx/Matrix.h"
#include "mozilla/layers/LayersMessages.h"
#include "mozilla/RefPtr.h"
#include "mozilla/SVGObserverUtils.h"
#include "mozilla/ShapeUtils.h"
#include "nsIFrame.h"
#include "nsLayoutUtils.h"
#include "nsStyleTransformMatrix.h"
#include <math.h>
namespace mozilla {
using nsStyleTransformMatrix::TransformReferenceBox;
/* static */
CSSPoint MotionPathUtils::ComputeAnchorPointAdjustment(const nsIFrame& aFrame) {
if (!aFrame.HasAnyStateBits(NS_FRAME_SVG_LAYOUT)) {
return {};
}
auto transformBox = aFrame.StyleDisplay()->mTransformBox;
if (transformBox == StyleTransformBox::ViewBox ||
transformBox == StyleTransformBox::BorderBox) {
return {};
}
if (aFrame.IsSVGContainerFrame()) {
nsRect boxRect = nsLayoutUtils::ComputeSVGReferenceRect(
const_cast<nsIFrame*>(&aFrame), StyleGeometryBox::FillBox);
return CSSPoint::FromAppUnits(boxRect.TopLeft());
}
return CSSPoint::FromAppUnits(aFrame.GetPosition());
}
// Convert the StyleCoordBox into the StyleGeometryBox in CSS layout.
static StyleGeometryBox CoordBoxToGeometryBoxInCSSLayout(
StyleCoordBox aCoordBox) {
switch (aCoordBox) {
case StyleCoordBox::ContentBox:
return StyleGeometryBox::ContentBox;
case StyleCoordBox::PaddingBox:
return StyleGeometryBox::PaddingBox;
case StyleCoordBox::BorderBox:
return StyleGeometryBox::BorderBox;
case StyleCoordBox::FillBox:
return StyleGeometryBox::ContentBox;
case StyleCoordBox::StrokeBox:
case StyleCoordBox::ViewBox:
return StyleGeometryBox::BorderBox;
}
MOZ_ASSERT_UNREACHABLE("Unknown coord-box type");
return StyleGeometryBox::BorderBox;
}
/* static */
const nsIFrame* MotionPathUtils::GetOffsetPathReferenceBox(
const nsIFrame* aFrame, nsRect& aOutputRect) {
const StyleOffsetPath& offsetPath = aFrame->StyleDisplay()->mOffsetPath;
if (offsetPath.IsNone()) {
return nullptr;
}
if (aFrame->HasAnyStateBits(NS_FRAME_SVG_LAYOUT)) {
MOZ_ASSERT(aFrame->GetContent()->IsSVGElement());
auto* viewportElement =
dom::SVGElement::FromNode(aFrame->GetContent())->GetCtx();
aOutputRect = nsLayoutUtils::ComputeSVGOriginBox(viewportElement);
return viewportElement ? viewportElement->GetPrimaryFrame() : nullptr;
}
const nsIFrame* containingBlock = aFrame->GetContainingBlock();
const StyleCoordBox coordBox = offsetPath.IsCoordBox()
? offsetPath.AsCoordBox()
: offsetPath.AsOffsetPath().coord_box;
aOutputRect = nsLayoutUtils::ComputeHTMLReferenceRect(
containingBlock, CoordBoxToGeometryBoxInCSSLayout(coordBox));
return containingBlock;
}
/* static */
CSSCoord MotionPathUtils::GetRayContainReferenceSize(nsIFrame* aFrame) {
// We use the border-box size to calculate the reduced path length when using
// "contain" keyword.
//
// Note: Per the spec, border-box is treated as stroke-box in the SVG context,
// To calculate stroke bounds for an element with `non-scaling-stroke` we
// need to resolve its transform to its outer-svg, but to resolve that
// transform when it has `transform-box:stroke-box` (or `border-box`)
// may require its stroke bounds. There's no ideal way to break this
// cyclical dependency, but we break it by using the FillBox.
const auto size = CSSSize::FromAppUnits(
(aFrame->HasAnyStateBits(NS_FRAME_SVG_LAYOUT)
? nsLayoutUtils::ComputeSVGReferenceRect(
aFrame,
aFrame->StyleSVGReset()->HasNonScalingStroke()
? StyleGeometryBox::FillBox
: StyleGeometryBox::StrokeBox,
nsLayoutUtils::MayHaveNonScalingStrokeCyclicDependency::Yes)
: nsLayoutUtils::ComputeHTMLReferenceRect(
aFrame, StyleGeometryBox::BorderBox))
.Size());
return std::max(size.width, size.height);
}
/* static */
nsTArray<nscoord> MotionPathUtils::ComputeBorderRadii(
const StyleBorderRadius& aBorderRadius, const nsRect& aCoordBox) {
const nsRect insetRect = ShapeUtils::ComputeInsetRect(
StyleRect<LengthPercentage>::WithAllSides(LengthPercentage::Zero()),
aCoordBox);
nsTArray<nscoord> result(8);
result.SetLength(8);
if (!ShapeUtils::ComputeRectRadii(aBorderRadius, aCoordBox, insetRect,
result.Elements())) {
result.Clear();
}
return result;
}
// The distance is measured between the origin and the intersection of the ray
// with the reference box of the containing block.
// Note: |aOrigin| and |aContaingBlock| should be in the same coordinate system
// (i.e. the nsIFrame::mRect of the containing block).
static CSSCoord ComputeSides(const CSSPoint& aOrigin,
const CSSRect& aContainingBlock,
const StyleAngle& aAngle) {
const CSSPoint& topLeft = aContainingBlock.TopLeft();
// 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)
// (topLeft) #--------*-----*--# (aContainingBlock.XMost(), topLeft.y)
// | | / |
// | | / |
// | b h |
// | |t/ |
// | |/ |
// (aOrigin) *---b'---* (aContainingBlock.XMost(), aOrigin.y)
// | | |
// | | |
// | | |
// | | |
// | | |
// #-----------------# (aContainingBlock.XMost(),
// (topLeft.x, aContainingBlock.YMost())
// aContainingBlock.YMost())
const double theta = aAngle.ToRadians();
double sint = std::sin(theta);
double cost = std::cos(theta);
const double b = cost >= 0 ? aOrigin.y.value - topLeft.y
: aContainingBlock.YMost() - aOrigin.y.value;
const double bPrime = sint >= 0 ? aContainingBlock.XMost() - aOrigin.x.value
: aOrigin.x.value - topLeft.x;
sint = std::fabs(sint);
cost = std::fabs(cost);
// The trigonometric formula here doesn't work well if |theta| is 0deg or
// 90deg, so we handle these edge cases first.
if (sint < std::numeric_limits<double>::epsilon()) {
// For 0deg (or 180deg), we use |b| directly.
return static_cast<float>(b);
}
if (cost < std::numeric_limits<double>::epsilon()) {
// For 90deg (or 270deg), we use |bPrime| directly. This can also avoid 0/0
// if both |b| and |cost| are 0.0. (i.e. b / cost).
return static_cast<float>(bPrime);
}
// Note: The following formula works well only when 0 < theta < 90deg. So we
// handle 0deg and 90deg above first.
//
// 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;
}
// Compute the position of "at <position>" together with offset starting
// position (i.e. offset-position).
static nsPoint ComputePosition(const StylePositionOrAuto& aAtPosition,
const StyleOffsetPosition& aOffsetPosition,
const nsRect& aCoordBox,
const nsPoint& aCurrentCoord) {
if (aAtPosition.IsPosition()) {
// Resolve this by using the <position> to position a 0x0 object area within
// the box’s containing block.
return ShapeUtils::ComputePosition(aAtPosition.AsPosition(), aCoordBox);
}
MOZ_ASSERT(aAtPosition.IsAuto(), "\"at <position>\" should be omitted");
// Use the offset starting position of the element, given by offset-position.
if (aOffsetPosition.IsPosition()) {
return ShapeUtils::ComputePosition(aOffsetPosition.AsPosition(), aCoordBox);
}
if (aOffsetPosition.IsNormal()) {
// If the element doesn’t have an offset starting position either, it
// behaves as at center.
const StylePosition& center = StylePosition::FromPercentage(0.5);
return ShapeUtils::ComputePosition(center, aCoordBox);
}
MOZ_ASSERT(aOffsetPosition.IsAuto());
return aCurrentCoord;
}
static CSSCoord ComputeRayPathLength(const StyleRaySize aRaySizeType,
const StyleAngle& aAngle,
const CSSPoint& aOrigin,
const CSSRect& aContainingBlock) {
if (aRaySizeType == StyleRaySize::Sides) {
// If the initial position is not within the box, the distance is 0.
//
// Note: If the origin is at XMost() (and/or YMost()), we should consider it
// to be inside containing block (because we expect 100% x (or y) coordinate
// is still to be considered inside the containing block.
if (!aContainingBlock.ContainsInclusively(aOrigin)) {
return 0.0;
}
return ComputeSides(aOrigin, aContainingBlock, aAngle);
}
// left: the length between the origin and the left side.
// right: the length between the origin and the right side.
// top: the length between the origin and the top side.
// bottom: the lenght between the origin and the bottom side.
const CSSPoint& topLeft = aContainingBlock.TopLeft();
const CSSCoord left = std::abs(aOrigin.x - topLeft.x);
const CSSCoord right = std::abs(aContainingBlock.XMost() - aOrigin.x);
const CSSCoord top = std::abs(aOrigin.y - topLeft.y);
const CSSCoord bottom = std::abs(aContainingBlock.YMost() - aOrigin.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);
}
case StyleRaySize::Sides:
MOZ_ASSERT_UNREACHABLE("Unsupported ray size");
}
return 0.0;
}
static CSSCoord ComputeRayUsedDistance(
const StyleRayFunction& aRay, const LengthPercentage& aDistance,
const CSSCoord& aPathLength, const CSSCoord& aRayContainReferenceLength) {
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.
return std::max((usedDistance - aRayContainReferenceLength / 2.0f).value,
0.0f);
}
/* static */
Maybe<ResolvedMotionPathData> MotionPathUtils::ResolveMotionPath(
const OffsetPathData& aPath, const LengthPercentage& aDistance,
const StyleOffsetRotate& aRotate, const StylePositionOrAuto& aAnchor,
const StyleOffsetPosition& aPosition, 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.IsShape()) {
const auto& data = aPath.AsShape();
RefPtr<gfx::Path> path = data.mGfxPath;
MOZ_ASSERT(path, "The empty path is not allowed");
// 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->ComputeLength();
gfx::Float usedDistance =
aDistance.ResolveToCSSPixels(CSSCoord(pathLength));
if (data.mIsClosedLoop) {
// 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.
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 = std::clamp(usedDistance, 0.0f, pathLength);
}
gfx::Point tangent;
point = path->ComputePointAtLength(usedDistance, &tangent);
// Basically, |point| should be a relative distance between the current
// position and the target position. The built |path| is in the coordinate
// system of its containing block. Therefore, we have to take the current
// position of this box into account to offset the translation so it's final
// position is not affected by other boxes in the same containing block.
point -= NSPointToPoint(data.mCurrentPosition, AppUnitsPerCSSPixel());
// If the path length is 0, it's unlikely to get a valid tangent angle, e.g.
// it may be (0, 0). And so we may get an undefined value from atan2().
// Therefore, we use 0rad as the default behavior.
directionAngle =
pathLength < std::numeric_limits<gfx::Float>::epsilon()
? 0.0
: atan2((double)tangent.y, (double)tangent.x); // in Radian.
} else if (aPath.IsRay()) {
const auto& ray = aPath.AsRay();
MOZ_ASSERT(ray.mRay);
// Compute the origin, where the ray’s line begins (the 0% position).
const CSSPoint origin = CSSPoint::FromAppUnits(ComputePosition(
ray.mRay->position, aPosition, ray.mCoordBox, ray.mCurrentPosition));
const CSSCoord pathLength =
ComputeRayPathLength(ray.mRay->size, ray.mRay->angle, origin,
CSSRect::FromAppUnits(ray.mCoordBox));
const CSSCoord usedDistance = ComputeRayUsedDistance(
*ray.mRay, aDistance, pathLength, ray.mContainReferenceLength);
// 0deg pointing up and positive angles representing clockwise rotation.
directionAngle =
StyleAngle{ray.mRay->angle.ToDegrees() - 90.0f}.ToRadians();
// The vector from the current position of this box to the origin of this
// polar coordinate system.
const gfx::Point vectorToOrigin =
(origin - CSSPoint::FromAppUnits(ray.mCurrentPosition))
.ToUnknownPoint();
// |vectorToOrigin| + The vector from the origin to this polar coordinate,
// (|usedDistance|, |directionAngle|), i.e. the vector from the current
// position to this polar coordinate.
point =
vectorToOrigin +
gfx::Point(usedDistance * static_cast<gfx::Float>(cos(directionAngle)),
usedDistance * static_cast<gfx::Float>(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.
// 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 inline bool IsClosedLoop(const StyleSVGPathData& aPathData) {
return !aPathData._0.AsSpan().empty() &&
aPathData._0.AsSpan().rbegin()->IsClose();
}
// Create a path for "inset(0 round X)", where X is the value of border-radius
// on the element that establishes the containing block for this element.
static already_AddRefed<gfx::Path> BuildSimpleInsetPath(
const StyleBorderRadius& aBorderRadius, const nsRect& aCoordBox,
gfx::PathBuilder* aPathBuilder) {
if (!aPathBuilder) {
return nullptr;
}
const nsRect insetRect = ShapeUtils::ComputeInsetRect(
StyleRect<LengthPercentage>::WithAllSides(LengthPercentage::Zero()),
aCoordBox);
nscoord radii[8];
const bool hasRadii =
ShapeUtils::ComputeRectRadii(aBorderRadius, aCoordBox, insetRect, radii);
return ShapeUtils::BuildRectPath(insetRect, hasRadii ? radii : nullptr,
aCoordBox, AppUnitsPerCSSPixel(),
aPathBuilder);
}
// Create a path for `path("m 0 0")`, which is the default URL path if we cannot
// resolve a SVG shape element.
static already_AddRefed<gfx::Path> BuildDefaultPathForURL(
gfx::PathBuilder* aBuilder) {
if (!aBuilder) {
return nullptr;
}
Array<const StylePathCommand, 1> array(StylePathCommand::Move(
StyleByTo::By, StyleCoordinatePair<StyleCSSFloat>{0.0, 0.0}));
return SVGPathData::BuildPath(array, aBuilder, StyleStrokeLinecap::Butt, 0.0);
}
// Generate data for motion path on the main thread.
static OffsetPathData GenerateOffsetPathData(const nsIFrame* aFrame) {
const StyleOffsetPath& offsetPath = aFrame->StyleDisplay()->mOffsetPath;
if (offsetPath.IsNone()) {
return OffsetPathData::None();
}
// Handle ray().
if (offsetPath.IsRay()) {
nsRect coordBox;
const nsIFrame* containingBlockFrame =
MotionPathUtils::GetOffsetPathReferenceBox(aFrame, coordBox);
return !containingBlockFrame
? OffsetPathData::None()
: OffsetPathData::Ray(
offsetPath.AsRay(), std::move(coordBox),
aFrame->GetOffsetTo(containingBlockFrame),
MotionPathUtils::GetRayContainReferenceSize(
const_cast<nsIFrame*>(aFrame)));
}
// Handle path(). We cache it so we handle it separately.
// cache all basic shapes, we can merge this branch into other basic shapes.
if (offsetPath.IsPath()) {
const StyleSVGPathData& pathData = offsetPath.AsSVGPathData();
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");
// to give it the current box position.
return OffsetPathData::Shape(gfxPath.forget(), {}, IsClosedLoop(pathData));
}
nsRect coordBox;
const nsIFrame* containingFrame =
MotionPathUtils::GetOffsetPathReferenceBox(aFrame, coordBox);
if (!containingFrame || coordBox.IsEmpty()) {
return OffsetPathData::None();
}
nsPoint currentPosition = aFrame->GetOffsetTo(containingFrame);
RefPtr<gfx::PathBuilder> builder = MotionPathUtils::GetPathBuilder();
if (offsetPath.IsUrl()) {
dom::SVGGeometryElement* element =
SVGObserverUtils::GetAndObserveGeometry(const_cast<nsIFrame*>(aFrame));
if (!element) {
// Note: This behaves as path("m 0 0") (a <basic-shape>).
RefPtr<gfx::Path> path = BuildDefaultPathForURL(builder);
// to give it the current box position.
return path ? OffsetPathData::Shape(path.forget(), {}, false)
: OffsetPathData::None();
}
// We just need this path to calculate the specific point and direction
// angle, so use measuring function and get the benefit of caching the path
// in the SVG shape element.
RefPtr<gfx::Path> path = element->GetOrBuildPathForMeasuring();
// The built |path| from SVG shape element doesn't take |coordBox| into
// account. It uses the SVG viewport as its coordinate system. So after
// mapping it into the CSS layout, we should use |coordBox| as its viewport
// and user coordinate system. |currentPosition| is based on the border-box
// of the containing block. Therefore, we have to apply an extra translation
// to put it at the correct position based on |coordBox|.
//
// Note: we reuse |OffsetPathData::ShapeData::mCurrentPosition| to include
// this extra translation, so we don't have to add an extra field.
nsPoint positionInCoordBox = currentPosition - coordBox.TopLeft();
return path ? OffsetPathData::Shape(path.forget(),
std::move(positionInCoordBox),
element->IsClosedLoop())
: OffsetPathData::None();
}
// The rest part is to handle "<basic-shape> || <coord-box>".
MOZ_ASSERT(offsetPath.IsBasicShapeOrCoordBox());
const nsStyleDisplay* disp = aFrame->StyleDisplay();
RefPtr<gfx::Path> path =
disp->mOffsetPath.IsCoordBox()
? BuildSimpleInsetPath(containingFrame->StyleBorder()->mBorderRadius,
coordBox, builder)
: MotionPathUtils::BuildPath(
disp->mOffsetPath.AsOffsetPath().path->AsShape(),
disp->mOffsetPosition, coordBox, currentPosition, builder);
return path ? OffsetPathData::Shape(path.forget(), std::move(currentPosition),
true)
: 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, display->mOffsetPosition,
transformOrigin, aRefBox, ComputeAnchorPointAdjustment(*aFrame));
}
// Generate data for motion path on the compositor thread.
static OffsetPathData GenerateOffsetPathData(
const StyleOffsetPath& aOffsetPath,
const StyleOffsetPosition& aOffsetPosition,
const layers::MotionPathData& aMotionPathData,
gfx::Path* aCachedMotionPath) {
if (aOffsetPath.IsNone()) {
return OffsetPathData::None();
}
// Handle ray().
if (aOffsetPath.IsRay()) {
return aMotionPathData.coordBox().IsEmpty()
? OffsetPathData::None()
: OffsetPathData::Ray(
aOffsetPath.AsRay(), aMotionPathData.coordBox(),
aMotionPathData.currentPosition(),
aMotionPathData.rayContainReferenceLength());
}
// Handle path().
if (aOffsetPath.IsPath()) {
const StyleSVGPathData& pathData = aOffsetPath.AsSVGPathData();
// 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::BuildSVGPath(pathData, builder);
}
// to give it the current box position.
return OffsetPathData::Shape(path.forget(), {}, IsClosedLoop(pathData));
}
// The rest part is to handle "<basic-shape> || <coord-box>".
MOZ_ASSERT(aOffsetPath.IsBasicShapeOrCoordBox());
const nsRect& coordBox = aMotionPathData.coordBox();
if (coordBox.IsEmpty()) {
return OffsetPathData::None();
}
RefPtr<gfx::PathBuilder> builder =
MotionPathUtils::GetCompositorPathBuilder();
if (!builder) {
return OffsetPathData::None();
}
RefPtr<gfx::Path> path;
if (aOffsetPath.IsCoordBox()) {
const nsRect insetRect = ShapeUtils::ComputeInsetRect(
StyleRect<LengthPercentage>::WithAllSides(LengthPercentage::Zero()),
coordBox);
const nsTArray<nscoord>& radii = aMotionPathData.coordBoxInsetRadii();
path = ShapeUtils::BuildRectPath(
insetRect, radii.IsEmpty() ? nullptr : radii.Elements(), coordBox,
AppUnitsPerCSSPixel(), builder);
} else {
path = MotionPathUtils::BuildPath(
aOffsetPath.AsOffsetPath().path->AsShape(), aOffsetPosition, coordBox,
aMotionPathData.currentPosition(), builder);
}
return path ? OffsetPathData::Shape(
path.forget(), nsPoint(aMotionPathData.currentPosition()),
true)
: OffsetPathData::None();
}
/* static */
Maybe<ResolvedMotionPathData> MotionPathUtils::ResolveMotionPath(
const StyleOffsetPath* aPath, const StyleLengthPercentage* aDistance,
const StyleOffsetRotate* aRotate, const StylePositionOrAuto* aAnchor,
const StyleOffsetPosition* aPosition,
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();
auto autoOffsetPosition = StyleOffsetPosition::Auto();
return ResolveMotionPath(
GenerateOffsetPathData(*aPath,
aPosition ? *aPosition : autoOffsetPosition,
*aMotionPathData, aCachedMotionPath),
aDistance ? *aDistance : zeroOffsetDistance,
aRotate ? *aRotate : autoOffsetRotate,
aAnchor ? *aAnchor : autoOffsetAnchor,
aPosition ? *aPosition : autoOffsetPosition, aMotionPathData->origin(),
aRefBox, aMotionPathData->anchorAdjustment());
}
/* static */
already_AddRefed<gfx::Path> MotionPathUtils::BuildSVGPath(
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::Path> BuildShape(
const Span<const StyleShapeCommand>& aShape, gfx::PathBuilder* aPathBuilder,
const nsRect& aCoordBox) {
if (!aPathBuilder) {
return nullptr;
}
// For motion path, we always use CSSPixel unit to compute the offset
// transform (i.e. motion path transform).
const auto rect = CSSRect::FromAppUnits(aCoordBox);
return SVGPathData::BuildPath(aShape, aPathBuilder, StyleStrokeLinecap::Butt,
0.0, rect.Size(),
rect.TopLeft().ToUnknownPoint());
}
/* static */
already_AddRefed<gfx::Path> MotionPathUtils::BuildPath(
const StyleBasicShape& aBasicShape,
const StyleOffsetPosition& aOffsetPosition, const nsRect& aCoordBox,
const nsPoint& aCurrentPosition, gfx::PathBuilder* aPathBuilder) {
if (!aPathBuilder) {
return nullptr;
}
switch (aBasicShape.tag) {
case StyleBasicShape::Tag::Circle: {
const nsPoint center =
ComputePosition(aBasicShape.AsCircle().position, aOffsetPosition,
aCoordBox, aCurrentPosition);
return ShapeUtils::BuildCirclePath(aBasicShape, aCoordBox, center,
AppUnitsPerCSSPixel(), aPathBuilder);
}
case StyleBasicShape::Tag::Ellipse: {
const nsPoint center =
ComputePosition(aBasicShape.AsEllipse().position, aOffsetPosition,
aCoordBox, aCurrentPosition);
return ShapeUtils::BuildEllipsePath(aBasicShape, aCoordBox, center,
AppUnitsPerCSSPixel(), aPathBuilder);
}
case StyleBasicShape::Tag::Rect:
return ShapeUtils::BuildInsetPath(aBasicShape, aCoordBox,
AppUnitsPerCSSPixel(), aPathBuilder);
case StyleBasicShape::Tag::Polygon:
return ShapeUtils::BuildPolygonPath(aBasicShape, aCoordBox,
AppUnitsPerCSSPixel(), aPathBuilder);
case StyleBasicShape::Tag::PathOrShape: {
// to also check its containing block as well. For now, we are still
// building its gfx::Path directly by its SVGPathData without other
const auto& pathOrShape = aBasicShape.AsPathOrShape();
if (pathOrShape.IsPath()) {
return BuildSVGPath(pathOrShape.AsPath().path, aPathBuilder);
}
// Note that shape() always defines the initial position, i.e. "from x y",
// by its first move command, so |aOffsetPosition|, i.e. offset-position
// property, is ignored.
return BuildShape(pathOrShape.AsShape().commands.AsSpan(), aPathBuilder,
aCoordBox);
}
}
return nullptr;
}
/* static */
already_AddRefed<gfx::PathBuilder> MotionPathUtils::GetPathBuilder() {
// Here we only need to build a valid path for motion path, so
// using the default values of stroke-width, stoke-linecap, and fill-rule
// is fine for now because what we want is to get the point and its normal
// vector along the path, instead of rendering it.
RefPtr<gfx::PathBuilder> builder =
gfxPlatform::GetPlatform()
->ScreenReferenceDrawTarget()
->CreatePathBuilder(gfx::FillRule::FILL_WINDING);
return builder.forget();
}
/* 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