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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
/*
* A class used for intermediate representations of the transform and
* transform-like properties.
*/
#include "nsStyleTransformMatrix.h"
#include "nsLayoutUtils.h"
#include "nsPresContext.h"
#include "mozilla/MotionPathUtils.h"
#include "mozilla/ServoBindings.h"
#include "mozilla/StaticPrefs_layout.h"
#include "mozilla/StyleAnimationValue.h"
#include "mozilla/SVGUtils.h"
#include "gfxMatrix.h"
#include "gfxQuaternion.h"
using namespace mozilla;
using namespace mozilla::gfx;
namespace nsStyleTransformMatrix {
/* Note on floating point precision: The transform matrix is an array
* of single precision 'float's, and so are most of the input values
* we get from the style system, but intermediate calculations
* involving angles need to be done in 'double'.
*/
// Define UNIFIED_CONTINUATIONS here and in nsDisplayList.cpp
// to have the transform property try
// to transform content with continuations as one unified block instead of
// several smaller ones. This is currently disabled because it doesn't work
// correctly, since when the frames are initially being reflowed, their
// continuations all compute their bounding rects independently of each other
// and consequently get the wrong value.
// #define UNIFIED_CONTINUATIONS
static nsRect GetSVGBox(const nsIFrame* aFrame) {
auto computeViewBox = [&]() {
// Percentages in transforms resolve against the width/height of the
// nearest viewport (or its viewBox if one is applied), and the
// transform is relative to {0,0} in current user space.
CSSSize size = CSSSize::FromUnknownSize(SVGUtils::GetContextSize(aFrame));
return nsRect(-aFrame->GetPosition(), CSSPixel::ToAppUnits(size));
};
auto transformBox = aFrame->StyleDisplay()->mTransformBox;
if ((transformBox == StyleTransformBox::StrokeBox ||
transformBox == StyleTransformBox::BorderBox) &&
aFrame->StyleSVGReset()->HasNonScalingStroke()) {
// 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 converting to
// `transform-box:fill-box` here.
transformBox = StyleTransformBox::FillBox;
}
// For SVG elements without associated CSS layout box, the used value for
// content-box is fill-box and for border-box is stroke-box.
switch (transformBox) {
case StyleTransformBox::ContentBox:
case StyleTransformBox::FillBox: {
// Percentages in transforms resolve against the SVG bbox, and the
// transform is relative to the top-left of the SVG bbox.
nsRect bboxInAppUnits = nsLayoutUtils::ComputeSVGReferenceRect(
const_cast<nsIFrame*>(aFrame), StyleGeometryBox::FillBox);
// The mRect of an SVG nsIFrame is its user space bounds *including*
// stroke and markers, whereas bboxInAppUnits is its user space bounds
// including fill only. We need to note the offset of the reference box
// from the frame's mRect in mX/mY.
return {bboxInAppUnits.x - aFrame->GetPosition().x,
bboxInAppUnits.y - aFrame->GetPosition().y, bboxInAppUnits.width,
bboxInAppUnits.height};
}
case StyleTransformBox::BorderBox:
if (!StaticPrefs::layout_css_transform_box_content_stroke_enabled()) {
// If stroke-box is disabled, we shouldn't use it and fall back to
// view-box.
return computeViewBox();
}
[[fallthrough]];
case StyleTransformBox::StrokeBox: {
// We are using SVGUtils::PathExtentsToMaxStrokeExtents() to compute the
// bbox contribution for stroke box (if it doesn't have simple bounds),
// so the |strokeBox| here may be larger than the author's expectation.
// Using Moz2D to compute the tighter bounding box is another way but it
// has some potential issues (see SVGGeometryFrame::GetBBoxContribution()
// for more details), and its result depends on the drawing backend. So
// for now we still rely on our default calcuclation for SVG geometry
// frame reflow code. At least this works for the shape elements which
// have simple bounds.
// SVGGeometryFrame::GetBBoxContribution() to get tighter stroke bounds.
nsRect strokeBox = nsLayoutUtils::ComputeSVGReferenceRect(
const_cast<nsIFrame*>(aFrame), StyleGeometryBox::StrokeBox,
nsLayoutUtils::MayHaveNonScalingStrokeCyclicDependency::Yes);
// The |nsIFrame::mRect| includes markers, so we have to compute the
// offsets without markers.
return nsRect{strokeBox.x - aFrame->GetPosition().x,
strokeBox.y - aFrame->GetPosition().y, strokeBox.width,
strokeBox.height};
}
case StyleTransformBox::ViewBox:
return computeViewBox();
}
MOZ_ASSERT_UNREACHABLE("All transform box should be handled.");
return {};
}
void TransformReferenceBox::EnsureDimensionsAreCached() {
if (mIsCached) {
return;
}
MOZ_ASSERT(mFrame);
mIsCached = true;
if (mFrame->HasAnyStateBits(NS_FRAME_SVG_LAYOUT)) {
mBox = GetSVGBox(mFrame);
return;
}
// For elements with associated CSS layout box, the used value for fill-box is
// content-box and for stroke-box and view-box is border-box.
switch (mFrame->StyleDisplay()->mTransformBox) {
case StyleTransformBox::FillBox:
case StyleTransformBox::ContentBox: {
mBox = mFrame->GetContentRectRelativeToSelf();
return;
}
case StyleTransformBox::StrokeBox:
// TODO: Implement this in the following patches.
return;
case StyleTransformBox::ViewBox:
case StyleTransformBox::BorderBox: {
// If UNIFIED_CONTINUATIONS is not defined, this is simply the frame's
// bounding rectangle, translated to the origin. Otherwise, it is the
// smallest rectangle containing a frame and all of its continuations. For
// example, if there is a <span> element with several continuations split
// over several lines, this function will return the rectangle containing
// all of those continuations.
nsRect rect;
#ifndef UNIFIED_CONTINUATIONS
rect = mFrame->GetRect();
#else
// Iterate the continuation list, unioning together the bounding rects:
for (const nsIFrame* currFrame = mFrame->FirstContinuation();
currFrame != nullptr; currFrame = currFrame->GetNextContinuation()) {
// Get the frame rect in local coordinates, then translate back to the
// original coordinates:
rect.UnionRect(result, nsRect(currFrame->GetOffsetTo(mFrame),
currFrame->GetSize()));
}
#endif
mBox = {0, 0, rect.Width(), rect.Height()};
return;
}
}
}
float ProcessTranslatePart(
const LengthPercentage& aValue, TransformReferenceBox* aRefBox,
TransformReferenceBox::DimensionGetter aDimensionGetter) {
return aValue.ResolveToCSSPixelsWith([&] {
return aRefBox && !aRefBox->IsEmpty()
? CSSPixel::FromAppUnits((aRefBox->*aDimensionGetter)())
: CSSCoord(0);
});
}
/**
* Helper functions to process all the transformation function types.
*
* These take a matrix parameter to accumulate the current matrix.
*/
/* Helper function to process a matrix entry. */
static void ProcessMatrix(Matrix4x4& aMatrix,
const StyleTransformOperation& aOp) {
const auto& matrix = aOp.AsMatrix();
gfxMatrix result;
result._11 = matrix.a;
result._12 = matrix.b;
result._21 = matrix.c;
result._22 = matrix.d;
result._31 = matrix.e;
result._32 = matrix.f;
aMatrix = result * aMatrix;
}
static void ProcessMatrix3D(Matrix4x4& aMatrix,
const StyleTransformOperation& aOp) {
Matrix4x4 temp;
const auto& matrix = aOp.AsMatrix3D();
temp._11 = matrix.m11;
temp._12 = matrix.m12;
temp._13 = matrix.m13;
temp._14 = matrix.m14;
temp._21 = matrix.m21;
temp._22 = matrix.m22;
temp._23 = matrix.m23;
temp._24 = matrix.m24;
temp._31 = matrix.m31;
temp._32 = matrix.m32;
temp._33 = matrix.m33;
temp._34 = matrix.m34;
temp._41 = matrix.m41;
temp._42 = matrix.m42;
temp._43 = matrix.m43;
temp._44 = matrix.m44;
aMatrix = temp * aMatrix;
}
// For accumulation for transform functions, |aOne| corresponds to |aB| and
// |aTwo| corresponds to |aA| for StyleAnimationValue::Accumulate().
class Accumulate {
public:
template <typename T>
static T operate(const T& aOne, const T& aTwo, double aCoeff) {
return aOne + aTwo * aCoeff;
}
static Point4D operateForPerspective(const Point4D& aOne, const Point4D& aTwo,
double aCoeff) {
return (aOne - Point4D(0, 0, 0, 1)) +
(aTwo - Point4D(0, 0, 0, 1)) * aCoeff + Point4D(0, 0, 0, 1);
}
static Point3D operateForScale(const Point3D& aOne, const Point3D& aTwo,
double aCoeff) {
// For scale, the identify element is 1, see AddTransformScale in
// StyleAnimationValue.cpp.
return (aOne - Point3D(1, 1, 1)) + (aTwo - Point3D(1, 1, 1)) * aCoeff +
Point3D(1, 1, 1);
}
static Matrix4x4 operateForRotate(const gfxQuaternion& aOne,
const gfxQuaternion& aTwo, double aCoeff) {
if (aCoeff == 0.0) {
return aOne.ToMatrix();
}
double theta = acos(std::clamp(aTwo.w, -1.0, 1.0));
double scale = (theta != 0.0) ? 1.0 / sin(theta) : 0.0;
theta *= aCoeff;
scale *= sin(theta);
gfxQuaternion result = gfxQuaternion(scale * aTwo.x, scale * aTwo.y,
scale * aTwo.z, cos(theta)) *
aOne;
return result.ToMatrix();
}
static Matrix4x4 operateForFallback(const Matrix4x4& aMatrix1,
const Matrix4x4& aMatrix2,
double aProgress) {
return aMatrix1;
}
static Matrix4x4 operateByServo(const Matrix4x4& aMatrix1,
const Matrix4x4& aMatrix2, double aCount) {
Matrix4x4 result;
Servo_MatrixTransform_Operate(/* aInterpolate = */ false,
&aMatrix1.components, &aMatrix2.components,
aCount, &result.components);
return result;
}
};
class Interpolate {
public:
template <typename T>
static T operate(const T& aOne, const T& aTwo, double aCoeff) {
return aOne + (aTwo - aOne) * aCoeff;
}
static Point4D operateForPerspective(const Point4D& aOne, const Point4D& aTwo,
double aCoeff) {
return aOne + (aTwo - aOne) * aCoeff;
}
static Point3D operateForScale(const Point3D& aOne, const Point3D& aTwo,
double aCoeff) {
return aOne + (aTwo - aOne) * aCoeff;
}
static Matrix4x4 operateForRotate(const gfxQuaternion& aOne,
const gfxQuaternion& aTwo, double aCoeff) {
return aOne.Slerp(aTwo, aCoeff).ToMatrix();
}
static Matrix4x4 operateForFallback(const Matrix4x4& aMatrix1,
const Matrix4x4& aMatrix2,
double aProgress) {
return aProgress < 0.5 ? aMatrix1 : aMatrix2;
}
static Matrix4x4 operateByServo(const Matrix4x4& aMatrix1,
const Matrix4x4& aMatrix2, double aProgress) {
Matrix4x4 result;
Servo_MatrixTransform_Operate(/* aInterpolate = */ true,
&aMatrix1.components, &aMatrix2.components,
aProgress, &result.components);
return result;
}
};
template <typename Operator>
static void ProcessMatrixOperator(Matrix4x4& aMatrix,
const StyleTransform& aFrom,
const StyleTransform& aTo, float aProgress,
TransformReferenceBox& aRefBox) {
float appUnitPerCSSPixel = AppUnitsPerCSSPixel();
Matrix4x4 matrix1 = ReadTransforms(aFrom, aRefBox, appUnitPerCSSPixel);
Matrix4x4 matrix2 = ReadTransforms(aTo, aRefBox, appUnitPerCSSPixel);
aMatrix = Operator::operateByServo(matrix1, matrix2, aProgress) * aMatrix;
}
/* Helper function to process two matrices that we need to interpolate between
*/
void ProcessInterpolateMatrix(Matrix4x4& aMatrix,
const StyleTransformOperation& aOp,
TransformReferenceBox& aRefBox) {
const auto& args = aOp.AsInterpolateMatrix();
ProcessMatrixOperator<Interpolate>(aMatrix, args.from_list, args.to_list,
args.progress._0, aRefBox);
}
void ProcessAccumulateMatrix(Matrix4x4& aMatrix,
const StyleTransformOperation& aOp,
TransformReferenceBox& aRefBox) {
const auto& args = aOp.AsAccumulateMatrix();
ProcessMatrixOperator<Accumulate>(aMatrix, args.from_list, args.to_list,
args.count, aRefBox);
}
/* Helper function to process a translatex function. */
static void ProcessTranslateX(Matrix4x4& aMatrix,
const LengthPercentage& aLength,
TransformReferenceBox& aRefBox) {
Point3D temp;
temp.x =
ProcessTranslatePart(aLength, &aRefBox, &TransformReferenceBox::Width);
aMatrix.PreTranslate(temp);
}
/* Helper function to process a translatey function. */
static void ProcessTranslateY(Matrix4x4& aMatrix,
const LengthPercentage& aLength,
TransformReferenceBox& aRefBox) {
Point3D temp;
temp.y =
ProcessTranslatePart(aLength, &aRefBox, &TransformReferenceBox::Height);
aMatrix.PreTranslate(temp);
}
static void ProcessTranslateZ(Matrix4x4& aMatrix, const Length& aLength) {
Point3D temp;
temp.z = aLength.ToCSSPixels();
aMatrix.PreTranslate(temp);
}
/* Helper function to process a translate function. */
static void ProcessTranslate(Matrix4x4& aMatrix, const LengthPercentage& aX,
const LengthPercentage& aY,
TransformReferenceBox& aRefBox) {
Point3D temp;
temp.x = ProcessTranslatePart(aX, &aRefBox, &TransformReferenceBox::Width);
temp.y = ProcessTranslatePart(aY, &aRefBox, &TransformReferenceBox::Height);
aMatrix.PreTranslate(temp);
}
static void ProcessTranslate3D(Matrix4x4& aMatrix, const LengthPercentage& aX,
const LengthPercentage& aY, const Length& aZ,
TransformReferenceBox& aRefBox) {
Point3D temp;
temp.x = ProcessTranslatePart(aX, &aRefBox, &TransformReferenceBox::Width);
temp.y = ProcessTranslatePart(aY, &aRefBox, &TransformReferenceBox::Height);
temp.z = aZ.ToCSSPixels();
aMatrix.PreTranslate(temp);
}
/* Helper function to set up a scale matrix. */
static void ProcessScaleHelper(Matrix4x4& aMatrix, float aXScale, float aYScale,
float aZScale) {
aMatrix.PreScale(aXScale, aYScale, aZScale);
}
static void ProcessScale3D(Matrix4x4& aMatrix,
const StyleTransformOperation& aOp) {
const auto& scale = aOp.AsScale3D();
ProcessScaleHelper(aMatrix, scale._0, scale._1, scale._2);
}
/* Helper function that, given a set of angles, constructs the appropriate
* skew matrix.
*/
static void ProcessSkewHelper(Matrix4x4& aMatrix, const StyleAngle& aXAngle,
const StyleAngle& aYAngle) {
aMatrix.SkewXY(aXAngle.ToRadians(), aYAngle.ToRadians());
}
static void ProcessRotate3D(Matrix4x4& aMatrix, float aX, float aY, float aZ,
const StyleAngle& aAngle) {
Matrix4x4 temp;
temp.SetRotateAxisAngle(aX, aY, aZ, aAngle.ToRadians());
aMatrix = temp * aMatrix;
}
static void ProcessPerspective(
Matrix4x4& aMatrix,
const StyleGenericPerspectiveFunction<Length>& aPerspective) {
if (aPerspective.IsNone()) {
return;
}
float p = aPerspective.AsLength().ToCSSPixels();
if (!std::isinf(p)) {
aMatrix.Perspective(std::max(p, 1.0f));
}
}
static void MatrixForTransformFunction(Matrix4x4& aMatrix,
const StyleTransformOperation& aOp,
TransformReferenceBox& aRefBox) {
/* Get the keyword for the transform. */
switch (aOp.tag) {
case StyleTransformOperation::Tag::TranslateX:
ProcessTranslateX(aMatrix, aOp.AsTranslateX(), aRefBox);
break;
case StyleTransformOperation::Tag::TranslateY:
ProcessTranslateY(aMatrix, aOp.AsTranslateY(), aRefBox);
break;
case StyleTransformOperation::Tag::TranslateZ:
ProcessTranslateZ(aMatrix, aOp.AsTranslateZ());
break;
case StyleTransformOperation::Tag::Translate:
ProcessTranslate(aMatrix, aOp.AsTranslate()._0, aOp.AsTranslate()._1,
aRefBox);
break;
case StyleTransformOperation::Tag::Translate3D:
return ProcessTranslate3D(aMatrix, aOp.AsTranslate3D()._0,
aOp.AsTranslate3D()._1, aOp.AsTranslate3D()._2,
aRefBox);
break;
case StyleTransformOperation::Tag::ScaleX:
ProcessScaleHelper(aMatrix, aOp.AsScaleX(), 1.0f, 1.0f);
break;
case StyleTransformOperation::Tag::ScaleY:
ProcessScaleHelper(aMatrix, 1.0f, aOp.AsScaleY(), 1.0f);
break;
case StyleTransformOperation::Tag::ScaleZ:
ProcessScaleHelper(aMatrix, 1.0f, 1.0f, aOp.AsScaleZ());
break;
case StyleTransformOperation::Tag::Scale:
ProcessScaleHelper(aMatrix, aOp.AsScale()._0, aOp.AsScale()._1, 1.0f);
break;
case StyleTransformOperation::Tag::Scale3D:
ProcessScale3D(aMatrix, aOp);
break;
case StyleTransformOperation::Tag::SkewX:
ProcessSkewHelper(aMatrix, aOp.AsSkewX(), StyleAngle::Zero());
break;
case StyleTransformOperation::Tag::SkewY:
ProcessSkewHelper(aMatrix, StyleAngle::Zero(), aOp.AsSkewY());
break;
case StyleTransformOperation::Tag::Skew:
ProcessSkewHelper(aMatrix, aOp.AsSkew()._0, aOp.AsSkew()._1);
break;
case StyleTransformOperation::Tag::RotateX:
aMatrix.RotateX(aOp.AsRotateX().ToRadians());
break;
case StyleTransformOperation::Tag::RotateY:
aMatrix.RotateY(aOp.AsRotateY().ToRadians());
break;
case StyleTransformOperation::Tag::RotateZ:
aMatrix.RotateZ(aOp.AsRotateZ().ToRadians());
break;
case StyleTransformOperation::Tag::Rotate:
aMatrix.RotateZ(aOp.AsRotate().ToRadians());
break;
case StyleTransformOperation::Tag::Rotate3D:
ProcessRotate3D(aMatrix, aOp.AsRotate3D()._0, aOp.AsRotate3D()._1,
aOp.AsRotate3D()._2, aOp.AsRotate3D()._3);
break;
case StyleTransformOperation::Tag::Matrix:
ProcessMatrix(aMatrix, aOp);
break;
case StyleTransformOperation::Tag::Matrix3D:
ProcessMatrix3D(aMatrix, aOp);
break;
case StyleTransformOperation::Tag::InterpolateMatrix:
ProcessInterpolateMatrix(aMatrix, aOp, aRefBox);
break;
case StyleTransformOperation::Tag::AccumulateMatrix:
ProcessAccumulateMatrix(aMatrix, aOp, aRefBox);
break;
case StyleTransformOperation::Tag::Perspective:
ProcessPerspective(aMatrix, aOp.AsPerspective());
break;
default:
MOZ_ASSERT_UNREACHABLE("Unknown transform function!");
}
}
Matrix4x4 ReadTransforms(const StyleTransform& aTransform,
TransformReferenceBox& aRefBox,
float aAppUnitsPerMatrixUnit) {
Matrix4x4 result;
for (const StyleTransformOperation& op : aTransform.Operations()) {
MatrixForTransformFunction(result, op, aRefBox);
}
float scale = float(AppUnitsPerCSSPixel()) / aAppUnitsPerMatrixUnit;
result.PreScale(1 / scale, 1 / scale, 1 / scale);
result.PostScale(scale, scale, scale);
return result;
}
static void ProcessTranslate(Matrix4x4& aMatrix,
const StyleTranslate& aTranslate,
TransformReferenceBox& aRefBox) {
switch (aTranslate.tag) {
case StyleTranslate::Tag::None:
return;
case StyleTranslate::Tag::Translate:
return ProcessTranslate3D(aMatrix, aTranslate.AsTranslate()._0,
aTranslate.AsTranslate()._1,
aTranslate.AsTranslate()._2, aRefBox);
default:
MOZ_ASSERT_UNREACHABLE("Huh?");
}
}
static void ProcessRotate(Matrix4x4& aMatrix, const StyleRotate& aRotate) {
switch (aRotate.tag) {
case StyleRotate::Tag::None:
return;
case StyleRotate::Tag::Rotate:
aMatrix.RotateZ(aRotate.AsRotate().ToRadians());
return;
case StyleRotate::Tag::Rotate3D:
return ProcessRotate3D(aMatrix, aRotate.AsRotate3D()._0,
aRotate.AsRotate3D()._1, aRotate.AsRotate3D()._2,
aRotate.AsRotate3D()._3);
default:
MOZ_ASSERT_UNREACHABLE("Huh?");
}
}
static void ProcessScale(Matrix4x4& aMatrix, const StyleScale& aScale) {
switch (aScale.tag) {
case StyleScale::Tag::None:
return;
case StyleScale::Tag::Scale:
return ProcessScaleHelper(aMatrix, aScale.AsScale()._0,
aScale.AsScale()._1, aScale.AsScale()._2);
default:
MOZ_ASSERT_UNREACHABLE("Huh?");
}
}
Matrix4x4 ReadTransforms(const StyleTranslate& aTranslate,
const StyleRotate& aRotate, const StyleScale& aScale,
const ResolvedMotionPathData* aMotion,
const StyleTransform& aTransform,
TransformReferenceBox& aRefBox,
float aAppUnitsPerMatrixUnit) {
Matrix4x4 result;
ProcessTranslate(result, aTranslate, aRefBox);
ProcessRotate(result, aRotate);
ProcessScale(result, aScale);
if (aMotion) {
// Create the equivalent translate and rotate function, according to the
// order in spec. We combine the translate and then the rotate.
//
// Besides, we have to shift the object by the delta between anchor-point
// and transform-origin, to make sure we rotate the object according to
// anchor-point.
result.PreTranslate(aMotion->mTranslate.x + aMotion->mShift.x,
aMotion->mTranslate.y + aMotion->mShift.y, 0.0);
if (aMotion->mRotate != 0.0) {
result.RotateZ(aMotion->mRotate);
}
// Shift the origin back to transform-origin.
result.PreTranslate(-aMotion->mShift.x, -aMotion->mShift.y, 0.0);
}
for (const StyleTransformOperation& op : aTransform.Operations()) {
MatrixForTransformFunction(result, op, aRefBox);
}
float scale = float(AppUnitsPerCSSPixel()) / aAppUnitsPerMatrixUnit;
result.PreScale(1 / scale, 1 / scale, 1 / scale);
result.PostScale(scale, scale, scale);
return result;
}
mozilla::CSSPoint Convert2DPosition(const mozilla::LengthPercentage& aX,
const mozilla::LengthPercentage& aY,
const CSSSize& aSize) {
return {
aX.ResolveToCSSPixels(aSize.width),
aY.ResolveToCSSPixels(aSize.height),
};
}
CSSPoint Convert2DPosition(const LengthPercentage& aX,
const LengthPercentage& aY,
TransformReferenceBox& aRefBox) {
return {
aX.ResolveToCSSPixelsWith(
[&] { return CSSPixel::FromAppUnits(aRefBox.Width()); }),
aY.ResolveToCSSPixelsWith(
[&] { return CSSPixel::FromAppUnits(aRefBox.Height()); }),
};
}
Point Convert2DPosition(const LengthPercentage& aX, const LengthPercentage& aY,
TransformReferenceBox& aRefBox,
int32_t aAppUnitsPerPixel) {
float scale = mozilla::AppUnitsPerCSSPixel() / float(aAppUnitsPerPixel);
CSSPoint p = Convert2DPosition(aX, aY, aRefBox);
return {p.x * scale, p.y * scale};
}
} // namespace nsStyleTransformMatrix