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gecko-dev/layout/style/nsStyleTransformMatrix.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/. */
/*
* A class used for intermediate representations of the -moz-transform property.
*/
#include "nsStyleTransformMatrix.h"
#include "nsCSSValue.h"
#include "nsLayoutUtils.h"
#include "nsPresContext.h"
#include "nsSVGUtils.h"
#include "nsCSSKeywords.h"
#include "mozilla/ServoBindings.h"
#include "mozilla/StyleAnimationValue.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
void TransformReferenceBox::EnsureDimensionsAreCached() {
if (mIsCached) {
return;
}
MOZ_ASSERT(mFrame);
mIsCached = true;
if (mFrame->GetStateBits() & NS_FRAME_SVG_LAYOUT) {
if (!nsLayoutUtils::SVGTransformBoxEnabled()) {
mX = -mFrame->GetPosition().x;
mY = -mFrame->GetPosition().y;
Size contextSize = nsSVGUtils::GetContextSize(mFrame);
mWidth = nsPresContext::CSSPixelsToAppUnits(contextSize.width);
mHeight = nsPresContext::CSSPixelsToAppUnits(contextSize.height);
} else if (mFrame->StyleDisplay()->mTransformBox ==
StyleGeometryBox::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::ComputeGeometryBox(
const_cast<nsIFrame*>(mFrame), 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.
mX = bboxInAppUnits.x - mFrame->GetPosition().x;
mY = bboxInAppUnits.y - mFrame->GetPosition().y;
mWidth = bboxInAppUnits.width;
mHeight = bboxInAppUnits.height;
} else {
// The value 'border-box' is treated as 'view-box' for SVG content.
MOZ_ASSERT(
mFrame->StyleDisplay()->mTransformBox == StyleGeometryBox::ViewBox ||
mFrame->StyleDisplay()->mTransformBox ==
StyleGeometryBox::BorderBox,
"Unexpected value for 'transform-box'");
// 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.
mX = -mFrame->GetPosition().x;
mY = -mFrame->GetPosition().y;
Size contextSize = nsSVGUtils::GetContextSize(mFrame);
mWidth = nsPresContext::CSSPixelsToAppUnits(contextSize.width);
mHeight = nsPresContext::CSSPixelsToAppUnits(contextSize.height);
}
return;
}
// 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
mX = 0;
mY = 0;
mWidth = rect.Width();
mHeight = rect.Height();
}
void TransformReferenceBox::Init(const nsSize& aDimensions) {
MOZ_ASSERT(!mFrame && !mIsCached);
mX = 0;
mY = 0;
mWidth = aDimensions.width;
mHeight = aDimensions.height;
mIsCached = true;
}
float ProcessTranslatePart(
const nsCSSValue& aValue, TransformReferenceBox* aRefBox,
TransformReferenceBox::DimensionGetter aDimensionGetter) {
nscoord offset = 0;
float percent = 0.0f;
if (aValue.GetUnit() == eCSSUnit_Percent) {
percent = aValue.GetPercentValue();
} else if (aValue.GetUnit() == eCSSUnit_Pixel ||
aValue.GetUnit() == eCSSUnit_Number) {
// Raw numbers are treated as being pixels.
return aValue.GetFloatValue();
} else if (aValue.IsCalcUnit()) {
// We can retrieve the Calc value directly because it has been computed
// from the Servo side and set by nsCSSValue::SetCalcValue().
nsStyleCoord::CalcValue calc = aValue.GetCalcValue();
percent = calc.mPercent;
offset = calc.mLength;
} else {
// Note: The unit of nsCSSValue passed from Servo side would be number,
// pixel, percent, or eCSSUnit_Calc, so it is impossible to go into
// this branch.
MOZ_CRASH("unexpected unit in ProcessTranslatePart");
}
float translation = NSAppUnitsToFloatPixels(offset, AppUnitsPerCSSPixel());
// We want to avoid calling aDimensionGetter if there's no percentage to be
// resolved (for performance reasons - see TransformReferenceBox).
if (percent != 0.0f && aRefBox && !aRefBox->IsEmpty()) {
translation +=
percent * NSAppUnitsToFloatPixels((aRefBox->*aDimensionGetter)(),
AppUnitsPerCSSPixel());
}
return translation;
}
/**
* 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 nsCSSValue::Array* aData,
TransformReferenceBox& aRefBox) {
MOZ_ASSERT(aData->Count() == 7, "Invalid array!");
gfxMatrix result;
/* Take the first four elements out of the array as floats and store
* them.
*/
result._11 = aData->Item(1).GetFloatValue();
result._12 = aData->Item(2).GetFloatValue();
result._21 = aData->Item(3).GetFloatValue();
result._22 = aData->Item(4).GetFloatValue();
/* The last two elements have their length parts stored in aDelta
* and their percent parts stored in aX[0] and aY[1].
*/
result._31 = ProcessTranslatePart(aData->Item(5), &aRefBox,
&TransformReferenceBox::Width);
result._32 = ProcessTranslatePart(aData->Item(6), &aRefBox,
&TransformReferenceBox::Height);
aMatrix = result * aMatrix;
}
static void ProcessMatrix3D(Matrix4x4& aMatrix, const nsCSSValue::Array* aData,
TransformReferenceBox& aRefBox) {
MOZ_ASSERT(aData->Count() == 17, "Invalid array!");
Matrix4x4 temp;
temp._11 = aData->Item(1).GetFloatValue();
temp._12 = aData->Item(2).GetFloatValue();
temp._13 = aData->Item(3).GetFloatValue();
temp._14 = aData->Item(4).GetFloatValue();
temp._21 = aData->Item(5).GetFloatValue();
temp._22 = aData->Item(6).GetFloatValue();
temp._23 = aData->Item(7).GetFloatValue();
temp._24 = aData->Item(8).GetFloatValue();
temp._31 = aData->Item(9).GetFloatValue();
temp._32 = aData->Item(10).GetFloatValue();
temp._33 = aData->Item(11).GetFloatValue();
temp._34 = aData->Item(12).GetFloatValue();
temp._44 = aData->Item(16).GetFloatValue();
temp._41 = ProcessTranslatePart(aData->Item(13), &aRefBox,
&TransformReferenceBox::Width);
temp._42 = ProcessTranslatePart(aData->Item(14), &aRefBox,
&TransformReferenceBox::Height);
temp._43 = ProcessTranslatePart(aData->Item(15), nullptr);
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(mozilla::clamped(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(MatrixTransformOperator::Accumulate,
&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(MatrixTransformOperator::Interpolate,
&aMatrix1.components, &aMatrix2.components,
aProgress, &result.components);
return result;
}
};
/**
* Calculate 2 matrices by decomposing them with Operator.
*
* @param aMatrix1 First matrix, using CSS pixel units.
* @param aMatrix2 Second matrix, using CSS pixel units.
* @param aProgress Coefficient for the Operator.
*/
template <typename Operator>
static Matrix4x4 OperateTransformMatrix(const Matrix4x4& aMatrix1,
const Matrix4x4& aMatrix2,
double aProgress) {
// Decompose both matrices
Point3D scale1(1, 1, 1), translate1;
Point4D perspective1(0, 0, 0, 1);
gfxQuaternion rotate1;
nsStyleTransformMatrix::ShearArray shear1{0.0f, 0.0f, 0.0f};
Point3D scale2(1, 1, 1), translate2;
Point4D perspective2(0, 0, 0, 1);
gfxQuaternion rotate2;
nsStyleTransformMatrix::ShearArray shear2{0.0f, 0.0f, 0.0f};
// Check if both matrices are decomposable.
bool wasDecomposed;
Matrix matrix2d1, matrix2d2;
if (aMatrix1.Is2D(&matrix2d1) && aMatrix2.Is2D(&matrix2d2)) {
wasDecomposed =
Decompose2DMatrix(matrix2d1, scale1, shear1, rotate1, translate1) &&
Decompose2DMatrix(matrix2d2, scale2, shear2, rotate2, translate2);
} else {
wasDecomposed = Decompose3DMatrix(aMatrix1, scale1, shear1, rotate1,
translate1, perspective1) &&
Decompose3DMatrix(aMatrix2, scale2, shear2, rotate2,
translate2, perspective2);
}
// Fallback to discrete operation if one of the matrices is not decomposable.
if (!wasDecomposed) {
return Operator::operateForFallback(aMatrix1, aMatrix2, aProgress);
}
Matrix4x4 result;
// Operate each of the pieces in response to |Operator|.
Point4D perspective =
Operator::operateForPerspective(perspective1, perspective2, aProgress);
result.SetTransposedVector(3, perspective);
Point3D translate = Operator::operate(translate1, translate2, aProgress);
result.PreTranslate(translate.x, translate.y, translate.z);
Matrix4x4 rotate = Operator::operateForRotate(rotate1, rotate2, aProgress);
if (!rotate.IsIdentity()) {
result = rotate * result;
}
// TODO: Would it be better to operate these as angles?
// How do we convert back to angles?
float yzshear = Operator::operate(shear1[ShearType::YZ],
shear2[ShearType::YZ], aProgress);
if (yzshear != 0.0) {
result.SkewYZ(yzshear);
}
float xzshear = Operator::operate(shear1[ShearType::XZ],
shear2[ShearType::XZ], aProgress);
if (xzshear != 0.0) {
result.SkewXZ(xzshear);
}
float xyshear = Operator::operate(shear1[ShearType::XY],
shear2[ShearType::XY], aProgress);
if (xyshear != 0.0) {
result.SkewXY(xyshear);
}
Point3D scale = Operator::operateForScale(scale1, scale2, aProgress);
if (scale != Point3D(1.0, 1.0, 1.0)) {
result.PreScale(scale.x, scale.y, scale.z);
}
return result;
}
template <typename Operator>
static Matrix4x4 OperateTransformMatrixByServo(const Matrix4x4& aMatrix1,
const Matrix4x4& aMatrix2,
double aProgress) {
return Operator::operateByServo(aMatrix1, aMatrix2, aProgress);
}
template <typename Operator>
static void ProcessMatrixOperator(Matrix4x4& aMatrix,
const nsCSSValue::Array* aData,
TransformReferenceBox& aRefBox) {
MOZ_ASSERT(aData->Count() == 4, "Invalid array!");
auto readTransform = [&](const nsCSSValue& aValue) -> Matrix4x4 {
const nsCSSValueList* list = nullptr;
switch (aValue.GetUnit()) {
case eCSSUnit_List:
// For Gecko style backend.
list = aValue.GetListValue();
break;
case eCSSUnit_SharedList:
// For Servo style backend. The transform lists of interpolatematrix
// are not created on the main thread (i.e. during parallel traversal),
// and nsCSSValueList_heap is not thread safe. Therefore, we use
// nsCSSValueSharedList as a workaround.
list = aValue.GetSharedListValue()->mHead;
break;
default:
list = nullptr;
}
Matrix4x4 matrix;
if (!list) {
return matrix;
}
float appUnitPerCSSPixel = AppUnitsPerCSSPixel();
matrix = nsStyleTransformMatrix::ReadTransforms(list, aRefBox,
appUnitPerCSSPixel);
return matrix;
};
Matrix4x4 matrix1 = readTransform(aData->Item(1));
Matrix4x4 matrix2 = readTransform(aData->Item(2));
double progress = aData->Item(3).GetPercentValue();
// We cannot use GeckoComputedStyle to check if we use Servo backend because
// it could be null in Gecko. Instead, use the unit of the nsCSSValue because
// we use eCSSUnit_SharedList for Servo backend.
if (aData->Item(1).GetUnit() == eCSSUnit_SharedList) {
aMatrix =
OperateTransformMatrixByServo<Operator>(matrix1, matrix2, progress) *
aMatrix;
return;
}
aMatrix =
OperateTransformMatrix<Operator>(matrix1, matrix2, progress) * aMatrix;
}
/* Helper function to process two matrices that we need to interpolate between
*/
void ProcessInterpolateMatrix(Matrix4x4& aMatrix,
const nsCSSValue::Array* aData,
TransformReferenceBox& aRefBox) {
ProcessMatrixOperator<Interpolate>(aMatrix, aData, aRefBox);
}
void ProcessAccumulateMatrix(Matrix4x4& aMatrix, const nsCSSValue::Array* aData,
TransformReferenceBox& aRefBox) {
ProcessMatrixOperator<Accumulate>(aMatrix, aData, aRefBox);
}
/* Helper function to process a translatex function. */
static void ProcessTranslateX(Matrix4x4& aMatrix,
const nsCSSValue::Array* aData,
TransformReferenceBox& aRefBox) {
MOZ_ASSERT(aData->Count() == 2, "Invalid array!");
Point3D temp;
temp.x = ProcessTranslatePart(aData->Item(1), &aRefBox,
&TransformReferenceBox::Width);
aMatrix.PreTranslate(temp);
}
/* Helper function to process a translatey function. */
static void ProcessTranslateY(Matrix4x4& aMatrix,
const nsCSSValue::Array* aData,
TransformReferenceBox& aRefBox) {
MOZ_ASSERT(aData->Count() == 2, "Invalid array!");
Point3D temp;
temp.y = ProcessTranslatePart(aData->Item(1), &aRefBox,
&TransformReferenceBox::Height);
aMatrix.PreTranslate(temp);
}
static void ProcessTranslateZ(Matrix4x4& aMatrix,
const nsCSSValue::Array* aData) {
MOZ_ASSERT(aData->Count() == 2, "Invalid array!");
Point3D temp;
temp.z = ProcessTranslatePart(aData->Item(1), nullptr);
aMatrix.PreTranslate(temp);
}
/* Helper function to process a translate function. */
static void ProcessTranslate(Matrix4x4& aMatrix, const nsCSSValue::Array* aData,
TransformReferenceBox& aRefBox) {
MOZ_ASSERT(aData->Count() == 2 || aData->Count() == 3, "Invalid array!");
Point3D temp;
temp.x = ProcessTranslatePart(aData->Item(1), &aRefBox,
&TransformReferenceBox::Width);
/* If we read in a Y component, set it appropriately */
if (aData->Count() == 3) {
temp.y = ProcessTranslatePart(aData->Item(2), &aRefBox,
&TransformReferenceBox::Height);
}
aMatrix.PreTranslate(temp);
}
static void ProcessTranslate3D(Matrix4x4& aMatrix,
const nsCSSValue::Array* aData,
TransformReferenceBox& aRefBox) {
MOZ_ASSERT(aData->Count() == 4, "Invalid array!");
Point3D temp;
temp.x = ProcessTranslatePart(aData->Item(1), &aRefBox,
&TransformReferenceBox::Width);
temp.y = ProcessTranslatePart(aData->Item(2), &aRefBox,
&TransformReferenceBox::Height);
temp.z = ProcessTranslatePart(aData->Item(3), nullptr);
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);
}
/* Process a scalex function. */
static void ProcessScaleX(Matrix4x4& aMatrix, const nsCSSValue::Array* aData) {
MOZ_ASSERT(aData->Count() == 2, "Bad array!");
ProcessScaleHelper(aMatrix, aData->Item(1).GetFloatValue(), 1.0f, 1.0f);
}
/* Process a scaley function. */
static void ProcessScaleY(Matrix4x4& aMatrix, const nsCSSValue::Array* aData) {
MOZ_ASSERT(aData->Count() == 2, "Bad array!");
ProcessScaleHelper(aMatrix, 1.0f, aData->Item(1).GetFloatValue(), 1.0f);
}
static void ProcessScaleZ(Matrix4x4& aMatrix, const nsCSSValue::Array* aData) {
MOZ_ASSERT(aData->Count() == 2, "Bad array!");
ProcessScaleHelper(aMatrix, 1.0f, 1.0f, aData->Item(1).GetFloatValue());
}
static void ProcessScale3D(Matrix4x4& aMatrix, const nsCSSValue::Array* aData) {
MOZ_ASSERT(aData->Count() == 4, "Bad array!");
ProcessScaleHelper(aMatrix, aData->Item(1).GetFloatValue(),
aData->Item(2).GetFloatValue(),
aData->Item(3).GetFloatValue());
}
/* Process a scale function. */
static void ProcessScale(Matrix4x4& aMatrix, const nsCSSValue::Array* aData) {
MOZ_ASSERT(aData->Count() == 2 || aData->Count() == 3, "Bad array!");
/* We either have one element or two. If we have one, it's for both X and Y.
* Otherwise it's one for each.
*/
const nsCSSValue& scaleX = aData->Item(1);
const nsCSSValue& scaleY = (aData->Count() == 2 ? scaleX : aData->Item(2));
ProcessScaleHelper(aMatrix, scaleX.GetFloatValue(), scaleY.GetFloatValue(),
1.0f);
}
/* Helper function that, given a set of angles, constructs the appropriate
* skew matrix.
*/
static void ProcessSkewHelper(Matrix4x4& aMatrix, double aXAngle,
double aYAngle) {
aMatrix.SkewXY(aXAngle, aYAngle);
}
/* Function that converts a skewx transform into a matrix. */
static void ProcessSkewX(Matrix4x4& aMatrix, const nsCSSValue::Array* aData) {
NS_ASSERTION(aData->Count() == 2, "Bad array!");
ProcessSkewHelper(aMatrix, aData->Item(1).GetAngleValueInRadians(), 0.0);
}
/* Function that converts a skewy transform into a matrix. */
static void ProcessSkewY(Matrix4x4& aMatrix, const nsCSSValue::Array* aData) {
NS_ASSERTION(aData->Count() == 2, "Bad array!");
ProcessSkewHelper(aMatrix, 0.0, aData->Item(1).GetAngleValueInRadians());
}
/* Function that converts a skew transform into a matrix. */
static void ProcessSkew(Matrix4x4& aMatrix, const nsCSSValue::Array* aData) {
NS_ASSERTION(aData->Count() == 2 || aData->Count() == 3, "Bad array!");
double xSkew = aData->Item(1).GetAngleValueInRadians();
double ySkew =
(aData->Count() == 2 ? 0.0 : aData->Item(2).GetAngleValueInRadians());
ProcessSkewHelper(aMatrix, xSkew, ySkew);
}
/* Function that converts a rotate transform into a matrix. */
static void ProcessRotateZ(Matrix4x4& aMatrix, const nsCSSValue::Array* aData) {
MOZ_ASSERT(aData->Count() == 2, "Invalid array!");
double theta = aData->Item(1).GetAngleValueInRadians();
aMatrix.RotateZ(theta);
}
static void ProcessRotateX(Matrix4x4& aMatrix, const nsCSSValue::Array* aData) {
MOZ_ASSERT(aData->Count() == 2, "Invalid array!");
double theta = aData->Item(1).GetAngleValueInRadians();
aMatrix.RotateX(theta);
}
static void ProcessRotateY(Matrix4x4& aMatrix, const nsCSSValue::Array* aData) {
MOZ_ASSERT(aData->Count() == 2, "Invalid array!");
double theta = aData->Item(1).GetAngleValueInRadians();
aMatrix.RotateY(theta);
}
static void ProcessRotate3D(Matrix4x4& aMatrix,
const nsCSSValue::Array* aData) {
MOZ_ASSERT(aData->Count() == 5, "Invalid array!");
double theta = aData->Item(4).GetAngleValueInRadians();
float x = aData->Item(1).GetFloatValue();
float y = aData->Item(2).GetFloatValue();
float z = aData->Item(3).GetFloatValue();
Matrix4x4 temp;
temp.SetRotateAxisAngle(x, y, z, theta);
aMatrix = temp * aMatrix;
}
static void ProcessPerspective(Matrix4x4& aMatrix,
const nsCSSValue::Array* aData) {
MOZ_ASSERT(aData->Count() == 2, "Invalid array!");
float depth = ProcessTranslatePart(aData->Item(1), nullptr);
ApplyPerspectiveToMatrix(aMatrix, depth);
}
/**
* SetToTransformFunction is essentially a giant switch statement that fans
* out to many smaller helper functions.
*/
static void MatrixForTransformFunction(Matrix4x4& aMatrix,
const nsCSSValue::Array* aData,
TransformReferenceBox& aRefBox) {
MOZ_ASSERT(aData, "Why did you want to get data from a null array?");
/* Get the keyword for the transform. */
switch (TransformFunctionOf(aData)) {
case eCSSKeyword_translatex:
ProcessTranslateX(aMatrix, aData, aRefBox);
break;
case eCSSKeyword_translatey:
ProcessTranslateY(aMatrix, aData, aRefBox);
break;
case eCSSKeyword_translatez:
ProcessTranslateZ(aMatrix, aData);
break;
case eCSSKeyword_translate:
ProcessTranslate(aMatrix, aData, aRefBox);
break;
case eCSSKeyword_translate3d:
ProcessTranslate3D(aMatrix, aData, aRefBox);
break;
case eCSSKeyword_scalex:
ProcessScaleX(aMatrix, aData);
break;
case eCSSKeyword_scaley:
ProcessScaleY(aMatrix, aData);
break;
case eCSSKeyword_scalez:
ProcessScaleZ(aMatrix, aData);
break;
case eCSSKeyword_scale:
ProcessScale(aMatrix, aData);
break;
case eCSSKeyword_scale3d:
ProcessScale3D(aMatrix, aData);
break;
case eCSSKeyword_skewx:
ProcessSkewX(aMatrix, aData);
break;
case eCSSKeyword_skewy:
ProcessSkewY(aMatrix, aData);
break;
case eCSSKeyword_skew:
ProcessSkew(aMatrix, aData);
break;
case eCSSKeyword_rotatex:
ProcessRotateX(aMatrix, aData);
break;
case eCSSKeyword_rotatey:
ProcessRotateY(aMatrix, aData);
break;
case eCSSKeyword_rotatez:
MOZ_FALLTHROUGH;
case eCSSKeyword_rotate:
ProcessRotateZ(aMatrix, aData);
break;
case eCSSKeyword_rotate3d:
ProcessRotate3D(aMatrix, aData);
break;
case eCSSKeyword_matrix:
ProcessMatrix(aMatrix, aData, aRefBox);
break;
case eCSSKeyword_matrix3d:
ProcessMatrix3D(aMatrix, aData, aRefBox);
break;
case eCSSKeyword_interpolatematrix:
ProcessMatrixOperator<Interpolate>(aMatrix, aData, aRefBox);
break;
case eCSSKeyword_accumulatematrix:
ProcessMatrixOperator<Accumulate>(aMatrix, aData, aRefBox);
break;
case eCSSKeyword_perspective:
ProcessPerspective(aMatrix, aData);
break;
default:
MOZ_ASSERT_UNREACHABLE("Unknown transform function!");
}
}
/**
* Return the transform function, as an nsCSSKeyword, for the given
* nsCSSValue::Array from a transform list.
*/
nsCSSKeyword TransformFunctionOf(const nsCSSValue::Array* aData) {
MOZ_ASSERT(aData->Item(0).GetUnit() == eCSSUnit_Enumerated);
return aData->Item(0).GetKeywordValue();
}
void SetIdentityMatrix(nsCSSValue::Array* aMatrix) {
MOZ_ASSERT(aMatrix, "aMatrix should be non-null");
nsCSSKeyword tfunc = TransformFunctionOf(aMatrix);
MOZ_ASSERT(tfunc == eCSSKeyword_matrix || tfunc == eCSSKeyword_matrix3d,
"Only accept matrix and matrix3d");
if (tfunc == eCSSKeyword_matrix) {
MOZ_ASSERT(aMatrix->Count() == 7, "Invalid matrix");
Matrix m;
for (size_t i = 0; i < 6; ++i) {
aMatrix->Item(i + 1).SetFloatValue(m.components[i], eCSSUnit_Number);
}
return;
}
MOZ_ASSERT(aMatrix->Count() == 17, "Invalid matrix3d");
Matrix4x4 m;
for (size_t i = 0; i < 16; ++i) {
aMatrix->Item(i + 1).SetFloatValue(m.components[i], eCSSUnit_Number);
}
}
static void ReadTransformsImpl(Matrix4x4& aMatrix, const nsCSSValueList* aList,
TransformReferenceBox& aRefBox) {
for (const nsCSSValueList* curr = aList; curr != nullptr;
curr = curr->mNext) {
const nsCSSValue& currElem = curr->mValue;
if (currElem.GetUnit() != eCSSUnit_Function) {
NS_ASSERTION(currElem.GetUnit() == eCSSUnit_None && !aList->mNext,
"stream should either be a list of functions or a "
"lone None");
continue;
}
NS_ASSERTION(currElem.GetArrayValue()->Count() >= 1,
"Incoming function is too short!");
/* Read in a single transform matrix. */
MatrixForTransformFunction(aMatrix, currElem.GetArrayValue(), aRefBox);
}
}
Matrix4x4 ReadTransforms(const nsCSSValueList* aList,
TransformReferenceBox& aRefBox,
float aAppUnitsPerMatrixUnit) {
Matrix4x4 result;
ReadTransformsImpl(result, aList, aRefBox);
float scale = float(AppUnitsPerCSSPixel()) / aAppUnitsPerMatrixUnit;
result.PreScale(1 / scale, 1 / scale, 1 / scale);
result.PostScale(scale, scale, scale);
return result;
}
Matrix4x4 ReadTransforms(const nsCSSValueList* aIndividualTransforms,
const Maybe<MotionPathData>& aMotion,
const nsCSSValueList* aTransform,
TransformReferenceBox& aRefBox,
float aAppUnitsPerMatrixUnit) {
Matrix4x4 result;
if (aIndividualTransforms) {
ReadTransformsImpl(result, aIndividualTransforms, aRefBox);
}
if (aMotion.isSome()) {
// Create the equivalent translate and rotate function, according to the
// order in spec. We combine the translate and then the rotate.
// https://drafts.fxtf.org/motion-1/#calculating-path-transform
result.PreTranslate(aMotion->mTranslate.x, aMotion->mTranslate.y, 0.0);
if (aMotion->mRotate != 0.0) {
result.RotateZ(aMotion->mRotate);
}
}
if (aTransform) {
ReadTransformsImpl(result, aTransform, aRefBox);
}
float scale = float(AppUnitsPerCSSPixel()) / aAppUnitsPerMatrixUnit;
result.PreScale(1 / scale, 1 / scale, 1 / scale);
result.PostScale(scale, scale, scale);
return result;
}
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};
}
/*
* The relevant section of the transitions specification:
* http://dev.w3.org/csswg/css3-transitions/#animation-of-property-types-
* defers all of the details to the 2-D and 3-D transforms specifications.
* For the 2-D transforms specification (all that's relevant for us, right
* now), the relevant section is:
* http://dev.w3.org/csswg/css3-2d-transforms/#animation
* This, in turn, refers to the unmatrix program in Graphics Gems,
* available from http://tog.acm.org/resources/GraphicsGems/ , and in
* particular as the file GraphicsGems/gemsii/unmatrix.c
* in http://tog.acm.org/resources/GraphicsGems/AllGems.tar.gz
*
* The unmatrix reference is for general 3-D transform matrices (any of the
* 16 components can have any value).
*
* For CSS 2-D transforms, we have a 2-D matrix with the bottom row constant:
*
* [ A C E ]
* [ B D F ]
* [ 0 0 1 ]
*
* For that case, I believe the algorithm in unmatrix reduces to:
*
* (1) If A * D - B * C == 0, the matrix is singular. Fail.
*
* (2) Set translation components (Tx and Ty) to the translation parts of
* the matrix (E and F) and then ignore them for the rest of the time.
* (For us, E and F each actually consist of three constants: a
* length, a multiplier for the width, and a multiplier for the
* height. This actually requires its own decomposition, but I'll
* keep that separate.)
*
* (3) Let the X scale (Sx) be sqrt(A^2 + B^2). Then divide both A and B
* by it.
*
* (4) Let the XY shear (K) be A * C + B * D. From C, subtract A times
* the XY shear. From D, subtract B times the XY shear.
*
* (5) Let the Y scale (Sy) be sqrt(C^2 + D^2). Divide C, D, and the XY
* shear (K) by it.
*
* (6) At this point, A * D - B * C is either 1 or -1. If it is -1,
* negate the XY shear (K), the X scale (Sx), and A, B, C, and D.
* (Alternatively, we could negate the XY shear (K) and the Y scale
* (Sy).)
*
* (7) Let the rotation be R = atan2(B, A).
*
* Then the resulting decomposed transformation is:
*
* translate(Tx, Ty) rotate(R) skewX(atan(K)) scale(Sx, Sy)
*
* An interesting result of this is that all of the simple transform
* functions (i.e., all functions other than matrix()), in isolation,
* decompose back to themselves except for:
* 'skewY(φ)', which is 'matrix(1, tan(φ), 0, 1, 0, 0)', which decomposes
* to 'rotate(φ) skewX(φ) scale(sec(φ), cos(φ))' since (ignoring the
* alternate sign possibilities that would get fixed in step 6):
* In step 3, the X scale factor is sqrt(1+tan²(φ)) = sqrt(sec²(φ)) =
* sec(φ). Thus, after step 3, A = 1/sec(φ) = cos(φ) and B = tan(φ) / sec(φ) =
* sin(φ). In step 4, the XY shear is sin(φ). Thus, after step 4, C =
* -cos(φ)sin(φ) and D = 1 - sin²(φ) = cos²(φ). Thus, in step 5, the Y scale is
* sqrt(cos²(φ)(sin²(φ) + cos²(φ)) = cos(φ). Thus, after step 5, C = -sin(φ), D
* = cos(φ), and the XY shear is tan(φ). Thus, in step 6, A * D - B * C =
* cos²(φ) + sin²(φ) = 1. In step 7, the rotation is thus φ.
*
* skew(θ, φ), which is matrix(1, tan(φ), tan(θ), 1, 0, 0), which decomposes
* to 'rotate(φ) skewX(θ + φ) scale(sec(φ), cos(φ))' since (ignoring
* the alternate sign possibilities that would get fixed in step 6):
* In step 3, the X scale factor is sqrt(1+tan²(φ)) = sqrt(sec²(φ)) =
* sec(φ). Thus, after step 3, A = 1/sec(φ) = cos(φ) and B = tan(φ) / sec(φ) =
* sin(φ). In step 4, the XY shear is cos(φ)tan(θ) + sin(φ). Thus, after step 4,
* C = tan(θ) - cos(φ)(cos(φ)tan(θ) + sin(φ)) = tan(θ)sin²(φ) - cos(φ)sin(φ)
* D = 1 - sin(φ)(cos(φ)tan(θ) + sin(φ)) = cos²(φ) - sin(φ)cos(φ)tan(θ)
* Thus, in step 5, the Y scale is sqrt(C² + D²) =
* sqrt(tan²(θ)(sin⁴(φ) + sin²(φ)cos²(φ)) -
* 2 tan(θ)(sin³(φ)cos(φ) + sin(φ)cos³(φ)) +
* (sin²(φ)cos²(φ) + cos⁴(φ))) =
* sqrt(tan²(θ)sin²(φ) - 2 tan(θ)sin(φ)cos(φ) + cos²(φ)) =
* cos(φ) - tan(θ)sin(φ) (taking the negative of the obvious solution so
* we avoid flipping in step 6).
* After step 5, C = -sin(φ) and D = cos(φ), and the XY shear is
* (cos(φ)tan(θ) + sin(φ)) / (cos(φ) - tan(θ)sin(φ)) =
* (dividing both numerator and denominator by cos(φ))
* (tan(θ) + tan(φ)) / (1 - tan(θ)tan(φ)) = tan(θ + φ).
* (See http://en.wikipedia.org/wiki/List_of_trigonometric_identities .)
* Thus, in step 6, A * D - B * C = cos²(φ) + sin²(φ) = 1.
* In step 7, the rotation is thus φ.
*
* To check this result, we can multiply things back together:
*
* [ cos(φ) -sin(φ) ] [ 1 tan(θ + φ) ] [ sec(φ) 0 ]
* [ sin(φ) cos(φ) ] [ 0 1 ] [ 0 cos(φ) ]
*
* [ cos(φ) cos(φ)tan(θ + φ) - sin(φ) ] [ sec(φ) 0 ]
* [ sin(φ) sin(φ)tan(θ + φ) + cos(φ) ] [ 0 cos(φ) ]
*
* but since tan(θ + φ) = (tan(θ) + tan(φ)) / (1 - tan(θ)tan(φ)),
* cos(φ)tan(θ + φ) - sin(φ)
* = cos(φ)(tan(θ) + tan(φ)) - sin(φ) + sin(φ)tan(θ)tan(φ)
* = cos(φ)tan(θ) + sin(φ) - sin(φ) + sin(φ)tan(θ)tan(φ)
* = cos(φ)tan(θ) + sin(φ)tan(θ)tan(φ)
* = tan(θ) (cos(φ) + sin(φ)tan(φ))
* = tan(θ) sec(φ) (cos²(φ) + sin²(φ))
* = tan(θ) sec(φ)
* and
* sin(φ)tan(θ + φ) + cos(φ)
* = sin(φ)(tan(θ) + tan(φ)) + cos(φ) - cos(φ)tan(θ)tan(φ)
* = tan(θ) (sin(φ) - sin(φ)) + sin(φ)tan(φ) + cos(φ)
* = sec(φ) (sin²(φ) + cos²(φ))
* = sec(φ)
* so the above is:
* [ cos(φ) tan(θ) sec(φ) ] [ sec(φ) 0 ]
* [ sin(φ) sec(φ) ] [ 0 cos(φ) ]
*
* [ 1 tan(θ) ]
* [ tan(φ) 1 ]
*/
/*
* Decompose2DMatrix implements the above decomposition algorithm.
*/
bool Decompose2DMatrix(const Matrix& aMatrix, Point3D& aScale,
ShearArray& aShear, gfxQuaternion& aRotate,
Point3D& aTranslate) {
float A = aMatrix._11, B = aMatrix._12, C = aMatrix._21, D = aMatrix._22;
if (A * D == B * C) {
// singular matrix
return false;
}
float scaleX = sqrt(A * A + B * B);
A /= scaleX;
B /= scaleX;
float XYshear = A * C + B * D;
C -= A * XYshear;
D -= B * XYshear;
float scaleY = sqrt(C * C + D * D);
C /= scaleY;
D /= scaleY;
XYshear /= scaleY;
float determinant = A * D - B * C;
// Determinant should now be 1 or -1.
if (0.99 > Abs(determinant) || Abs(determinant) > 1.01) {
return false;
}
if (determinant < 0) {
A = -A;
B = -B;
C = -C;
D = -D;
XYshear = -XYshear;
scaleX = -scaleX;
}
float rotate = atan2f(B, A);
aRotate = gfxQuaternion(0, 0, sin(rotate / 2), cos(rotate / 2));
aShear[ShearType::XY] = XYshear;
aScale.x = scaleX;
aScale.y = scaleY;
aTranslate.x = aMatrix._31;
aTranslate.y = aMatrix._32;
return true;
}
/**
* Implementation of the unmatrix algorithm, specified by:
*
* http://dev.w3.org/csswg/css3-2d-transforms/#unmatrix
*
* This, in turn, refers to the unmatrix program in Graphics Gems,
* available from http://tog.acm.org/resources/GraphicsGems/ , and in
* particular as the file GraphicsGems/gemsii/unmatrix.c
* in http://tog.acm.org/resources/GraphicsGems/AllGems.tar.gz
*/
bool Decompose3DMatrix(const Matrix4x4& aMatrix, Point3D& aScale,
ShearArray& aShear, gfxQuaternion& aRotate,
Point3D& aTranslate, Point4D& aPerspective) {
Matrix4x4 local = aMatrix;
if (local[3][3] == 0) {
return false;
}
/* Normalize the matrix */
local.Normalize();
/**
* perspective is used to solve for perspective, but it also provides
* an easy way to test for singularity of the upper 3x3 component.
*/
Matrix4x4 perspective = local;
Point4D empty(0, 0, 0, 1);
perspective.SetTransposedVector(3, empty);
if (perspective.Determinant() == 0.0) {
return false;
}
/* First, isolate perspective. */
if (local[0][3] != 0 || local[1][3] != 0 || local[2][3] != 0) {
/* aPerspective is the right hand side of the equation. */
aPerspective = local.TransposedVector(3);
/**
* Solve the equation by inverting perspective and multiplying
* aPerspective by the inverse.
*/
perspective.Invert();
aPerspective = perspective.TransposeTransform4D(aPerspective);
/* Clear the perspective partition */
local.SetTransposedVector(3, empty);
} else {
aPerspective = Point4D(0, 0, 0, 1);
}
/* Next take care of translation */
for (int i = 0; i < 3; i++) {
aTranslate[i] = local[3][i];
local[3][i] = 0;
}
/* Now get scale and shear. */
/* Compute X scale factor and normalize first row. */
aScale.x = local[0].Length();
local[0] /= aScale.x;
/* Compute XY shear factor and make 2nd local orthogonal to 1st. */
aShear[ShearType::XY] = local[0].DotProduct(local[1]);
local[1] -= local[0] * aShear[ShearType::XY];
/* Now, compute Y scale and normalize 2nd local. */
aScale.y = local[1].Length();
local[1] /= aScale.y;
aShear[ShearType::XY] /= aScale.y;
/* Compute XZ and YZ shears, make 3rd local orthogonal */
aShear[ShearType::XZ] = local[0].DotProduct(local[2]);
local[2] -= local[0] * aShear[ShearType::XZ];
aShear[ShearType::YZ] = local[1].DotProduct(local[2]);
local[2] -= local[1] * aShear[ShearType::YZ];
/* Next, get Z scale and normalize 3rd local. */
aScale.z = local[2].Length();
local[2] /= aScale.z;
aShear[ShearType::XZ] /= aScale.z;
aShear[ShearType::YZ] /= aScale.z;
/**
* At this point, the matrix (in locals) is orthonormal.
* Check for a coordinate system flip. If the determinant
* is -1, then negate the matrix and the scaling factors.
*/
if (local[0].DotProduct(local[1].CrossProduct(local[2])) < 0) {
aScale *= -1;
for (int i = 0; i < 3; i++) {
local[i] *= -1;
}
}
/* Now, get the rotations out */
aRotate = gfxQuaternion(local);
return true;
}
Matrix CSSValueArrayTo2DMatrix(nsCSSValue::Array* aArray) {
MOZ_ASSERT(aArray && TransformFunctionOf(aArray) == eCSSKeyword_matrix &&
aArray->Count() == 7);
Matrix m(aArray->Item(1).GetFloatValue(), aArray->Item(2).GetFloatValue(),
aArray->Item(3).GetFloatValue(), aArray->Item(4).GetFloatValue(),
aArray->Item(5).GetFloatValue(), aArray->Item(6).GetFloatValue());
return m;
}
Matrix4x4 CSSValueArrayTo3DMatrix(nsCSSValue::Array* aArray) {
MOZ_ASSERT(aArray && TransformFunctionOf(aArray) == eCSSKeyword_matrix3d &&
aArray->Count() == 17);
gfx::Float array[16];
for (size_t i = 0; i < 16; ++i) {
array[i] = aArray->Item(i + 1).GetFloatValue();
}
Matrix4x4 m(array);
return m;
}
Size GetScaleValue(const nsCSSValueSharedList* aList,
const nsIFrame* aForFrame) {
MOZ_ASSERT(aList && aList->mHead);
MOZ_ASSERT(aForFrame);
TransformReferenceBox refBox(aForFrame);
Matrix4x4 transform = ReadTransforms(
aList->mHead, refBox, aForFrame->PresContext()->AppUnitsPerDevPixel());
Matrix transform2d;
bool canDraw2D = transform.CanDraw2D(&transform2d);
if (!canDraw2D) {
return Size();
}
return transform2d.ScaleFactors(true);
}
} // namespace nsStyleTransformMatrix
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