The Tor Browser: layout/style/nsStyleTransformMatrix.cpp@6474c204b198 (annotated)

layout/style/nsStyleTransformMatrix.cpp@6474c204b198 (annotated)

layout/style/nsStyleTransformMatrix.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* 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 "nsPresContext.h"
 #include "nsRuleNode.h"
 #include "nsCSSKeywords.h"
 #include "nsStyleAnimation.h"
 #include "gfxMatrix.h"
 using namespace mozilla;
 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'.
  */
 /* Force small values to zero.  We do this to avoid having sin(360deg)
  * evaluate to a tiny but nonzero value.
  */
 static double FlushToZero(double aVal)
 {
   if (-FLT_EPSILON < aVal && aVal < FLT_EPSILON)
     return 0.0f;
   else
     return aVal;
 }
 float
 ProcessTranslatePart(const nsCSSValue& aValue,
                      nsStyleContext* aContext,
                      nsPresContext* aPresContext,
                      bool& aCanStoreInRuleTree,
                      nscoord aSize,
                      float aAppUnitsPerMatrixUnit)
 {
   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) {
     // Handle this here (even though nsRuleNode::CalcLength handles it
     // fine) so that callers are allowed to pass a null style context
     // and pres context to SetToTransformFunction if they know (as
     // nsStyleAnimation does) that all lengths within the transform
     // function have already been computed to pixels and percents.
     //
     // Raw numbers are treated as being pixels.
     //
     // Don't convert to aValue to AppUnits here to avoid precision issues.
     return aValue.GetFloatValue() *
            (float(nsPresContext::AppUnitsPerCSSPixel()) / aAppUnitsPerMatrixUnit);
   } else if (aValue.IsCalcUnit()) {
     nsRuleNode::ComputedCalc result =
       nsRuleNode::SpecifiedCalcToComputedCalc(aValue, aContext, aPresContext,
                                               aCanStoreInRuleTree);
     percent = result.mPercent;
     offset = result.mLength;
   } else {
     offset = nsRuleNode::CalcLength(aValue, aContext, aPresContext,
                                     aCanStoreInRuleTree);
   }
   return (percent * NSAppUnitsToFloatPixels(aSize, aAppUnitsPerMatrixUnit)) +
          NSAppUnitsToFloatPixels(offset, aAppUnitsPerMatrixUnit);
 }
 /**
  * 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(gfx3DMatrix& aMatrix,
               const nsCSSValue::Array* aData,
               nsStyleContext* aContext,
               nsPresContext* aPresContext,
               bool& aCanStoreInRuleTree,
               nsRect& aBounds, float aAppUnitsPerMatrixUnit)
 {
   NS_PRECONDITION(aData->Count() == 7, "Invalid array!");
   gfxMatrix result;
   /* Take the first four elements out of the array as floats and store
    * them.
    */
   result.xx = aData->Item(1).GetFloatValue();
   result.yx = aData->Item(2).GetFloatValue();
   result.xy = aData->Item(3).GetFloatValue();
   result.yy = 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.x0 = ProcessTranslatePart(aData->Item(5),
                                    aContext, aPresContext, aCanStoreInRuleTree,
                                    aBounds.Width(), aAppUnitsPerMatrixUnit);
   result.y0 = ProcessTranslatePart(aData->Item(6),
                                    aContext, aPresContext, aCanStoreInRuleTree,
                                    aBounds.Height(), aAppUnitsPerMatrixUnit);
   aMatrix.PreMultiply(result);
 }
 static void
 ProcessMatrix3D(gfx3DMatrix& aMatrix,
                 const nsCSSValue::Array* aData,
                 nsStyleContext* aContext,
                 nsPresContext* aPresContext,
                 bool& aCanStoreInRuleTree,
                 nsRect& aBounds, float aAppUnitsPerMatrixUnit)
 {
   NS_PRECONDITION(aData->Count() == 17, "Invalid array!");
   gfx3DMatrix 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),
                                   aContext, aPresContext, aCanStoreInRuleTree,
                                   aBounds.Width(), aAppUnitsPerMatrixUnit);
   temp._42 = ProcessTranslatePart(aData->Item(14),
                                   aContext, aPresContext, aCanStoreInRuleTree,
                                   aBounds.Height(), aAppUnitsPerMatrixUnit);
   temp._43 = ProcessTranslatePart(aData->Item(15),
                                   aContext, aPresContext, aCanStoreInRuleTree,
                                   aBounds.Height(), aAppUnitsPerMatrixUnit);
   aMatrix.PreMultiply(temp);
 }
 /* Helper function to process two matrices that we need to interpolate between */
 void
 ProcessInterpolateMatrix(gfx3DMatrix& aMatrix,
                          const nsCSSValue::Array* aData,
                          nsStyleContext* aContext,
                          nsPresContext* aPresContext,
                          bool& aCanStoreInRuleTree,
                          nsRect& aBounds, float aAppUnitsPerMatrixUnit)
 {
   NS_PRECONDITION(aData->Count() == 4, "Invalid array!");
   gfx3DMatrix matrix1, matrix2;
   if (aData->Item(1).GetUnit() == eCSSUnit_List) {
     matrix1 = nsStyleTransformMatrix::ReadTransforms(aData->Item(1).GetListValue(),
                              aContext, aPresContext,
                              aCanStoreInRuleTree,
                              aBounds, aAppUnitsPerMatrixUnit);
   }
   if (aData->Item(2).GetUnit() == eCSSUnit_List) {
     matrix2 = ReadTransforms(aData->Item(2).GetListValue(),
                              aContext, aPresContext,
                              aCanStoreInRuleTree,
                              aBounds, aAppUnitsPerMatrixUnit);
   }
   double progress = aData->Item(3).GetPercentValue();
   aMatrix = nsStyleAnimation::InterpolateTransformMatrix(matrix1, matrix2, progress) * aMatrix;
 }
 /* Helper function to process a translatex function. */
 static void
 ProcessTranslateX(gfx3DMatrix& aMatrix,
                   const nsCSSValue::Array* aData,
                   nsStyleContext* aContext,
                   nsPresContext* aPresContext,
                   bool& aCanStoreInRuleTree,
                   nsRect& aBounds, float aAppUnitsPerMatrixUnit)
 {
   NS_PRECONDITION(aData->Count() == 2, "Invalid array!");
   gfxPoint3D temp;
   temp.x = ProcessTranslatePart(aData->Item(1),
                                 aContext, aPresContext, aCanStoreInRuleTree,
                                 aBounds.Width(), aAppUnitsPerMatrixUnit);
   aMatrix.Translate(temp);
 }
 /* Helper function to process a translatey function. */
 static void
 ProcessTranslateY(gfx3DMatrix& aMatrix,
                   const nsCSSValue::Array* aData,
                   nsStyleContext* aContext,
                   nsPresContext* aPresContext,
                   bool& aCanStoreInRuleTree,
                   nsRect& aBounds, float aAppUnitsPerMatrixUnit)
 {
   NS_PRECONDITION(aData->Count() == 2, "Invalid array!");
   gfxPoint3D temp;
   temp.y = ProcessTranslatePart(aData->Item(1),
                                 aContext, aPresContext, aCanStoreInRuleTree,
                                 aBounds.Height(), aAppUnitsPerMatrixUnit);
   aMatrix.Translate(temp);
 }
 static void
 ProcessTranslateZ(gfx3DMatrix& aMatrix,
                   const nsCSSValue::Array* aData,
                   nsStyleContext* aContext,
                                           nsPresContext* aPresContext,
                                           bool& aCanStoreInRuleTree,
                                           float aAppUnitsPerMatrixUnit)
 {
   NS_PRECONDITION(aData->Count() == 2, "Invalid array!");
   gfxPoint3D temp;
   temp.z = ProcessTranslatePart(aData->Item(1),
                                 aContext, aPresContext, aCanStoreInRuleTree,
 , aAppUnitsPerMatrixUnit);
   aMatrix.Translate(temp);
 }
 /* Helper function to process a translate function. */
 static void
 ProcessTranslate(gfx3DMatrix& aMatrix,
                  const nsCSSValue::Array* aData,
                  nsStyleContext* aContext,
                  nsPresContext* aPresContext,
                  bool& aCanStoreInRuleTree,
                  nsRect& aBounds, float aAppUnitsPerMatrixUnit)
 {
   NS_PRECONDITION(aData->Count() == 2 || aData->Count() == 3, "Invalid array!");
   gfxPoint3D temp;
   temp.x = ProcessTranslatePart(aData->Item(1),
                                 aContext, aPresContext, aCanStoreInRuleTree,
                                 aBounds.Width(), aAppUnitsPerMatrixUnit);
   /* If we read in a Y component, set it appropriately */
   if (aData->Count() == 3) {
     temp.y = ProcessTranslatePart(aData->Item(2),
                                   aContext, aPresContext, aCanStoreInRuleTree,
                                   aBounds.Height(), aAppUnitsPerMatrixUnit);
   }
   aMatrix.Translate(temp);
 }
 static void
 ProcessTranslate3D(gfx3DMatrix& aMatrix,
                    const nsCSSValue::Array* aData,
                    nsStyleContext* aContext,
                    nsPresContext* aPresContext,
                    bool& aCanStoreInRuleTree,
                    nsRect& aBounds, float aAppUnitsPerMatrixUnit)
 {
   NS_PRECONDITION(aData->Count() == 4, "Invalid array!");
   gfxPoint3D temp;
   temp.x = ProcessTranslatePart(aData->Item(1),
                                 aContext, aPresContext, aCanStoreInRuleTree,
                                 aBounds.Width(), aAppUnitsPerMatrixUnit);
   temp.y = ProcessTranslatePart(aData->Item(2),
                                 aContext, aPresContext, aCanStoreInRuleTree,
                                 aBounds.Height(), aAppUnitsPerMatrixUnit);
   temp.z = ProcessTranslatePart(aData->Item(3),
                                 aContext, aPresContext, aCanStoreInRuleTree,
 , aAppUnitsPerMatrixUnit);
   aMatrix.Translate(temp);
 }
 /* Helper function to set up a scale matrix. */
 static void
 ProcessScaleHelper(gfx3DMatrix& aMatrix,
                    float aXScale,
                    float aYScale,
                    float aZScale)
 {
   aMatrix.Scale(aXScale, aYScale, aZScale);
 }
 /* Process a scalex function. */
 static void
 ProcessScaleX(gfx3DMatrix& aMatrix, const nsCSSValue::Array* aData)
 {
   NS_PRECONDITION(aData->Count() == 2, "Bad array!");
   ProcessScaleHelper(aMatrix, aData->Item(1).GetFloatValue(), 1.0f, 1.0f);
 }
 /* Process a scaley function. */
 static void
 ProcessScaleY(gfx3DMatrix& aMatrix, const nsCSSValue::Array* aData)
 {
   NS_PRECONDITION(aData->Count() == 2, "Bad array!");
   ProcessScaleHelper(aMatrix, 1.0f, aData->Item(1).GetFloatValue(), 1.0f);
 }
 static void
 ProcessScaleZ(gfx3DMatrix& aMatrix, const nsCSSValue::Array* aData)
 {
   NS_PRECONDITION(aData->Count() == 2, "Bad array!");
   ProcessScaleHelper(aMatrix, 1.0f, 1.0f, aData->Item(1).GetFloatValue());
 }
 static void
 ProcessScale3D(gfx3DMatrix& aMatrix, const nsCSSValue::Array* aData)
 {
   NS_PRECONDITION(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(gfx3DMatrix& aMatrix, const nsCSSValue::Array* aData)
 {
   NS_PRECONDITION(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(),
 .0f);
 }
 /* Helper function that, given a set of angles, constructs the appropriate
  * skew matrix.
  */
 static void
 ProcessSkewHelper(gfx3DMatrix& aMatrix, double aXAngle, double aYAngle)
 {
   aMatrix.SkewXY(aXAngle, aYAngle);
 }
 /* Function that converts a skewx transform into a matrix. */
 static void
 ProcessSkewX(gfx3DMatrix& 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(gfx3DMatrix& 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(gfx3DMatrix& 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(gfx3DMatrix& aMatrix, const nsCSSValue::Array* aData)
 {
   NS_PRECONDITION(aData->Count() == 2, "Invalid array!");
   double theta = aData->Item(1).GetAngleValueInRadians();
   aMatrix.RotateZ(theta);
 }
 static void
 ProcessRotateX(gfx3DMatrix& aMatrix, const nsCSSValue::Array* aData)
 {
   NS_PRECONDITION(aData->Count() == 2, "Invalid array!");
   double theta = aData->Item(1).GetAngleValueInRadians();
   aMatrix.RotateX(theta);
 }
 static void
 ProcessRotateY(gfx3DMatrix& aMatrix, const nsCSSValue::Array* aData)
 {
   NS_PRECONDITION(aData->Count() == 2, "Invalid array!");
   double theta = aData->Item(1).GetAngleValueInRadians();
   aMatrix.RotateY(theta);
 }
 static void
 ProcessRotate3D(gfx3DMatrix& aMatrix, const nsCSSValue::Array* aData)
 {
   NS_PRECONDITION(aData->Count() == 5, "Invalid array!");
   /* We want our matrix to look like this:
    * |       1 + (1-cos(angle))*(x*x-1)   -z*sin(angle)+(1-cos(angle))*x*y   y*sin(angle)+(1-cos(angle))*x*z   0 |
    * |  z*sin(angle)+(1-cos(angle))*x*y         1 + (1-cos(angle))*(y*y-1)  -x*sin(angle)+(1-cos(angle))*y*z   0 |
    * | -y*sin(angle)+(1-cos(angle))*x*z    x*sin(angle)+(1-cos(angle))*y*z        1 + (1-cos(angle))*(z*z-1)   0 |
    * |                                0                                  0                                 0   1 |
    * (see http://www.w3.org/TR/css3-3d-transforms/#transform-functions)
    */
   /* The current spec specifies a matrix that rotates in the wrong direction. For now we just negate
    * the angle provided to get the correct rotation direction until the spec is updated.
    * See bug 704468.
    */
   double theta = -aData->Item(4).GetAngleValueInRadians();
   float cosTheta = FlushToZero(cos(theta));
   float sinTheta = FlushToZero(sin(theta));
   float x = aData->Item(1).GetFloatValue();
   float y = aData->Item(2).GetFloatValue();
   float z = aData->Item(3).GetFloatValue();
   /* Normalize [x,y,z] */
   float length = sqrt(x*x + y*y + z*z);
   if (length == 0.0) {
     return;
   }
   x /= length;
   y /= length;
   z /= length;
   gfx3DMatrix temp;
   /* Create our matrix */
   temp._11 = 1 + (1 - cosTheta) * (x * x - 1);
   temp._12 = -z * sinTheta + (1 - cosTheta) * x * y;
   temp._13 = y * sinTheta + (1 - cosTheta) * x * z;
   temp._14 = 0.0f;
   temp._21 = z * sinTheta + (1 - cosTheta) * x * y;
   temp._22 = 1 + (1 - cosTheta) * (y * y - 1);
   temp._23 = -x * sinTheta + (1 - cosTheta) * y * z;
   temp._24 = 0.0f;
   temp._31 = -y * sinTheta + (1 - cosTheta) * x * z;
   temp._32 = x * sinTheta + (1 - cosTheta) * y * z;
   temp._33 = 1 + (1 - cosTheta) * (z * z - 1);
   temp._34 = 0.0f;
   temp._41 = 0.0f;
   temp._42 = 0.0f;
   temp._43 = 0.0f;
   temp._44 = 1.0f;
   aMatrix = temp * aMatrix;
 }
 static void
 ProcessPerspective(gfx3DMatrix& aMatrix,
                    const nsCSSValue::Array* aData,
                    nsStyleContext *aContext,
                    nsPresContext *aPresContext,
                    bool &aCanStoreInRuleTree,
                    float aAppUnitsPerMatrixUnit)
 {
   NS_PRECONDITION(aData->Count() == 2, "Invalid array!");
   float depth = ProcessTranslatePart(aData->Item(1), aContext,
                                      aPresContext, aCanStoreInRuleTree,
 , aAppUnitsPerMatrixUnit);
   aMatrix.Perspective(depth);
 }
 /**
  * SetToTransformFunction is essentially a giant switch statement that fans
  * out to many smaller helper functions.
  */
 static void
 MatrixForTransformFunction(gfx3DMatrix& aMatrix,
                            const nsCSSValue::Array * aData,
                            nsStyleContext* aContext,
                            nsPresContext* aPresContext,
                            bool& aCanStoreInRuleTree,
                            nsRect& aBounds,
                            float aAppUnitsPerMatrixUnit)
 {
   NS_PRECONDITION(aData, "Why did you want to get data from a null array?");
   // It's OK if aContext and aPresContext are null if the caller already
   // knows that all length units have been converted to pixels (as
   // nsStyleAnimation does).
   /* Get the keyword for the transform. */
   switch (TransformFunctionOf(aData)) {
   case eCSSKeyword_translatex:
     ProcessTranslateX(aMatrix, aData, aContext, aPresContext,
                       aCanStoreInRuleTree, aBounds, aAppUnitsPerMatrixUnit);
     break;
   case eCSSKeyword_translatey:
     ProcessTranslateY(aMatrix, aData, aContext, aPresContext,
                       aCanStoreInRuleTree, aBounds, aAppUnitsPerMatrixUnit);
     break;
   case eCSSKeyword_translatez:
     ProcessTranslateZ(aMatrix, aData, aContext, aPresContext,
                       aCanStoreInRuleTree, aAppUnitsPerMatrixUnit);
     break;
   case eCSSKeyword_translate:
     ProcessTranslate(aMatrix, aData, aContext, aPresContext,
                      aCanStoreInRuleTree, aBounds, aAppUnitsPerMatrixUnit);
     break;
   case eCSSKeyword_translate3d:
     ProcessTranslate3D(aMatrix, aData, aContext, aPresContext,
                        aCanStoreInRuleTree, aBounds, aAppUnitsPerMatrixUnit);
     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:
   case eCSSKeyword_rotate:
     ProcessRotateZ(aMatrix, aData);
     break;
   case eCSSKeyword_rotate3d:
     ProcessRotate3D(aMatrix, aData);
     break;
   case eCSSKeyword_matrix:
     ProcessMatrix(aMatrix, aData, aContext, aPresContext,
                   aCanStoreInRuleTree, aBounds, aAppUnitsPerMatrixUnit);
     break;
   case eCSSKeyword_matrix3d:
     ProcessMatrix3D(aMatrix, aData, aContext, aPresContext,
                     aCanStoreInRuleTree, aBounds, aAppUnitsPerMatrixUnit);
     break;
   case eCSSKeyword_interpolatematrix:
     ProcessInterpolateMatrix(aMatrix, aData, aContext, aPresContext,
                              aCanStoreInRuleTree, aBounds, aAppUnitsPerMatrixUnit);
     break;
   case eCSSKeyword_perspective:
     ProcessPerspective(aMatrix, aData, aContext, aPresContext,
                        aCanStoreInRuleTree, aAppUnitsPerMatrixUnit);
     break;
   default:
     NS_NOTREACHED("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();
 }
 gfx3DMatrix
 ReadTransforms(const nsCSSValueList* aList,
                nsStyleContext* aContext,
                nsPresContext* aPresContext,
                bool &aCanStoreInRuleTree,
                nsRect& aBounds,
                float aAppUnitsPerMatrixUnit)
 {
   gfx3DMatrix result;
   for (const nsCSSValueList* curr = aList; curr != nullptr; curr = curr->mNext) {
     const nsCSSValue &currElem = curr->mValue;
     NS_ASSERTION(currElem.GetUnit() == eCSSUnit_Function,
                  "Stream should consist solely of functions!");
     NS_ASSERTION(currElem.GetArrayValue()->Count() >= 1,
                  "Incoming function is too short!");
     /* Read in a single transform matrix. */
     MatrixForTransformFunction(result, currElem.GetArrayValue(), aContext,
                                aPresContext, aCanStoreInRuleTree,
                                aBounds, aAppUnitsPerMatrixUnit);
   }
   return result;
 }
 } // namespace nsStyleTransformMatrix

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layout/style/nsStyleTransformMatrix.cpp@6474c204b198 (annotated)

layout/style/nsStyleTransformMatrix.cpp