зеркало из https://github.com/mozilla/gecko-dev.git
528 строки
17 KiB
C++
528 строки
17 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is mozilla.org code.
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*
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* The Initial Developer of the Original Code is
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* Mozilla Corporation
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*
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* Contributor(s):
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* Keith Schwarz <kschwarz@mozilla.com> (original author)
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either of the GNU General Public License Version 2 or later (the "GPL"),
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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/*
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* A class used for intermediate representations of the -moz-transform property.
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*/
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#include "nsStyleTransformMatrix.h"
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#include "nsAutoPtr.h"
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#include "nsCSSValue.h"
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#include "nsStyleContext.h"
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#include "nsPresContext.h"
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#include "nsRuleNode.h"
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#include "nsCSSKeywords.h"
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#include <math.h>
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/* Arguably, this loses precision, but it doesn't hurt! */
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const float kPi = 3.1415926535897932384626433f;
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const float kEpsilon = 0.0001f;
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/* Computes tan(theta). For values of theta such that
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* tan(theta) is undefined or arbitrarily large, SafeTangent
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* returns a managably large or small value of the correct sign.
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*/
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static float SafeTangent(float aTheta)
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{
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/* We'll do this by computing sin and cos theta. If cos(theta) is
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* is too close to zero, we'll set it to some arbitrary epsilon value
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* that avoid float overflow or undefined result.
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*/
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float sinTheta = sin(aTheta);
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float cosTheta = cos(aTheta);
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/* Bound cos(theta) to be in the range [-1, -epsilon) U (epsilon, 1] */
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if (cosTheta >= 0 && cosTheta < kEpsilon)
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cosTheta = kEpsilon;
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else if (cosTheta < 0 && cosTheta >= -kEpsilon)
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cosTheta = -kEpsilon;
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return sinTheta / cosTheta;
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}
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/* Converts an nsCSSValue containing an angle into an equivalent measure
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* of radians.
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*/
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static float CSSToRadians(const nsCSSValue &aValue)
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{
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NS_PRECONDITION(aValue.IsAngularUnit(),
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"Expected an angle, but didn't find one!");
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switch (aValue.GetUnit()) {
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case eCSSUnit_Degree:
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/* 360deg = 2pi rad, so deg = pi / 180 rad */
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return aValue.GetFloatValue() * kPi / 180.0f;
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case eCSSUnit_Grad:
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/* 400grad = 2pi rad, so grad = pi / 200 rad */
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return aValue.GetFloatValue() * kPi / 200.0f;
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case eCSSUnit_Radian:
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/* Yay identity transforms! */
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return aValue.GetFloatValue();
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default:
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NS_NOTREACHED("Unexpected angular unit!");
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return 0.0f;
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}
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}
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/* Constructor sets the data to the identity matrix. */
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nsStyleTransformMatrix::nsStyleTransformMatrix()
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{
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SetToIdentity();
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}
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/* SetToIdentity just fills in the appropriate values. */
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void nsStyleTransformMatrix::SetToIdentity()
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{
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/* Set the main matrix to the identity. */
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mMain[0] = 1.0f;
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mMain[1] = 0.0f;
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mMain[2] = 0.0f;
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mMain[3] = 1.0f;
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mDelta[0] = 0;
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mDelta[1] = 0;
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/* Both translation matrices are zero. */
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mX[0] = 0.0f;
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mX[1] = 0.0f;
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mY[0] = 0.0f;
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mY[1] = 0.0f;
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}
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/* Adds the constant translation to the scale factor translation components. */
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nscoord nsStyleTransformMatrix::GetXTranslation(const nsRect& aBounds) const
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{
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return nscoord(aBounds.width * mX[0] + aBounds.height * mY[0]) + mDelta[0];
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}
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nscoord nsStyleTransformMatrix::GetYTranslation(const nsRect& aBounds) const
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{
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return nscoord(aBounds.width * mX[1] + aBounds.height * mY[1]) + mDelta[1];
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}
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/* GetThebesMatrix converts the stored matrix in a few steps. */
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gfxMatrix nsStyleTransformMatrix::GetThebesMatrix(const nsRect& aBounds,
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PRInt32 aScale) const
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{
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/* Compute the graphics matrix. We take the stored main elements, along with
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* the delta, and add in the matrices:
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*
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* | 0 0 dx1|
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* | 0 0 dx2| * width
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* | 0 0 0|
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*
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* | 0 0 dy1|
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* | 0 0 dy2| * height
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* | 0 0 0|
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*/
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return gfxMatrix(mMain[0], mMain[1], mMain[2], mMain[3],
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NSAppUnitsToFloatPixels(GetXTranslation(aBounds), aScale),
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NSAppUnitsToFloatPixels(GetYTranslation(aBounds), aScale));
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}
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/* Performs the matrix multiplication necessary to multiply the two matrices,
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* then hands back a reference to ourself.
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*/
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nsStyleTransformMatrix&
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nsStyleTransformMatrix::operator *= (const nsStyleTransformMatrix &aOther)
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{
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/* We'll buffer all of our results into a temporary storage location
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* during this operation since we don't want to overwrite the values of
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* the old matrix with the values of the new.
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*/
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float newMatrix[4];
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nscoord newDelta[2];
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float newX[2];
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float newY[2];
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/* [this] [aOther]
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* |a1 c1 e1| |a0 c0 e0| |a0a1 + b0c1 c0a1 + d0c1 e0a1 + f0c1 + e1|
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* |b1 d1 f1|x|b0 d0 f0| = |a0b1 + b0d1 c0b1 + d0d1 e0b1 + f0d1 + f1|
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* |0 0 1 | | 0 0 1| | 0 0 1|
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*/
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newMatrix[0] = aOther.mMain[0] * mMain[0] + aOther.mMain[1] * mMain[2];
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newMatrix[1] = aOther.mMain[0] * mMain[1] + aOther.mMain[1] * mMain[3];
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newMatrix[2] = aOther.mMain[2] * mMain[0] + aOther.mMain[3] * mMain[2];
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newMatrix[3] = aOther.mMain[2] * mMain[1] + aOther.mMain[3] * mMain[3];
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newDelta[0] =
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NSCoordMultiply(aOther.mDelta[0], mMain[0]) +
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NSCoordMultiply(aOther.mDelta[1], mMain[2]) + mDelta[0];
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newDelta[1] =
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NSCoordMultiply(aOther.mDelta[0], mMain[1]) +
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NSCoordMultiply(aOther.mDelta[1], mMain[3]) + mDelta[1];
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/* For consistent terminology, let u0, u1, v0, and v1 be the four transform
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* coordinates from our matrix, and let x0, x1, y0, and y1 be the four
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* transform coordinates from the other matrix. Then the new transform
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* coordinates are:
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*
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* u0' = a1u0 + c1u1 + x0
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* u1' = b1u0 + d1u1 + x1
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* v0' = a1v0 + c1v1 + y0
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* v1' = b1v0 + d1v1 + y1
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*/
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newX[0] = mMain[0] * aOther.mX[0] + mMain[2] * aOther.mX[1] + mX[0];
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newX[1] = mMain[1] * aOther.mX[0] + mMain[3] * aOther.mX[1] + mX[1];
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newY[0] = mMain[0] * aOther.mY[0] + mMain[2] * aOther.mY[1] + mY[0];
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newY[1] = mMain[1] * aOther.mY[0] + mMain[3] * aOther.mY[1] + mY[1];
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/* Now, write everything back in. */
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for (PRInt32 index = 0; index < 4; ++index)
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mMain[index] = newMatrix[index];
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for (PRInt32 index = 0; index < 2; ++index) {
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mDelta[index] = newDelta[index];
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mX[index] = newX[index];
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mY[index] = newY[index];
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}
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/* As promised, return a reference to ourselves. */
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return *this;
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}
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/* op* is implemented in terms of op*=. */
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const nsStyleTransformMatrix
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nsStyleTransformMatrix::operator *(const nsStyleTransformMatrix &aOther) const
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{
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return nsStyleTransformMatrix(*this) *= aOther;
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}
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/* Helper function to fill in an nscoord with the specified nsCSSValue. */
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static void SetCoordToValue(const nsCSSValue &aValue,
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nsStyleContext* aContext,
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nsPresContext* aPresContext, nscoord &aOut)
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{
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PRBool unused = PR_FALSE;
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aOut = nsRuleNode::CalcLength(aValue, aContext, aPresContext, unused);
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NS_POSTCONDITION(!unused, "How did we inherit a value?");
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}
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/* Helper function to process a matrix entry. */
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static void ProcessMatrix(float aMain[4], nscoord aDelta[2],
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float aX[2], float aY[2],
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const nsCSSValue::Array* aData,
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nsStyleContext* aContext,
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nsPresContext* aPresContext)
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{
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NS_PRECONDITION(aData->Count() == 7, "Invalid array!");
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/* Take the first four elements out of the array as floats and store
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* them in aMain.
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*/
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for (PRUint16 index = 1; index <= 4; ++index)
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aMain[index - 1] = aData->Item(index).GetFloatValue();
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/* For the fifth element, if it's a percentage, store it in aX[0].
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* Otherwise, it's a length that needs to go in aDelta[0]
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*/
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if (aData->Item(5).GetUnit() == eCSSUnit_Percent)
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aX[0] = aData->Item(5).GetPercentValue();
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else
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SetCoordToValue(aData->Item(5), aContext, aPresContext, aDelta[0]);
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/* For the final element, if it's a percentage, store it in aY[1].
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* Otherwise, it's a length that needs to go in aDelta[1].
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*/
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if (aData->Item(6).GetUnit() == eCSSUnit_Percent)
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aY[1] = aData->Item(5).GetPercentValue();
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else
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SetCoordToValue(aData->Item(6), aContext, aPresContext, aDelta[1]);
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}
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/* Helper function to process a translatex function. */
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static void ProcessTranslateX(nscoord aDelta[2], float aX[2],
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const nsCSSValue::Array* aData,
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nsStyleContext* aContext,
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nsPresContext* aPresContext)
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{
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NS_PRECONDITION(aData->Count() == 2, "Invalid array!");
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/* There are two cases. If we have a number, we want our matrix to look
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* like this:
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*
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* | 1 0 dx|
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* | 0 1 0|
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* | 0 0 1|
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* So E = value
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*
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* Otherwise, we might have a percentage, so we want to set the dX component
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* to the percent.
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*/
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if (aData->Item(1).GetUnit() != eCSSUnit_Percent)
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SetCoordToValue(aData->Item(1), aContext, aPresContext, aDelta[0]);
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else
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aX[0] = aData->Item(1).GetPercentValue();
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}
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/* Helper function to process a translatey function. */
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static void ProcessTranslateY(nscoord aDelta[2], float aY[2],
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const nsCSSValue::Array* aData,
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nsStyleContext* aContext,
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nsPresContext* aPresContext)
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{
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NS_PRECONDITION(aData->Count() == 2, "Invalid array!");
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/* There are two cases. If we have a number, we want our matrix to look
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* like this:
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*
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* | 1 0 0|
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* | 0 1 dy|
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* | 0 0 1|
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* So E = value
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*
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* Otherwise, we might have a percentage, so we want to set the dY component
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* to the percent.
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*/
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if (aData->Item(1).GetUnit() != eCSSUnit_Percent)
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SetCoordToValue(aData->Item(1), aContext, aPresContext, aDelta[1]);
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else
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aY[1] = aData->Item(1).GetPercentValue();
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}
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/* Helper function to process a translate function. */
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static void ProcessTranslate(nscoord aDelta[2], float aX[2], float aY[2],
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const nsCSSValue::Array* aData,
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nsStyleContext* aContext,
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nsPresContext* aPresContext)
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{
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NS_PRECONDITION(aData->Count() == 2 || aData->Count() == 3, "Invalid array!");
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/* There are several cases to consider.
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* First, we might have one value, or we might have two. If we have
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* two, we need to consider both dX and dY components.
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* Next, the values might be lengths, or they might be percents. If they're
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* percents, store them in the dX and dY components. Otherwise, store them in
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* the main matrix.
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*/
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const nsCSSValue &dx = aData->Item(1);
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if (dx.GetUnit() == eCSSUnit_Percent)
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aX[0] = dx.GetPercentValue();
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else
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SetCoordToValue(dx, aContext, aPresContext, aDelta[0]);
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/* If we read in a Y component, set it appropriately */
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if (aData->Count() == 3) {
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const nsCSSValue &dy = aData->Item(2);
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if (dy.GetUnit() == eCSSUnit_Percent)
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aY[1] = dy.GetPercentValue();
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else
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SetCoordToValue(dy, aContext, aPresContext, aDelta[1]);
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}
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}
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/* Helper function to set up a scale matrix. */
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static void ProcessScaleHelper(float aXScale, float aYScale, float aMain[4])
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{
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/* We want our matrix to look like this:
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* | dx 0 0|
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* | 0 dy 0|
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* | 0 0 1|
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* So A = value
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*/
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aMain[0] = aXScale;
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aMain[3] = aYScale;
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}
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/* Process a scalex function. */
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static void ProcessScaleX(float aMain[4], const nsCSSValue::Array* aData)
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{
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NS_PRECONDITION(aData->Count() == 2, "Bad array!");
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ProcessScaleHelper(aData->Item(1).GetFloatValue(), 1.0f, aMain);
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}
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/* Process a scaley function. */
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static void ProcessScaleY(float aMain[4], const nsCSSValue::Array* aData)
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{
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NS_PRECONDITION(aData->Count() == 2, "Bad array!");
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ProcessScaleHelper(1.0f, aData->Item(1).GetFloatValue(), aMain);
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}
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/* Process a scale function. */
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static void ProcessScale(float aMain[4], const nsCSSValue::Array* aData)
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{
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NS_PRECONDITION(aData->Count() == 2 || aData->Count() == 3, "Bad array!");
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/* We either have one element or two. If we have one, it's for both X and Y.
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* Otherwise it's one for each.
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*/
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const nsCSSValue& scaleX = aData->Item(1);
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const nsCSSValue& scaleY = (aData->Count() == 2 ? scaleX :
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aData->Item(2));
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ProcessScaleHelper(scaleX.GetFloatValue(),
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scaleY.GetFloatValue(), aMain);
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}
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/* Helper function that, given a set of angles, constructs the appropriate
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* skew matrix.
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*/
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static void ProcessSkewHelper(float aXAngle, float aYAngle, float aMain[4])
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{
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/* We want our matrix to look like this:
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* | 1 tan(ThetaX) 0|
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* | tan(ThetaY) 1 0|
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* | 0 0 1|
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* However, to avoid infinte values, we'll use the SafeTangent function
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* instead of the C standard tan function.
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*/
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aMain[2] = SafeTangent(aXAngle);
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aMain[1] = SafeTangent(aYAngle);
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}
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/* Function that converts a skewx transform into a matrix. */
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static void ProcessSkewX(float aMain[4], const nsCSSValue::Array* aData)
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{
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NS_ASSERTION(aData->Count() == 2, "Bad array!");
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ProcessSkewHelper(CSSToRadians(aData->Item(1)), 0.0f, aMain);
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}
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/* Function that converts a skewy transform into a matrix. */
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static void ProcessSkewY(float aMain[4], const nsCSSValue::Array* aData)
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{
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NS_ASSERTION(aData->Count() == 2, "Bad array!");
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ProcessSkewHelper(0.0f, CSSToRadians(aData->Item(1)), aMain);
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}
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/* Function that converts a skew transform into a matrix. */
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static void ProcessSkew(float aMain[4], const nsCSSValue::Array* aData)
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{
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NS_ASSERTION(aData->Count() == 2 || aData->Count() == 3, "Bad array!");
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float xSkew = CSSToRadians(aData->Item(1));
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float ySkew = (aData->Count() == 2 ? 0.0f : CSSToRadians(aData->Item(2)));
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ProcessSkewHelper(xSkew, ySkew, aMain);
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}
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/* Function that converts a rotate transform into a matrix. */
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static void ProcessRotate(float aMain[4], const nsCSSValue::Array* aData)
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{
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NS_PRECONDITION(aData->Count() == 2, "Invalid array!");
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/* We want our matrix to look like this:
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* | cos(theta) -sin(theta) 0|
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* | sin(theta) cos(theta) 0|
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* | 0 0 1|
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* (see http://www.w3.org/TR/SVG/coords.html#RotationDefined)
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*/
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float theta = CSSToRadians(aData->Item(1));
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float cosTheta = cos(theta);
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float sinTheta = sin(theta);
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aMain[0] = cosTheta;
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aMain[1] = sinTheta;
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aMain[2] = -sinTheta;
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aMain[3] = cosTheta;
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}
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/**
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* SetToTransformFunction is essentially a giant switch statement that fans
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* out to many smaller helper functions.
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*/
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void
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nsStyleTransformMatrix::SetToTransformFunction(const nsCSSValue::Array * aData,
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nsStyleContext* aContext,
|
|
nsPresContext* aPresContext)
|
|
{
|
|
NS_PRECONDITION(aData, "Why did you want to get data from a null array?");
|
|
NS_PRECONDITION(aContext, "Need a context for unit conversion!");
|
|
NS_PRECONDITION(aPresContext, "Need a context for unit conversion!");
|
|
|
|
/* Reset the matrix to the identity so that each subfunction can just
|
|
* worry about its own components.
|
|
*/
|
|
SetToIdentity();
|
|
|
|
/* Get the keyword for the transform. */
|
|
nsAutoString keyword;
|
|
aData->Item(0).GetStringValue(keyword);
|
|
switch (nsCSSKeywords::LookupKeyword(keyword)) {
|
|
case eCSSKeyword_translatex:
|
|
ProcessTranslateX(mDelta, mX, aData, aContext, aPresContext);
|
|
break;
|
|
case eCSSKeyword_translatey:
|
|
ProcessTranslateY(mDelta, mY, aData, aContext, aPresContext);
|
|
break;
|
|
case eCSSKeyword_translate:
|
|
ProcessTranslate(mDelta, mX, mY, aData, aContext, aPresContext);
|
|
break;
|
|
case eCSSKeyword_scalex:
|
|
ProcessScaleX(mMain, aData);
|
|
break;
|
|
case eCSSKeyword_scaley:
|
|
ProcessScaleY(mMain, aData);
|
|
break;
|
|
case eCSSKeyword_scale:
|
|
ProcessScale(mMain, aData);
|
|
break;
|
|
case eCSSKeyword_skewx:
|
|
ProcessSkewX(mMain, aData);
|
|
break;
|
|
case eCSSKeyword_skewy:
|
|
ProcessSkewY(mMain, aData);
|
|
break;
|
|
case eCSSKeyword_skew:
|
|
ProcessSkew(mMain, aData);
|
|
break;
|
|
case eCSSKeyword_rotate:
|
|
ProcessRotate(mMain, aData);
|
|
break;
|
|
case eCSSKeyword_matrix:
|
|
ProcessMatrix(mMain, mDelta, mX, mY, aData, aContext, aPresContext);
|
|
break;
|
|
default:
|
|
NS_NOTREACHED("Unknown transform function!");
|
|
}
|
|
}
|
|
|
|
/* Does an element-by-element comparison and returns whether or not the
|
|
* matrices are equal.
|
|
*/
|
|
PRBool
|
|
nsStyleTransformMatrix::operator ==(const nsStyleTransformMatrix &aOther) const
|
|
{
|
|
for (PRInt32 index = 0; index < 4; ++index)
|
|
if (mMain[index] != aOther.mMain[index])
|
|
return PR_FALSE;
|
|
|
|
for (PRInt32 index = 0; index < 2; ++index)
|
|
if (mDelta[index] != aOther.mDelta[index] ||
|
|
mX[index] != aOther.mX[index] ||
|
|
mY[index] != aOther.mY[index])
|
|
return PR_FALSE;
|
|
|
|
return PR_TRUE;
|
|
}
|