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       1             : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2             : /* vim: set ts=8 sts=2 et sw=2 tw=80: */
       3             : /* This Source Code Form is subject to the terms of the Mozilla Public
       4             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       5             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       6             : 
       7             : /**
       8             :  * Notes on transforms in Mozilla and the SVG code.
       9             :  *
      10             :  * It's important to note that the matrix convention used in the SVG standard
      11             :  * is the opposite convention to the one used in the Mozilla code or, more
      12             :  * specifically, the convention used in Thebes code (code using gfxMatrix).
      13             :  * Whereas the SVG standard uses the column vector convention, Thebes code uses
      14             :  * the row vector convention. Thus, whereas in the SVG standard you have
      15             :  * [M1][M2][M3]|p|, in Thebes you have |p|'[M3]'[M2]'[M1]'. In other words, the
      16             :  * following are equivalent:
      17             :  *
      18             :  *                       / a1 c1 tx1 \   / a2 c2 tx2 \   / a3 c3 tx3 \   / x \
      19             :  * SVG:                  | b1 d1 ty1 |   | b2 d2 ty2 |   | b3 d3 ty3 |   | y |
      20             :  *                       \  0  0   1 /   \  0  0   1 /   \  0  0   1 /   \ 1 /
      21             :  *
      22             :  *                       /  a3  b3 0 \   /  a2  b2 0 \   /  a1  b1 0 \
      23             :  * Thebes:   [ x y 1 ]   |  c3  d3 0 |   |  c2  d2 0 |   |  c1  d1 0 |
      24             :  *                       \ tx3 ty3 1 /   \ tx2 ty2 1 /   \ tx1 ty1 1 /
      25             :  *
      26             :  * Because the Thebes representation of a transform is the transpose of the SVG
      27             :  * representation, our transform order must be reversed when representing SVG
      28             :  * transforms using gfxMatrix in the SVG code. Since the SVG implementation
      29             :  * stores and obtains matrices in SVG order, to do this we must pre-multiply
      30             :  * gfxMatrix objects that represent SVG transforms instead of post-multiplying
      31             :  * them as we would for matrices using SVG's column vector convention.
      32             :  * Pre-multiplying may look wrong if you're only familiar with the SVG
      33             :  * convention, but in that case hopefully the above explanation clears things
      34             :  * up.
      35             :  */
      36             : 
      37             : #ifndef mozilla_dom_SVGMatrix_h
      38             : #define mozilla_dom_SVGMatrix_h
      39             : 
      40             : #include "mozilla/dom/SVGTransform.h"
      41             : #include "gfxMatrix.h"
      42             : #include "nsCycleCollectionParticipant.h"
      43             : #include "nsWrapperCache.h"
      44             : #include "mozilla/Attributes.h"
      45             : 
      46             : namespace mozilla {
      47             : namespace dom {
      48             : 
      49             : /**
      50             :  * DOM wrapper for an SVG matrix.
      51             :  */
      52             : class SVGMatrix final : public nsWrapperCache
      53             : {
      54             : public:
      55           0 :   NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(SVGMatrix)
      56           0 :   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(SVGMatrix)
      57             : 
      58             :   /**
      59             :    * Ctor for SVGMatrix objects that belong to a SVGTransform.
      60             :    */
      61           0 :   explicit SVGMatrix(SVGTransform& aTransform) : mTransform(&aTransform) {}
      62             : 
      63             :   /**
      64             :    * Ctors for SVGMatrix objects created independently of a SVGTransform.
      65             :    */
      66             :   // Default ctor for gfxMatrix will produce identity mx
      67           0 :   SVGMatrix() {}
      68             : 
      69           0 :   explicit SVGMatrix(const gfxMatrix &aMatrix) : mMatrix(aMatrix) {}
      70             : 
      71           0 :   const gfxMatrix& GetMatrix() const {
      72           0 :     return mTransform ? mTransform->Matrixgfx() : mMatrix;
      73             :   }
      74             : 
      75             :   // WebIDL
      76             :   SVGTransform* GetParentObject() const;
      77             :   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
      78             : 
      79           0 :   float A() const { return static_cast<float>(GetMatrix()._11); }
      80             :   void SetA(float aA, ErrorResult& rv);
      81           0 :   float B() const { return static_cast<float>(GetMatrix()._12); }
      82             :   void SetB(float aB, ErrorResult& rv);
      83           0 :   float C() const { return static_cast<float>(GetMatrix()._21); }
      84             :   void SetC(float aC, ErrorResult& rv);
      85           0 :   float D() const { return static_cast<float>(GetMatrix()._22); }
      86             :   void SetD(float aD, ErrorResult& rv);
      87           0 :   float E() const { return static_cast<float>(GetMatrix()._31); }
      88             :   void SetE(float aE, ErrorResult& rv);
      89           0 :   float F() const { return static_cast<float>(GetMatrix()._32); }
      90             :   void SetF(float aF, ErrorResult& rv);
      91             :   already_AddRefed<SVGMatrix> Multiply(SVGMatrix& aMatrix);
      92             :   already_AddRefed<SVGMatrix> Inverse(ErrorResult& aRv);
      93             :   already_AddRefed<SVGMatrix> Translate(float x, float y);
      94             :   already_AddRefed<SVGMatrix> Scale(float scaleFactor);
      95             :   already_AddRefed<SVGMatrix> ScaleNonUniform(float scaleFactorX,
      96             :                                               float scaleFactorY);
      97             :   already_AddRefed<SVGMatrix> Rotate(float angle);
      98             :   already_AddRefed<SVGMatrix> RotateFromVector(float x,
      99             :                                                float y,
     100             :                                                ErrorResult& aRv);
     101             :   already_AddRefed<SVGMatrix> FlipX();
     102             :   already_AddRefed<SVGMatrix> FlipY();
     103             :   already_AddRefed<SVGMatrix> SkewX(float angle, ErrorResult& rv);
     104             :   already_AddRefed<SVGMatrix> SkewY(float angle, ErrorResult& rv);
     105             : 
     106             : private:
     107           0 :   ~SVGMatrix() {}
     108             : 
     109           0 :   void SetMatrix(const gfxMatrix& aMatrix) {
     110           0 :     if (mTransform) {
     111           0 :       mTransform->SetMatrix(aMatrix);
     112             :     } else {
     113           0 :       mMatrix = aMatrix;
     114             :     }
     115           0 :   }
     116             : 
     117           0 :   bool IsAnimVal() const {
     118           0 :     return mTransform ? mTransform->IsAnimVal() : false;
     119             :   }
     120             : 
     121             :   RefPtr<SVGTransform> mTransform;
     122             : 
     123             :   // Typically we operate on the matrix data accessed via mTransform but for
     124             :   // matrices that exist independently of an SVGTransform we use mMatrix below.
     125             :   gfxMatrix mMatrix;
     126             : };
     127             : 
     128             : } // namespace dom
     129             : } // namespace mozilla
     130             : 
     131             : #endif // mozilla_dom_SVGMatrix_h