/* -*- 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/. */ /** * Notes on transforms in Mozilla and the SVG code. * * It's important to note that the matrix convention used in the SVG standard * is the opposite convention to the one used in the Mozilla code or, more * specifically, the convention used in Thebes code (code using gfxMatrix). * Whereas the SVG standard uses the column vector convention, Thebes code uses * the row vector convention. Thus, whereas in the SVG standard you have * [M1][M2][M3]|p|, in Thebes you have |p|'[M3]'[M2]'[M1]'. In other words, the * following are equivalent: * * / a1 c1 tx1 \ / a2 c2 tx2 \ / a3 c3 tx3 \ / x \ * SVG: | b1 d1 ty1 | | b2 d2 ty2 | | b3 d3 ty3 | | y | * \ 0 0 1 / \ 0 0 1 / \ 0 0 1 / \ 1 / * * / a3 b3 0 \ / a2 b2 0 \ / a1 b1 0 \ * Thebes: [ x y 1 ] | c3 d3 0 | | c2 d2 0 | | c1 d1 0 | * \ tx3 ty3 1 / \ tx2 ty2 1 / \ tx1 ty1 1 / * * Because the Thebes representation of a transform is the transpose of the SVG * representation, our transform order must be reversed when representing SVG * transforms using gfxMatrix in the SVG code. Since the SVG implementation * stores and obtains matrices in SVG order, to do this we must pre-multiply * gfxMatrix objects that represent SVG transforms instead of post-multiplying * them as we would for matrices using SVG's column vector convention. * Pre-multiplying may look wrong if you're only familiar with the SVG * convention, but in that case hopefully the above explanation clears things * up. */ #ifndef mozilla_dom_SVGMatrix_h #define mozilla_dom_SVGMatrix_h #include "mozilla/dom/SVGTransform.h" #include "gfxMatrix.h" #include "nsCycleCollectionParticipant.h" #include "nsWrapperCache.h" #include "mozilla/Attributes.h" namespace mozilla { namespace dom { /** * DOM wrapper for an SVG matrix. */ class SVGMatrix final : public nsWrapperCache { public: NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(SVGMatrix) NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(SVGMatrix) /** * Ctor for SVGMatrix objects that belong to a SVGTransform. */ explicit SVGMatrix(SVGTransform& aTransform) : mTransform(&aTransform) {} /** * Ctors for SVGMatrix objects created independently of a SVGTransform. */ // Default ctor for gfxMatrix will produce identity mx SVGMatrix() {} explicit SVGMatrix(const gfxMatrix &aMatrix) : mMatrix(aMatrix) {} const gfxMatrix& GetMatrix() const { return mTransform ? mTransform->Matrixgfx() : mMatrix; } // WebIDL SVGTransform* GetParentObject() const; virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override; float A() const { return static_cast<float>(GetMatrix()._11); } void SetA(float aA, ErrorResult& rv); float B() const { return static_cast<float>(GetMatrix()._12); } void SetB(float aB, ErrorResult& rv); float C() const { return static_cast<float>(GetMatrix()._21); } void SetC(float aC, ErrorResult& rv); float D() const { return static_cast<float>(GetMatrix()._22); } void SetD(float aD, ErrorResult& rv); float E() const { return static_cast<float>(GetMatrix()._31); } void SetE(float aE, ErrorResult& rv); float F() const { return static_cast<float>(GetMatrix()._32); } void SetF(float aF, ErrorResult& rv); already_AddRefed<SVGMatrix> Multiply(SVGMatrix& aMatrix); already_AddRefed<SVGMatrix> Inverse(ErrorResult& aRv); already_AddRefed<SVGMatrix> Translate(float x, float y); already_AddRefed<SVGMatrix> Scale(float scaleFactor); already_AddRefed<SVGMatrix> ScaleNonUniform(float scaleFactorX, float scaleFactorY); already_AddRefed<SVGMatrix> Rotate(float angle); already_AddRefed<SVGMatrix> RotateFromVector(float x, float y, ErrorResult& aRv); already_AddRefed<SVGMatrix> FlipX(); already_AddRefed<SVGMatrix> FlipY(); already_AddRefed<SVGMatrix> SkewX(float angle, ErrorResult& rv); already_AddRefed<SVGMatrix> SkewY(float angle, ErrorResult& rv); private: ~SVGMatrix() {} void SetMatrix(const gfxMatrix& aMatrix) { if (mTransform) { mTransform->SetMatrix(aMatrix); } else { mMatrix = aMatrix; } } bool IsAnimVal() const { return mTransform ? mTransform->IsAnimVal() : false; } RefPtr<SVGTransform> mTransform; // Typically we operate on the matrix data accessed via mTransform but for // matrices that exist independently of an SVGTransform we use mMatrix below. gfxMatrix mMatrix; }; } // namespace dom } // namespace mozilla #endif // mozilla_dom_SVGMatrix_h