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/* -*- Mode: C++; tab-width: 8; 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/. */
/**
* 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
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