/* -*- 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 DOM_SVG_SVGMATRIX_H_
#define DOM_SVG_SVGMATRIX_H_
#include "DOMSVGTransform.h"
#include "gfxMatrix.h"
#include "nsCycleCollectionParticipant.h"
#include "nsWrapperCache.h"
#include "mozilla/Attributes.h"
namespace mozilla::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_NATIVE_WRAPPERCACHE_CLASS(SVGMatrix)
/**
* Ctor for SVGMatrix objects that belong to a DOMSVGTransform.
*/
explicit SVGMatrix(DOMSVGTransform& aTransform) : mTransform(&aTransform) {}
/**
* Ctors for SVGMatrix objects created independently of a DOMSVGTransform.
*/
// Default ctor for gfxMatrix will produce identity mx
SVGMatrix() =
default;
explicit SVGMatrix(
const gfxMatrix& aMatrix) : mMatrix(aMatrix) {}
// WebIDL
DOMSVGTransform* GetParentObject()
const;
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() =
default;
const gfxMatrix& GetMatrix()
const {
return mTransform ? mTransform->Matrixgfx() : mMatrix;
}
void SetMatrix(
const gfxMatrix& aMatrix) {
if (mTransform) {
mTransform->SetMatrix(aMatrix);
}
else {
mMatrix = aMatrix;
}
}
bool IsAnimVal()
const {
return mTransform ? mTransform->IsAnimVal() :
false;
}
RefPtr<DOMSVGTransform> mTransform;
// Typically we operate on the matrix data accessed via mTransform but for
// matrices that exist independently of an DOMSVGTransform we use mMatrix
// below.
gfxMatrix mMatrix;
};
}
// namespace mozilla::dom
#endif // DOM_SVG_SVGMATRIX_H_
