зеркало из https://github.com/mozilla/gecko-dev.git
132 строки
5.0 KiB
C++
132 строки
5.0 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/**
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* Notes on transforms in Mozilla and the SVG code.
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*
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* It's important to note that the matrix convention used in the SVG standard
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* is the opposite convention to the one used in the Mozilla code or, more
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* specifically, the convention used in Thebes code (code using gfxMatrix).
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* Whereas the SVG standard uses the column vector convention, Thebes code uses
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* the row vector convention. Thus, whereas in the SVG standard you have
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* [M1][M2][M3]|p|, in Thebes you have |p|'[M3]'[M2]'[M1]'. In other words, the
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* following are equivalent:
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*
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* / a1 c1 tx1 \ / a2 c2 tx2 \ / a3 c3 tx3 \ / x \
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* SVG: | b1 d1 ty1 | | b2 d2 ty2 | | b3 d3 ty3 | | y |
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* \ 0 0 1 / \ 0 0 1 / \ 0 0 1 / \ 1 /
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*
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* / a3 b3 0 \ / a2 b2 0 \ / a1 b1 0 \
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* Thebes: [ x y 1 ] | c3 d3 0 | | c2 d2 0 | | c1 d1 0 |
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* \ tx3 ty3 1 / \ tx2 ty2 1 / \ tx1 ty1 1 /
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*
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* Because the Thebes representation of a transform is the transpose of the SVG
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* representation, our transform order must be reversed when representing SVG
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* transforms using gfxMatrix in the SVG code. Since the SVG implementation
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* stores and obtains matrices in SVG order, to do this we must pre-multiply
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* gfxMatrix objects that represent SVG transforms instead of post-multiplying
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* them as we would for matrices using SVG's column vector convention.
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* Pre-multiplying may look wrong if you're only familiar with the SVG
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* convention, but in that case hopefully the above explanation clears things
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* up.
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*/
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#ifndef DOM_SVG_SVGMATRIX_H_
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#define DOM_SVG_SVGMATRIX_H_
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#include "DOMSVGTransform.h"
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#include "gfxMatrix.h"
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#include "nsCycleCollectionParticipant.h"
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#include "nsWrapperCache.h"
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#include "mozilla/Attributes.h"
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namespace mozilla {
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namespace dom {
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/**
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* DOM wrapper for an SVG matrix.
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*/
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class SVGMatrix final : public nsWrapperCache {
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public:
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NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(SVGMatrix)
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NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(SVGMatrix)
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/**
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* Ctor for SVGMatrix objects that belong to a DOMSVGTransform.
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*/
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explicit SVGMatrix(DOMSVGTransform& aTransform) : mTransform(&aTransform) {}
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/**
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* Ctors for SVGMatrix objects created independently of a DOMSVGTransform.
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*/
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// Default ctor for gfxMatrix will produce identity mx
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SVGMatrix() = default;
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explicit SVGMatrix(const gfxMatrix& aMatrix) : mMatrix(aMatrix) {}
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// WebIDL
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DOMSVGTransform* GetParentObject() const;
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virtual JSObject* WrapObject(JSContext* aCx,
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JS::Handle<JSObject*> aGivenProto) override;
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float A() const { return static_cast<float>(GetMatrix()._11); }
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void SetA(float aA, ErrorResult& rv);
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float B() const { return static_cast<float>(GetMatrix()._12); }
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void SetB(float aB, ErrorResult& rv);
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float C() const { return static_cast<float>(GetMatrix()._21); }
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void SetC(float aC, ErrorResult& rv);
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float D() const { return static_cast<float>(GetMatrix()._22); }
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void SetD(float aD, ErrorResult& rv);
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float E() const { return static_cast<float>(GetMatrix()._31); }
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void SetE(float aE, ErrorResult& rv);
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float F() const { return static_cast<float>(GetMatrix()._32); }
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void SetF(float aF, ErrorResult& rv);
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already_AddRefed<SVGMatrix> Multiply(SVGMatrix& aMatrix);
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already_AddRefed<SVGMatrix> Inverse(ErrorResult& aRv);
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already_AddRefed<SVGMatrix> Translate(float x, float y);
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already_AddRefed<SVGMatrix> Scale(float scaleFactor);
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already_AddRefed<SVGMatrix> ScaleNonUniform(float scaleFactorX,
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float scaleFactorY);
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already_AddRefed<SVGMatrix> Rotate(float angle);
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already_AddRefed<SVGMatrix> RotateFromVector(float x, float y,
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ErrorResult& aRv);
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already_AddRefed<SVGMatrix> FlipX();
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already_AddRefed<SVGMatrix> FlipY();
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already_AddRefed<SVGMatrix> SkewX(float angle, ErrorResult& rv);
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already_AddRefed<SVGMatrix> SkewY(float angle, ErrorResult& rv);
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private:
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~SVGMatrix() = default;
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const gfxMatrix& GetMatrix() const {
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return mTransform ? mTransform->Matrixgfx() : mMatrix;
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}
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void SetMatrix(const gfxMatrix& aMatrix) {
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if (mTransform) {
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mTransform->SetMatrix(aMatrix);
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} else {
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mMatrix = aMatrix;
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}
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}
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bool IsAnimVal() const {
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return mTransform ? mTransform->IsAnimVal() : false;
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}
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RefPtr<DOMSVGTransform> mTransform;
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// Typically we operate on the matrix data accessed via mTransform but for
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// matrices that exist independently of an DOMSVGTransform we use mMatrix
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// below.
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gfxMatrix mMatrix;
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};
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} // namespace dom
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} // namespace mozilla
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#endif // DOM_SVG_SVGMATRIX_H_
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