SkMatrix.h

/*
 * Copyright 2006 The Android Open Source Project
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */


#ifndef SkMatrix_DEFINED
#define SkMatrix_DEFINED

#include "SkRect.h"

struct SkRSXform;
class SkString;

SK_BEGIN_REQUIRE_DENSE
class SK_API SkMatrix {
public:
    static SkMatrix SK_WARN_UNUSED_RESULT MakeScale(SkScalar sx, SkScalar sy) {
        SkMatrix m;
        m.setScale(sx, sy);
        return m;
    }

    static SkMatrix SK_WARN_UNUSED_RESULT MakeScale(SkScalar scale) {
        SkMatrix m;
        m.setScale(scale, scale);
        return m;
    }

    static SkMatrix SK_WARN_UNUSED_RESULT MakeTrans(SkScalar dx, SkScalar dy) {
        SkMatrix m;
        m.setTranslate(dx, dy);
        return m;
    }

    enum TypeMask {
        kIdentity_Mask      = 0,
        kTranslate_Mask     = 0x01,  
        kScale_Mask         = 0x02,  
        kAffine_Mask        = 0x04,  
        kPerspective_Mask   = 0x08   
    };

    TypeMask getType() const {
        if (fTypeMask & kUnknown_Mask) {
            fTypeMask = this->computeTypeMask();
        }
        // only return the public masks
        return (TypeMask)(fTypeMask & 0xF);
    }

    bool isIdentity() const {
        return this->getType() == 0;
    }

    bool isScaleTranslate() const {
        return !(this->getType() & ~(kScale_Mask | kTranslate_Mask));
    }

    bool rectStaysRect() const {
        if (fTypeMask & kUnknown_Mask) {
            fTypeMask = this->computeTypeMask();
        }
        return (fTypeMask & kRectStaysRect_Mask) != 0;
    }
    // alias for rectStaysRect()
    bool preservesAxisAlignment() const { return this->rectStaysRect(); }

    bool hasPerspective() const {
        return SkToBool(this->getPerspectiveTypeMaskOnly() &
                        kPerspective_Mask);
    }

    bool isSimilarity(SkScalar tol = SK_ScalarNearlyZero) const;

    bool preservesRightAngles(SkScalar tol = SK_ScalarNearlyZero) const;

    enum {
        kMScaleX,
        kMSkewX,
        kMTransX,
        kMSkewY,
        kMScaleY,
        kMTransY,
        kMPersp0,
        kMPersp1,
        kMPersp2
    };

    enum {
        kAScaleX,
        kASkewY,
        kASkewX,
        kAScaleY,
        kATransX,
        kATransY
    };

    SkScalar operator[](int index) const {
        SkASSERT((unsigned)index < 9);
        return fMat[index];
    }

    SkScalar get(int index) const {
        SkASSERT((unsigned)index < 9);
        return fMat[index];
    }

    SkScalar getScaleX() const { return fMat[kMScaleX]; }
    SkScalar getScaleY() const { return fMat[kMScaleY]; }
    SkScalar getSkewY() const { return fMat[kMSkewY]; }
    SkScalar getSkewX() const { return fMat[kMSkewX]; }
    SkScalar getTranslateX() const { return fMat[kMTransX]; }
    SkScalar getTranslateY() const { return fMat[kMTransY]; }
    SkScalar getPerspX() const { return fMat[kMPersp0]; }
    SkScalar getPerspY() const { return fMat[kMPersp1]; }

    SkScalar& operator[](int index) {
        SkASSERT((unsigned)index < 9);
        this->setTypeMask(kUnknown_Mask);
        return fMat[index];
    }

    void set(int index, SkScalar value) {
        SkASSERT((unsigned)index < 9);
        fMat[index] = value;
        this->setTypeMask(kUnknown_Mask);
    }

    void setScaleX(SkScalar v) { this->set(kMScaleX, v); }
    void setScaleY(SkScalar v) { this->set(kMScaleY, v); }
    void setSkewY(SkScalar v) { this->set(kMSkewY, v); }
    void setSkewX(SkScalar v) { this->set(kMSkewX, v); }
    void setTranslateX(SkScalar v) { this->set(kMTransX, v); }
    void setTranslateY(SkScalar v) { this->set(kMTransY, v); }
    void setPerspX(SkScalar v) { this->set(kMPersp0, v); }
    void setPerspY(SkScalar v) { this->set(kMPersp1, v); }

    void setAll(SkScalar scaleX, SkScalar skewX,  SkScalar transX,
                SkScalar skewY,  SkScalar scaleY, SkScalar transY,
                SkScalar persp0, SkScalar persp1, SkScalar persp2) {
        fMat[kMScaleX] = scaleX;
        fMat[kMSkewX]  = skewX;
        fMat[kMTransX] = transX;
        fMat[kMSkewY]  = skewY;
        fMat[kMScaleY] = scaleY;
        fMat[kMTransY] = transY;
        fMat[kMPersp0] = persp0;
        fMat[kMPersp1] = persp1;
        fMat[kMPersp2] = persp2;
        this->setTypeMask(kUnknown_Mask);
    }

    void get9(SkScalar buffer[9]) const {
        memcpy(buffer, fMat, 9 * sizeof(SkScalar));
    }

    void set9(const SkScalar buffer[9]);

    void reset();
    // alias for reset()
    void setIdentity() { this->reset(); }

    void setTranslate(SkScalar dx, SkScalar dy);
    void setTranslate(const SkVector& v) { this->setTranslate(v.fX, v.fY); }

    void setScale(SkScalar sx, SkScalar sy, SkScalar px, SkScalar py);
    void setScale(SkScalar sx, SkScalar sy);
    bool setIDiv(int divx, int divy);
    void setRotate(SkScalar degrees, SkScalar px, SkScalar py);
    void setRotate(SkScalar degrees);
    void setSinCos(SkScalar sinValue, SkScalar cosValue,
                   SkScalar px, SkScalar py);
    void setSinCos(SkScalar sinValue, SkScalar cosValue);

    SkMatrix& setRSXform(const SkRSXform&);

    void setSkew(SkScalar kx, SkScalar ky, SkScalar px, SkScalar py);
    void setSkew(SkScalar kx, SkScalar ky);
    void setConcat(const SkMatrix& a, const SkMatrix& b);

    void preTranslate(SkScalar dx, SkScalar dy);
    void preScale(SkScalar sx, SkScalar sy, SkScalar px, SkScalar py);
    void preScale(SkScalar sx, SkScalar sy);
    void preRotate(SkScalar degrees, SkScalar px, SkScalar py);
    void preRotate(SkScalar degrees);
    void preSkew(SkScalar kx, SkScalar ky, SkScalar px, SkScalar py);
    void preSkew(SkScalar kx, SkScalar ky);
    void preConcat(const SkMatrix& other);

    void postTranslate(SkScalar dx, SkScalar dy);
    void postScale(SkScalar sx, SkScalar sy, SkScalar px, SkScalar py);
    void postScale(SkScalar sx, SkScalar sy);
    bool postIDiv(int divx, int divy);
    void postRotate(SkScalar degrees, SkScalar px, SkScalar py);
    void postRotate(SkScalar degrees);
    void postSkew(SkScalar kx, SkScalar ky, SkScalar px, SkScalar py);
    void postSkew(SkScalar kx, SkScalar ky);
    void postConcat(const SkMatrix& other);

    enum ScaleToFit {
        kFill_ScaleToFit,
        kStart_ScaleToFit,
        kCenter_ScaleToFit,
        kEnd_ScaleToFit
    };

    bool setRectToRect(const SkRect& src, const SkRect& dst, ScaleToFit stf);
    static SkMatrix MakeRectToRect(const SkRect& src, const SkRect& dst, ScaleToFit stf) {
        SkMatrix m;
        m.setRectToRect(src, dst, stf);
        return m;
    }

    bool setPolyToPoly(const SkPoint src[], const SkPoint dst[], int count);

    bool SK_WARN_UNUSED_RESULT invert(SkMatrix* inverse) const {
        // Allow the trivial case to be inlined.
        if (this->isIdentity()) {
            if (inverse) {
                inverse->reset();
            }
            return true;
        }
        return this->invertNonIdentity(inverse);
    }

    static void SetAffineIdentity(SkScalar affine[6]);

    bool SK_WARN_UNUSED_RESULT asAffine(SkScalar affine[6]) const;

    void setAffine(const SkScalar affine[6]);

    void mapPoints(SkPoint dst[], const SkPoint src[], int count) const {
        SkASSERT((dst && src && count > 0) || 0 == count);
        // no partial overlap
        SkASSERT(src == dst || &dst[count] <= &src[0] || &src[count] <= &dst[0]);
        this->getMapPtsProc()(*this, dst, src, count);
    }

    void mapPoints(SkPoint pts[], int count) const {
        this->mapPoints(pts, pts, count);
    }

    void mapPointsWithStride(SkPoint pts[], size_t stride, int count) const {
        SkASSERT(stride >= sizeof(SkPoint));
        SkASSERT(0 == stride % sizeof(SkScalar));
        for (int i = 0; i < count; ++i) {
            this->mapPoints(pts, pts, 1);
            pts = (SkPoint*)((intptr_t)pts + stride);
        }
    }

    void mapPointsWithStride(SkPoint dst[], const SkPoint src[], size_t stride, int count) const {
        SkASSERT(stride >= sizeof(SkPoint));
        SkASSERT(0 == stride % sizeof(SkScalar));
        for (int i = 0; i < count; ++i) {
            this->mapPoints(dst, src, 1);
            src = (SkPoint*)((intptr_t)src + stride);
            dst = (SkPoint*)((intptr_t)dst + stride);
        }
    }

    void mapHomogeneousPoints(SkScalar dst[], const SkScalar src[], int count) const;

    void mapXY(SkScalar x, SkScalar y, SkPoint* result) const {
        SkASSERT(result);
        this->getMapXYProc()(*this, x, y, result);
    }

    SkPoint mapXY(SkScalar x, SkScalar y) const {
        SkPoint result;
        this->getMapXYProc()(*this, x, y, &result);
        return result;
    }

    void mapVectors(SkVector dst[], const SkVector src[], int count) const;

    void mapVectors(SkVector vecs[], int count) const {
        this->mapVectors(vecs, vecs, count);
    }

    void mapVector(SkScalar dx, SkScalar dy, SkVector* result) const {
        SkVector vec = { dx, dy };
        this->mapVectors(result, &vec, 1);
    }

    SkVector mapVector(SkScalar dx, SkScalar dy) const {
        SkVector vec = { dx, dy };
        this->mapVectors(&vec, &vec, 1);
        return vec;
    }

    bool mapRect(SkRect* dst, const SkRect& src) const;

    bool mapRect(SkRect* rect) const {
        return this->mapRect(rect, *rect);
    }

    void mapRectToQuad(SkPoint dst[4], const SkRect& rect) const {
        // This could potentially be faster if we only transformed each x and y of the rect once.
        rect.toQuad(dst);
        this->mapPoints(dst, 4);
    }

    void mapRectScaleTranslate(SkRect* dst, const SkRect& src) const;
    
    SkScalar mapRadius(SkScalar radius) const;

    typedef void (*MapXYProc)(const SkMatrix& mat, SkScalar x, SkScalar y,
                                 SkPoint* result);

    static MapXYProc GetMapXYProc(TypeMask mask) {
        SkASSERT((mask & ~kAllMasks) == 0);
        return gMapXYProcs[mask & kAllMasks];
    }

    MapXYProc getMapXYProc() const {
        return GetMapXYProc(this->getType());
    }

    typedef void (*MapPtsProc)(const SkMatrix& mat, SkPoint dst[],
                                  const SkPoint src[], int count);

    static MapPtsProc GetMapPtsProc(TypeMask mask) {
        SkASSERT((mask & ~kAllMasks) == 0);
        return gMapPtsProcs[mask & kAllMasks];
    }

    MapPtsProc getMapPtsProc() const {
        return GetMapPtsProc(this->getType());
    }

    bool isFixedStepInX() const;

    SkVector fixedStepInX(SkScalar y) const;

    bool cheapEqualTo(const SkMatrix& m) const {
        return 0 == memcmp(fMat, m.fMat, sizeof(fMat));
    }

    // mac chromium dbg requires SK_API to make operator== visible
    friend SK_API bool operator==(const SkMatrix& a, const SkMatrix& b);
    friend SK_API bool operator!=(const SkMatrix& a, const SkMatrix& b) {
        return !(a == b);
    }

    enum {
        // writeTo/readFromMemory will never return a value larger than this
        kMaxFlattenSize = 9 * sizeof(SkScalar) + sizeof(uint32_t)
    };
    // return the number of bytes written, whether or not buffer is null
    size_t writeToMemory(void* buffer) const;
    size_t readFromMemory(const void* buffer, size_t length);

    void dump() const;
    void toString(SkString*) const;

    SkScalar getMinScale() const;

    SkScalar getMaxScale() const;

    bool SK_WARN_UNUSED_RESULT getMinMaxScales(SkScalar scaleFactors[2]) const;

    bool decomposeScale(SkSize* scale, SkMatrix* remaining = NULL) const;

    static const SkMatrix& I();

    static const SkMatrix& InvalidMatrix();

    static SkMatrix Concat(const SkMatrix& a, const SkMatrix& b) {
        SkMatrix result;
        result.setConcat(a, b);
        return result;
    }

    void dirtyMatrixTypeCache() {
        this->setTypeMask(kUnknown_Mask);
    }

    void setScaleTranslate(SkScalar sx, SkScalar sy, SkScalar tx, SkScalar ty) {
        fMat[kMScaleX] = sx;
        fMat[kMSkewX]  = 0;
        fMat[kMTransX] = tx;
        
        fMat[kMSkewY]  = 0;
        fMat[kMScaleY] = sy;
        fMat[kMTransY] = ty;
        
        fMat[kMPersp0] = 0;
        fMat[kMPersp1] = 0;
        fMat[kMPersp2] = 1;
        
        unsigned mask = 0;
        if (sx != 1 || sy != 1) {
            mask |= kScale_Mask;
        }
        if (tx || ty) {
            mask |= kTranslate_Mask;
        }
        this->setTypeMask(mask | kRectStaysRect_Mask);
    }
    
    bool isFinite() const { return SkScalarsAreFinite(fMat, 9); }

private:
    enum {
        kRectStaysRect_Mask = 0x10,

        kOnlyPerspectiveValid_Mask = 0x40,

        kUnknown_Mask = 0x80,

        kORableMasks =  kTranslate_Mask |
                        kScale_Mask |
                        kAffine_Mask |
                        kPerspective_Mask,

        kAllMasks = kTranslate_Mask |
                    kScale_Mask |
                    kAffine_Mask |
                    kPerspective_Mask |
                    kRectStaysRect_Mask
    };

    SkScalar         fMat[9];
    mutable uint32_t fTypeMask;

    static void ComputeInv(SkScalar dst[9], const SkScalar src[9], double invDet, bool isPersp);

    uint8_t computeTypeMask() const;
    uint8_t computePerspectiveTypeMask() const;

    void setTypeMask(int mask) {
        // allow kUnknown or a valid mask
        SkASSERT(kUnknown_Mask == mask || (mask & kAllMasks) == mask ||
                 ((kUnknown_Mask | kOnlyPerspectiveValid_Mask) & mask)
                 == (kUnknown_Mask | kOnlyPerspectiveValid_Mask));
        fTypeMask = SkToU8(mask);
    }

    void orTypeMask(int mask) {
        SkASSERT((mask & kORableMasks) == mask);
        fTypeMask = SkToU8(fTypeMask | mask);
    }

    void clearTypeMask(int mask) {
        // only allow a valid mask
        SkASSERT((mask & kAllMasks) == mask);
        fTypeMask = fTypeMask & ~mask;
    }

    TypeMask getPerspectiveTypeMaskOnly() const {
        if ((fTypeMask & kUnknown_Mask) &&
            !(fTypeMask & kOnlyPerspectiveValid_Mask)) {
            fTypeMask = this->computePerspectiveTypeMask();
        }
        return (TypeMask)(fTypeMask & 0xF);
    }

    bool isTriviallyIdentity() const {
        if (fTypeMask & kUnknown_Mask) {
            return false;
        }
        return ((fTypeMask & 0xF) == 0);
    }

    inline void updateTranslateMask() {
        if ((fMat[kMTransX] != 0) | (fMat[kMTransY] != 0)) {
            fTypeMask |= kTranslate_Mask;
        } else {
            fTypeMask &= ~kTranslate_Mask;
        }
    }

    bool SK_WARN_UNUSED_RESULT invertNonIdentity(SkMatrix* inverse) const;

    static bool Poly2Proc(const SkPoint[], SkMatrix*, const SkPoint& scale);
    static bool Poly3Proc(const SkPoint[], SkMatrix*, const SkPoint& scale);
    static bool Poly4Proc(const SkPoint[], SkMatrix*, const SkPoint& scale);

    static void Identity_xy(const SkMatrix&, SkScalar, SkScalar, SkPoint*);
    static void Trans_xy(const SkMatrix&, SkScalar, SkScalar, SkPoint*);
    static void Scale_xy(const SkMatrix&, SkScalar, SkScalar, SkPoint*);
    static void ScaleTrans_xy(const SkMatrix&, SkScalar, SkScalar, SkPoint*);
    static void Rot_xy(const SkMatrix&, SkScalar, SkScalar, SkPoint*);
    static void RotTrans_xy(const SkMatrix&, SkScalar, SkScalar, SkPoint*);
    static void Persp_xy(const SkMatrix&, SkScalar, SkScalar, SkPoint*);

    static const MapXYProc gMapXYProcs[];

    static void Identity_pts(const SkMatrix&, SkPoint[], const SkPoint[], int);
    static void Trans_pts(const SkMatrix&, SkPoint dst[], const SkPoint[], int);
    static void Scale_pts(const SkMatrix&, SkPoint dst[], const SkPoint[], int);
    static void ScaleTrans_pts(const SkMatrix&, SkPoint dst[], const SkPoint[],
                               int count);
    static void Persp_pts(const SkMatrix&, SkPoint dst[], const SkPoint[], int);

    static void Affine_vpts(const SkMatrix&, SkPoint dst[], const SkPoint[], int);

    static const MapPtsProc gMapPtsProcs[];

    friend class SkPerspIter;
    friend class SkMatrixPriv;
};
SK_END_REQUIRE_DENSE

#endif