skia2/include/core/SkDraw.h

/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef SkDraw_DEFINED
#define SkDraw_DEFINED

#include "SkBitmap.h"
#include "SkCanvas.h"
#include "SkMask.h"
#include "SkMatrix.h"
#include "SkPaint.h"
#include "SkRect.h"
#include "SkAutoKern.h"

class SkBounder;
class SkDevice;
class SkPath;
class SkRegion;
struct SkDrawProcs;

class SkDraw {
public:
    SkDraw();
    SkDraw(const SkDraw& src);

    void    drawPaint(const SkPaint&) const;
    void    drawPoints(SkCanvas::PointMode, size_t count, const SkPoint[],
                       const SkPaint&, bool forceUseDevice = false) const;
    void    drawRect(const SkRect&, const SkPaint&) const;
    /*  To save on mallocs, we allow a flag that tells us that srcPath is
        mutable, so that we don't have to make copies of it as we transform it.
    */
    void    drawPath(const SkPath& srcPath, const SkPaint&,
                     const SkMatrix* prePathMatrix, bool pathIsMutable) const;
    void    drawBitmap(const SkBitmap&, const SkMatrix&, const SkPaint&) const;
    void    drawSprite(const SkBitmap&, int x, int y, const SkPaint&) const;
    void    drawText(const char text[], size_t byteLength, SkScalar x,
                     SkScalar y, const SkPaint& paint) const;
    void    drawPosText(const char text[], size_t byteLength,
                        const SkScalar pos[], SkScalar constY,
                        int scalarsPerPosition, const SkPaint& paint) const;
    void    drawTextOnPath(const char text[], size_t byteLength,
                        const SkPath&, const SkMatrix*, const SkPaint&) const;
    void    drawVertices(SkCanvas::VertexMode mode, int count,
                         const SkPoint vertices[], const SkPoint textures[],
                         const SkColor colors[], SkXfermode* xmode,
                         const uint16_t indices[], int ptCount,
                         const SkPaint& paint) const;
        
    void drawPath(const SkPath& src, const SkPaint& paint) const {
        this->drawPath(src, paint, NULL, false);
    }

    /** Helper function that creates a mask from a path and an optional maskfilter.
        Note however, that the resulting mask will not have been actually filtered,
        that must be done afterwards (by calling filterMask). The maskfilter is provided
        solely to assist in computing the mask's bounds (if the mode requests that).
    */
    static bool DrawToMask(const SkPath& devPath, const SkIRect* clipBounds,
                           SkMaskFilter* filter, const SkMatrix* filterMatrix,
                           SkMask* mask, SkMask::CreateMode mode);

private:
    void    drawText_asPaths(const char text[], size_t byteLength,
                             SkScalar x, SkScalar y, const SkPaint&) const;
    void    drawDevMask(const SkMask& mask, const SkPaint&) const;
    void    drawBitmapAsMask(const SkBitmap&, const SkPaint&) const;

public:
    const SkBitmap* fBitmap;        // required
    const SkMatrix* fMatrix;        // required
    const SkRegion* fClip;          // required

    SkDevice*       fDevice;        // optional
    SkBounder*      fBounder;       // optional
    SkDrawProcs*    fProcs;         // optional

    const SkMatrix* fMVMatrix;      // optional
    const SkMatrix* fExtMatrix;     // optional

#ifdef SK_DEBUG
    void validate() const;
#else
    void validate() const {}
#endif
};

class SkGlyphCache;

class SkTextToPathIter {
public:
    SkTextToPathIter(const char text[], size_t length, const SkPaint&,
                     bool applyStrokeAndPathEffects, bool forceLinearTextOn);
    ~SkTextToPathIter();

    const SkPaint&  getPaint() const { return fPaint; }
    SkScalar        getPathScale() const { return fScale; }

    const SkPath*   next(SkScalar* xpos);   //!< returns nil when there are no more paths

private:
    SkGlyphCache*   fCache;
    SkPaint         fPaint;
    SkScalar        fScale;
    SkFixed         fPrevAdvance;
    const char*     fText;
    const char*     fStop;
    SkMeasureCacheProc fGlyphCacheProc;

    const SkPath*   fPath;      // returned in next
    SkScalar        fXPos;      // accumulated xpos, returned in next
    SkAutoKern      fAutoKern;
};

#endif