skia2/include/core/SkBitmapDevice.h

/*
 * Copyright 2013 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SkBitmapDevice_DEFINED
#define SkBitmapDevice_DEFINED

#include "SkDevice.h"

///////////////////////////////////////////////////////////////////////////////
class SK_API SkBitmapDevice : public SkBaseDevice {
public:
    SK_DECLARE_INST_COUNT(SkBitmapDevice)

    /**
     *  Construct a new device with the specified bitmap as its backend. It is
     *  valid for the bitmap to have no pixels associated with it. In that case,
     *  any drawing to this device will have no effect.
    */
    SkBitmapDevice(const SkBitmap& bitmap);
private:
    /**
     *  Construct a new device with the specified bitmap as its backend. It is
     *  valid for the bitmap to have no pixels associated with it. In that case,
     *  any drawing to this device will have no effect.
    */
    SkBitmapDevice(const SkBitmap& bitmap, const SkDeviceProperties& deviceProperties);
    static SkBitmapDevice* Create(const SkImageInfo&, const SkDeviceProperties*);
public:
    static SkBitmapDevice* Create(const SkImageInfo& info) {
        return Create(info, NULL);
    }

    SkImageInfo imageInfo() const SK_OVERRIDE;

protected:
    bool onShouldDisableLCD(const SkPaint&) const SK_OVERRIDE;

    /** These are called inside the per-device-layer loop for each draw call.
     When these are called, we have already applied any saveLayer operations,
     and are handling any looping from the paint, and any effects from the
     DrawFilter.
     */
    void drawPaint(const SkDraw&, const SkPaint& paint) SK_OVERRIDE;
    virtual void drawPoints(const SkDraw&, SkCanvas::PointMode mode, size_t count,
                            const SkPoint[], const SkPaint& paint) SK_OVERRIDE;
    virtual void drawRect(const SkDraw&, const SkRect& r,
                          const SkPaint& paint) SK_OVERRIDE;
    virtual void drawOval(const SkDraw&, const SkRect& oval,
                          const SkPaint& paint) SK_OVERRIDE;
    virtual void drawRRect(const SkDraw&, const SkRRect& rr,
                           const SkPaint& paint) SK_OVERRIDE;

    /**
     *  If pathIsMutable, then the implementation is allowed to cast path to a
     *  non-const pointer and modify it in place (as an optimization). Canvas
     *  may do this to implement helpers such as drawOval, by placing a temp
     *  path on the stack to hold the representation of the oval.
     *
     *  If prePathMatrix is not null, it should logically be applied before any
     *  stroking or other effects. If there are no effects on the paint that
     *  affect the geometry/rasterization, then the pre matrix can just be
     *  pre-concated with the current matrix.
     */
    virtual void drawPath(const SkDraw&, const SkPath& path,
                          const SkPaint& paint,
                          const SkMatrix* prePathMatrix = NULL,
                          bool pathIsMutable = false) SK_OVERRIDE;
    virtual void drawBitmap(const SkDraw&, const SkBitmap& bitmap,
                            const SkMatrix& matrix, const SkPaint& paint) SK_OVERRIDE;
    virtual void drawSprite(const SkDraw&, const SkBitmap& bitmap,
                            int x, int y, const SkPaint& paint) SK_OVERRIDE;

    /**
     *  The default impl. will create a bitmap-shader from the bitmap,
     *  and call drawRect with it.
     */
    virtual void drawBitmapRect(const SkDraw&, const SkBitmap&,
                                const SkRect* srcOrNull, const SkRect& dst,
                                const SkPaint& paint,
                                SkCanvas::DrawBitmapRectFlags flags) SK_OVERRIDE;

    /**
     *  Does not handle text decoration.
     *  Decorations (underline and stike-thru) will be handled by SkCanvas.
     */
    virtual void drawText(const SkDraw&, const void* text, size_t len,
                          SkScalar x, SkScalar y, const SkPaint& paint) SK_OVERRIDE;
    virtual void drawPosText(const SkDraw&, const void* text, size_t len,
                             const SkScalar pos[], int scalarsPerPos,
                             const SkPoint& offset, const SkPaint& paint) SK_OVERRIDE;
    virtual void drawTextOnPath(const SkDraw&, const void* text, size_t len,
                                const SkPath& path, const SkMatrix* matrix,
                                const SkPaint& paint) SK_OVERRIDE;
    virtual void drawVertices(const SkDraw&, SkCanvas::VertexMode, int vertexCount,
                              const SkPoint verts[], const SkPoint texs[],
                              const SkColor colors[], SkXfermode* xmode,
                              const uint16_t indices[], int indexCount,
                              const SkPaint& paint) SK_OVERRIDE;
    /** The SkBaseDevice passed will be an SkBaseDevice which was returned by a call to
        onCreateCompatibleDevice on this device with kSaveLayer_Usage.
     */
    virtual void drawDevice(const SkDraw&, SkBaseDevice*, int x, int y,
                            const SkPaint&) SK_OVERRIDE;

    ///////////////////////////////////////////////////////////////////////////

    /** Update as needed the pixel value in the bitmap, so that the caller can
        access the pixels directly. Note: only the pixels field should be
        altered. The config/width/height/rowbytes must remain unchanged.
        @return the device contents as a bitmap
    */
    const SkBitmap& onAccessBitmap() SK_OVERRIDE;

    SkPixelRef* getPixelRef() const { return fBitmap.pixelRef(); }
    // just for subclasses, to assign a custom pixelref
    SkPixelRef* setPixelRef(SkPixelRef* pr) {
        fBitmap.setPixelRef(pr);
        return pr;
    }

    bool onReadPixels(const SkImageInfo&, void*, size_t, int x, int y) SK_OVERRIDE;
    bool onWritePixels(const SkImageInfo&, const void*, size_t, int, int) SK_OVERRIDE;
    void* onAccessPixels(SkImageInfo* info, size_t* rowBytes) SK_OVERRIDE;

    /** Called when this device is installed into a Canvas. Balanced by a call
        to unlockPixels() when the device is removed from a Canvas.
    */
    void lockPixels() SK_OVERRIDE;
    void unlockPixels() SK_OVERRIDE;

private:
    friend class SkCanvas;
    friend struct DeviceCM; //for setMatrixClip
    friend class SkDraw;
    friend class SkDrawIter;
    friend class SkDeviceFilteredPaint;
    friend class SkDeviceImageFilterProxy;

    friend class SkSurface_Raster;

    // used to change the backend's pixels (and possibly config/rowbytes)
    // but cannot change the width/height, so there should be no change to
    // any clip information.
    void replaceBitmapBackendForRasterSurface(const SkBitmap&) SK_OVERRIDE;

    SkBaseDevice* onCreateCompatibleDevice(const CreateInfo&) SK_OVERRIDE;

    SkSurface* newSurface(const SkImageInfo&, const SkSurfaceProps&) SK_OVERRIDE;
    const void* peekPixels(SkImageInfo*, size_t* rowBytes) SK_OVERRIDE;

    SkImageFilter::Cache* getImageFilterCache() SK_OVERRIDE;

    SkBitmap    fBitmap;

    typedef SkBaseDevice INHERITED;
};

#endif // SkBitmapDevice_DEFINED