src/pdf/SkPDFShader.h

/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */


#ifndef SkPDFShader_DEFINED
#define SkPDFShader_DEFINED

#include "SkPDFStream.h"
#include "SkPDFTypes.h"
#include "SkMatrix.h"
#include "SkRefCnt.h"
#include "SkShader.h"

class SkObjRef;
class SkPDFCatalog;

/** \class SkPDFShader

    In PDF parlance, this is a pattern, used in place of a color when the
    pattern color space is selected.
*/

class SkPDFShader {
public:
    /** Get the PDF shader for the passed SkShader. If the SkShader is
     *  invalid in some way, returns NULL. The reference count of
     *  the object is incremented and it is the caller's responsibility to
     *  unreference it when done.  This is needed to accommodate the weak
     *  reference pattern used when the returned object is new and has no
     *  other references.
     *  @param shader      The SkShader to emulate.
     *  @param matrix      The current transform. (PDF shaders are absolutely
     *                     positioned, relative to where the page is drawn.)
     *  @param surfceBBox  The bounding box of the drawing surface (with matrix
     *                     already applied).
     *  @param rasterScale Additional scale to be applied for early rasterization.
     */
    static SkPDFObject* GetPDFShader(const SkShader& shader,
                                     const SkMatrix& matrix,
                                     const SkIRect& surfaceBBox,
                                     SkScalar rasterScale);

    class State;
    bool equals(const SkPDFShader::State&) const;

protected:
    SkAutoTDelete<const State> fShaderState;

    // This is an internal method.
    // CanonicalShadersMutex() should already be acquired.
    // This also takes ownership of shaderState.
    static SkPDFObject* GetPDFShaderByState(State* shaderState);
    static SkPDFObject* AddToCanonIfValid(SkPDFShader*);
    static void RemoveFromCanonIfValid(SkPDFShader*);

    SkPDFShader(State*);
    virtual ~SkPDFShader();

    virtual bool isValid() = 0;
    virtual SkPDFObject* toPDFObject() = 0;
};

#endif