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/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrSWMaskHelper_DEFINED
#define GrSWMaskHelper_DEFINED
#include "GrColor.h"
#include "SkMatrix.h"
#include "GrNoncopyable.h"
#include "SkBitmap.h"
#include "SkDraw.h"
#include "SkRasterClip.h"
#include "SkRegion.h"
#include "GrDrawState.h"
class GrAutoScratchTexture;
class GrContext;
class GrTexture;
class SkPath;
class SkStrokeRec;
class GrDrawTarget;
/**
* The GrSWMaskHelper helps generate clip masks using the software rendering
* path. It is intended to be used as:
*
* GrSWMaskHelper helper(context);
* helper.init(...);
*
* draw one or more paths/rects specifying the required boolean ops
*
* toTexture(); // to get it from the internal bitmap to the GPU
*
* The result of this process will be the final mask (on the GPU) in the
* upper left hand corner of the texture.
*/
class GrSWMaskHelper : public GrNoncopyable {
public:
GrSWMaskHelper(GrContext* context)
: fContext(context) {
}
// set up the internal state in preparation for draws. Since many masks
// may be accumulated in the helper during creation, "resultBounds"
// allows the caller to specify the region of interest - to limit the
// amount of work.
bool init(const GrIRect& resultBounds, const SkMatrix* matrix);
// Draw a single rect into the accumulation bitmap using the specified op
void draw(const GrRect& rect, SkRegion::Op op,
bool antiAlias, uint8_t alpha);
// Draw a single path into the accumuation bitmap using the specified op
void draw(const SkPath& path, const SkStrokeRec& stroke, SkRegion::Op op,
bool antiAlias, uint8_t alpha);
// Helper function to get a scratch texture suitable for capturing the
// result (i.e., right size & format)
bool getTexture(GrAutoScratchTexture* texture);
// Move the mask generation results from the internal bitmap to the gpu.
// The space outside of the mask is cleared using "alpha"
void toTexture(GrTexture* texture, uint8_t alpha);
// Reset the internal bitmap
void clear(uint8_t alpha) {
fBM.eraseColor(SkColorSetARGB(alpha, alpha, alpha, alpha));
}
// Canonical usage utility that draws a single path and uploads it
// to the GPU. The result is returned in "result".
static GrTexture* DrawPathMaskToTexture(GrContext* context,
const SkPath& path,
const SkStrokeRec& stroke,
const GrIRect& resultBounds,
bool antiAlias,
SkMatrix* matrix);
// This utility routine is used to add a path's mask to some other draw.
// The ClipMaskManager uses it to accumulate clip masks while the
// GrSoftwarePathRenderer uses it to fulfill a drawPath call.
// It draws with "texture" as a path mask into "target" using "rect" as
// geometry and the current drawState. The current drawState is altered to
// accommodate the mask.
// Note that this method assumes that the GrPaint::kTotalStages slot in
// the draw state can be used to hold the mask texture stage.
// This method is really only intended to be used with the
// output of DrawPathMaskToTexture.
static void DrawToTargetWithPathMask(GrTexture* texture,
GrDrawTarget* target,
const GrIRect& rect);
protected:
private:
GrContext* fContext;
SkMatrix fMatrix;
SkBitmap fBM;
SkDraw fDraw;
SkRasterClip fRasterClip;
typedef GrNoncopyable INHERITED;
};
#endif // GrSWMaskHelper_DEFINED
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