blob: f2bb34b30c090df98c8c365ceae0e472b96a945b [file] [log] [blame]
/*
* 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 "SkAutoPixmapStorage.h"
#include "GrColor.h"
#include "SkBitmap.h"
#include "SkDraw.h"
#include "SkMatrix.h"
#include "SkRasterClip.h"
#include "SkRegion.h"
#include "SkTypes.h"
class GrClip;
class GrPaint;
class GrShape;
class GrTextureProvider;
class GrStyle;
class GrTexture;
struct GrUserStencilSettings;
/**
* 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 : SkNoncopyable {
public:
GrSWMaskHelper(GrTextureProvider* texProvider) : fTexProvider(texProvider) { }
// 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 SkIRect& resultBounds, const SkMatrix* matrix);
// Draw a single rect into the accumulation bitmap using the specified op
void drawRect(const SkRect& rect, SkRegion::Op op, bool antiAlias, uint8_t alpha);
// Draw a single path into the accumuation bitmap using the specified op
void drawShape(const GrShape&, SkRegion::Op op, bool antiAlias, uint8_t alpha);
// Move the mask generation results from the internal bitmap to the gpu.
void toTexture(GrTexture* texture);
// Convert mask generation results to a signed distance field
void toSDF(unsigned char* sdf);
// Reset the internal bitmap
void clear(uint8_t alpha) {
fPixels.erase(SkColorSetARGB(alpha, 0xFF, 0xFF, 0xFF));
}
// Canonical usage utility that draws a single path and uploads it
// to the GPU. The result is returned.
static GrTexture* DrawShapeMaskToTexture(GrTextureProvider*,
const GrShape&,
const SkIRect& resultBounds,
bool antiAlias,
const SkMatrix* matrix);
// This utility routine is used to add a shape's mask to some other draw.
// The GrClipStackClip 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 DrawToTargetWithShapeMask(GrTexture* texture,
GrDrawContext*,
const GrPaint& paint,
const GrUserStencilSettings& userStencilSettings,
const GrClip&,
const SkMatrix& viewMatrix,
const SkIRect& rect);
private:
// Helper function to get a scratch texture suitable for capturing the
// result (i.e., right size & format)
GrTexture* createTexture();
GrTextureProvider* fTexProvider;
SkMatrix fMatrix;
SkAutoPixmapStorage fPixels;
SkDraw fDraw;
SkRasterClip fRasterClip;
typedef SkNoncopyable INHERITED;
};
#endif // GrSWMaskHelper_DEFINED