michael@0: /*
michael@0:  * Copyright 2012 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #ifndef GrSWMaskHelper_DEFINED
michael@0: #define GrSWMaskHelper_DEFINED
michael@0: 
michael@0: #include "GrColor.h"
michael@0: #include "GrDrawState.h"
michael@0: #include "SkBitmap.h"
michael@0: #include "SkDraw.h"
michael@0: #include "SkMatrix.h"
michael@0: #include "SkRasterClip.h"
michael@0: #include "SkRegion.h"
michael@0: #include "SkTypes.h"
michael@0: 
michael@0: class GrAutoScratchTexture;
michael@0: class GrContext;
michael@0: class GrTexture;
michael@0: class SkPath;
michael@0: class SkStrokeRec;
michael@0: class GrDrawTarget;
michael@0: 
michael@0: /**
michael@0:  * The GrSWMaskHelper helps generate clip masks using the software rendering
michael@0:  * path. It is intended to be used as:
michael@0:  *
michael@0:  *   GrSWMaskHelper helper(context);
michael@0:  *   helper.init(...);
michael@0:  *
michael@0:  *      draw one or more paths/rects specifying the required boolean ops
michael@0:  *
michael@0:  *   toTexture();   // to get it from the internal bitmap to the GPU
michael@0:  *
michael@0:  * The result of this process will be the final mask (on the GPU) in the
michael@0:  * upper left hand corner of the texture.
michael@0:  */
michael@0: class GrSWMaskHelper : public SkNoncopyable {
michael@0: public:
michael@0:     GrSWMaskHelper(GrContext* context)
michael@0:     : fContext(context) {
michael@0:     }
michael@0: 
michael@0:     // set up the internal state in preparation for draws. Since many masks
michael@0:     // may be accumulated in the helper during creation, "resultBounds"
michael@0:     // allows the caller to specify the region of interest - to limit the
michael@0:     // amount of work.
michael@0:     bool init(const SkIRect& resultBounds, const SkMatrix* matrix);
michael@0: 
michael@0:     // Draw a single rect into the accumulation bitmap using the specified op
michael@0:     void draw(const SkRect& rect, SkRegion::Op op,
michael@0:               bool antiAlias, uint8_t alpha);
michael@0: 
michael@0:     // Draw a single path into the accumuation bitmap using the specified op
michael@0:     void draw(const SkPath& path, const SkStrokeRec& stroke, SkRegion::Op op,
michael@0:               bool antiAlias, uint8_t alpha);
michael@0: 
michael@0:     // Helper function to get a scratch texture suitable for capturing the
michael@0:     // result (i.e., right size & format)
michael@0:     bool getTexture(GrAutoScratchTexture* texture);
michael@0: 
michael@0:     // Move the mask generation results from the internal bitmap to the gpu.
michael@0:     void toTexture(GrTexture* texture);
michael@0: 
michael@0:     // Reset the internal bitmap
michael@0:     void clear(uint8_t alpha) {
michael@0:         fBM.eraseColor(SkColorSetARGB(alpha, alpha, alpha, alpha));
michael@0:     }
michael@0: 
michael@0:     // Canonical usage utility that draws a single path and uploads it
michael@0:     // to the GPU. The result is returned in "result".
michael@0:     static GrTexture* DrawPathMaskToTexture(GrContext* context,
michael@0:                                             const SkPath& path,
michael@0:                                             const SkStrokeRec& stroke,
michael@0:                                             const SkIRect& resultBounds,
michael@0:                                             bool antiAlias,
michael@0:                                             SkMatrix* matrix);
michael@0: 
michael@0:     // This utility routine is used to add a path's mask to some other draw.
michael@0:     // The ClipMaskManager uses it to accumulate clip masks while the
michael@0:     // GrSoftwarePathRenderer uses it to fulfill a drawPath call.
michael@0:     // It draws with "texture" as a path mask into "target" using "rect" as
michael@0:     // geometry and the current drawState. The current drawState is altered to
michael@0:     // accommodate the mask.
michael@0:     // Note that this method assumes that the GrPaint::kTotalStages slot in
michael@0:     // the draw state can be used to hold the mask texture stage.
michael@0:     // This method is really only intended to be used with the
michael@0:     // output of DrawPathMaskToTexture.
michael@0:     static void DrawToTargetWithPathMask(GrTexture* texture,
michael@0:                                          GrDrawTarget* target,
michael@0:                                          const SkIRect& rect);
michael@0: 
michael@0: protected:
michael@0: private:
michael@0:     GrContext*      fContext;
michael@0:     SkMatrix        fMatrix;
michael@0:     SkBitmap        fBM;
michael@0:     SkDraw          fDraw;
michael@0:     SkRasterClip    fRasterClip;
michael@0: 
michael@0:     typedef SkNoncopyable INHERITED;
michael@0: };
michael@0: 
michael@0: #endif // GrSWMaskHelper_DEFINED