Begin atlasing

include/core/SkSurface.h

 /*
  * 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 SkSurface_DEFINED
 #define SkSurface_DEFINED
 
@@ skipping 59 matching lines @@
         /**
          *  This will use the standard text rendering method
          */
         kStandard_TextRenderMode,
         /**
          *  This will use signed distance fields for text rendering when possible
          */
         kDistanceField_TextRenderMode,
     };
 
+    enum RenderTargetFlags {
+        kNone_RenderTargetFlag      = 0x0,
+        /*
+         * By default a RenderTarget-based surface will be cleared on creation.
+         * Pass in this flag to prevent the clear from happening.
+         */
+        kDontClear_RenderTargetFlag = 0x01,
+    };
+
     /**
      *  Return a new surface using the specified render target.
      */
     static SkSurface* NewRenderTargetDirect(GrRenderTarget*,
-                                            TextRenderMode trm = kStandard_TextRenderMode);
+                                            TextRenderMode trm = kStandard_TextRenderMode,
+                                            RenderTargetFlags flags = kNone_RenderTargetFlag);
 
     /**
      *  Return a new surface whose contents will be drawn to an offscreen
      *  render target, allocated by the surface.
      */
     static SkSurface* NewRenderTarget(GrContext*, const SkImageInfo&, int sampleCount = 0,
-                                      TextRenderMode trm = kStandard_TextRenderMode);
+                                      TextRenderMode trm = kStandard_TextRenderMode,
+                                      RenderTargetFlags flags = kNone_RenderTargetFlag);
 
     /**
      *  Return a new surface whose contents will be drawn to an offscreen
      *  render target, allocated by the surface from the scratch texture pool
      *  managed by the GrContext. The scratch texture pool serves the purpose
      *  of retaining textures after they are no longer in use in order to
      *  re-use them later without having to re-allocate.  Scratch textures
      *  should be used in cases where high turnover is expected. This allows,
      *  for example, the copy on write to recycle a texture from a recently
      *  released SkImage snapshot of the surface.
      *  Note: Scratch textures count against the GrContext's cached resource
      *  budget.
      */
     static SkSurface* NewScratchRenderTarget(GrContext*, const SkImageInfo&, int sampleCount = 0,
-                                             TextRenderMode trm = kStandard_TextRenderMode);
+                                             TextRenderMode trm = kStandard_TextRenderMode,
+                                             RenderTargetFlags flags = kNone_RenderTargetFlag);
 
     int width() const { return fWidth; }
     int height() const { return fHeight; }
 
     /**
      *  Returns a unique non-zero, unique value identifying the content of this
      *  surface. Each time the content is changed changed, either by drawing
      *  into this surface, or explicitly calling notifyContentChanged()) this
      *  method will return a new value.
      *
@@ skipping 86 matching lines @@
 
 private:
     const int   fWidth;
     const int   fHeight;
     uint32_t    fGenerationID;
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif