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      1 /*
      2  * Copyright 2012 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #ifndef SkImagePriv_DEFINED
      9 #define SkImagePriv_DEFINED
     10 
     11 #include "SkImage.h"
     12 #include "SkSurface.h"
     13 
     14 enum SkCopyPixelsMode {
     15     kIfMutable_SkCopyPixelsMode,  //!< only copy src pixels if they are marked mutable
     16     kAlways_SkCopyPixelsMode,     //!< always copy src pixels (even if they are marked immutable)
     17     kNever_SkCopyPixelsMode,      //!< never copy src pixels (even if they are marked mutable)
     18 };
     19 
     20 // A good size for creating shader contexts on the stack.
     21 enum {kSkBlitterContextSize = 3332};
     22 
     23 // If alloc is non-nullptr, it will be used to allocate the returned SkShader, and MUST outlive
     24 // the SkShader.
     25 sk_sp<SkShader> SkMakeBitmapShader(const SkBitmap& src, SkShader::TileMode, SkShader::TileMode,
     26                                    const SkMatrix* localMatrix, SkCopyPixelsMode);
     27 
     28 /**
     29  *  Examines the bitmap to decide if it can share the existing pixelRef, or
     30  *  if it needs to make a deep-copy of the pixels.
     31  *
     32  *  The bitmap's pixelref will be shared if either the bitmap is marked as
     33  *  immutable, or CopyPixelsMode allows it. Shared pixel refs are also
     34  *  locked when kLocked_SharedPixelRefMode is specified.
     35  *
     36  *  Passing kLocked_SharedPixelRefMode allows the image's peekPixels() method
     37  *  to succeed, but it will force any lazy decodes/generators to execute if
     38  *  they exist on the pixelref.
     39  *
     40  *  It is illegal to call this with a texture-backed bitmap.
     41  *
     42  *  If the bitmap's colortype cannot be converted into a corresponding
     43  *  SkImageInfo, or the bitmap's pixels cannot be accessed, this will return
     44  *  nullptr.
     45  */
     46 extern SK_API sk_sp<SkImage> SkMakeImageFromRasterBitmap(const SkBitmap&, SkCopyPixelsMode);
     47 
     48 // Given an image created from SkNewImageFromBitmap, return its pixelref. This
     49 // may be called to see if the surface and the image share the same pixelref,
     50 // in which case the surface may need to perform a copy-on-write.
     51 extern const SkPixelRef* SkBitmapImageGetPixelRef(const SkImage* rasterImage);
     52 
     53 /**
     54  *  Will attempt to upload and lock the contents of the image as a texture, so that subsequent
     55  *  draws to a gpu-target will come from that texture (and not by looking at the original image
     56  *  src). In particular this is intended to use the texture even if the image's original content
     57  *  changes subsequent to this call (i.e. the src is mutable!).
     58  *
     59  *  All successful calls must be balanced by an equal number of calls to SkImage_unpinAsTexture().
     60  *
     61  *  Once in this "pinned" state, the image has all of the same thread restrictions that exist
     62  *  for a natively created gpu image (e.g. SkImage::MakeFromTexture)
     63  *  - all drawing, pinning, unpinning must happen in the same thread as the GrContext.
     64  *
     65  *  @return true if the image was successfully uploaded and locked into a texture
     66  */
     67 bool SkImage_pinAsTexture(const SkImage*, GrContext*);
     68 
     69 /**
     70  *  The balancing call to a successful invokation of SkImage_pinAsTexture.  When a balanced number of
     71  *  calls have been made, then the "pinned" texture is free to be purged, etc. This also means that a
     72  *  subsequent "pin" call will look at the original content again, and if its uniqueID/generationID
     73  *  has changed, then a newer texture will be uploaded/pinned.
     74  *
     75  *  The context passed to unpin must match the one passed to pin.
     76  */
     77 void SkImage_unpinAsTexture(const SkImage*, GrContext*);
     78 
     79 /**
     80  *  Returns a new image containing the same pixel values as the source, but with a different color
     81  *  space assigned. This performs no color space conversion. Primarily used in tests, to visualize
     82  *  the results of rendering in wide or narrow gamuts.
     83  */
     84 sk_sp<SkImage> SkImageMakeRasterCopyAndAssignColorSpace(const SkImage*, SkColorSpace*);
     85 
     86 #endif
     87