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 the bounds of the image relative to its encoded buffer. For all non-lazy images,
81  *  this returns (0,0,width,height). For a lazy-image, it may return a subset of that rect.
82  */
83 SkIRect SkImage_getSubset(const SkImage*);
84 
85 /**
86  *  Returns a new image containing the same pixel values as the source, but with a different color
87  *  space assigned. This performs no color space conversion. Primarily used in tests, to visualize
88  *  the results of rendering in wide or narrow gamuts.
89  */
90 sk_sp<SkImage> SkImageMakeRasterCopyAndAssignColorSpace(const SkImage*, SkColorSpace*);
91 
92 #endif
93