diff options
author | djsollen@google.com <djsollen@google.com@2bbb7eff-a529-9590-31e7-b0007b416f81> | 2013-08-29 20:20:40 +0000 |
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committer | djsollen@google.com <djsollen@google.com@2bbb7eff-a529-9590-31e7-b0007b416f81> | 2013-08-29 20:20:40 +0000 |
commit | 5587ac09beec4c056332504f3fa85990520b43fd (patch) | |
tree | fc6a3a59cabd7a0814c717d5c0cc0aef23105808 /include/utils | |
parent | 5696baa16bc3cfbf99b9abfcdd178d0afe3213da (diff) |
Create a semi-stable API for capturing the state of an SkCanvas and reconstructing that state across different versions of Skia.
R=joth@chromium.org, mtklein@google.com, reed@google.com, scroggo@google.com
Committed: https://code.google.com/p/skia/source/detail?r=11010
Review URL: https://codereview.chromium.org/23545017
git-svn-id: http://skia.googlecode.com/svn/trunk@11013 2bbb7eff-a529-9590-31e7-b0007b416f81
Diffstat (limited to 'include/utils')
-rw-r--r-- | include/utils/SkCanvasStateUtils.h | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/include/utils/SkCanvasStateUtils.h b/include/utils/SkCanvasStateUtils.h new file mode 100644 index 0000000000..f8266c9b32 --- /dev/null +++ b/include/utils/SkCanvasStateUtils.h @@ -0,0 +1,76 @@ +/* + * Copyright 2013 Google Inc. + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ + +#ifndef SkCanvasStateUtils_DEFINED +#define SkCanvasStateUtils_DEFINED + +#include "SkCanvas.h" + +class SkCanvasState; + +/** + * A set of functions that are useful for copying an SkCanvas across a library + * boundary where the Skia libraries on either side of the boundary may not be + * version identical. The expected usage is outline below... + * + * Lib Boundary + * CaptureCanvasState(...) ||| + * SkCanvas --> SkCanvasState ||| + * ||| CreateFromCanvasState(...) + * ||| SkCanvasState --> SkCanvas` + * ||| Draw into SkCanvas` + * ||| Unref SkCanvas` + * ReleaseCanvasState(...) ||| + * + */ +namespace SkCanvasStateUtils { + /** + * Captures the current state of the canvas into an opaque ptr that is safe + * to pass between different instances of Skia (which may or may not be the + * same version). The function will return NULL in the event that one of the + * following conditions are true. + * 1) the canvas device type is not supported (currently only raster is supported) + * 2) the canvas clip type is not supported (currently only non-AA clips are supported) + * + * It is recommended that the original canvas also not be used until all + * canvases that have been created using its captured state have been dereferenced. + * + * Finally, it is important to note that any draw filters attached to the + * canvas are NOT currently captured. + * + * @param canvas The canvas you wish to capture the current state of. + * @return NULL or an opaque ptr that can be passed to CreateFromCanvasState + * to reconstruct the canvas. The caller is responsible for calling + * ReleaseCanvasState to free the memory associated with this state. + */ + SK_API SkCanvasState* CaptureCanvasState(SkCanvas* canvas); + + /** + * Create a new SkCanvas from the captured state of another SkCanvas. The + * function will return NULL in the event that one of the + * following conditions are true. + * 1) the captured state is in an unrecognized format + * 2) the captured canvas device type is not supported + * + * @param canvas The canvas you wish to capture the current state of. + * @return NULL or an SkCanvas* whose devices and matrix/clip state are + * identical to the captured canvas. The caller is responsible for + * calling unref on the SkCanvas. + */ + SK_API SkCanvas* CreateFromCanvasState(const SkCanvasState* state); + + /** + * Free the memory associated with the captured canvas state. The state + * should not be released until all SkCanvas objects created using that + * state have been dereferenced. + * + * @param state The captured state you wish to dispose of. + */ + SK_API void ReleaseCanvasState(SkCanvasState* state); +}; + +#endif |