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- /*
- * 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 "include/core/SkCanvas.h"
- class SkCanvasState;
- /**
- * A set of functions that are useful for copying the state of an SkCanvas
- * across a library boundary where the Skia library on the other side of the
- * boundary may be newer. The expected usage is outline below...
- *
- * Lib Boundary
- * CaptureCanvasState(...) |||
- * SkCanvas --> SkCanvasState |||
- * ||| CreateFromCanvasState(...)
- * ||| SkCanvasState --> SkCanvas`
- * ||| Draw into SkCanvas`
- * ||| Unref SkCanvas`
- * ReleaseCanvasState(...) |||
- *
- */
- class SK_API SkCanvasStateUtils {
- public:
- /**
- * Captures the current state of the canvas into an opaque ptr that is safe
- * to pass to a different instance of Skia (which may be the same version,
- * or may be newer). 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.
- */
- static 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 state Opaque object created by CaptureCanvasState.
- * @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.
- */
- static std::unique_ptr<SkCanvas> MakeFromCanvasState(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. Must be called from the same library
- * instance that created the state via CaptureCanvasState.
- *
- * @param state The captured state you wish to dispose of.
- */
- static void ReleaseCanvasState(SkCanvasState* state);
- };
- #endif
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