1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/include/utils/SkCanvasStateUtils.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,76 @@
1.4 +/*
1.5 + * Copyright 2013 Google Inc.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#ifndef SkCanvasStateUtils_DEFINED
1.12 +#define SkCanvasStateUtils_DEFINED
1.13 +
1.14 +#include "SkCanvas.h"
1.15 +
1.16 +class SkCanvasState;
1.17 +
1.18 +/**
1.19 + * A set of functions that are useful for copying an SkCanvas across a library
1.20 + * boundary where the Skia libraries on either side of the boundary may not be
1.21 + * version identical. The expected usage is outline below...
1.22 + *
1.23 + * Lib Boundary
1.24 + * CaptureCanvasState(...) |||
1.25 + * SkCanvas --> SkCanvasState |||
1.26 + * ||| CreateFromCanvasState(...)
1.27 + * ||| SkCanvasState --> SkCanvas`
1.28 + * ||| Draw into SkCanvas`
1.29 + * ||| Unref SkCanvas`
1.30 + * ReleaseCanvasState(...) |||
1.31 + *
1.32 + */
1.33 +namespace SkCanvasStateUtils {
1.34 + /**
1.35 + * Captures the current state of the canvas into an opaque ptr that is safe
1.36 + * to pass between different instances of Skia (which may or may not be the
1.37 + * same version). The function will return NULL in the event that one of the
1.38 + * following conditions are true.
1.39 + * 1) the canvas device type is not supported (currently only raster is supported)
1.40 + * 2) the canvas clip type is not supported (currently only non-AA clips are supported)
1.41 + *
1.42 + * It is recommended that the original canvas also not be used until all
1.43 + * canvases that have been created using its captured state have been dereferenced.
1.44 + *
1.45 + * Finally, it is important to note that any draw filters attached to the
1.46 + * canvas are NOT currently captured.
1.47 + *
1.48 + * @param canvas The canvas you wish to capture the current state of.
1.49 + * @return NULL or an opaque ptr that can be passed to CreateFromCanvasState
1.50 + * to reconstruct the canvas. The caller is responsible for calling
1.51 + * ReleaseCanvasState to free the memory associated with this state.
1.52 + */
1.53 + SK_API SkCanvasState* CaptureCanvasState(SkCanvas* canvas);
1.54 +
1.55 + /**
1.56 + * Create a new SkCanvas from the captured state of another SkCanvas. The
1.57 + * function will return NULL in the event that one of the
1.58 + * following conditions are true.
1.59 + * 1) the captured state is in an unrecognized format
1.60 + * 2) the captured canvas device type is not supported
1.61 + *
1.62 + * @param canvas The canvas you wish to capture the current state of.
1.63 + * @return NULL or an SkCanvas* whose devices and matrix/clip state are
1.64 + * identical to the captured canvas. The caller is responsible for
1.65 + * calling unref on the SkCanvas.
1.66 + */
1.67 + SK_API SkCanvas* CreateFromCanvasState(const SkCanvasState* state);
1.68 +
1.69 + /**
1.70 + * Free the memory associated with the captured canvas state. The state
1.71 + * should not be released until all SkCanvas objects created using that
1.72 + * state have been dereferenced.
1.73 + *
1.74 + * @param state The captured state you wish to dispose of.
1.75 + */
1.76 + SK_API void ReleaseCanvasState(SkCanvasState* state);
1.77 +};
1.78 +
1.79 +#endif
