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79 lines
3.1 KiB
79 lines
3.1 KiB
4 months ago
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/*
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* Copyright 2013 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkCanvasStateUtils_DEFINED
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#define SkCanvasStateUtils_DEFINED
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#include "include/core/SkCanvas.h"
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class SkCanvasState;
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/**
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* A set of functions that are useful for copying the state of an SkCanvas
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* across a library boundary where the Skia library on the other side of the
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* boundary may be newer. The expected usage is outline below...
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*
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* Lib Boundary
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* CaptureCanvasState(...) |||
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* SkCanvas --> SkCanvasState |||
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* ||| CreateFromCanvasState(...)
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* ||| SkCanvasState --> SkCanvas`
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* ||| Draw into SkCanvas`
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* ||| Unref SkCanvas`
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* ReleaseCanvasState(...) |||
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*
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*/
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class SK_API SkCanvasStateUtils {
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public:
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/**
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* Captures the current state of the canvas into an opaque ptr that is safe
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* to pass to a different instance of Skia (which may be the same version,
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* or may be newer). The function will return NULL in the event that one of the
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* following conditions are true.
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* 1) the canvas device type is not supported (currently only raster is supported)
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* 2) the canvas clip type is not supported (currently only non-AA clips are supported)
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*
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* It is recommended that the original canvas also not be used until all
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* canvases that have been created using its captured state have been dereferenced.
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*
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* Finally, it is important to note that any draw filters attached to the
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* canvas are NOT currently captured.
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*
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* @param canvas The canvas you wish to capture the current state of.
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* @return NULL or an opaque ptr that can be passed to CreateFromCanvasState
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* to reconstruct the canvas. The caller is responsible for calling
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* ReleaseCanvasState to free the memory associated with this state.
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*/
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static SkCanvasState* CaptureCanvasState(SkCanvas* canvas);
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/**
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* Create a new SkCanvas from the captured state of another SkCanvas. The
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* function will return NULL in the event that one of the
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* following conditions are true.
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* 1) the captured state is in an unrecognized format
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* 2) the captured canvas device type is not supported
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*
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* @param state Opaque object created by CaptureCanvasState.
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* @return NULL or an SkCanvas* whose devices and matrix/clip state are
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* identical to the captured canvas. The caller is responsible for
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* calling unref on the SkCanvas.
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*/
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static std::unique_ptr<SkCanvas> MakeFromCanvasState(const SkCanvasState* state);
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/**
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* Free the memory associated with the captured canvas state. The state
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* should not be released until all SkCanvas objects created using that
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* state have been dereferenced. Must be called from the same library
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* instance that created the state via CaptureCanvasState.
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*
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* @param state The captured state you wish to dispose of.
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*/
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static void ReleaseCanvasState(SkCanvasState* state);
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};
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#endif
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