3cb3840c9a
(patchset #2 id:20001 of https://codereview.chromium.org/903993002/)"
This reverts commit c4e8772492.
BUG=skia:
TBR=
NOTREECHECKS=True
Review URL: https://codereview.chromium.org/898343004
77 lines
2.5 KiB
C++
77 lines
2.5 KiB
C++
/*
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* Copyright 2014 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 SkDrawable_DEFINED
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#define SkDrawable_DEFINED
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#include "SkRefCnt.h"
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class SkCanvas;
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class SkPicture;
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struct SkRect;
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/**
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* Base-class for objects that draw into SkCanvas.
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*
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* The object has a generation ID, which is guaranteed to be unique across all drawables. To
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* allow for clients of the drawable that may want to cache the results, the drawable must
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* change its generation ID whenever its internal state changes such that it will draw differently.
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*/
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class SkDrawable : public SkRefCnt {
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public:
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SkDrawable();
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/**
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* Draws into the specified content. The drawing sequence will be balanced upon return
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* (i.e. the saveLevel() on the canvas will match what it was when draw() was called,
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* and the current matrix and clip settings will not be changed.
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*/
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void draw(SkCanvas*);
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SkPicture* newPictureSnapshot();
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/**
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* Return a unique value for this instance. If two calls to this return the same value,
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* it is presumed that calling the draw() method will render the same thing as well.
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*
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* Subclasses that change their state should call notifyDrawingChanged() to ensure that
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* a new value will be returned the next time it is called.
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*/
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uint32_t getGenerationID();
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/**
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* Return the (conservative) bounds of what the drawable will draw. If the drawable can
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* change what it draws (e.g. animation or in response to some external change), then this
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* must return a bounds that is always valid for all possible states.
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*/
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SkRect getBounds();
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/**
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* Calling this invalidates the previous generation ID, and causes a new one to be computed
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* the next time getGenerationID() is called. Typically this is called by the object itself,
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* in response to its internal state changing.
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*/
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void notifyDrawingChanged();
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protected:
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virtual SkRect onGetBounds() = 0;
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virtual void onDraw(SkCanvas*) = 0;
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/**
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* Default implementation calls onDraw() with a canvas that records into a picture. Subclasses
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* may override if they have a more efficient way to return a picture for the current state
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* of their drawable. Note: this picture must draw the same as what would be drawn from
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* onDraw().
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*/
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virtual SkPicture* onNewPictureSnapshot();
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private:
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int32_t fGenerationID;
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};
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#endif
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