зеркало из https://github.com/mozilla/moz-skia.git
71 строка
2.6 KiB
C++
71 строка
2.6 KiB
C++
|
|
/*
|
|
* Copyright 2011 The Android Open Source Project
|
|
*
|
|
* Use of this source code is governed by a BSD-style license that can be
|
|
* found in the LICENSE file.
|
|
*/
|
|
|
|
|
|
#ifndef SkDrawLooper_DEFINED
|
|
#define SkDrawLooper_DEFINED
|
|
|
|
#include "SkFlattenable.h"
|
|
|
|
class SkCanvas;
|
|
class SkPaint;
|
|
|
|
/** \class SkDrawLooper
|
|
Subclasses of SkDrawLooper can be attached to a SkPaint. Where they are,
|
|
and something is drawn to a canvas with that paint, the looper subclass will
|
|
be called, allowing it to modify the canvas and/or paint for that draw call.
|
|
More than that, via the next() method, the looper can modify the draw to be
|
|
invoked multiple times (hence the name loop-er), allow it to perform effects
|
|
like shadows or frame/fills, that require more than one pass.
|
|
*/
|
|
class SK_API SkDrawLooper : public SkFlattenable {
|
|
public:
|
|
/**
|
|
* Called right before something is being drawn. This will be followed by
|
|
* calls to next() until next() returns false.
|
|
*/
|
|
virtual void init(SkCanvas*) = 0;
|
|
|
|
/**
|
|
* Called in a loop (after init()). Each time true is returned, the object
|
|
* is drawn (possibly with a modified canvas and/or paint). When false is
|
|
* finally returned, drawing for the object stops.
|
|
*
|
|
* On each call, the paint will be in its original state, but the canvas
|
|
* will be as it was following the previous call to next() or init().
|
|
*
|
|
* The implementation must ensure that, when next() finally returns false,
|
|
* that the canvas has been restored to the state it was initially, before
|
|
* init() was first called.
|
|
*/
|
|
virtual bool next(SkCanvas*, SkPaint* paint) = 0;
|
|
|
|
/**
|
|
* The fast bounds functions are used to enable the paint to be culled early
|
|
* in the drawing pipeline. If a subclass can support this feature it must
|
|
* return true for the canComputeFastBounds() function. If that function
|
|
* returns false then computeFastBounds behavior is undefined otherwise it
|
|
* is expected to have the following behavior. Given the parent paint and
|
|
* the parent's bounding rect the subclass must fill in and return the
|
|
* storage rect, where the storage rect is with the union of the src rect
|
|
* and the looper's bounding rect.
|
|
*/
|
|
virtual bool canComputeFastBounds(const SkPaint& paint);
|
|
virtual void computeFastBounds(const SkPaint& paint,
|
|
const SkRect& src, SkRect* dst);
|
|
|
|
protected:
|
|
SkDrawLooper() {}
|
|
SkDrawLooper(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {}
|
|
|
|
private:
|
|
typedef SkFlattenable INHERITED;
|
|
};
|
|
|
|
#endif
|