0f10f7bf1f
This change is motivated by the desire to see the text information in the debugger when not in developer mode. It is structured so user's can disable it if the capability is not wanted. R=bsalomon@google.com Author: robertphillips@google.com Review URL: https://codereview.chromium.org/197763008 git-svn-id: http://skia.googlecode.com/svn/trunk@13795 2bbb7eff-a529-9590-31e7-b0007b416f81
103 lines
3.7 KiB
C++
103 lines
3.7 KiB
C++
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/*
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* Copyright 2011 The Android Open Source Project
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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 SkDrawLooper_DEFINED
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#define SkDrawLooper_DEFINED
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#include "SkFlattenable.h"
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class SkCanvas;
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class SkPaint;
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struct SkRect;
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class SkString;
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/** \class SkDrawLooper
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Subclasses of SkDrawLooper can be attached to a SkPaint. Where they are,
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and something is drawn to a canvas with that paint, the looper subclass will
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be called, allowing it to modify the canvas and/or paint for that draw call.
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More than that, via the next() method, the looper can modify the draw to be
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invoked multiple times (hence the name loop-er), allow it to perform effects
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like shadows or frame/fills, that require more than one pass.
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*/
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class SK_API SkDrawLooper : public SkFlattenable {
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public:
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SK_DECLARE_INST_COUNT(SkDrawLooper)
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/**
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* Holds state during a draw. Users call next() until it returns false.
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*
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* Subclasses of SkDrawLooper should create a subclass of this object to
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* hold state specific to their subclass.
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*/
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class SK_API Context : public SkNoncopyable {
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public:
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Context() {}
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virtual ~Context() {}
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/**
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* Called in a loop on objects returned by SkDrawLooper::createContext().
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* Each time true is returned, the object is drawn (possibly with a modified
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* canvas and/or paint). When false is finally returned, drawing for the object
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* stops.
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*
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* On each call, the paint will be in its original state, but the
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* canvas will be as it was following the previous call to next() or
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* createContext().
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*
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* The implementation must ensure that, when next() finally returns
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* false, the canvas has been restored to the state it was
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* initially, before createContext() was first called.
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*/
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virtual bool next(SkCanvas* canvas, SkPaint* paint) = 0;
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};
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/**
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* Called right before something is being drawn. Returns a Context
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* whose next() method should be called until it returns false.
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* The caller has to ensure that the storage pointer provides enough
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* memory for the Context. The required size can be queried by calling
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* contextSize(). It is also the caller's responsibility to destroy the
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* object after use.
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*/
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virtual Context* createContext(SkCanvas*, void* storage) const = 0;
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/**
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* Returns the number of bytes needed to store subclasses of Context (belonging to the
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* corresponding SkDrawLooper subclass).
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*/
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virtual size_t contextSize() const = 0;
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/**
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* The fast bounds functions are used to enable the paint to be culled early
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* in the drawing pipeline. If a subclass can support this feature it must
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* return true for the canComputeFastBounds() function. If that function
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* returns false then computeFastBounds behavior is undefined otherwise it
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* is expected to have the following behavior. Given the parent paint and
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* the parent's bounding rect the subclass must fill in and return the
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* storage rect, where the storage rect is with the union of the src rect
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* and the looper's bounding rect.
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*/
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virtual bool canComputeFastBounds(const SkPaint& paint) const;
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virtual void computeFastBounds(const SkPaint& paint,
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const SkRect& src, SkRect* dst) const;
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SK_TO_STRING_PUREVIRT()
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SK_DEFINE_FLATTENABLE_TYPE(SkDrawLooper)
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protected:
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SkDrawLooper() {}
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SkDrawLooper(SkReadBuffer& buffer) : INHERITED(buffer) {}
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private:
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typedef SkFlattenable INHERITED;
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};
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#endif
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