71 lines
2.4 KiB
C
71 lines
2.4 KiB
C
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/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef SkPageFlipper_DEFINED
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#define SkPageFlipper_DEFINED
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#include "SkRegion.h"
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/** SkPageFlipper manages alternating inval/dirty regions for a rectangular area
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(like a bitmap). You call inval() to accumulate inval areas, and then when
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you're ready to "flip" pages (i.e. draw into the one you've been
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invalidating) you call update, which swaps the inval regions, and returns
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two things to you: 1) the final inval region to be drawn into, and 2) the
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region of pixels that should be copied from the "front" page onto the one
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you're about to draw into. This copyBits region will be disjoint from the
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inval region, so both need to be handled.
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*/
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class SkPageFlipper {
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public:
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SkPageFlipper();
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SkPageFlipper(int width, int height);
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int width() const { return fWidth; }
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int height() const { return fHeight; }
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void resize(int width, int height);
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bool isDirty() const { return !fDirty1->isEmpty(); }
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const SkRegion& dirtyRgn() const { return *fDirty1; }
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void inval();
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void inval(const SkIRect&);
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void inval(const SkRegion&);
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void inval(const SkRect&, bool antialias);
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/** When you're ready to write to the back page, call update. The returned
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region is the invalidate are that needs to be drawn to. The copyBits
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region (provided by the caller) is the area that should be copied from
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the front page to the back page (will not intersect with the returned
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inval region.
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Once this is called, the two internal regions are swapped, so the *new*
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back inval region is ready to receive new inval calls.
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*/
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const SkRegion& update(SkRegion* copyBits);
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private:
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SkRegion* fDirty0;
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SkRegion* fDirty1;
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SkRegion fDirty0Storage;
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SkRegion fDirty1Storage;
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int fWidth;
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int fHeight;
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};
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#endif
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