reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2008 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #ifndef SkPageFlipper_DEFINED |
| 18 | #define SkPageFlipper_DEFINED |
| 19 | |
| 20 | #include "SkRegion.h" |
| 21 | |
| 22 | /** SkPageFlipper manages alternating inval/dirty regions for a rectangular area |
| 23 | (like a bitmap). You call inval() to accumulate inval areas, and then when |
| 24 | you're ready to "flip" pages (i.e. draw into the one you've been |
| 25 | invalidating) you call update, which swaps the inval regions, and returns |
| 26 | two things to you: 1) the final inval region to be drawn into, and 2) the |
| 27 | region of pixels that should be copied from the "front" page onto the one |
| 28 | you're about to draw into. This copyBits region will be disjoint from the |
| 29 | inval region, so both need to be handled. |
| 30 | */ |
| 31 | class SkPageFlipper { |
| 32 | public: |
| 33 | SkPageFlipper(); |
| 34 | SkPageFlipper(int width, int height); |
| 35 | |
| 36 | int width() const { return fWidth; } |
| 37 | int height() const { return fHeight; } |
| 38 | |
| 39 | void resize(int width, int height); |
| 40 | |
| 41 | bool isDirty() const { return !fDirty1->isEmpty(); } |
| 42 | const SkRegion& dirtyRgn() const { return *fDirty1; } |
| 43 | |
| 44 | void inval(); |
| 45 | void inval(const SkIRect&); |
| 46 | void inval(const SkRegion&); |
| 47 | void inval(const SkRect&, bool antialias); |
| 48 | |
| 49 | /** When you're ready to write to the back page, call update. The returned |
| 50 | region is the invalidate are that needs to be drawn to. The copyBits |
| 51 | region (provided by the caller) is the area that should be copied from |
| 52 | the front page to the back page (will not intersect with the returned |
| 53 | inval region. |
| 54 | |
| 55 | Once this is called, the two internal regions are swapped, so the *new* |
| 56 | back inval region is ready to receive new inval calls. |
| 57 | */ |
| 58 | const SkRegion& update(SkRegion* copyBits); |
| 59 | |
| 60 | private: |
| 61 | SkRegion* fDirty0; |
| 62 | SkRegion* fDirty1; |
| 63 | SkRegion fDirty0Storage; |
| 64 | SkRegion fDirty1Storage; |
| 65 | int fWidth; |
| 66 | int fHeight; |
| 67 | }; |
| 68 | |
| 69 | #endif |
| 70 | |