1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/include/images/SkPageFlipper.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,62 @@
1.4 +
1.5 +/*
1.6 + * Copyright 2008 The Android Open Source Project
1.7 + *
1.8 + * Use of this source code is governed by a BSD-style license that can be
1.9 + * found in the LICENSE file.
1.10 + */
1.11 +
1.12 +
1.13 +#ifndef SkPageFlipper_DEFINED
1.14 +#define SkPageFlipper_DEFINED
1.15 +
1.16 +#include "SkRegion.h"
1.17 +
1.18 +/** SkPageFlipper manages alternating inval/dirty regions for a rectangular area
1.19 + (like a bitmap). You call inval() to accumulate inval areas, and then when
1.20 + you're ready to "flip" pages (i.e. draw into the one you've been
1.21 + invalidating) you call update, which swaps the inval regions, and returns
1.22 + two things to you: 1) the final inval region to be drawn into, and 2) the
1.23 + region of pixels that should be copied from the "front" page onto the one
1.24 + you're about to draw into. This copyBits region will be disjoint from the
1.25 + inval region, so both need to be handled.
1.26 + */
1.27 +class SkPageFlipper {
1.28 +public:
1.29 + SkPageFlipper();
1.30 + SkPageFlipper(int width, int height);
1.31 +
1.32 + int width() const { return fWidth; }
1.33 + int height() const { return fHeight; }
1.34 +
1.35 + void resize(int width, int height);
1.36 +
1.37 + bool isDirty() const { return !fDirty1->isEmpty(); }
1.38 + const SkRegion& dirtyRgn() const { return *fDirty1; }
1.39 +
1.40 + void inval();
1.41 + void inval(const SkIRect&);
1.42 + void inval(const SkRegion&);
1.43 + void inval(const SkRect&, bool antialias);
1.44 +
1.45 + /** When you're ready to write to the back page, call update. The returned
1.46 + region is the invalidate are that needs to be drawn to. The copyBits
1.47 + region (provided by the caller) is the area that should be copied from
1.48 + the front page to the back page (will not intersect with the returned
1.49 + inval region.
1.50 +
1.51 + Once this is called, the two internal regions are swapped, so the *new*
1.52 + back inval region is ready to receive new inval calls.
1.53 + */
1.54 + const SkRegion& update(SkRegion* copyBits);
1.55 +
1.56 +private:
1.57 + SkRegion* fDirty0;
1.58 + SkRegion* fDirty1;
1.59 + SkRegion fDirty0Storage;
1.60 + SkRegion fDirty1Storage;
1.61 + int fWidth;
1.62 + int fHeight;
1.63 +};
1.64 +
1.65 +#endif
