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- /*
- * Copyright 2013 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- #ifndef SkMipMap_DEFINED
- #define SkMipMap_DEFINED
- #include "include/core/SkPixmap.h"
- #include "include/core/SkScalar.h"
- #include "include/core/SkSize.h"
- #include "include/private/SkImageInfoPriv.h"
- #include "src/core/SkCachedData.h"
- #include "src/shaders/SkShaderBase.h"
- class SkBitmap;
- class SkDiscardableMemory;
- typedef SkDiscardableMemory* (*SkDiscardableFactoryProc)(size_t bytes);
- /*
- * SkMipMap will generate mipmap levels when given a base mipmap level image.
- *
- * Any function which deals with mipmap levels indices will start with index 0
- * being the first mipmap level which was generated. Said another way, it does
- * not include the base level in its range.
- */
- class SkMipMap : public SkCachedData {
- public:
- static SkMipMap* Build(const SkPixmap& src, SkDiscardableFactoryProc);
- static SkMipMap* Build(const SkBitmap& src, SkDiscardableFactoryProc);
- // Determines how many levels a SkMipMap will have without creating that mipmap.
- // This does not include the base mipmap level that the user provided when
- // creating the SkMipMap.
- static int ComputeLevelCount(int baseWidth, int baseHeight);
- // Determines the size of a given mipmap level.
- // |level| is an index into the generated mipmap levels. It does not include
- // the base level. So index 0 represents mipmap level 1.
- static SkISize ComputeLevelSize(int baseWidth, int baseHeight, int level);
- // We use a block of (possibly discardable) memory to hold an array of Level structs, followed
- // by the pixel data for each level. On 32-bit platforms, Level would naturally be 4 byte
- // aligned, so the pixel data could end up with 4 byte alignment. If the pixel data is F16,
- // it must be 8 byte aligned. To ensure this, keep the Level struct 8 byte aligned as well.
- struct alignas(8) Level {
- SkPixmap fPixmap;
- SkSize fScale; // < 1.0
- };
- bool extractLevel(const SkSize& scale, Level*) const;
- // countLevels returns the number of mipmap levels generated (which does not
- // include the base mipmap level).
- int countLevels() const;
- // |index| is an index into the generated mipmap levels. It does not include
- // the base level. So index 0 represents mipmap level 1.
- bool getLevel(int index, Level*) const;
- protected:
- void onDataChange(void* oldData, void* newData) override {
- fLevels = (Level*)newData; // could be nullptr
- }
- private:
- sk_sp<SkColorSpace> fCS;
- Level* fLevels; // managed by the baseclass, may be null due to onDataChanged.
- int fCount;
- SkMipMap(void* malloc, size_t size) : INHERITED(malloc, size) {}
- SkMipMap(size_t size, SkDiscardableMemory* dm) : INHERITED(size, dm) {}
- static size_t AllocLevelsSize(int levelCount, size_t pixelSize);
- typedef SkCachedData INHERITED;
- };
- #endif
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