/* * 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 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