blob: 89312b9dec52a53410e2d85d66cef430e13bfa2b [file] [log] [blame]
* 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 {
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);
static int ComputeLevelCount(SkISize s) { return ComputeLevelCount(s.width(), s.height()); }
// 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;
void onDataChange(void* oldData, void* newData) override {
fLevels = (Level*)newData; // could be nullptr
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;