blob: 67d4f63dcc0c990d39693e4d4a80efabb0cda2e8 [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 "src/core/SkCachedData.h"
#include "src/core/SkImageInfoPriv.h"
#include "src/shaders/SkShaderBase.h"
class SkBitmap;
class SkData;
class SkDiscardableMemory;
class SkMipmapBuilder;
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 {
~SkMipmap() override;
// Allocate and fill-in a mipmap. If computeContents is false, we just allocated
// and compute the sizes/rowbytes, but leave the pixel-data uninitialized.
static SkMipmap* Build(const SkPixmap& src, SkDiscardableFactoryProc,
bool computeContents = true);
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);
// Computes the fractional level based on the scaling in X and Y.
static float ComputeLevel(SkSize scaleSize);
// 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(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;
bool validForRootLevel(const SkImageInfo&) 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);
SkMipmap(size_t size, SkDiscardableMemory* dm);
static size_t AllocLevelsSize(int levelCount, size_t pixelSize);