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skia2/include/core/SkImageInfo.h
Brian Osman a7a2324f14 Reland "Add kR8_unorm_SkColorType" 
This is a reland of 3225c8cc46

Original change's description:
> Add kR8_unorm_SkColorType
>
> Change-Id: I97b5bc7f90715664f233ca7b7c41c0ecbfc29ac4
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/505679
> Reviewed-by: Michael Ludwig <michaelludwig@google.com>
> Reviewed-by: Greg Daniel <egdaniel@google.com>
> Commit-Queue: Brian Osman <brianosman@google.com>

Change-Id: I73fa17625d57e0e58da1b70e2e59ba200383cfe7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/506460
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Brian Osman <brianosman@google.com>
2022-02-10 18:00:19 +00:00

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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 SkImageInfo_DEFINED
#define SkImageInfo_DEFINED
#include "include/core/SkColorSpace.h"
#include "include/core/SkMath.h"
#include "include/core/SkRect.h"
#include "include/core/SkSize.h"
#include "include/private/SkTFitsIn.h"
#include "include/private/SkTo.h"
class SkReadBuffer;
class SkWriteBuffer;
/** \enum SkImageInfo::SkAlphaType
Describes how to interpret the alpha component of a pixel. A pixel may
be opaque, or alpha, describing multiple levels of transparency.
In simple blending, alpha weights the draw color and the destination
color to create a new color. If alpha describes a weight from zero to one:
new color = draw color * alpha + destination color * (1 - alpha)
In practice alpha is encoded in two or more bits, where 1.0 equals all bits set.
RGB may have alpha included in each component value; the stored
value is the original RGB multiplied by alpha. Premultiplied color
components improve performance.
*/
enum SkAlphaType : int {
kUnknown_SkAlphaType, //!< uninitialized
kOpaque_SkAlphaType, //!< pixel is opaque
kPremul_SkAlphaType, //!< pixel components are premultiplied by alpha
kUnpremul_SkAlphaType, //!< pixel components are independent of alpha
kLastEnum_SkAlphaType = kUnpremul_SkAlphaType, //!< last valid value
};
/** Returns true if SkAlphaType equals kOpaque_SkAlphaType.
kOpaque_SkAlphaType is a hint that the SkColorType is opaque, or that all
alpha values are set to their 1.0 equivalent. If SkAlphaType is
kOpaque_SkAlphaType, and SkColorType is not opaque, then the result of
drawing any pixel with a alpha value less than 1.0 is undefined.
*/
static inline bool SkAlphaTypeIsOpaque(SkAlphaType at) {
return kOpaque_SkAlphaType == at;
}
///////////////////////////////////////////////////////////////////////////////
/** \enum SkImageInfo::SkColorType
Describes how pixel bits encode color. A pixel may be an alpha mask, a grayscale, RGB, or ARGB.
kN32_SkColorType selects the native 32-bit ARGB format for the current configuration. This can
lead to inconsistent results across platforms, so use with caution.
*/
enum SkColorType : int {
kUnknown_SkColorType, //!< uninitialized
kAlpha_8_SkColorType, //!< pixel with alpha in 8-bit byte
kRGB_565_SkColorType, //!< pixel with 5 bits red, 6 bits green, 5 bits blue, in 16-bit word
kARGB_4444_SkColorType, //!< pixel with 4 bits for alpha, red, green, blue; in 16-bit word
kRGBA_8888_SkColorType, //!< pixel with 8 bits for red, green, blue, alpha; in 32-bit word
kRGB_888x_SkColorType, //!< pixel with 8 bits each for red, green, blue; in 32-bit word
kBGRA_8888_SkColorType, //!< pixel with 8 bits for blue, green, red, alpha; in 32-bit word
kRGBA_1010102_SkColorType, //!< 10 bits for red, green, blue; 2 bits for alpha; in 32-bit word
kBGRA_1010102_SkColorType, //!< 10 bits for blue, green, red; 2 bits for alpha; in 32-bit word
kRGB_101010x_SkColorType, //!< pixel with 10 bits each for red, green, blue; in 32-bit word
kBGR_101010x_SkColorType, //!< pixel with 10 bits each for blue, green, red; in 32-bit word
kGray_8_SkColorType, //!< pixel with grayscale level in 8-bit byte
kRGBA_F16Norm_SkColorType, //!< pixel with half floats in [0,1] for red, green, blue, alpha;
// in 64-bit word
kRGBA_F16_SkColorType, //!< pixel with half floats for red, green, blue, alpha;
// in 64-bit word
kRGBA_F32_SkColorType, //!< pixel using C float for red, green, blue, alpha; in 128-bit word
// The following 6 colortypes are just for reading from - not for rendering to
kR8G8_unorm_SkColorType, //!< pixel with a uint8_t for red and green
kA16_float_SkColorType, //!< pixel with a half float for alpha
kR16G16_float_SkColorType, //!< pixel with a half float for red and green
kA16_unorm_SkColorType, //!< pixel with a little endian uint16_t for alpha
kR16G16_unorm_SkColorType, //!< pixel with a little endian uint16_t for red and green
kR16G16B16A16_unorm_SkColorType, //!< pixel with a little endian uint16_t for red, green, blue
// and alpha
kSRGBA_8888_SkColorType,
kR8_unorm_SkColorType,
kLastEnum_SkColorType = kR8_unorm_SkColorType, //!< last valid value
#if SK_PMCOLOR_BYTE_ORDER(B,G,R,A)
kN32_SkColorType = kBGRA_8888_SkColorType,//!< native 32-bit BGRA encoding
#elif SK_PMCOLOR_BYTE_ORDER(R,G,B,A)
kN32_SkColorType = kRGBA_8888_SkColorType,//!< native 32-bit RGBA encoding
#else
#error "SK_*32_SHIFT values must correspond to BGRA or RGBA byte order"
#endif
};
/** Returns the number of bytes required to store a pixel, including unused padding.
Returns zero if ct is kUnknown_SkColorType or invalid.
@return bytes per pixel
*/
SK_API int SkColorTypeBytesPerPixel(SkColorType ct);
/** Returns true if SkColorType always decodes alpha to 1.0, making the pixel
fully opaque. If true, SkColorType does not reserve bits to encode alpha.
@return true if alpha is always set to 1.0
*/
SK_API bool SkColorTypeIsAlwaysOpaque(SkColorType ct);
/** Returns true if canonical can be set to a valid SkAlphaType for colorType. If
there is more than one valid canonical SkAlphaType, set to alphaType, if valid.
If true is returned and canonical is not nullptr, store valid SkAlphaType.
Returns false only if alphaType is kUnknown_SkAlphaType, color type is not
kUnknown_SkColorType, and SkColorType is not always opaque. If false is returned,
canonical is ignored.
@param canonical storage for SkAlphaType
@return true if valid SkAlphaType can be associated with colorType
*/
SK_API bool SkColorTypeValidateAlphaType(SkColorType colorType, SkAlphaType alphaType,
SkAlphaType* canonical = nullptr);
/** \enum SkImageInfo::SkYUVColorSpace
Describes color range of YUV pixels. The color mapping from YUV to RGB varies
depending on the source. YUV pixels may be generated by JPEG images, standard
video streams, or high definition video streams. Each has its own mapping from
YUV to RGB.
JPEG YUV values encode the full range of 0 to 255 for all three components.
Video YUV values often range from 16 to 235 for Y and from 16 to 240 for U and V (limited).
Details of encoding and conversion to RGB are described in YCbCr color space.
The identity colorspace exists to provide a utility mapping from Y to R, U to G and V to B.
It can be used to visualize the YUV planes or to explicitly post process the YUV channels.
*/
enum SkYUVColorSpace : int {
kJPEG_Full_SkYUVColorSpace, //!< describes full range
kRec601_Limited_SkYUVColorSpace, //!< describes SDTV range
kRec709_Full_SkYUVColorSpace, //!< describes HDTV range
kRec709_Limited_SkYUVColorSpace,
kBT2020_8bit_Full_SkYUVColorSpace, //!< describes UHDTV range, non-constant-luminance
kBT2020_8bit_Limited_SkYUVColorSpace,
kBT2020_10bit_Full_SkYUVColorSpace,
kBT2020_10bit_Limited_SkYUVColorSpace,
kBT2020_12bit_Full_SkYUVColorSpace,
kBT2020_12bit_Limited_SkYUVColorSpace,
kIdentity_SkYUVColorSpace, //!< maps Y->R, U->G, V->B
kLastEnum_SkYUVColorSpace = kIdentity_SkYUVColorSpace, //!< last valid value
// Legacy (deprecated) names:
kJPEG_SkYUVColorSpace = kJPEG_Full_SkYUVColorSpace,
kRec601_SkYUVColorSpace = kRec601_Limited_SkYUVColorSpace,
kRec709_SkYUVColorSpace = kRec709_Limited_SkYUVColorSpace,
kBT2020_SkYUVColorSpace = kBT2020_8bit_Limited_SkYUVColorSpace,
};
/** \struct SkColorInfo
Describes pixel and encoding. SkImageInfo can be created from SkColorInfo by
providing dimensions.
It encodes how pixel bits describe alpha, transparency; color components red, blue,
and green; and SkColorSpace, the range and linearity of colors.
*/
class SK_API SkColorInfo {
public:
/** Creates an SkColorInfo with kUnknown_SkColorType, kUnknown_SkAlphaType,
and no SkColorSpace.
@return empty SkImageInfo
*/
SkColorInfo() = default;
/** Creates SkColorInfo from SkColorType ct, SkAlphaType at, and optionally SkColorSpace cs.
If SkColorSpace cs is nullptr and SkColorInfo is part of drawing source: SkColorSpace
defaults to sRGB, mapping into SkSurface SkColorSpace.
Parameters are not validated to see if their values are legal, or that the
combination is supported.
@return created SkColorInfo
*/
SkColorInfo(SkColorType ct, SkAlphaType at, sk_sp<SkColorSpace> cs)
: fColorSpace(std::move(cs)), fColorType(ct), fAlphaType(at) {}
SkColorInfo(const SkColorInfo&) = default;
SkColorInfo(SkColorInfo&&) = default;
SkColorInfo& operator=(const SkColorInfo&) = default;
SkColorInfo& operator=(SkColorInfo&&) = default;
SkColorSpace* colorSpace() const { return fColorSpace.get(); }
sk_sp<SkColorSpace> refColorSpace() const { return fColorSpace; }
SkColorType colorType() const { return fColorType; }
SkAlphaType alphaType() const { return fAlphaType; }
bool isOpaque() const {
return SkAlphaTypeIsOpaque(fAlphaType)
|| SkColorTypeIsAlwaysOpaque(fColorType);
}
bool gammaCloseToSRGB() const { return fColorSpace && fColorSpace->gammaCloseToSRGB(); }
/** Does other represent the same color type, alpha type, and color space? */
bool operator==(const SkColorInfo& other) const {
return fColorType == other.fColorType && fAlphaType == other.fAlphaType &&
SkColorSpace::Equals(fColorSpace.get(), other.fColorSpace.get());
}
/** Does other represent a different color type, alpha type, or color space? */
bool operator!=(const SkColorInfo& other) const { return !(*this == other); }
/** Creates SkColorInfo with same SkColorType, SkColorSpace, with SkAlphaType set
to newAlphaType.
Created SkColorInfo contains newAlphaType even if it is incompatible with
SkColorType, in which case SkAlphaType in SkColorInfo is ignored.
*/
SkColorInfo makeAlphaType(SkAlphaType newAlphaType) const {
return SkColorInfo(this->colorType(), newAlphaType, this->refColorSpace());
}
/** Creates new SkColorInfo with same SkAlphaType, SkColorSpace, with SkColorType
set to newColorType.
*/
SkColorInfo makeColorType(SkColorType newColorType) const {
return SkColorInfo(newColorType, this->alphaType(), this->refColorSpace());
}
/** Creates SkColorInfo with same SkAlphaType, SkColorType, with SkColorSpace
set to cs. cs may be nullptr.
*/
SkColorInfo makeColorSpace(sk_sp<SkColorSpace> cs) const {
return SkColorInfo(this->colorType(), this->alphaType(), std::move(cs));
}
/** Returns number of bytes per pixel required by SkColorType.
Returns zero if colorType() is kUnknown_SkColorType.
@return bytes in pixel
example: https://fiddle.skia.org/c/@ImageInfo_bytesPerPixel
*/
int bytesPerPixel() const;
/** Returns bit shift converting row bytes to row pixels.
Returns zero for kUnknown_SkColorType.
@return one of: 0, 1, 2, 3, 4; left shift to convert pixels to bytes
example: https://fiddle.skia.org/c/@ImageInfo_shiftPerPixel
*/
int shiftPerPixel() const;
private:
sk_sp<SkColorSpace> fColorSpace;
SkColorType fColorType = kUnknown_SkColorType;
SkAlphaType fAlphaType = kUnknown_SkAlphaType;
};
/** \struct SkImageInfo
Describes pixel dimensions and encoding. SkBitmap, SkImage, PixMap, and SkSurface
can be created from SkImageInfo. SkImageInfo can be retrieved from SkBitmap and
SkPixmap, but not from SkImage and SkSurface. For example, SkImage and SkSurface
implementations may defer pixel depth, so may not completely specify SkImageInfo.
SkImageInfo contains dimensions, the pixel integral width and height. It encodes
how pixel bits describe alpha, transparency; color components red, blue,
and green; and SkColorSpace, the range and linearity of colors.
*/
struct SK_API SkImageInfo {
public:
/** Creates an empty SkImageInfo with kUnknown_SkColorType, kUnknown_SkAlphaType,
a width and height of zero, and no SkColorSpace.
@return empty SkImageInfo
*/
SkImageInfo() = default;
/** Creates SkImageInfo from integral dimensions width and height, SkColorType ct,
SkAlphaType at, and optionally SkColorSpace cs.
If SkColorSpace cs is nullptr and SkImageInfo is part of drawing source: SkColorSpace
defaults to sRGB, mapping into SkSurface SkColorSpace.
Parameters are not validated to see if their values are legal, or that the
combination is supported.
@param width pixel column count; must be zero or greater
@param height pixel row count; must be zero or greater
@param cs range of colors; may be nullptr
@return created SkImageInfo
*/
static SkImageInfo Make(int width, int height, SkColorType ct, SkAlphaType at,
sk_sp<SkColorSpace> cs = nullptr) {
return SkImageInfo({width, height}, {ct, at, std::move(cs)});
}
static SkImageInfo Make(SkISize dimensions, SkColorType ct, SkAlphaType at,
sk_sp<SkColorSpace> cs = nullptr) {
return SkImageInfo(dimensions, {ct, at, std::move(cs)});
}
/** Creates SkImageInfo from integral dimensions and SkColorInfo colorInfo,
Parameters are not validated to see if their values are legal, or that the
combination is supported.
@param dimensions pixel column and row count; must be zeros or greater
@param SkColorInfo the pixel encoding consisting of SkColorType, SkAlphaType, and
SkColorSpace (which may be nullptr)
@return created SkImageInfo
*/
static SkImageInfo Make(SkISize dimensions, const SkColorInfo& colorInfo) {
return SkImageInfo(dimensions, colorInfo);
}
static SkImageInfo Make(SkISize dimensions, SkColorInfo&& colorInfo) {
return SkImageInfo(dimensions, std::move(colorInfo));
}
/** Creates SkImageInfo from integral dimensions width and height, kN32_SkColorType,
SkAlphaType at, and optionally SkColorSpace cs. kN32_SkColorType will equal either
kBGRA_8888_SkColorType or kRGBA_8888_SkColorType, whichever is optimal.
If SkColorSpace cs is nullptr and SkImageInfo is part of drawing source: SkColorSpace
defaults to sRGB, mapping into SkSurface SkColorSpace.
Parameters are not validated to see if their values are legal, or that the
combination is supported.
@param width pixel column count; must be zero or greater
@param height pixel row count; must be zero or greater
@param cs range of colors; may be nullptr
@return created SkImageInfo
*/
static SkImageInfo MakeN32(int width, int height, SkAlphaType at,
sk_sp<SkColorSpace> cs = nullptr) {
return Make({width, height}, kN32_SkColorType, at, std::move(cs));
}
/** Creates SkImageInfo from integral dimensions width and height, kN32_SkColorType,
SkAlphaType at, with sRGB SkColorSpace.
Parameters are not validated to see if their values are legal, or that the
combination is supported.
@param width pixel column count; must be zero or greater
@param height pixel row count; must be zero or greater
@return created SkImageInfo
example: https://fiddle.skia.org/c/@ImageInfo_MakeS32
*/
static SkImageInfo MakeS32(int width, int height, SkAlphaType at);
/** Creates SkImageInfo from integral dimensions width and height, kN32_SkColorType,
kPremul_SkAlphaType, with optional SkColorSpace.
If SkColorSpace cs is nullptr and SkImageInfo is part of drawing source: SkColorSpace
defaults to sRGB, mapping into SkSurface SkColorSpace.
Parameters are not validated to see if their values are legal, or that the
combination is supported.
@param width pixel column count; must be zero or greater
@param height pixel row count; must be zero or greater
@param cs range of colors; may be nullptr
@return created SkImageInfo
*/
static SkImageInfo MakeN32Premul(int width, int height, sk_sp<SkColorSpace> cs = nullptr) {
return Make({width, height}, kN32_SkColorType, kPremul_SkAlphaType, std::move(cs));
}
/** Creates SkImageInfo from integral dimensions width and height, kN32_SkColorType,
kPremul_SkAlphaType, with SkColorSpace set to nullptr.
If SkImageInfo is part of drawing source: SkColorSpace defaults to sRGB, mapping
into SkSurface SkColorSpace.
Parameters are not validated to see if their values are legal, or that the
combination is supported.
@param dimensions width and height, each must be zero or greater
@param cs range of colors; may be nullptr
@return created SkImageInfo
*/
static SkImageInfo MakeN32Premul(SkISize dimensions, sk_sp<SkColorSpace> cs = nullptr) {
return Make(dimensions, kN32_SkColorType, kPremul_SkAlphaType, std::move(cs));
}
/** Creates SkImageInfo from integral dimensions width and height, kAlpha_8_SkColorType,
kPremul_SkAlphaType, with SkColorSpace set to nullptr.
@param width pixel column count; must be zero or greater
@param height pixel row count; must be zero or greater
@return created SkImageInfo
*/
static SkImageInfo MakeA8(int width, int height) {
return Make({width, height}, kAlpha_8_SkColorType, kPremul_SkAlphaType, nullptr);
}
/** Creates SkImageInfo from integral dimensions, kAlpha_8_SkColorType,
kPremul_SkAlphaType, with SkColorSpace set to nullptr.
@param dimensions pixel row and column count; must be zero or greater
@return created SkImageInfo
*/
static SkImageInfo MakeA8(SkISize dimensions) {
return Make(dimensions, kAlpha_8_SkColorType, kPremul_SkAlphaType, nullptr);
}
/** Creates SkImageInfo from integral dimensions width and height, kUnknown_SkColorType,
kUnknown_SkAlphaType, with SkColorSpace set to nullptr.
Returned SkImageInfo as part of source does not draw, and as part of destination
can not be drawn to.
@param width pixel column count; must be zero or greater
@param height pixel row count; must be zero or greater
@return created SkImageInfo
*/
static SkImageInfo MakeUnknown(int width, int height) {
return Make({width, height}, kUnknown_SkColorType, kUnknown_SkAlphaType, nullptr);
}
/** Creates SkImageInfo from integral dimensions width and height set to zero,
kUnknown_SkColorType, kUnknown_SkAlphaType, with SkColorSpace set to nullptr.
Returned SkImageInfo as part of source does not draw, and as part of destination
can not be drawn to.
@return created SkImageInfo
*/
static SkImageInfo MakeUnknown() {
return MakeUnknown(0, 0);
}
/** Returns pixel count in each row.
@return pixel width
*/
int width() const { return fDimensions.width(); }
/** Returns pixel row count.
@return pixel height
*/
int height() const { return fDimensions.height(); }
SkColorType colorType() const { return fColorInfo.colorType(); }
SkAlphaType alphaType() const { return fColorInfo.alphaType(); }
/** Returns SkColorSpace, the range of colors. The reference count of
SkColorSpace is unchanged. The returned SkColorSpace is immutable.
@return SkColorSpace, or nullptr
*/
SkColorSpace* colorSpace() const { return fColorInfo.colorSpace(); }
/** Returns smart pointer to SkColorSpace, the range of colors. The smart pointer
tracks the number of objects sharing this SkColorSpace reference so the memory
is released when the owners destruct.
The returned SkColorSpace is immutable.
@return SkColorSpace wrapped in a smart pointer
*/
sk_sp<SkColorSpace> refColorSpace() const { return fColorInfo.refColorSpace(); }
/** Returns if SkImageInfo describes an empty area of pixels by checking if either
width or height is zero or smaller.
@return true if either dimension is zero or smaller
*/
bool isEmpty() const { return fDimensions.isEmpty(); }
/** Returns the dimensionless SkColorInfo that represents the same color type,
alpha type, and color space as this SkImageInfo.
*/
const SkColorInfo& colorInfo() const { return fColorInfo; }
/** Returns true if SkAlphaType is set to hint that all pixels are opaque; their
alpha value is implicitly or explicitly 1.0. If true, and all pixels are
not opaque, Skia may draw incorrectly.
Does not check if SkColorType allows alpha, or if any pixel value has
transparency.
@return true if SkAlphaType is kOpaque_SkAlphaType
*/
bool isOpaque() const { return fColorInfo.isOpaque(); }
/** Returns SkISize { width(), height() }.
@return integral size of width() and height()
*/
SkISize dimensions() const { return fDimensions; }
/** Returns SkIRect { 0, 0, width(), height() }.
@return integral rectangle from origin to width() and height()
*/
SkIRect bounds() const { return SkIRect::MakeSize(fDimensions); }
/** Returns true if associated SkColorSpace is not nullptr, and SkColorSpace gamma
is approximately the same as sRGB.
This includes the
@return true if SkColorSpace gamma is approximately the same as sRGB
*/
bool gammaCloseToSRGB() const { return fColorInfo.gammaCloseToSRGB(); }
/** Creates SkImageInfo with the same SkColorType, SkColorSpace, and SkAlphaType,
with dimensions set to width and height.
@param newWidth pixel column count; must be zero or greater
@param newHeight pixel row count; must be zero or greater
@return created SkImageInfo
*/
SkImageInfo makeWH(int newWidth, int newHeight) const {
return Make({newWidth, newHeight}, fColorInfo);
}
/** Creates SkImageInfo with the same SkColorType, SkColorSpace, and SkAlphaType,
with dimensions set to newDimensions.
@param newSize pixel column and row count; must be zero or greater
@return created SkImageInfo
*/
SkImageInfo makeDimensions(SkISize newSize) const {
return Make(newSize, fColorInfo);
}
/** Creates SkImageInfo with same SkColorType, SkColorSpace, width, and height,
with SkAlphaType set to newAlphaType.
Created SkImageInfo contains newAlphaType even if it is incompatible with
SkColorType, in which case SkAlphaType in SkImageInfo is ignored.
@return created SkImageInfo
*/
SkImageInfo makeAlphaType(SkAlphaType newAlphaType) const {
return Make(fDimensions, fColorInfo.makeAlphaType(newAlphaType));
}
/** Creates SkImageInfo with same SkAlphaType, SkColorSpace, width, and height,
with SkColorType set to newColorType.
@return created SkImageInfo
*/
SkImageInfo makeColorType(SkColorType newColorType) const {
return Make(fDimensions, fColorInfo.makeColorType(newColorType));
}
/** Creates SkImageInfo with same SkAlphaType, SkColorType, width, and height,
with SkColorSpace set to cs.
@param cs range of colors; may be nullptr
@return created SkImageInfo
*/
SkImageInfo makeColorSpace(sk_sp<SkColorSpace> cs) const {
return Make(fDimensions, fColorInfo.makeColorSpace(std::move(cs)));
}
/** Returns number of bytes per pixel required by SkColorType.
Returns zero if colorType( is kUnknown_SkColorType.
@return bytes in pixel
*/
int bytesPerPixel() const { return fColorInfo.bytesPerPixel(); }
/** Returns bit shift converting row bytes to row pixels.
Returns zero for kUnknown_SkColorType.
@return one of: 0, 1, 2, 3; left shift to convert pixels to bytes
*/
int shiftPerPixel() const { return fColorInfo.shiftPerPixel(); }
/** Returns minimum bytes per row, computed from pixel width() and SkColorType, which
specifies bytesPerPixel(). SkBitmap maximum value for row bytes must fit
in 31 bits.
@return width() times bytesPerPixel() as unsigned 64-bit integer
*/
uint64_t minRowBytes64() const {
return (uint64_t)sk_64_mul(this->width(), this->bytesPerPixel());
}
/** Returns minimum bytes per row, computed from pixel width() and SkColorType, which
specifies bytesPerPixel(). SkBitmap maximum value for row bytes must fit
in 31 bits.
@return width() times bytesPerPixel() as size_t
*/
size_t minRowBytes() const {
uint64_t minRowBytes = this->minRowBytes64();
if (!SkTFitsIn<int32_t>(minRowBytes)) {
return 0;
}
return (size_t)minRowBytes;
}
/** Returns byte offset of pixel from pixel base address.
Asserts in debug build if x or y is outside of bounds. Does not assert if
rowBytes is smaller than minRowBytes(), even though result may be incorrect.
@param x column index, zero or greater, and less than width()
@param y row index, zero or greater, and less than height()
@param rowBytes size of pixel row or larger
@return offset within pixel array
example: https://fiddle.skia.org/c/@ImageInfo_computeOffset
*/
size_t computeOffset(int x, int y, size_t rowBytes) const;
/** Compares SkImageInfo with other, and returns true if width, height, SkColorType,
SkAlphaType, and SkColorSpace are equivalent.
@param other SkImageInfo to compare
@return true if SkImageInfo equals other
*/
bool operator==(const SkImageInfo& other) const {
return fDimensions == other.fDimensions && fColorInfo == other.fColorInfo;
}
/** Compares SkImageInfo with other, and returns true if width, height, SkColorType,
SkAlphaType, and SkColorSpace are not equivalent.
@param other SkImageInfo to compare
@return true if SkImageInfo is not equal to other
*/
bool operator!=(const SkImageInfo& other) const {
return !(*this == other);
}
/** Returns storage required by pixel array, given SkImageInfo dimensions, SkColorType,
and rowBytes. rowBytes is assumed to be at least as large as minRowBytes().
Returns zero if height is zero.
Returns SIZE_MAX if answer exceeds the range of size_t.
@param rowBytes size of pixel row or larger
@return memory required by pixel buffer
example: https://fiddle.skia.org/c/@ImageInfo_computeByteSize
*/
size_t computeByteSize(size_t rowBytes) const;
/** Returns storage required by pixel array, given SkImageInfo dimensions, and
SkColorType. Uses minRowBytes() to compute bytes for pixel row.
Returns zero if height is zero.
Returns SIZE_MAX if answer exceeds the range of size_t.
@return least memory required by pixel buffer
*/
size_t computeMinByteSize() const {
return this->computeByteSize(this->minRowBytes());
}
/** Returns true if byteSize equals SIZE_MAX. computeByteSize() and
computeMinByteSize() return SIZE_MAX if size_t can not hold buffer size.
@param byteSize result of computeByteSize() or computeMinByteSize()
@return true if computeByteSize() or computeMinByteSize() result exceeds size_t
*/
static bool ByteSizeOverflowed(size_t byteSize) {
return SIZE_MAX == byteSize;
}
/** Returns true if rowBytes is valid for this SkImageInfo.
@param rowBytes size of pixel row including padding
@return true if rowBytes is large enough to contain pixel row and is properly
aligned
*/
bool validRowBytes(size_t rowBytes) const {
if (rowBytes < this->minRowBytes64()) {
return false;
}
int shift = this->shiftPerPixel();
size_t alignedRowBytes = rowBytes >> shift << shift;
return alignedRowBytes == rowBytes;
}
/** Creates an empty SkImageInfo with kUnknown_SkColorType, kUnknown_SkAlphaType,
a width and height of zero, and no SkColorSpace.
*/
void reset() { *this = {}; }
/** Asserts if internal values are illegal or inconsistent. Only available if
SK_DEBUG is defined at compile time.
*/
SkDEBUGCODE(void validate() const;)
private:
SkColorInfo fColorInfo;
SkISize fDimensions = {0, 0};
SkImageInfo(SkISize dimensions, const SkColorInfo& colorInfo)
: fColorInfo(colorInfo), fDimensions(dimensions) {}
SkImageInfo(SkISize dimensions, SkColorInfo&& colorInfo)
: fColorInfo(std::move(colorInfo)), fDimensions(dimensions) {}
};
#endif
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