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/*
* Copyright 2020 Google LLC
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkYUVAInfo_DEFINED
#define SkYUVAInfo_DEFINED
#include "include/codec/SkEncodedOrigin.h"
#include "include/core/SkImageInfo.h"
#include "include/core/SkSize.h"
#include <array>
#include <tuple>
/**
* Specifies the structure of planes for a YUV image with optional alpha. The actual planar data
* is not part of this structure and depending on usage is in external textures or pixmaps.
*/
class SK_API SkYUVAInfo {
public:
enum YUVAChannels { kY, kU, kV, kA, kLast = kA };
static constexpr int kYUVAChannelCount = static_cast<int>(YUVAChannels::kLast + 1);
struct YUVALocation; // For internal use.
using YUVALocations = std::array<YUVALocation, kYUVAChannelCount>;
/**
* Specifies how YUV (and optionally A) are divided among planes. Planes are separated by
* underscores in the enum value names. Within each plane the pixmap/texture channels are
* mapped to the YUVA channels in the order specified, e.g. for kY_UV Y is in channel 0 of plane
* 0, U is in channel 0 of plane 1, and V is in channel 1 of plane 1. Channel ordering
* within a pixmap/texture given the channels it contains:
* A: 0:A
* Luminance/Gray: 0:Gray
* Luminance/Gray + Alpha: 0:Gray, 1:A
* RG 0:R, 1:G
* RGB 0:R, 1:G, 2:B
* RGBA 0:R, 1:G, 2:B, 3:A
*/
enum class PlaneConfig {
kUnknown,
kY_U_V, ///< Plane 0: Y, Plane 1: U, Plane 2: V
kY_V_U, ///< Plane 0: Y, Plane 1: V, Plane 2: U
kY_UV, ///< Plane 0: Y, Plane 1: UV
kY_VU, ///< Plane 0: Y, Plane 1: VU
kYUV, ///< Plane 0: YUV
kUYV, ///< Plane 0: UYV
kY_U_V_A, ///< Plane 0: Y, Plane 1: U, Plane 2: V, Plane 3: A
kY_V_U_A, ///< Plane 0: Y, Plane 1: V, Plane 2: U, Plane 3: A
kY_UV_A, ///< Plane 0: Y, Plane 1: UV, Plane 2: A
kY_VU_A, ///< Plane 0: Y, Plane 1: VU, Plane 2: A
kYUVA, ///< Plane 0: YUVA
kUYVA, ///< Plane 0: UYVA
kLast = kUYVA
};
/**
* UV subsampling is also specified in the enum value names using J:a:b notation (e.g. 4:2:0 is
* 1/2 horizontal and 1/2 vertical resolution for U and V). If alpha is present it is not sub-
* sampled. Note that Subsampling values other than k444 are only valid with PlaneConfig values
* that have U and V in different planes than Y (and A, if present).
*/
enum class Subsampling {
kUnknown,
k444, ///< No subsampling. UV values for each Y.
k422, ///< 1 set of UV values for each 2x1 block of Y values.
k420, ///< 1 set of UV values for each 2x2 block of Y values.
k440, ///< 1 set of UV values for each 1x2 block of Y values.
k411, ///< 1 set of UV values for each 4x1 block of Y values.
k410, ///< 1 set of UV values for each 4x2 block of Y values.
kLast = k410
};
/**
* Describes how subsampled chroma values are sited relative to luma values.
*
* Currently only centered siting is supported but will expand to support additional sitings.
*/
enum class Siting {
/**
* Subsampled chroma value is sited at the center of the block of corresponding luma values.
*/
kCentered,
};
static constexpr int kMaxPlanes = 4;
/** ratio of Y/A values to U/V values in x and y. */
static std::tuple<int, int> SubsamplingFactors(Subsampling);
/**
* SubsamplingFactors(Subsampling) if planedIdx refers to a U/V plane and otherwise {1, 1} if
* inputs are valid. Invalid inputs consist of incompatible PlaneConfig/Subsampling/planeIdx
* combinations. {0, 0} is returned for invalid inputs.
*/
static std::tuple<int, int> PlaneSubsamplingFactors(PlaneConfig, Subsampling, int planeIdx);
/**
* Given image dimensions, a planer configuration, subsampling, and origin, determine the
* expected size of each plane. Returns the number of expected planes. planeDimensions[0]
* through planeDimensions[<ret>] are written. The input image dimensions are as displayed
* (after the planes have been transformed to the intended display orientation). The plane
* dimensions are output as the planes are stored in memory (may be rotated from image
* dimensions).
*/
static int PlaneDimensions(SkISize imageDimensions,
PlaneConfig,
Subsampling,
SkEncodedOrigin,
SkISize planeDimensions[kMaxPlanes]);
/** Number of planes for a given PlaneConfig. */
static constexpr int NumPlanes(PlaneConfig);
/**
* Number of Y, U, V, A channels in the ith plane for a given PlaneConfig (or 0 if i is
* invalid).
*/
static constexpr int NumChannelsInPlane(PlaneConfig, int i);
/**
* Given a PlaneConfig and a set of channel flags for each plane, convert to YUVALocations
* representation. Fails if channel flags aren't valid for the PlaneConfig (i.e. don't have
* enough channels in a plane) by returning an invalid set of locations (plane indices are -1).
*/
static YUVALocations GetYUVALocations(PlaneConfig, const uint32_t* planeChannelFlags);
/** Does the PlaneConfig have alpha values? */
static bool HasAlpha(PlaneConfig);
SkYUVAInfo() = default;
SkYUVAInfo(const SkYUVAInfo&) = default;
/**
* 'dimensions' should specify the size of the full resolution image (after planes have been
* oriented to how the image is displayed as indicated by 'origin').
*/
SkYUVAInfo(SkISize dimensions,
PlaneConfig,
Subsampling,
SkYUVColorSpace,
SkEncodedOrigin origin = kTopLeft_SkEncodedOrigin,
Siting sitingX = Siting::kCentered,
Siting sitingY = Siting::kCentered);
SkYUVAInfo& operator=(const SkYUVAInfo& that) = default;
PlaneConfig planeConfig() const { return fPlaneConfig; }
Subsampling subsampling() const { return fSubsampling; }
std::tuple<int, int> planeSubsamplingFactors(int planeIdx) const {
return PlaneSubsamplingFactors(fPlaneConfig, fSubsampling, planeIdx);
}
/**
* Dimensions of the full resolution image (after planes have been oriented to how the image
* is displayed as indicated by fOrigin).
*/
SkISize dimensions() const { return fDimensions; }
int width() const { return fDimensions.width(); }
int height() const { return fDimensions.height(); }
SkYUVColorSpace yuvColorSpace() const { return fYUVColorSpace; }
Siting sitingX() const { return fSitingX; }
Siting sitingY() const { return fSitingY; }
SkEncodedOrigin origin() const { return fOrigin; }
SkMatrix originMatrix() const {
return SkEncodedOriginToMatrix(fOrigin, this->width(), this->height());
}
bool hasAlpha() const { return HasAlpha(fPlaneConfig); }
/**
* Returns the number of planes and initializes planeDimensions[0]..planeDimensions[<ret>] to
* the expected dimensions for each plane. Dimensions are as stored in memory, before
* transformation to image display space as indicated by origin().
*/
int planeDimensions(SkISize planeDimensions[kMaxPlanes]) const {
return PlaneDimensions(fDimensions, fPlaneConfig, fSubsampling, fOrigin, planeDimensions);
}
/**
* Given a per-plane row bytes, determine size to allocate for all planes. Optionally retrieves
* the per-plane byte sizes in planeSizes if not null. If total size overflows will return
* SIZE_MAX and set all planeSizes to SIZE_MAX.
*/
size_t computeTotalBytes(const size_t rowBytes[kMaxPlanes],
size_t planeSizes[kMaxPlanes] = nullptr) const;
int numPlanes() const { return NumPlanes(fPlaneConfig); }
int numChannelsInPlane(int i) const { return NumChannelsInPlane(fPlaneConfig, i); }
/**
* Given a set of channel flags for each plane, converts this->planeConfig() to YUVALocations
* representation. Fails if the channel flags aren't valid for the PlaneConfig (i.e. don't have
* enough channels in a plane) by returning default initialized locations (all plane indices are
* -1).
*/
YUVALocations toYUVALocations(const uint32_t* channelFlags) const;
/**
* Makes a SkYUVAInfo that is identical to this one but with the passed Subsampling. If the
* passed Subsampling is not k444 and this info's PlaneConfig is not compatible with chroma
* subsampling (because Y is in the same plane as UV) then the result will be an invalid
* SkYUVAInfo.
*/
SkYUVAInfo makeSubsampling(SkYUVAInfo::Subsampling) const;
/**
* Makes a SkYUVAInfo that is identical to this one but with the passed dimensions. If the
* passed dimensions is empty then the result will be an invalid SkYUVAInfo.
*/
SkYUVAInfo makeDimensions(SkISize) const;
bool operator==(const SkYUVAInfo& that) const;
bool operator!=(const SkYUVAInfo& that) const { return !(*this == that); }
bool isValid() const { return fPlaneConfig != PlaneConfig::kUnknown; }
private:
SkISize fDimensions = {0, 0};
PlaneConfig fPlaneConfig = PlaneConfig::kUnknown;
Subsampling fSubsampling = Subsampling::kUnknown;
SkYUVColorSpace fYUVColorSpace = SkYUVColorSpace::kIdentity_SkYUVColorSpace;
/**
* YUVA data often comes from formats like JPEG that support EXIF orientation.
* Code that operates on the raw YUV data often needs to know that orientation.
*/
SkEncodedOrigin fOrigin = kTopLeft_SkEncodedOrigin;
Siting fSitingX = Siting::kCentered;
Siting fSitingY = Siting::kCentered;
};
constexpr int SkYUVAInfo::NumPlanes(PlaneConfig planeConfig) {
switch (planeConfig) {
case PlaneConfig::kUnknown: return 0;
case PlaneConfig::kY_U_V: return 3;
case PlaneConfig::kY_V_U: return 3;
case PlaneConfig::kY_UV: return 2;
case PlaneConfig::kY_VU: return 2;
case PlaneConfig::kYUV: return 1;
case PlaneConfig::kUYV: return 1;
case PlaneConfig::kY_U_V_A: return 4;
case PlaneConfig::kY_V_U_A: return 4;
case PlaneConfig::kY_UV_A: return 3;
case PlaneConfig::kY_VU_A: return 3;
case PlaneConfig::kYUVA: return 1;
case PlaneConfig::kUYVA: return 1;
}
SkUNREACHABLE;
}
constexpr int SkYUVAInfo::NumChannelsInPlane(PlaneConfig config, int i) {
switch (config) {
case PlaneConfig::kUnknown:
return 0;
case SkYUVAInfo::PlaneConfig::kY_U_V:
case SkYUVAInfo::PlaneConfig::kY_V_U:
return i >= 0 && i < 3 ? 1 : 0;
case SkYUVAInfo::PlaneConfig::kY_UV:
case SkYUVAInfo::PlaneConfig::kY_VU:
switch (i) {
case 0: return 1;
case 1: return 2;
default: return 0;
}
case SkYUVAInfo::PlaneConfig::kYUV:
case SkYUVAInfo::PlaneConfig::kUYV:
return i == 0 ? 3 : 0;
case SkYUVAInfo::PlaneConfig::kY_U_V_A:
case SkYUVAInfo::PlaneConfig::kY_V_U_A:
return i >= 0 && i < 4 ? 1 : 0;
case SkYUVAInfo::PlaneConfig::kY_UV_A:
case SkYUVAInfo::PlaneConfig::kY_VU_A:
switch (i) {
case 0: return 1;
case 1: return 2;
case 2: return 1;
default: return 0;
}
case SkYUVAInfo::PlaneConfig::kYUVA:
case SkYUVAInfo::PlaneConfig::kUYVA:
return i == 0 ? 4 : 0;
}
return 0;
}
#endif