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/*
* Copyright 2015 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkCodecPriv_DEFINED
#define SkCodecPriv_DEFINED
#include "SkColorPriv.h"
#include "SkColorSpaceXform.h"
#include "SkColorTable.h"
#include "SkEncodedInfo.h"
#include "SkImageInfo.h"
#include "SkTypes.h"
#ifdef SK_PRINT_CODEC_MESSAGES
#define SkCodecPrintf SkDebugf
#else
#define SkCodecPrintf(...)
#endif
// FIXME: Consider sharing with dm, nanbench, and tools.
static inline float get_scale_from_sample_size(int sampleSize) {
return 1.0f / ((float) sampleSize);
}
static inline bool is_valid_subset(const SkIRect& subset, const SkISize& imageDims) {
return SkIRect::MakeSize(imageDims).contains(subset);
}
/*
* returns a scaled dimension based on the original dimension and the sampleSize
* NOTE: we round down here for scaled dimension to match the behavior of SkImageDecoder
* FIXME: I think we should call this get_sampled_dimension().
*/
static inline int get_scaled_dimension(int srcDimension, int sampleSize) {
if (sampleSize > srcDimension) {
return 1;
}
return srcDimension / sampleSize;
}
/*
* Returns the first coordinate that we will keep during a scaled decode.
* The output can be interpreted as an x-coordinate or a y-coordinate.
*
* This does not need to be called and is not called when sampleFactor == 1.
*/
static inline int get_start_coord(int sampleFactor) { return sampleFactor / 2; };
/*
* Given a coordinate in the original image, this returns the corresponding
* coordinate in the scaled image. This function is meaningless if
* IsCoordNecessary returns false.
* The output can be interpreted as an x-coordinate or a y-coordinate.
*
* This does not need to be called and is not called when sampleFactor == 1.
*/
static inline int get_dst_coord(int srcCoord, int sampleFactor) { return srcCoord / sampleFactor; };
/*
* When scaling, we will discard certain y-coordinates (rows) and
* x-coordinates (columns). This function returns true if we should keep the
* coordinate and false otherwise.
* The inputs may be x-coordinates or y-coordinates.
*
* This does not need to be called and is not called when sampleFactor == 1.
*/
static inline bool is_coord_necessary(int srcCoord, int sampleFactor, int scaledDim) {
// Get the first coordinate that we want to keep
int startCoord = get_start_coord(sampleFactor);
// Return false on edge cases
if (srcCoord < startCoord || get_dst_coord(srcCoord, sampleFactor) >= scaledDim) {
return false;
}
// Every sampleFactor rows are necessary
return ((srcCoord - startCoord) % sampleFactor) == 0;
}
static inline bool valid_alpha(SkAlphaType dstAlpha, SkAlphaType srcAlpha) {
if (kUnknown_SkAlphaType == dstAlpha) {
return false;
}
if (srcAlpha != dstAlpha) {
if (kOpaque_SkAlphaType == srcAlpha) {
// If the source is opaque, we can support any.
SkCodecPrintf("Warning: an opaque image should be decoded as opaque "
"- it is being decoded as non-opaque, which will draw slower\n");
return true;
}
// The source is not opaque
switch (dstAlpha) {
case kPremul_SkAlphaType:
case kUnpremul_SkAlphaType:
// The source is not opaque, so either of these is okay
break;
default:
// We cannot decode a non-opaque image to opaque (or unknown)
return false;
}
}
return true;
}
/*
* If there is a color table, get a pointer to the colors, otherwise return nullptr
*/
static inline const SkPMColor* get_color_ptr(SkColorTable* colorTable) {
return nullptr != colorTable ? colorTable->readColors() : nullptr;
}
static inline SkColorSpaceXform::ColorFormat select_xform_format(SkColorType colorType) {
switch (colorType) {
case kRGBA_8888_SkColorType:
return SkColorSpaceXform::kRGBA_8888_ColorFormat;
case kBGRA_8888_SkColorType:
return SkColorSpaceXform::kBGRA_8888_ColorFormat;
case kRGBA_F16_SkColorType:
return SkColorSpaceXform::kRGBA_F16_ColorFormat;
case kIndex_8_SkColorType:
#ifdef SK_PMCOLOR_IS_RGBA
return SkColorSpaceXform::kRGBA_8888_ColorFormat;
#else
return SkColorSpaceXform::kBGRA_8888_ColorFormat;
#endif
default:
SkASSERT(false);
return SkColorSpaceXform::kRGBA_8888_ColorFormat;
}
}
/*
* Given that the encoded image uses a color table, return the fill value
*/
static inline uint64_t get_color_table_fill_value(SkColorType dstColorType, SkAlphaType alphaType,
const SkPMColor* colorPtr, uint8_t fillIndex, SkColorSpaceXform* colorXform) {
SkASSERT(nullptr != colorPtr);
switch (dstColorType) {
case kRGBA_8888_SkColorType:
case kBGRA_8888_SkColorType:
return colorPtr[fillIndex];
case kRGB_565_SkColorType:
return SkPixel32ToPixel16(colorPtr[fillIndex]);
case kIndex_8_SkColorType:
return fillIndex;
case kRGBA_F16_SkColorType: {
SkASSERT(colorXform);
uint64_t dstColor;
uint32_t srcColor = colorPtr[fillIndex];
SkAssertResult(colorXform->apply(select_xform_format(dstColorType), &dstColor,
SkColorSpaceXform::kRGBA_8888_ColorFormat, &srcColor, 1, alphaType));
return dstColor;
}
default:
SkASSERT(false);
return 0;
}
}
/*
*
* Copy the codec color table back to the client when kIndex8 color type is requested
*/
static inline void copy_color_table(const SkImageInfo& dstInfo, SkColorTable* colorTable,
SkPMColor* inputColorPtr, int* inputColorCount) {
if (kIndex_8_SkColorType == dstInfo.colorType()) {
SkASSERT(nullptr != inputColorPtr);
SkASSERT(nullptr != inputColorCount);
SkASSERT(nullptr != colorTable);
memcpy(inputColorPtr, colorTable->readColors(), *inputColorCount * sizeof(SkPMColor));
}
}
/*
* Compute row bytes for an image using pixels per byte
*/
static inline size_t compute_row_bytes_ppb(int width, uint32_t pixelsPerByte) {
return (width + pixelsPerByte - 1) / pixelsPerByte;
}
/*
* Compute row bytes for an image using bytes per pixel
*/
static inline size_t compute_row_bytes_bpp(int width, uint32_t bytesPerPixel) {
return width * bytesPerPixel;
}
/*
* Compute row bytes for an image
*/
static inline size_t compute_row_bytes(int width, uint32_t bitsPerPixel) {
if (bitsPerPixel < 16) {
SkASSERT(0 == 8 % bitsPerPixel);
const uint32_t pixelsPerByte = 8 / bitsPerPixel;
return compute_row_bytes_ppb(width, pixelsPerByte);
} else {
SkASSERT(0 == bitsPerPixel % 8);
const uint32_t bytesPerPixel = bitsPerPixel / 8;
return compute_row_bytes_bpp(width, bytesPerPixel);
}
}
/*
* Get a byte from a buffer
* This method is unsafe, the caller is responsible for performing a check
*/
static inline uint8_t get_byte(uint8_t* buffer, uint32_t i) {
return buffer[i];
}
/*
* Get a short from a buffer
* This method is unsafe, the caller is responsible for performing a check
*/
static inline uint16_t get_short(uint8_t* buffer, uint32_t i) {
uint16_t result;
memcpy(&result, &(buffer[i]), 2);
#ifdef SK_CPU_BENDIAN
return SkEndianSwap16(result);
#else
return result;
#endif
}
/*
* Get an int from a buffer
* This method is unsafe, the caller is responsible for performing a check
*/
static inline uint32_t get_int(uint8_t* buffer, uint32_t i) {
uint32_t result;
memcpy(&result, &(buffer[i]), 4);
#ifdef SK_CPU_BENDIAN
return SkEndianSwap32(result);
#else
return result;
#endif
}
/*
* @param data Buffer to read bytes from
* @param isLittleEndian Output parameter
* Indicates if the data is little endian
* Is unaffected on false returns
*/
static inline bool is_valid_endian_marker(const uint8_t* data, bool* isLittleEndian) {
// II indicates Intel (little endian) and MM indicates motorola (big endian).
if (('I' != data[0] || 'I' != data[1]) && ('M' != data[0] || 'M' != data[1])) {
return false;
}
*isLittleEndian = ('I' == data[0]);
return true;
}
static inline uint16_t get_endian_short(const uint8_t* data, bool littleEndian) {
if (littleEndian) {
return (data[1] << 8) | (data[0]);
}
return (data[0] << 8) | (data[1]);
}
static inline SkPMColor premultiply_argb_as_rgba(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
if (a != 255) {
r = SkMulDiv255Round(r, a);
g = SkMulDiv255Round(g, a);
b = SkMulDiv255Round(b, a);
}
return SkPackARGB_as_RGBA(a, r, g, b);
}
static inline SkPMColor premultiply_argb_as_bgra(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
if (a != 255) {
r = SkMulDiv255Round(r, a);
g = SkMulDiv255Round(g, a);
b = SkMulDiv255Round(b, a);
}
return SkPackARGB_as_BGRA(a, r, g, b);
}
static inline bool is_rgba(SkColorType colorType) {
#ifdef SK_PMCOLOR_IS_RGBA
return (kBGRA_8888_SkColorType != colorType);
#else
return (kRGBA_8888_SkColorType == colorType);
#endif
}
// Method for coverting to a 32 bit pixel.
typedef uint32_t (*PackColorProc)(U8CPU a, U8CPU r, U8CPU g, U8CPU b);
static inline PackColorProc choose_pack_color_proc(bool isPremul, SkColorType colorType) {
bool isRGBA = is_rgba(colorType);
if (isPremul) {
if (isRGBA) {
return &premultiply_argb_as_rgba;
} else {
return &premultiply_argb_as_bgra;
}
} else {
if (isRGBA) {
return &SkPackARGB_as_RGBA;
} else {
return &SkPackARGB_as_BGRA;
}
}
}
static inline bool needs_premul(const SkImageInfo& dstInfo, const SkEncodedInfo& encodedInfo) {
return kPremul_SkAlphaType == dstInfo.alphaType() &&
SkEncodedInfo::kUnpremul_Alpha == encodedInfo.alpha();
}
static inline bool needs_color_xform(const SkImageInfo& dstInfo, const SkImageInfo& srcInfo,
bool needsPremul) {
// F16 is by definition a linear space, so we always must perform a color xform.
bool isF16 = kRGBA_F16_SkColorType == dstInfo.colorType();
// Need a color xform when dst space does not match the src.
bool srcDstNotEqual = !SkColorSpace::Equals(srcInfo.colorSpace(), dstInfo.colorSpace());
// We never perform a color xform in legacy mode.
bool isLegacy = nullptr == dstInfo.colorSpace();
return !isLegacy && (needsPremul || isF16 || srcDstNotEqual);
}
static inline SkAlphaType select_xform_alpha(SkAlphaType dstAlphaType, SkAlphaType srcAlphaType) {
return (kOpaque_SkAlphaType == srcAlphaType) ? kOpaque_SkAlphaType : dstAlphaType;
}
static inline bool apply_xform_on_decode(SkColorType dstColorType, SkEncodedInfo::Color srcColor) {
// We will apply the color xform when reading the color table, unless F16 is requested.
return SkEncodedInfo::kPalette_Color != srcColor || kRGBA_F16_SkColorType == dstColorType;
}
/*
* Alpha Type Conversions
* - kOpaque to kOpaque, kUnpremul, kPremul is valid
* - kUnpremul to kUnpremul, kPremul is valid
*
* Color Type Conversions
* - Always support kRGBA_8888, kBGRA_8888
* - Support kRGBA_F16 when there is a linear dst color space
* - Support kIndex8 if it matches the src
* - Support k565 if kOpaque and color correction is not required
* - Support k565 if it matches the src, kOpaque, and color correction is not required
*/
static inline bool conversion_possible(const SkImageInfo& dst, const SkImageInfo& src) {
// Ensure the alpha type is valid.
if (!valid_alpha(dst.alphaType(), src.alphaType())) {
return false;
}
// Check for supported color types.
switch (dst.colorType()) {
case kRGBA_8888_SkColorType:
case kBGRA_8888_SkColorType:
return true;
case kRGBA_F16_SkColorType:
return dst.colorSpace() && dst.colorSpace()->gammaIsLinear();
case kIndex_8_SkColorType:
return kIndex_8_SkColorType == src.colorType();
case kRGB_565_SkColorType:
return kOpaque_SkAlphaType == src.alphaType() && !needs_color_xform(dst, src, false);
case kGray_8_SkColorType:
return kGray_8_SkColorType == src.colorType() &&
kOpaque_SkAlphaType == src.alphaType() && !needs_color_xform(dst, src, false);
default:
return false;
}
}
#endif // SkCodecPriv_DEFINED