skia2/include/private/SkImageInfoPriv.h
Mike Klein 12d4b6e545 let's like, chill out about all these rules, man
There's really no reason to prevent any of these conversions;
they all have somewhat reasonable behavior:

   - converting between grey in different color spaces
     should probably work just fine
   - we'll convert color to gray using a fixed set of
     luminance coefficients, but that's better than failing
   - we'll invent {r,g,b} = {0,0,0} if we convert alpha
     to something with color
   - converting to opaque formats without thinking about
     premul/unpremul is probably fine, better than just
     not working at all
   - a missing src color space can always be assumed to be sRGB

Updates to ReadPixelsTest:
   - skip more supported test cases in test_conversion(),
     each with a TODO
   - conversions from non-opaque to opaque should now work
   - conversion from A8 to non-A8 should sometimes now
     work on GPUs, and the test needed a little bit of
     a tweak to not expect A8 to carry around color somehow.

Updates to SRGBReadWritePixelsTest:
   - writing untagged pixels shouldn't fail anymore;
     instead, it should behave like it was tagged sRGB

Change-Id: I19e78f3a6c89ef74fbcbc985d3fbd77fa984b1c2
Reviewed-on: https://skia-review.googlesource.com/147815
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
2018-08-21 22:23:54 +00:00

125 lines
4.5 KiB
C

/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkImageInfoPriv_DEFINED
#define SkImageInfoPriv_DEFINED
#include "SkImageInfo.h"
enum SkColorTypeComponentFlag {
kRed_SkColorTypeComponentFlag = 0x1,
kGreen_SkColorTypeComponentFlag = 0x2,
kBlue_SkColorTypeComponentFlag = 0x4,
kAlpha_SkColorTypeComponentFlag = 0x8,
kGray_SkColorTypeComponentFlag = 0x10,
kRGB_SkColorTypeComponentFlags = kRed_SkColorTypeComponentFlag |
kGreen_SkColorTypeComponentFlag |
kBlue_SkColorTypeComponentFlag,
kRGBA_SkColorTypeComponentFlags = kRGB_SkColorTypeComponentFlags |
kAlpha_SkColorTypeComponentFlag,
};
static inline uint32_t SkColorTypeComponentFlags(SkColorType ct) {
switch (ct) {
case kUnknown_SkColorType: return 0;
case kAlpha_8_SkColorType: return kAlpha_SkColorTypeComponentFlag;
case kRGB_565_SkColorType: return kRGB_SkColorTypeComponentFlags;
case kARGB_4444_SkColorType: return kRGBA_SkColorTypeComponentFlags;
case kRGBA_8888_SkColorType: return kRGBA_SkColorTypeComponentFlags;
case kRGB_888x_SkColorType: return kRGB_SkColorTypeComponentFlags;
case kBGRA_8888_SkColorType: return kRGBA_SkColorTypeComponentFlags;
case kRGBA_1010102_SkColorType: return kRGBA_SkColorTypeComponentFlags;
case kRGB_101010x_SkColorType: return kRGB_SkColorTypeComponentFlags;
case kGray_8_SkColorType: return kGray_SkColorTypeComponentFlag;
case kRGBA_F16_SkColorType: return kRGBA_SkColorTypeComponentFlags;
case kRGBA_F32_SkColorType: return kRGBA_SkColorTypeComponentFlags;
}
return 0;
}
static inline bool SkColorTypeIsAlphaOnly(SkColorType ct) {
return kAlpha_SkColorTypeComponentFlag == SkColorTypeComponentFlags(ct);
}
static inline bool SkAlphaTypeIsValid(unsigned value) {
return value <= kLastEnum_SkAlphaType;
}
static inline bool SkColorTypeIsGray(SkColorType ct) {
auto flags = SkColorTypeComponentFlags(ct);
// Currently assuming that a color type has only gray or does not have gray.
SkASSERT(!(kGray_SkColorTypeComponentFlag & flags) || kGray_SkColorTypeComponentFlag == flags);
return kGray_SkColorTypeComponentFlag == flags;
}
static int SkColorTypeShiftPerPixel(SkColorType ct) {
switch (ct) {
case kUnknown_SkColorType: return 0;
case kAlpha_8_SkColorType: return 0;
case kRGB_565_SkColorType: return 1;
case kARGB_4444_SkColorType: return 1;
case kRGBA_8888_SkColorType: return 2;
case kRGB_888x_SkColorType: return 2;
case kBGRA_8888_SkColorType: return 2;
case kRGBA_1010102_SkColorType: return 2;
case kRGB_101010x_SkColorType: return 2;
case kGray_8_SkColorType: return 0;
case kRGBA_F16_SkColorType: return 3;
case kRGBA_F32_SkColorType: return 4;
}
return 0;
}
static inline size_t SkColorTypeMinRowBytes(SkColorType ct, int width) {
return width * SkColorTypeBytesPerPixel(ct);
}
static inline bool SkColorTypeIsValid(unsigned value) {
return value <= kLastEnum_SkColorType;
}
static inline size_t SkColorTypeComputeOffset(SkColorType ct, int x, int y, size_t rowBytes) {
if (kUnknown_SkColorType == ct) {
return 0;
}
return y * rowBytes + (x << SkColorTypeShiftPerPixel(ct));
}
/**
* Returns true if |info| contains a valid combination of width, height, colorType, and alphaType.
*/
static inline bool SkImageInfoIsValid(const SkImageInfo& info) {
if (info.width() <= 0 || info.height() <= 0) {
return false;
}
const int kMaxDimension = SK_MaxS32 >> 2;
if (info.width() > kMaxDimension || info.height() > kMaxDimension) {
return false;
}
if (kUnknown_SkColorType == info.colorType() || kUnknown_SkAlphaType == info.alphaType()) {
return false;
}
if (kOpaque_SkAlphaType != info.alphaType() &&
(kRGB_565_SkColorType == info.colorType() || kGray_8_SkColorType == info.colorType())) {
return false;
}
return true;
}
/**
* Returns true if Skia has defined a pixel conversion from the |src| to the |dst|.
* Returns false otherwise.
*/
static inline bool SkImageInfoValidConversion(const SkImageInfo& dst, const SkImageInfo& src) {
return SkImageInfoIsValid(dst) && SkImageInfoIsValid(src);
}
#endif // SkImageInfoPriv_DEFINED