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skcms→56f2a09 add sRGB profile and ApproximatelyEqualProfiles()

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Change-Id: Ic6408fdc8819342da175ec8b99b5838669b1b2ae
Reviewed-on: https://skia-review.googlesource.com/120501
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>
This commit is contained in:
Mike Klein 2018-04-11 13:53:40 -04:00 committed by Skia Commit-Bot
parent 54aefc7410
commit 3462eb0346
2 changed files with 125 additions and 7 deletions
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8
third_party/skcms/skcms.h vendored
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@ -99,6 +99,14 @@ typedef struct {
skcms_A2B A2B;
} skcms_ICCProfile;
// The sRGB color profile is so commonly used that we offer a canonical skcms_ICCProfile for it.
extern const skcms_ICCProfile skcms_sRGB_profile;
// Practical equality test for two skcms_ICCProfiles.
// The implementation is subject to change, but it will always try to answer
// "can I substitute A for B?" and "can I skip transforming from A to B?".
bool skcms_ApproximatelyEqualProfiles(const skcms_ICCProfile* A, const skcms_ICCProfile* B);
// Parse an ICC profile and return true if possible, otherwise return false.
// The buffer is not copied, it must remain valid as long as the skcms_ICCProfile
// will be used.

124
third_party/skcms/src/ICCProfile.c vendored
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@ -14,13 +14,10 @@
#include <stdlib.h>
#include <string.h>
static uint32_t make_signature(uint8_t a, uint8_t b, uint8_t c, uint8_t d) {
return (uint32_t)(a << 24)
| (uint32_t)(b << 16)
| (uint32_t)(c << 8)
| (uint32_t)(d << 0);
}
// A macro so that it can be used in the initialization of skcms_sRGB_profile.
// Think, static uint32_t make_signature(uint8_t, uint8_t, uint8_t, uint8_t).
#define make_signature(a,b,c,d) \
( (uint32_t)((a) << 24) | (uint32_t)((b) << 16) | (uint32_t)((c) << 8) | (uint32_t)((d) << 0) )
static uint16_t read_big_u16(const uint8_t* ptr) {
uint16_t be;
@ -772,3 +769,116 @@ bool skcms_Parse(const void* buf, size_t len, skcms_ICCProfile* profile) {
return true;
}
const skcms_ICCProfile skcms_sRGB_profile = {
// These fields are moot when not a skcms_Parse()'d profile.
.buffer = NULL,
.size = 0,
.tag_count = 0,
// We choose to represent sRGB with its canonical transfer function,
// and with its canonical XYZD50 gamut matrix.
.data_color_space = make_signature('R', 'G', 'B', ' '),
.pcs = make_signature('X', 'Y', 'Z', ' '),
.has_trc = true,
.has_toXYZD50 = true,
.has_A2B = false,
.trc = {
{{0, {2.4f, (float)(1/1.055), (float)(0.055/1.055), (float)(1/12.92), 0.04045f, 0, 0 }}},
{{0, {2.4f, (float)(1/1.055), (float)(0.055/1.055), (float)(1/12.92), 0.04045f, 0, 0 }}},
{{0, {2.4f, (float)(1/1.055), (float)(0.055/1.055), (float)(1/12.92), 0.04045f, 0, 0 }}},
},
.toXYZD50 = {{
{ 0.436065674f, 0.385147095f, 0.143066406f },
{ 0.222488403f, 0.716873169f, 0.060607910f },
{ 0.013916016f, 0.097076416f, 0.714096069f },
}},
};
bool skcms_ApproximatelyEqualProfiles(const skcms_ICCProfile* A, const skcms_ICCProfile* B) {
// For now this is the essentially the same strategy we use in test_only.c
// for our skcms_Transform() smoke tests:
// 1) transform A to XYZD50
// 2) transform B to XYZD50
// 3) return true if they're similar enough
// Our current criterion in 3) is maximum 1 bit error per XYZD50 byte.
// Here are 252 of a random shuffle of all possible bytes.
// 252 is evenly divisible by 3 and 4. Only 192, 10, 241, and 43 are missing.
static const uint8_t k252_bytes[] = {
8, 179, 128, 204, 253, 38, 134, 184, 68, 102, 32, 138, 99, 39, 169, 215,
119, 26, 3, 223, 95, 239, 52, 132, 114, 74, 81, 234, 97, 116, 244, 205, 30,
154, 173, 12, 51, 159, 122, 153, 61, 226, 236, 178, 229, 55, 181, 220, 191,
194, 160, 126, 168, 82, 131, 18, 180, 245, 163, 22, 246, 69, 235, 252, 57,
108, 14, 6, 152, 240, 255, 171, 242, 20, 227, 177, 238, 96, 85, 16, 211,
70, 200, 149, 155, 146, 127, 145, 100, 151, 109, 19, 165, 208, 195, 164,
137, 254, 182, 248, 64, 201, 45, 209, 5, 147, 207, 210, 113, 162, 83, 225,
9, 31, 15, 231, 115, 37, 58, 53, 24, 49, 197, 56, 120, 172, 48, 21, 214,
129, 111, 11, 50, 187, 196, 34, 60, 103, 71, 144, 47, 203, 77, 80, 232,
140, 222, 250, 206, 166, 247, 139, 249, 221, 72, 106, 27, 199, 117, 54,
219, 135, 118, 40, 79, 41, 251, 46, 93, 212, 92, 233, 148, 28, 121, 63,
123, 158, 105, 59, 29, 42, 143, 23, 0, 107, 176, 87, 104, 183, 156, 193,
189, 90, 188, 65, 190, 17, 198, 7, 186, 161, 1, 124, 78, 125, 170, 133,
174, 218, 67, 157, 75, 101, 89, 217, 62, 33, 141, 228, 25, 35, 91, 230, 4,
2, 13, 73, 86, 167, 237, 84, 243, 44, 185, 66, 130, 110, 150, 142, 216, 88,
112, 36, 224, 136, 202, 76, 94, 98, 175, 213
};
static const skcms_ICCProfile kXYZD50 = {
.buffer = NULL,
.size = 0,
.tag_count = 0,
.data_color_space = make_signature('R', 'G', 'B', ' '),
.pcs = make_signature('X', 'Y', 'Z', ' '),
.has_trc = true,
.has_toXYZD50 = true,
.has_A2B = false,
.trc = {
{{0, {1,1,0,0,0,0,0}}},
{{0, {1,1,0,0,0,0,0}}},
{{0, {1,1,0,0,0,0,0}}},
},
.toXYZD50 = {{
{1,0,0},
{0,1,0},
{0,0,1},
}},
};
if (A->data_color_space != B->data_color_space) {
return false;
}
// Interpret as RGB_888 if data color space is RGB or GRAY, RGBA_8888 if CMYK.
skcms_PixelFormat fmt = skcms_PixelFormat_RGB_888;
size_t npixels = 84;
if (A->data_color_space == make_signature('C', 'M', 'Y', 'K')) {
fmt = skcms_PixelFormat_RGBA_8888;
npixels = 63;
}
uint8_t dstA[252],
dstB[252];
if (!skcms_Transform(k252_bytes, fmt, skcms_AlphaFormat_Unpremul, A,
dstA, skcms_PixelFormat_RGB_888, skcms_AlphaFormat_Unpremul, &kXYZD50,
npixels)) {
return false;
}
if (!skcms_Transform(k252_bytes, fmt, skcms_AlphaFormat_Unpremul, B,
dstB, skcms_PixelFormat_RGB_888, skcms_AlphaFormat_Unpremul, &kXYZD50,
npixels)) {
return false;
}
for (size_t i = 0; i < 252; i++) {
if (abs((int)dstA[i] - (int)dstB[i]) > 1) {
return false;
}
}
return true;
}