1
//////////////////////////////////////////////////////////////////////////////
3
// Copyright (c) 2004, Industrial Light & Magic, a division of Lucasfilm
4
// Entertainment Company Ltd. Portions contributed and copyright held by
5
// others as indicated. All rights reserved.
7
// Redistribution and use in source and binary forms, with or without
8
// modification, are permitted provided that the following conditions are
11
// * Redistributions of source code must retain the above
12
// copyright notice, this list of conditions and the following
15
// * Redistributions in binary form must reproduce the above
16
// copyright notice, this list of conditions and the following
17
// disclaimer in the documentation and/or other materials provided with
20
// * Neither the name of Industrial Light & Magic nor the names of
21
// any other contributors to this software may be used to endorse or
22
// promote products derived from this software without specific prior
23
// written permission.
25
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
26
// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
27
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
29
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
30
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
31
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
32
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
33
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
34
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
35
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37
//////////////////////////////////////////////////////////////////////////////
39
//-----------------------------------------------------------------------------
41
// Conversion between RGBA and YCA data.
43
//-----------------------------------------------------------------------------
45
#include <ImfRgbaYca.h>
49
using namespace Imath;
57
computeYw (const Chromaticities &cr)
59
M44f m = RGBtoXYZ (cr, 1);
60
return V3f (m[0][1], m[1][1], m[2][1]) / (m[0][1] + m[1][1] + m[2][1]);
65
RGBAtoYCA (const V3f &yw,
68
const Rgba rgbaIn[/*n*/],
71
for (int i = 0; i < n; ++i)
74
Rgba &out = ycaOut[i];
77
// Conversion to YCA and subsequent chroma subsampling
78
// work only if R, G and B are finite and non-negative.
81
if (!in.r.isFinite() || in.r < 0)
84
if (!in.g.isFinite() || in.g < 0)
87
if (!in.b.isFinite() || in.b < 0)
90
if (in.r == in.g && in.g == in.b)
93
// Special case -- R, G and B are equal. To avoid rounding
94
// errors, we explicitly set the output luminance channel
95
// to G, and the chroma channels to 0.
97
// The special cases here and in YCAtoRGBA() ensure that
98
// converting black-and white images from RGBA to YCA and
108
out.g = in.r * yw.x + in.g * yw.y + in.b * yw.z;
112
if (abs (in.r - Y) < HALF_MAX * Y)
113
out.r = (in.r - Y) / Y;
117
if (abs (in.b - Y) < HALF_MAX * Y)
118
out.b = (in.b - Y) / Y;
132
decimateChromaHoriz (int n,
133
const Rgba ycaIn[/*n+N-1*/],
137
assert (ycaIn != ycaOut);
143
for (int i = begin, j = 0; i < end; ++i, ++j)
147
ycaOut[j].r = ycaIn[i - 13].r * 0.001064 +
148
ycaIn[i - 11].r * -0.003771 +
149
ycaIn[i - 9].r * 0.009801 +
150
ycaIn[i - 7].r * -0.021586 +
151
ycaIn[i - 5].r * 0.043978 +
152
ycaIn[i - 3].r * -0.093067 +
153
ycaIn[i - 1].r * 0.313659 +
154
ycaIn[i ].r * 0.499846 +
155
ycaIn[i + 1].r * 0.313659 +
156
ycaIn[i + 3].r * -0.093067 +
157
ycaIn[i + 5].r * 0.043978 +
158
ycaIn[i + 7].r * -0.021586 +
159
ycaIn[i + 9].r * 0.009801 +
160
ycaIn[i + 11].r * -0.003771 +
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ycaIn[i + 13].r * 0.001064;
163
ycaOut[j].b = ycaIn[i - 13].b * 0.001064 +
164
ycaIn[i - 11].b * -0.003771 +
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ycaIn[i - 9].b * 0.009801 +
166
ycaIn[i - 7].b * -0.021586 +
167
ycaIn[i - 5].b * 0.043978 +
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ycaIn[i - 3].b * -0.093067 +
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ycaIn[i - 1].b * 0.313659 +
170
ycaIn[i ].b * 0.499846 +
171
ycaIn[i + 1].b * 0.313659 +
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ycaIn[i + 3].b * -0.093067 +
173
ycaIn[i + 5].b * 0.043978 +
174
ycaIn[i + 7].b * -0.021586 +
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ycaIn[i + 9].b * 0.009801 +
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ycaIn[i + 11].b * -0.003771 +
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ycaIn[i + 13].b * 0.001064;
180
ycaOut[j].g = ycaIn[i].g;
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ycaOut[j].a = ycaIn[i].a;
187
decimateChromaVert (int n,
188
const Rgba * const ycaIn[N],
191
for (int i = 0; i < n; ++i)
195
ycaOut[i].r = ycaIn[ 0][i].r * 0.001064 +
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ycaIn[ 2][i].r * -0.003771 +
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ycaIn[ 4][i].r * 0.009801 +
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ycaIn[ 6][i].r * -0.021586 +
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ycaIn[ 8][i].r * 0.043978 +
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ycaIn[10][i].r * -0.093067 +
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ycaIn[12][i].r * 0.313659 +
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ycaIn[13][i].r * 0.499846 +
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ycaIn[14][i].r * 0.313659 +
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ycaIn[16][i].r * -0.093067 +
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ycaIn[18][i].r * 0.043978 +
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ycaIn[20][i].r * -0.021586 +
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ycaIn[22][i].r * 0.009801 +
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ycaIn[24][i].r * -0.003771 +
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ycaIn[26][i].r * 0.001064;
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ycaOut[i].b = ycaIn[ 0][i].b * 0.001064 +
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ycaIn[ 2][i].b * -0.003771 +
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ycaIn[ 4][i].b * 0.009801 +
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ycaIn[ 6][i].b * -0.021586 +
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ycaIn[ 8][i].b * 0.043978 +
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ycaIn[10][i].b * -0.093067 +
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ycaIn[12][i].b * 0.313659 +
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ycaIn[13][i].b * 0.499846 +
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ycaIn[14][i].b * 0.313659 +
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ycaIn[16][i].b * -0.093067 +
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ycaIn[18][i].b * 0.043978 +
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ycaIn[20][i].b * -0.021586 +
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ycaIn[22][i].b * 0.009801 +
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ycaIn[24][i].b * -0.003771 +
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ycaIn[26][i].b * 0.001064;
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ycaOut[i].g = ycaIn[13][i].g;
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ycaOut[i].a = ycaIn[13][i].a;
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const Rgba ycaIn[/*n*/],
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for (int i = 0; i < n; ++i)
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ycaOut[i].g = ycaIn[i].g.round (roundY);
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ycaOut[i].a = ycaIn[i].a;
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ycaOut[i].r = ycaIn[i].r.round (roundC);
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ycaOut[i].b = ycaIn[i].b.round (roundC);
256
reconstructChromaHoriz (int n,
257
const Rgba ycaIn[/*n+N-1*/],
261
assert (ycaIn != ycaOut);
267
for (int i = begin, j = 0; i < end; ++i, ++j)
271
ycaOut[j].r = ycaIn[i - 13].r * 0.002128 +
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ycaIn[i - 11].r * -0.007540 +
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ycaIn[i - 9].r * 0.019597 +
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ycaIn[i - 7].r * -0.043159 +
275
ycaIn[i - 5].r * 0.087929 +
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ycaIn[i - 3].r * -0.186077 +
277
ycaIn[i - 1].r * 0.627123 +
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ycaIn[i + 1].r * 0.627123 +
279
ycaIn[i + 3].r * -0.186077 +
280
ycaIn[i + 5].r * 0.087929 +
281
ycaIn[i + 7].r * -0.043159 +
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ycaIn[i + 9].r * 0.019597 +
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ycaIn[i + 11].r * -0.007540 +
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ycaIn[i + 13].r * 0.002128;
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ycaOut[j].b = ycaIn[i - 13].b * 0.002128 +
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ycaIn[i - 11].b * -0.007540 +
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ycaIn[i - 9].b * 0.019597 +
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ycaIn[i - 7].b * -0.043159 +
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ycaIn[i - 5].b * 0.087929 +
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ycaIn[i - 3].b * -0.186077 +
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ycaIn[i - 1].b * 0.627123 +
293
ycaIn[i + 1].b * 0.627123 +
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ycaIn[i + 3].b * -0.186077 +
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ycaIn[i + 5].b * 0.087929 +
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ycaIn[i + 7].b * -0.043159 +
297
ycaIn[i + 9].b * 0.019597 +
298
ycaIn[i + 11].b * -0.007540 +
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ycaIn[i + 13].b * 0.002128;
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ycaOut[j].r = ycaIn[i].r;
304
ycaOut[j].b = ycaIn[i].b;
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ycaOut[j].g = ycaIn[i].g;
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ycaOut[j].a = ycaIn[i].a;
314
reconstructChromaVert (int n,
315
const Rgba * const ycaIn[N],
318
for (int i = 0; i < n; ++i)
320
ycaOut[i].r = ycaIn[ 0][i].r * 0.002128 +
321
ycaIn[ 2][i].r * -0.007540 +
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ycaIn[ 4][i].r * 0.019597 +
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ycaIn[ 6][i].r * -0.043159 +
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ycaIn[ 8][i].r * 0.087929 +
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ycaIn[10][i].r * -0.186077 +
326
ycaIn[12][i].r * 0.627123 +
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ycaIn[14][i].r * 0.627123 +
328
ycaIn[16][i].r * -0.186077 +
329
ycaIn[18][i].r * 0.087929 +
330
ycaIn[20][i].r * -0.043159 +
331
ycaIn[22][i].r * 0.019597 +
332
ycaIn[24][i].r * -0.007540 +
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ycaIn[26][i].r * 0.002128;
335
ycaOut[i].b = ycaIn[ 0][i].b * 0.002128 +
336
ycaIn[ 2][i].b * -0.007540 +
337
ycaIn[ 4][i].b * 0.019597 +
338
ycaIn[ 6][i].b * -0.043159 +
339
ycaIn[ 8][i].b * 0.087929 +
340
ycaIn[10][i].b * -0.186077 +
341
ycaIn[12][i].b * 0.627123 +
342
ycaIn[14][i].b * 0.627123 +
343
ycaIn[16][i].b * -0.186077 +
344
ycaIn[18][i].b * 0.087929 +
345
ycaIn[20][i].b * -0.043159 +
346
ycaIn[22][i].b * 0.019597 +
347
ycaIn[24][i].b * -0.007540 +
348
ycaIn[26][i].b * 0.002128;
350
ycaOut[i].g = ycaIn[13][i].g;
351
ycaOut[i].a = ycaIn[13][i].a;
357
YCAtoRGBA (const Imath::V3f &yw,
359
const Rgba ycaIn[/*n*/],
362
for (int i = 0; i < n; ++i)
364
const Rgba &in = ycaIn[i];
365
Rgba &out = rgbaOut[i];
367
if (in.r == 0 && in.b == 0)
370
// Special case -- both chroma channels are 0. To avoid
371
// rounding errors, we explicitly set the output R, G and B
372
// channels equal to the input luminance.
374
// The special cases here and in RGBAtoYCA() ensure that
375
// converting black-and white images from RGBA to YCA and
387
float r = (in.r + 1) * Y;
388
float b = (in.b + 1) * Y;
389
float g = (Y - r * yw.x - b * yw.z) / yw.y;
403
saturation (const Rgba &in)
405
float rgbMax = max (in.r, max (in.g, in.b));
406
float rgbMin = min (in.r, min (in.g, in.b));
409
return 1 - rgbMin / rgbMax;
416
desaturate (const Rgba &in, float f, const V3f &yw, Rgba &out)
418
float rgbMax = max (in.r, max (in.g, in.b));
420
out.r = max (float (rgbMax - (rgbMax - in.r) * f), 0.0f);
421
out.g = max (float (rgbMax - (rgbMax - in.g) * f), 0.0f);
422
out.b = max (float (rgbMax - (rgbMax - in.b) * f), 0.0f);
425
float Yin = in.r * yw.x + in.g * yw.y + in.b * yw.z;
426
float Yout = out.r * yw.x + out.g * yw.y + out.b * yw.z;
440
fixSaturation (const Imath::V3f &yw,
442
const Rgba * const rgbaIn[3],
445
for (int i = 0; i < n; ++i)
447
const int i0 = max (i - 1, 0);
448
const int i1 = min (i + 1, n - 1);
450
const Rgba &neighbor0 = rgbaIn[0][i0];
451
const Rgba &neighbor1 = rgbaIn[0][i1];
452
const Rgba &neighbor2 = rgbaIn[2][i0];
453
const Rgba &neighbor3 = rgbaIn[2][i1];
455
float sMean = min (1.0f, 0.25f * (saturation (neighbor0) +
456
saturation (neighbor1) +
457
saturation (neighbor2) +
458
saturation (neighbor3)));
460
const Rgba &in = rgbaIn[1][i];
461
Rgba &out = rgbaOut[i];
463
float s = saturation (in);
467
float sMax = min (1.0f, 1 - (1 - sMean) * 0.25f);
471
desaturate (in, sMax / s, yw, out);
481
} // namespace RgbaYca
1
//////////////////////////////////////////////////////////////////////////////
3
// Copyright (c) 2004, Industrial Light & Magic, a division of Lucasfilm
4
// Entertainment Company Ltd. Portions contributed and copyright held by
5
// others as indicated. All rights reserved.
7
// Redistribution and use in source and binary forms, with or without
8
// modification, are permitted provided that the following conditions are
11
// * Redistributions of source code must retain the above
12
// copyright notice, this list of conditions and the following
15
// * Redistributions in binary form must reproduce the above
16
// copyright notice, this list of conditions and the following
17
// disclaimer in the documentation and/or other materials provided with
20
// * Neither the name of Industrial Light & Magic nor the names of
21
// any other contributors to this software may be used to endorse or
22
// promote products derived from this software without specific prior
23
// written permission.
25
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
26
// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
27
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
29
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
30
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
31
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
32
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
33
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
34
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
35
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37
//////////////////////////////////////////////////////////////////////////////
39
//-----------------------------------------------------------------------------
41
// Conversion between RGBA and YCA data.
43
//-----------------------------------------------------------------------------
45
#include <ImfRgbaYca.h>
49
using namespace Imath;
57
computeYw (const Chromaticities &cr)
59
M44f m = RGBtoXYZ (cr, 1);
60
return V3f (m[0][1], m[1][1], m[2][1]) / (m[0][1] + m[1][1] + m[2][1]);
65
RGBAtoYCA (const V3f &yw,
68
const Rgba rgbaIn[/*n*/],
71
for (int i = 0; i < n; ++i)
74
Rgba &out = ycaOut[i];
77
// Conversion to YCA and subsequent chroma subsampling
78
// work only if R, G and B are finite and non-negative.
81
if (!in.r.isFinite() || in.r < 0)
84
if (!in.g.isFinite() || in.g < 0)
87
if (!in.b.isFinite() || in.b < 0)
90
if (in.r == in.g && in.g == in.b)
93
// Special case -- R, G and B are equal. To avoid rounding
94
// errors, we explicitly set the output luminance channel
95
// to G, and the chroma channels to 0.
97
// The special cases here and in YCAtoRGBA() ensure that
98
// converting black-and white images from RGBA to YCA and
108
out.g = in.r * yw.x + in.g * yw.y + in.b * yw.z;
112
if (abs (in.r - Y) < HALF_MAX * Y)
113
out.r = (in.r - Y) / Y;
117
if (abs (in.b - Y) < HALF_MAX * Y)
118
out.b = (in.b - Y) / Y;
132
decimateChromaHoriz (int n,
133
const Rgba ycaIn[/*n+N-1*/],
137
assert (ycaIn != ycaOut);
143
for (int i = begin, j = 0; i < end; ++i, ++j)
147
ycaOut[j].r = ycaIn[i - 13].r * 0.001064 +
148
ycaIn[i - 11].r * -0.003771 +
149
ycaIn[i - 9].r * 0.009801 +
150
ycaIn[i - 7].r * -0.021586 +
151
ycaIn[i - 5].r * 0.043978 +
152
ycaIn[i - 3].r * -0.093067 +
153
ycaIn[i - 1].r * 0.313659 +
154
ycaIn[i ].r * 0.499846 +
155
ycaIn[i + 1].r * 0.313659 +
156
ycaIn[i + 3].r * -0.093067 +
157
ycaIn[i + 5].r * 0.043978 +
158
ycaIn[i + 7].r * -0.021586 +
159
ycaIn[i + 9].r * 0.009801 +
160
ycaIn[i + 11].r * -0.003771 +
161
ycaIn[i + 13].r * 0.001064;
163
ycaOut[j].b = ycaIn[i - 13].b * 0.001064 +
164
ycaIn[i - 11].b * -0.003771 +
165
ycaIn[i - 9].b * 0.009801 +
166
ycaIn[i - 7].b * -0.021586 +
167
ycaIn[i - 5].b * 0.043978 +
168
ycaIn[i - 3].b * -0.093067 +
169
ycaIn[i - 1].b * 0.313659 +
170
ycaIn[i ].b * 0.499846 +
171
ycaIn[i + 1].b * 0.313659 +
172
ycaIn[i + 3].b * -0.093067 +
173
ycaIn[i + 5].b * 0.043978 +
174
ycaIn[i + 7].b * -0.021586 +
175
ycaIn[i + 9].b * 0.009801 +
176
ycaIn[i + 11].b * -0.003771 +
177
ycaIn[i + 13].b * 0.001064;
180
ycaOut[j].g = ycaIn[i].g;
181
ycaOut[j].a = ycaIn[i].a;
187
decimateChromaVert (int n,
188
const Rgba * const ycaIn[N],
191
for (int i = 0; i < n; ++i)
195
ycaOut[i].r = ycaIn[ 0][i].r * 0.001064 +
196
ycaIn[ 2][i].r * -0.003771 +
197
ycaIn[ 4][i].r * 0.009801 +
198
ycaIn[ 6][i].r * -0.021586 +
199
ycaIn[ 8][i].r * 0.043978 +
200
ycaIn[10][i].r * -0.093067 +
201
ycaIn[12][i].r * 0.313659 +
202
ycaIn[13][i].r * 0.499846 +
203
ycaIn[14][i].r * 0.313659 +
204
ycaIn[16][i].r * -0.093067 +
205
ycaIn[18][i].r * 0.043978 +
206
ycaIn[20][i].r * -0.021586 +
207
ycaIn[22][i].r * 0.009801 +
208
ycaIn[24][i].r * -0.003771 +
209
ycaIn[26][i].r * 0.001064;
211
ycaOut[i].b = ycaIn[ 0][i].b * 0.001064 +
212
ycaIn[ 2][i].b * -0.003771 +
213
ycaIn[ 4][i].b * 0.009801 +
214
ycaIn[ 6][i].b * -0.021586 +
215
ycaIn[ 8][i].b * 0.043978 +
216
ycaIn[10][i].b * -0.093067 +
217
ycaIn[12][i].b * 0.313659 +
218
ycaIn[13][i].b * 0.499846 +
219
ycaIn[14][i].b * 0.313659 +
220
ycaIn[16][i].b * -0.093067 +
221
ycaIn[18][i].b * 0.043978 +
222
ycaIn[20][i].b * -0.021586 +
223
ycaIn[22][i].b * 0.009801 +
224
ycaIn[24][i].b * -0.003771 +
225
ycaIn[26][i].b * 0.001064;
228
ycaOut[i].g = ycaIn[13][i].g;
229
ycaOut[i].a = ycaIn[13][i].a;
238
const Rgba ycaIn[/*n*/],
241
for (int i = 0; i < n; ++i)
243
ycaOut[i].g = ycaIn[i].g.round (roundY);
244
ycaOut[i].a = ycaIn[i].a;
248
ycaOut[i].r = ycaIn[i].r.round (roundC);
249
ycaOut[i].b = ycaIn[i].b.round (roundC);
256
reconstructChromaHoriz (int n,
257
const Rgba ycaIn[/*n+N-1*/],
261
assert (ycaIn != ycaOut);
267
for (int i = begin, j = 0; i < end; ++i, ++j)
271
ycaOut[j].r = ycaIn[i - 13].r * 0.002128 +
272
ycaIn[i - 11].r * -0.007540 +
273
ycaIn[i - 9].r * 0.019597 +
274
ycaIn[i - 7].r * -0.043159 +
275
ycaIn[i - 5].r * 0.087929 +
276
ycaIn[i - 3].r * -0.186077 +
277
ycaIn[i - 1].r * 0.627123 +
278
ycaIn[i + 1].r * 0.627123 +
279
ycaIn[i + 3].r * -0.186077 +
280
ycaIn[i + 5].r * 0.087929 +
281
ycaIn[i + 7].r * -0.043159 +
282
ycaIn[i + 9].r * 0.019597 +
283
ycaIn[i + 11].r * -0.007540 +
284
ycaIn[i + 13].r * 0.002128;
286
ycaOut[j].b = ycaIn[i - 13].b * 0.002128 +
287
ycaIn[i - 11].b * -0.007540 +
288
ycaIn[i - 9].b * 0.019597 +
289
ycaIn[i - 7].b * -0.043159 +
290
ycaIn[i - 5].b * 0.087929 +
291
ycaIn[i - 3].b * -0.186077 +
292
ycaIn[i - 1].b * 0.627123 +
293
ycaIn[i + 1].b * 0.627123 +
294
ycaIn[i + 3].b * -0.186077 +
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ycaIn[i + 5].b * 0.087929 +
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ycaIn[i + 7].b * -0.043159 +
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ycaIn[i + 9].b * 0.019597 +
298
ycaIn[i + 11].b * -0.007540 +
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ycaIn[i + 13].b * 0.002128;
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ycaOut[j].r = ycaIn[i].r;
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ycaOut[j].b = ycaIn[i].b;
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ycaOut[j].g = ycaIn[i].g;
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ycaOut[j].a = ycaIn[i].a;
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reconstructChromaVert (int n,
315
const Rgba * const ycaIn[N],
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for (int i = 0; i < n; ++i)
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ycaOut[i].r = ycaIn[ 0][i].r * 0.002128 +
321
ycaIn[ 2][i].r * -0.007540 +
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ycaIn[ 4][i].r * 0.019597 +
323
ycaIn[ 6][i].r * -0.043159 +
324
ycaIn[ 8][i].r * 0.087929 +
325
ycaIn[10][i].r * -0.186077 +
326
ycaIn[12][i].r * 0.627123 +
327
ycaIn[14][i].r * 0.627123 +
328
ycaIn[16][i].r * -0.186077 +
329
ycaIn[18][i].r * 0.087929 +
330
ycaIn[20][i].r * -0.043159 +
331
ycaIn[22][i].r * 0.019597 +
332
ycaIn[24][i].r * -0.007540 +
333
ycaIn[26][i].r * 0.002128;
335
ycaOut[i].b = ycaIn[ 0][i].b * 0.002128 +
336
ycaIn[ 2][i].b * -0.007540 +
337
ycaIn[ 4][i].b * 0.019597 +
338
ycaIn[ 6][i].b * -0.043159 +
339
ycaIn[ 8][i].b * 0.087929 +
340
ycaIn[10][i].b * -0.186077 +
341
ycaIn[12][i].b * 0.627123 +
342
ycaIn[14][i].b * 0.627123 +
343
ycaIn[16][i].b * -0.186077 +
344
ycaIn[18][i].b * 0.087929 +
345
ycaIn[20][i].b * -0.043159 +
346
ycaIn[22][i].b * 0.019597 +
347
ycaIn[24][i].b * -0.007540 +
348
ycaIn[26][i].b * 0.002128;
350
ycaOut[i].g = ycaIn[13][i].g;
351
ycaOut[i].a = ycaIn[13][i].a;
357
YCAtoRGBA (const Imath::V3f &yw,
359
const Rgba ycaIn[/*n*/],
362
for (int i = 0; i < n; ++i)
364
const Rgba &in = ycaIn[i];
365
Rgba &out = rgbaOut[i];
367
if (in.r == 0 && in.b == 0)
370
// Special case -- both chroma channels are 0. To avoid
371
// rounding errors, we explicitly set the output R, G and B
372
// channels equal to the input luminance.
374
// The special cases here and in RGBAtoYCA() ensure that
375
// converting black-and white images from RGBA to YCA and
387
float r = (in.r + 1) * Y;
388
float b = (in.b + 1) * Y;
389
float g = (Y - r * yw.x - b * yw.z) / yw.y;
403
saturation (const Rgba &in)
405
float rgbMax = max (in.r, max (in.g, in.b));
406
float rgbMin = min (in.r, min (in.g, in.b));
409
return 1 - rgbMin / rgbMax;
416
desaturate (const Rgba &in, float f, const V3f &yw, Rgba &out)
418
float rgbMax = max (in.r, max (in.g, in.b));
420
out.r = max (float (rgbMax - (rgbMax - in.r) * f), 0.0f);
421
out.g = max (float (rgbMax - (rgbMax - in.g) * f), 0.0f);
422
out.b = max (float (rgbMax - (rgbMax - in.b) * f), 0.0f);
425
float Yin = in.r * yw.x + in.g * yw.y + in.b * yw.z;
426
float Yout = out.r * yw.x + out.g * yw.y + out.b * yw.z;
440
fixSaturation (const Imath::V3f &yw,
442
const Rgba * const rgbaIn[3],
445
for (int i = 0; i < n; ++i)
447
const int i0 = max (i - 1, 0);
448
const int i1 = min (i + 1, n - 1);
450
const Rgba &neighbor0 = rgbaIn[0][i0];
451
const Rgba &neighbor1 = rgbaIn[0][i1];
452
const Rgba &neighbor2 = rgbaIn[2][i0];
453
const Rgba &neighbor3 = rgbaIn[2][i1];
455
float sMean = min (1.0f, 0.25f * (saturation (neighbor0) +
456
saturation (neighbor1) +
457
saturation (neighbor2) +
458
saturation (neighbor3)));
460
const Rgba &in = rgbaIn[1][i];
461
Rgba &out = rgbaOut[i];
463
float s = saturation (in);
467
float sMax = min (1.0f, 1 - (1 - sMean) * 0.25f);
471
desaturate (in, sMax / s, yw, out);
481
} // namespace RgbaYca