/src/FreeImage/Source/OpenEXR/IlmImf/ImfLut.cpp

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  2//
  3// Copyright (c) 2002, Industrial Light & Magic, a division of Lucas
  4// Digital Ltd. LLC
  5// 
  6// All rights reserved.
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 33///////////////////////////////////////////////////////////////////////////
 34
 35
 36
 37//-----------------------------------------------------------------------------
 38//
 39//	Lookup tables for efficient application
 40//	of half --> half functions to pixel data,
 41//	and some commonly applied functions.
 42//
 43//-----------------------------------------------------------------------------
 44
 45#include <ImfLut.h>
 46#include <math.h>
 47#include <assert.h>
 48
 49namespace Imf {
 50
 51
 52void
 53HalfLut::apply (half *data, int nData, int stride) const
 54{
 55    while (nData)
 56    {
 57	*data = _lut (*data);
 58	data += stride;
 59	nData -= 1;
 60    }
 61}
 62
 63
 64void
 65HalfLut::apply (const Slice &data, const Imath::Box2i &dataWindow) const
 66{
 67    assert (data.type == HALF);
 68    assert (dataWindow.min.x % data.xSampling == 0);
 69    assert (dataWindow.min.y % data.ySampling == 0);
 70    assert ((dataWindow.max.x - dataWindow.min.x + 1) % data.xSampling == 0);
 71    assert ((dataWindow.max.y - dataWindow.min.y + 1) % data.ySampling == 0);
 72
 73    char *base = data.base + data.yStride *
 74		 (dataWindow.min.y / data.ySampling);
 75
 76    for (int y = dataWindow.min.y;
 77	 y <= dataWindow.max.y;
 78	 y += data.ySampling)
 79    {
 80	char *pixel = base + data.xStride *
 81		      (dataWindow.min.x / data.xSampling);
 82
 83	for (int x = dataWindow.min.x;
 84	     x <= dataWindow.max.x;
 85	     x += data.xSampling)
 86	{
 87	    *(half *)pixel = _lut (*(half *)pixel);
 88	    pixel += data.xStride;
 89	}
 90
 91	base += data.yStride;
 92    }
 93}
 94
 95
 96void
 97RgbaLut::apply (Rgba *data, int nData, int stride) const
 98{
 99    while (nData)
100    {
101	if (_chn & WRITE_R)
102	    data->r = _lut (data->r);
103
104	if (_chn & WRITE_G)
105	    data->g = _lut (data->g);
106
107	if (_chn & WRITE_B)
108	    data->b = _lut (data->b);
109
110	if (_chn & WRITE_A)
111	    data->a = _lut (data->a);
112
113	data += stride;
114	nData -= 1;
115    }
116}
117
118
119void
120RgbaLut::apply (Rgba *base,
121		int xStride, int yStride,
122		const Imath::Box2i &dataWindow) const
123{
124    base += dataWindow.min.y * yStride;
125
126    for (int y = dataWindow.min.y; y <= dataWindow.max.y; ++y)
127    {
128	Rgba *pixel = base + dataWindow.min.x * xStride;
129
130	for (int x = dataWindow.min.x; x <= dataWindow.max.x; ++x)
131	{
132	    if (_chn & WRITE_R)
133		pixel->r = _lut (pixel->r);
134
135	    if (_chn & WRITE_G)
136		pixel->g = _lut (pixel->g);
137
138	    if (_chn & WRITE_B)
139		pixel->b = _lut (pixel->b);
140
141	    if (_chn & WRITE_A)
142		pixel->a = _lut (pixel->a);
143
144	    pixel += xStride;
145	}
146
147	base += yStride;
148    }
149}
150
151
152half
153round12log (half x)
154{
155    const float middleval = pow (2.0, -2.5);
156    int int12log;
157
158    if (x <= 0)
159    {
160	return 0;
161    }
162    else
163    {
164	int12log = int (2000.5 + 200.0 * log (x / middleval) / log (2.0));
165
166	if (int12log > 4095)
167	    int12log = 4095;
168
169	if (int12log < 1)
170	    int12log = 1;
171    }
172
173    return middleval * pow (2.0, (int12log - 2000.0) / 200.0);
174}
175
176} // namespace Imf