97 lines
3.5 KiB
C
97 lines
3.5 KiB
C
/****************************************************************************
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* apps/graphics/traveler/tools/libwld/wld_rgb2pixel.c
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*
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* Copyright (C) 2016 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <math.h>
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#include "trv_types.h"
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#include "wld_color.h"
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/****************************************************************************
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* Name: wld_rgb2pixel
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* Description: Map a RGB triplet into the corresponding pixel. The
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* value range of ech RGB value is assume to lie within 0 through
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* TRV_PIXEL_MAX.
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****************************************************************************/
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trv_pixel_t wld_rgb2pixel(color_rgb_t * pixel)
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{
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#if RGB_CUBE_SIZE < MIN_LUM_LEVELS
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color_lum_t lum;
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/* Convert the RGB Value into a luminance value. Get the luminance associated
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* with the RGB value.
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*/
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lum.luminance = sqrt(pixel->red * pixel->red
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+ pixel->green * pixel->green
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+ pixel->blue * pixel->blue);
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/* Convert the RGB Component into unit vector + luminance */
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if (lum.luminance > 0.0)
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{
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lum.red = (float)pixel->red / lum.luminance;
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lum.green = (float)pixel->green / lum.luminance;
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lum.blue = (float)pixel->blue / lum.luminance;
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}
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else
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{
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lum.red = lum.green = lum.blue = g_unit_vector[GREY_NDX].red;
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}
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return wld_lum2pixel(&lum);
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#else
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trv_pixel_t ret;
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int red;
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int green;
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int blue;
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red = MIN((pixel->red * RGB_CUBE_SIZE) / (TRV_PIXEL_MAX + 1),
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RGB_CUBE_SIZE - 1);
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green = MIN((pixel->green * RGB_CUBE_SIZE) / (TRV_PIXEL_MAX + 1),
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RGB_CUBE_SIZE - 1);
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blue = MIN((pixel->blue * RGB_CUBE_SIZE) / (TRV_PIXEL_MAX + 1),
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RGB_CUBE_SIZE - 1);
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ret = (red * RGB_CUBE_SIZE + green) * RGB_CUBE_SIZE + blue;
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return ret;
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#endif
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}
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