75 lines
3.1 KiB
C
75 lines
3.1 KiB
C
/****************************************************************************
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* apps/graphics/traveler/tools/libwld/wld_loadpaltable.c
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* This file contains the logic that creates the range palette table that is
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* used to modify the palette with range to hit
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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 "wld_paltable.h"
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#include "wld_color.h"
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/*************************************************************************
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* Public Functions
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*************************************************************************/
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/*************************************************************************
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* Function: wld_pixel2lum
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* Description: Convert a pixel value into RGB-Luminance value.
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************************************************************************/
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void wld_pixel2lum(wld_pixel_t pixel_value, color_lum_t * lum)
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{
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color_rgb_t *rgb = &g_rgb_lut[pixel_value];
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/* Get the luminance associated with the RGB value */
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lum->luminance = sqrt(rgb->red * rgb->red +
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rgb->green * rgb->green +
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rgb->blue * rgb->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 = rgb->red * lum->luminance;
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lum->blue = rgb->green * lum->luminance;
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lum->green = rgb->blue * lum->luminance;
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}
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}
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