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102 lines
4.2 KiB
102 lines
4.2 KiB
/**************************************************************************** |
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* graphics/color/nxglib_yuv2rgb.c |
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* |
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* Copyright (C) 2008-2009, 2011 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 <nuttx/config.h> |
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#include <stdint.h> |
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#include <debug.h> |
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#include <fixedmath.h> |
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#include <nuttx/nx/nxglib.h> |
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/**************************************************************************** |
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* Pre-Processor Definitions |
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****************************************************************************/ |
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#define b16_P3441 0x0000581a /* 0.344147 */ |
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#define b16_P7141 0x0000b6d2 /* 0.714142 */ |
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#define b16_1P402 0x000166ea /* 1.402008 */ |
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#define b16_1P772 0x0001c5a2 /* 1.722003 */ |
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#define b16_128P0 0x00800000 /* 128.000000 */ |
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/**************************************************************************** |
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* Private Types |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Function Prototypes |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Data |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Functions |
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****************************************************************************/ |
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/**************************************************************************** |
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* Public Functions |
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****************************************************************************/ |
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/**************************************************************************** |
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* Name: nxgl_yuv2rgb |
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* |
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* Description: |
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* Convert 8-bit RGB triplet to 8-bit YUV triplet |
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* |
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****************************************************************************/ |
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void nxgl_yuv2rgb(uint8_t y, uint8_t u, uint8_t v, |
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uint8_t *r, uint8_t *g, uint8_t *b) |
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{ |
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b16_t vm128 = itob16(v) - b16_128P0; |
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b16_t um128 = itob16(u) - b16_128P0; |
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/* Per the JFIF specification: |
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* |
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* R = Y + 1.40200 * (V - 128.0) |
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* G = Y - 0.34414 * (U - 128.0) - 0.71414 * (V - 128.0) |
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* B = Y + 1.77200 * (U - 128.0) |
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*/ |
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*r = (uint8_t)b16toi(itob16(y) + b16muli(b16_1P402, vm128)); |
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*g = (uint8_t)b16toi(itob16(y) - b16muli(b16_P3441, um128) - b16muli(b16_P7141, vm128)); |
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*b = (uint8_t)b16toi(itob16(y) + b16muli(b16_1P772, um128)); |
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}
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