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103 lines
4.4 KiB
103 lines
4.4 KiB
/**************************************************************************** |
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* graphics/color/nxglib_rgb2yuv.c |
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* |
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* Copyright (C) 2008, 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_P0813 0x000014d0 /* 0.0813 */ |
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#define b16_P1140 0x00001d2f /* 0.1140 */ |
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#define b16_P1687 0x00002b30 /* 0.1687 */ |
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#define b16_P2990 0x00004c8b /* 0.2990 */ |
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#define b16_P3313 0x000054d0 /* 0.3313 */ |
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#define b16_P4187 0x00006b30 /* 0.4187 */ |
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#define b16_P5000 0x00008000 /* 0.5000 */ |
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#define b16_P5870 0x00009646 /* 0.5870 */ |
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#define b16_128P0 0x00800000 /* 128.0 */ |
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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_rgb2yuv |
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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_rgb2yuv(uint8_t r, uint8_t g, uint8_t b, |
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uint8_t *y, uint8_t *u, uint8_t *v) |
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{ |
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/* Per the JFIF specification: |
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* |
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* Y = (0.2990 * R) + (0.5870 * G) + (0.1140 * B) |
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* U = 128 - (0.1687 * R) - (0.3313 * G) + (0.5000 * B) |
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* V = 128 + (0.5000 * R) - (0.4187 * G) - (0.0813 * B); |
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*/ |
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*y = (uint8_t)b16toi(b16muli(b16_P2990, r) + b16muli(b16_P5870, g) + b16muli(b16_P1140, b)); |
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*u = (uint8_t)b16toi(b16_128P0 - b16muli(b16_P1687, r) - b16muli(b16_P3313, g) + b16muli(b16_P5000, b)); |
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*v = (uint8_t)b16toi(b16_128P0 + b16muli(b16_P5000, r) - b16muli(b16_P4187, g) - b16muli(b16_P0813, b)); |
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}
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