diff options
Diffstat (limited to 'nuttx/graphics/nxglib/nxglib_yuv2rgb.c')
-rw-r--r-- | nuttx/graphics/nxglib/nxglib_yuv2rgb.c | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/nuttx/graphics/nxglib/nxglib_yuv2rgb.c b/nuttx/graphics/nxglib/nxglib_yuv2rgb.c new file mode 100644 index 000000000..9a3cb1f22 --- /dev/null +++ b/nuttx/graphics/nxglib/nxglib_yuv2rgb.c @@ -0,0 +1,102 @@ +/**************************************************************************** + * graphics/color/nxglib_yuv2rgb.c + * + * Copyright (C) 2008-2009, 2011 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <stdint.h> +#include <debug.h> +#include <fixedmath.h> + +#include <nuttx/nx/nxglib.h> + +/**************************************************************************** + * Pre-Processor Definitions + ****************************************************************************/ + +#define b16_P3441 0x0000581a /* 0.344147 */ +#define b16_P7141 0x0000b6d2 /* 0.714142 */ +#define b16_1P402 0x000166ea /* 1.402008 */ +#define b16_1P772 0x0001c5a2 /* 1.722003 */ +#define b16_128P0 0x00800000 /* 128.000000 */ + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Private Data + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: nxgl_yuv2rgb + * + * Description: + * Convert 8-bit RGB triplet to 8-bit YUV triplet + * + ****************************************************************************/ + +void nxgl_yuv2rgb(uint8_t y, uint8_t u, uint8_t v, + uint8_t *r, uint8_t *g, uint8_t *b) +{ + b16_t vm128 = itob16(v) - b16_128P0; + b16_t um128 = itob16(u) - b16_128P0; + + /* Per the JFIF specification: + * + * R = Y + 1.40200 * (V - 128.0) + * G = Y - 0.34414 * (U - 128.0) - 0.71414 * (V - 128.0) + * B = Y + 1.77200 * (U - 128.0) + */ + + *r = (uint8_t)b16toi(itob16(y) + b16muli(b16_1P402, vm128)); + *g = (uint8_t)b16toi(itob16(y) - b16muli(b16_P3441, um128) - b16muli(b16_P7141, vm128)); + *b = (uint8_t)b16toi(itob16(y) + b16muli(b16_1P772, um128)); +} |