diff options
Diffstat (limited to 'nuttx/graphics/nxglib/nxglib_rgb2yuv.c')
-rw-r--r-- | nuttx/graphics/nxglib/nxglib_rgb2yuv.c | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/nuttx/graphics/nxglib/nxglib_rgb2yuv.c b/nuttx/graphics/nxglib/nxglib_rgb2yuv.c new file mode 100644 index 000000000..31eff23fa --- /dev/null +++ b/nuttx/graphics/nxglib/nxglib_rgb2yuv.c @@ -0,0 +1,103 @@ +/**************************************************************************** + * graphics/color/nxglib_rgb2yuv.c + * + * Copyright (C) 2008, 2011 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <gnutt@nuttx.org> + * + * 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_P0813 0x000014d0 /* 0.0813 */ +#define b16_P1140 0x00001d2f /* 0.1140 */ +#define b16_P1687 0x00002b30 /* 0.1687 */ +#define b16_P2990 0x00004c8b /* 0.2990 */ +#define b16_P3313 0x000054d0 /* 0.3313 */ +#define b16_P4187 0x00006b30 /* 0.4187 */ +#define b16_P5000 0x00008000 /* 0.5000 */ +#define b16_P5870 0x00009646 /* 0.5870 */ +#define b16_128P0 0x00800000 /* 128.0 */ + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Private Data + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: nxgl_rgb2yuv + * + * Description: + * Convert 8-bit RGB triplet to 8-bit YUV triplet + * + ****************************************************************************/ + +void nxgl_rgb2yuv(uint8_t r, uint8_t g, uint8_t b, + uint8_t *y, uint8_t *u, uint8_t *v) +{ + /* Per the JFIF specification: + * + * Y = (0.2990 * R) + (0.5870 * G) + (0.1140 * B) + * U = 128 - (0.1687 * R) - (0.3313 * G) + (0.5000 * B) + * V = 128 + (0.5000 * R) - (0.4187 * G) - (0.0813 * B); + */ + + *y = (uint8_t)b16toi(b16muli(b16_P2990, r) + b16muli(b16_P5870, g) + b16muli(b16_P1140, b)); + *u = (uint8_t)b16toi(b16_128P0 - b16muli(b16_P1687, r) - b16muli(b16_P3313, g) + b16muli(b16_P5000, b)); + *v = (uint8_t)b16toi(b16_128P0 + b16muli(b16_P5000, r) - b16muli(b16_P4187, g) - b16muli(b16_P0813, b)); +} |