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- /****************************************************************************
- * libs/libnx/nxglib/nxglib_yuv2rgb.c
- *
- * Copyright (C) 2008-2009, 2011, 2013 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_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));
- }
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