nuttx/libs/libnx/nxglib/nxglib_yuv2rgb.c
Alin Jerpelea 88fa869a04 libnx: Author Gregory Nutt: update licenses to Apache
Gregory Nutt has submitted the SGA and we can migrate the licenses
 to Apache.

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
2021-02-25 01:44:30 -08:00

72 lines
2.7 KiB
C

/****************************************************************************
* libs/libnx/nxglib/nxglib_yuv2rgb.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* 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 */
/****************************************************************************
* 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));
}