Linux: Framebuffer测试程序

最新推荐文章于 2024-12-15 19:28:12 发布

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最新推荐文章于 2024-12-15 19:28:12 发布

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本文介绍了一个简单的C语言程序，用于在24位模式下通过fb设备接口填充颜色到帧缓冲区。用户可以通过指定红、绿、蓝三个颜色通道的值来设置屏幕背景色。

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fb设为24位模式：

fbset -fb /dev/fb0 -g 800 600 800 600 24 -n

用r g b填充fb：

use-fb 255 0 0 //red

use-fb 0 255 0 //green

...

use-fb.c 代码:

/* use-fb.c*/

#include <stdio.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <sys/mman.h>
#include <stdlib.h>

struct fb_var_screeninfo vinfo;

int
main(int argc, char *argv[])
{
int fbfd, fbsize, i;
int red, green, blue;
unsigned char *fbbuf;

if (argc != 4) {
printf("usage: use-fb red green blue/n");
exit(0);
}
red = atoi(argv[1]);
green = atoi(argv[2]);
blue = atoi(argv[3]);

/* Open video memory */
if ((fbfd = open("/dev/fb0", O_RDWR)) < 0) {
exit(1);
}
/* Get variable display parameters */
if (ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {
printf("Bad vscreeninfo ioctl/n");
exit(2);
}
/* Size of frame buffer */
fbsize = vinfo.xres*vinfo.yres*(vinfo.bits_per_pixel/8);
/* Map video memory */
if ((fbbuf = mmap(0, fbsize, PROT_READ | PROT_WRITE,
MAP_SHARED, fbfd, 0)) == (void *) -1) {
exit(3);
}
/* Clear the screen */
for (i = 0; i < fbsize; i++) {
*(fbbuf + i++) = red;
*(fbbuf + i++) = green;
*(fbbuf + i) = blue;
}

printf("clear screen with rgb:%s %s %s/n", argv[1], argv[2], argv[3]);
munmap(fbbuf, fbsize);
close(fbfd);
}