fbtest.c

来自「linux下操作framebuffer的例子」· C语言 代码 · 共 160 行

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

#define FBDEV "/dev/fb0"
static char * default_framebuffer = FBDEV;

struct fb_dev
{
	int fb;
	void * fb_mem;
	int fb_width,fb_height,fb_line_len,fb_size;
	int fb_bpp;
};

static struct fb_dev fbdev;
#if 0
static void draw(int color)
{
	int i,j;
	unsigned short int *p = (unsigned short int*)fbdev.fb_mem;

	for(i=0;i<fbdev.fb_height;i++,p+=fbdev.fb_line_len/2)
	{
		for(j=0;j<fbdev.fb_width;j++)
			p[j] = color;
	}

}
#endif

static void draw(void)
{
	int i,j;
	unsigned short int *p = (unsigned short int *)fbdev.fb_mem;
	
	for(i=0;i<fbdev.fb_height;i++)
	{
		if(i<fbdev.fb_height/2)
			for(j=0;j<fbdev.fb_width;j++)
				*p++ = 0xf800;
		else
			for(j=1;j<fbdev.fb_width;j++)
				*p++ = 0x1f;
	}				
}			
int framebuffer_open(void)
{
	int fb;
	struct fb_var_screeninfo fb_vinfo;
	struct fb_fix_screeninfo fb_finfo;
	char * fb_dev_name = NULL;

	if(!(fb_dev_name = getenv("FRAMEBUFFER")))
		fb_dev_name = default_framebuffer;

	fb = open(fb_dev_name,O_RDWR);
	if(fb<0)
	{
		printf("device %s open failed\n",fb_dev_name);
		return -1;
	}

	if(ioctl(fb,FBIOGET_VSCREENINFO,&fb_vinfo))
	{
		printf("Can't get VSCREENINFO:%s\n",strerror(errno));
		close(fb);
		return -1;
	}
	ioctl(fb, FBIOPUT_VSCREENINFO, &fb_vinfo);

	if(ioctl(fb,FBIOGET_FSCREENINFO,&fb_finfo))
	{
		printf("Can't get FSCREENINFO:%s\n",strerror(errno));
		return -1;
	}

	fbdev.fb_bpp = fb_vinfo.red.length + fb_vinfo.green.length + fb_vinfo.blue.length + fb_vinfo.transp.length;

	fbdev.fb_width = fb_vinfo.xres;
	fbdev.fb_height = fb_vinfo.yres;
	fbdev.fb_line_len = fb_finfo.line_length;
	fbdev.fb_size = fb_finfo.smem_len;


	printf("frame buffer:%d(%d)x%d,%dbpp,0x%xbyte\n",fbdev.fb_width,fbdev.fb_line_len,fbdev.fb_height,fbdev.fb_bpp,fbdev.fb_size);
	if(fbdev.fb_bpp !=16)
	{
		printf("frame buffer must be 16bpp mode\n");
		exit(0);
	}

	fbdev.fb_mem = mmap(NULL,fbdev.fb_size,PROT_READ|PROT_WRITE,MAP_SHARED,fb,0);
	if(fbdev.fb_mem == NULL || (int)fbdev.fb_mem == -1)
	{
		fbdev.fb_mem = NULL;
		printf("mmap failed\n");
		close(fb);
		return -1;
	}

	fbdev.fb = fb;
	memset(fbdev.fb_mem,0x0,fbdev.fb_size);
	return 0;
}

void framebuffer_close()
{
	if(fbdev.fb_mem)
	{
		munmap(fbdev.fb_mem,fbdev.fb_size);
		fbdev.fb_mem = NULL;
	}
	if(fbdev.fb)
	{
		close(fbdev.fb);
		fbdev.fb =0;
	}
}


int main(void)
{
//	int i;
	framebuffer_open();
#if 0
	for(i=0;i<16;i++)
	{
		printf("%d,color=0x%x",i,i<<i);
		draw(1<<i);
		getchar();
	
	}
#endif
	draw();
	framebuffer_close();
	return 0;
}