FrameBuffer编程二（简单程序下）

1、开发平台sc6410,编译器arm-linux-gcc 4.3

以下为源代码：

#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <linux/types.h>
#include <linux/fb.h>
#include <linux/videodev2.h>

int main(int argc ,char *argv[])
{
    int fbfd = 0;
    struct fb_var_screeninfo vinfo;
    struct fb_fix_screeninfo finfo;
    long int screensize = 0;
    char *fbp = NULL;
    int x = 0 , y = 0;
    long int location = 0 ;
    int sav = 0;

//open framebuffer device
    fbfd = open("/dev/fb0",O_RDWR);
    if(!fbfd){
            printf("Error:cannot open the framebuffer device!\n");
            exit(1);
        }   
    printf("well you open the framebuffer sucessful!\n");
//get the fixed screen information
    if(ioctl(fbfd,FBIOGET_FSCREENINFO,&finfo)){
            printf("Error reading fixed information\n");
            exit(2);
        }
//get the variable screen information
    if(ioctl(fbfd,FBIOGET_VSCREENINFO,&vinfo)){
            printf("Error reading variable information\n");
            exit(3);
        }
//show these information
    printf("vinfo.xres=%d\n",vinfo.xres);
    printf("vinfo.yres=%d\n",vinfo.yres);
    printf("vinfo.bit_per_bits=%d\n",vinfo.bits_per_pixel);
    printf("vinfo.xoffset=%d\n",vinfo.xoffset);
    printf("vinfo.yoffset=%d\n",vinfo.yoffset);
    printf("finfo.line_length=%d\n",finfo.line_length);   
    screensize = vinfo.xres*vinfo.yres*vinfo.bits_per_pixel/8;

//map the device to memory
    fbp = (char *)mmap(0,screensize,PROT_READ|PROT_WRITE,MAP_SHARED,fbfd,0);
    if((int)fbp == -1){
        printf("Error:failed to map framebuffer device to memory\n");
        exit(4);
    }
    memset(fbp,0,screensize);
//plot the screen the colour for black
    for(x=0;x<vinfo.xres;x++)
        for(y=0;y<vinfo.yres;y++){
            location =(x+vinfo.xoffset)*(vinfo.bits_per_pixel/8)+(y+vinfo.yoffset)*finfo.line_length;
            *(fbp+location)=0xFF;
            *(fbp+location+1)=0x00;
            }   
    sleep(10);
//release the memory
    munmap(fbp,screensize);
    close(fbfd);
    return 0;
}

编译下载到开发板上运行的结果截图为(而你的开发板的显示屏会变蓝色)：