一个采用framebuffer方式显示的例子，最基础的显示点

#include <unistd.h> #include <stdio.h> #include <fcntl.h> #include <linux/fb.h> #include <sys/mman.h> int main () { int fp=0; struct fb_var_screeninfo vinfo; struct fb_fix_screeninfo finfo; long screensize=0; char *fbp = 0; int x = 0, y = 0; long location = 0; fp = open ("/dev/fb0",O_RDWR); if (fp < 0){ printf("Error : Can not open framebuffer device\n"); exit(1); } if (ioctl(fp,FBIOGET_FSCREENINFO,&finfo)){ printf("Error reading fixed information\n"); exit(2); } if (ioctl(fp,FBIOGET_VSCREENINFO,&vinfo)){ printf("Error reading variable information\n"); exit(3); } screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8; /*这就是把fp所指的文件中从开始到screensize大小的内容给映射出来，得到一个指向这块空间的指针*/ fbp =(char *) mmap (0, screensize, PROT_READ | PROT_WRITE, MAP_SHARED, fp,0); if ((int) fbp == -1) { printf ("Error: failed to map framebuffer device to memory.\n"); exit (4); } /*这是你想画的点的位置坐标,(0，0)点在屏幕左上角*/ x = 100; y = 100; location = x * (vinfo.bits_per_pixel / 8) + y * finfo.line_length; *(fbp + location) = 100; /* 蓝色的色深 */ /*直接赋值来改变屏幕上某点的颜色*/ *(fbp + location + 1) = 15; /* 绿色的色深*/ *(fbp + location + 2) = 200; /* 红色的色深*/ *(fbp + location + 3) = 0; /* 是否透明*/ munmap (fbp, screensize); /*解除映射*/ close (fp); /*关闭文件*/ return 0; }