framebuffer測試程式

#include <unistd.h>    #include <stdio.h>    #include <fcntl.h>    #include <linux/fb.h>    #include <sys/mman.h>#define fb_write16(b,addr) (*(volatile unsigned short int *) (addr) = (b))
unsigned short int color_lut[16] = {0x0000,
/* 0x0000, 0 oúé«*/0x0015,
/* 0x0015,  1 à¶é«*/0x07f5,
/* 0x07F5,  2*/0xfb40,
/* 0xFB40,  3*/0x0661,
/* 0x0661,  4*/0xd45f,
/* 0xD45F,  5*/0x6af3,
/* 0x6A3F,  6*/0xdefb,
/* 0xDEFB,  7*/0x2570,
/* 0x2570,  8*/0x057f,
/* 0x057F,  9*/0x57ea,
/* 0x57EA,  10*/0x57ff,
/* 0x57FF,  11*/0xf800,
/* 0xF800,  12*/0xfabf,
/* 0xFABF,  13*/0xffea,
/* 0xFFEA,  14*/0xffff,
/* 0xFFFF   15*/};
int fbfd = 0;char *fbp = 0;long int location = 0;struct fb_var_screeninfo vinfo;struct fb_fix_screeninfo finfo;void draw_rect();
int main(){        int i = 0;        long int screensize = 0;               // Open the file for reading and writing        fbfd = open("/dev/fb0", O_RDWR);        if (!fbfd) {            printf("Error: cannot open framebuffer device.\n");            exit(1);        }        printf("The framebuffer device was opened successfully.\n");
        // Get fixed screen information        if (ioctl(fbfd, FBIOGET_FSCREENINFO, &finfo)) {            printf("Error reading fixed information.\n");            exit(2);        }
        // Get variable screen information        if (ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {            printf("Error reading variable information.\n");            exit(3);        }
        printf("%dx%d, %dbpp\n", vinfo.xres, vinfo.yres, vinfo.bits_per_pixel);
        // Figure out the size of the screen in bytes        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);        }        printf("The framebuffer device was mapped to memory successfully.\n");draw_rect();
        munmap(fbp, screensize);        close(fbfd);        return 0;    }void draw_rect(){unsigned char *dst;unsigned int location;int x, y;printf("line length %d,xoffset %d\n",finfo.line_length,vinfo.xoffset);
for( y = 0; y < vinfo.yres; y++ ) {for( x = 0; x < vinfo.xres; x++ ){location=y*finfo.line_length+(x+vinfo.xoffset)*(vinfo.bits_per_pixel/8);dst=fbp+location; fb_write16(color_lut[x/40], dst);}   
 }return;}