LCD测试程序

/*

 * LCD测试程序

 * 测试linux下LCD驱动是否正确

 * 时间:2011-11-10

 */

 

#include

#include

#include

#include

#include

 

int main()

{

    int fbfd = 0;

    struct fb_var_screeninfo vinfo;

    struct fb_fix_screeninfo finfo;

    long int screensize = 0;

    char *fbp = 0;

    int x = 0, y = 0;

    long int location = 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;

    //bits_per_pixel 为位数，一个字节为8位，bits_per_pixel/8 为一个像素占用的字节数

    // 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");

 

    x = 100; y = 100;       // Where we are going to put the pixel

 

    // Figure out where in memory to put the pixel

    for (y = 100; y < 300; y++)

        for (x = 100; x < 300; x++) {

                            // 计算出显示坐标在分配内存区域的位置

            location = (x+vinfo.xoffset) * (vinfo.bits_per_pixel/8) +

                       (y+vinfo.yoffset) * finfo.line_length;

      // line_length= xres*bits_per_pixel/8

            if (vinfo.bits_per_pixel == 32) {

                *(fbp + location) = 100;        // Some blue

                *(fbp + location + 1) = 15+(x-100)/2;     // A little green

                *(fbp + location + 2) = 200-(y-100)/5;    // A lot of red

                *(fbp + location + 3) = 0;      // No transparency

             // 24色需要4个字节填充，第四个字节填空

            } else  { //assume 16bpp

                int b = 10;

                int g = (x-100)/6;     // A little green

                int r = 31-(y-100)/16;    // A lot of red

                unsigned short int t = r<<11 | g << 5 | b;

                *((unsigned short int*)(fbp + location)) = t; //强制转换为16位

           // 16 色需要2个字节填充，看是565 还是5551 格式

            }

 

        }

    munmap(fbp, screensize);

    close(fbfd);

    return 0;

}

 

源码： lcd.rar