整理:android 读取 屏幕 图形 fb0

<h2 class="titName SG_txta" style="">Android下截屏 及 格式转换</h2>/dev/graphics/fb0 fb0dd bs=$((320*320*2)) count=2 if=fb0 of=screenshot1.xmp./565to888 <screenshot1.xmp >screenshot888.xmpconvert -depth 8 -size 216x204 rgb:screenshot888.xmp  screenshot888.png#display /tmp/screenshot888.png

http://wiseideal.iteye.com/blog/1250175

#include <unistd.h>#include <stdio.h>#include <fcntl.h>#include <linux/fb.h>#include <sys/mman.h>int version = 0;inline static unsigned short int make16color(unsigned char r, unsigned char g, unsigned char b){    return ( (((r >> 3) & 31) << 11) | (((g >> 2) & 63) << 5)  |  ((b >> 3) & 31)        );}int main() {    int fbfd = 0;    struct fb_var_screeninfo vinfo;    struct fb_fix_screeninfo finfo;    long int screensize = 0; char *fbp = 0;    long int x = 0, y = 0;    int guage_height = 20, step = 10;    long int location = 0;    // Open the file for reading and writing    fbfd = open("/dev/graphics/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("id %s\n",finfo.id);       //s3c2410fb    printf("smem_start %ld\n",finfo.smem_start); //帧缓冲 内存开始地址,物理地址    printf("smem_len %d\n",finfo.smem_len); // 帧缓冲 内存 长度    printf("type %d\n",finfo.type);    printf("type_aux %d\n",finfo.type_aux);//平面交织交替    printf("visual %d\n",finfo.visual); //记录 色彩模式   2    printf("xpanstep %d\n",finfo.xpanstep);//如果没有硬件panning，赋0    printf("ypanstep %d\n",finfo.ypanstep);    printf("line_length %d\n",finfo.line_length);    //640    printf("mmio_start %ld\n",finfo.mmio_start);//内存映射IO开始地址 物理地址    printf("mmio_len %d\n",finfo.mmio_len);//内存映射IO 长度    printf("accel %d\n\n",finfo.accel);        printf("xres %d\n",vinfo.xres); //可见解析度  320    printf("yres %d\n",vinfo.yres);            //240    printf("xres_virturl %d\n",vinfo.xres_virtual); //虚拟解析度  320    printf("yres_virtual %d\n",vinfo.yres_virtual);              //240    printf("xoffset %d\n",vinfo.xoffset); //虚拟到可见的偏移        0    printf("yoffset %d\n",vinfo.yoffset);                        // 0    printf("bits_per_pixel %d\n",vinfo.bits_per_pixel); //每像素位数 bpp  16    printf("grayscale %d\n",vinfo.grayscale);//非零时，指灰度        printf("fb_bitfield red.offset %d\n",vinfo.red.offset);     //11  偏移11位    printf("fb_bitfield .length %d\n",vinfo.red.length);        // 5    printf("fb_bitfield .msb_right %d\n",vinfo.red.msb_right);  //  0    printf("fb_bitfield green.offset %d\n",vinfo.green.offset);  //5 偏移5位    printf("fb_bitfield .length %d\n",vinfo.green.length);       // 6    printf("fb_bitfield .msb_right %d\n",vinfo.green.msb_right); // 0    printf("fb_bitfield blue.offset %d\n",vinfo.blue.offset);    printf("fb_bitfield .length %d\n",vinfo.blue.length);    printf("fb_bitfield .msb_right %d\n",vinfo.blue.msb_right);    printf("fb_bitfield transp.offset %d\n",vinfo.transp.offset);    printf("fb_bitfield .length %d\n",vinfo.transp.length);    printf("fb_bitfield .msb_right %d\n",vinfo.transp.msb_right);    printf("nonstd %d\n",vinfo.nonstd); //!=0 非标准像素格式    printf("activate %d\n",vinfo.activate);    printf("height %d\n",vinfo.height); //高度/  240    printf("widht %d\n",vinfo.width);   //          320    printf("accel_flags %d\n",vinfo.accel_flags); //看 fb_info.flags    //定时，除了 pixclock之外，其他的都以像素时钟为单位    printf("pixclock %d\n",vinfo.pixclock);//像素时钟，皮秒   80000    printf("left_margin %d\n",vinfo.left_margin);//行切换：从同步到绘图之间的延迟    28    printf("right_margin %d\n",vinfo.right_margin);//行切换：从绘图到同步之间的延迟   24    printf("upper_margin %d\n",vinfo.upper_margin);//帧切换：从同步到绘图之间的延迟   6    printf("lower_margin %d\n",vinfo.lower_margin);//帧切换：从绘图到同步之间的延迟    2    printf("hsync_len %d\n",vinfo.hsync_len); //hor 水平同步的长度         42    printf("vsync_len %d\n",vinfo.vsync_len); //vir 垂直同步的长度         12    printf("sync %d\n",vinfo.sync); //    printf("vmode %d\n",vinfo.vmode);    printf("rotate %d\n",vinfo.rotate);    // Figure out the size of the screen in bytes    screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8;;printf("screensize = %ld\n", screensize);    // Map the device to memory    fbp = (char *)mmap(0, screensize*2, 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");/*printf("White Screen\n");//while(1){for(x =0;x<640*5;x+=2){*((unsigned short int*)(fbp + x)) = 0xffff;}usleep(200);}for(x =0;x<640;x+=2){y =*((unsigned short int*)(fbp + x));printf("x = %lx, temp = %lx\n", x, y);}*/ //set to black color first memset(fbp, 0, screensize);    //draw rectangle    y = (vinfo.yres - guage_height) / 2 - 2;       // Where we are going to put the pixel    for (x = step - 2; x < vinfo.xres - step + 2; x++) {        location = (x+vinfo.xoffset) * (vinfo.bits_per_pixel/8) +                       (y+vinfo.yoffset) * finfo.line_length;        *((unsigned short int*)(fbp + location)) = 255;    }    y = (vinfo.yres + guage_height) / 2 + 2;       // Where we are going to put the pixel    for (x = step - 2; x < vinfo.xres - step + 2; x++) {        location = (x+vinfo.xoffset) * (vinfo.bits_per_pixel/8) +                       (y+vinfo.yoffset) * finfo.line_length;        *((unsigned short int*)(fbp + location)) = 255;    }    x = step - 2;    for (y = (vinfo.yres - guage_height) / 2 - 2; y < (vinfo.yres + guage_height) / 2 + 2; y++) {        location = (x+vinfo.xoffset) * (vinfo.bits_per_pixel/8) +                       (y+vinfo.yoffset) * finfo.line_length;        *((unsigned short int*)(fbp + location)) = 255;    }    x = vinfo.xres - step + 2;    for (y = (vinfo.yres - guage_height) / 2 - 2; y < (vinfo.yres + guage_height) / 2 + 2; y++) {        location = (x+vinfo.xoffset) * (vinfo.bits_per_pixel/8) +                       (y+vinfo.yoffset) * finfo.line_length;        *((unsigned short int*)(fbp + location)) = 255;    }       // Figure out where in memory to put the pixel    for ( x = step; x < vinfo.xres - step; x++ ) {        for ( y = (vinfo.yres - guage_height) / 2; y < (vinfo.yres + guage_height) / 2; y++ ) {            location = (x+vinfo.xoffset) * (vinfo.bits_per_pixel/8) +                       (y+vinfo.yoffset) * finfo.line_length;            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            } else { //assume 16bpp                unsigned char b = 255 * x / (vinfo.xres - step);                unsigned char g = 255;     // (x - 100)/6 A little green                unsigned char r = 255;    // A lot of red                unsigned short int t = make16color(r, g, b);                *((unsigned short int*)(fbp + location)) = t;            }        }  printf("x = %d, temp = %ld\n", x, location);        //sleep to see it        usleep(200);    }    //clean framebuffer    munmap(fbp, screensize);    close(fbfd);version =16;printf("version %d  %s\n",version,__TIME__);    return 0;}

http://blog.csdn.net/louiswangbing/article/details/6655040