基于网上一个代码改的。

源地址：http://blog.csdn.net/z1179675084/article/details/14645359

// 注意，由于fb_bpp = 16的情况没用到，以下修改后的代码只调整了fb_bpp不为16的情况

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

static unsigned int capframe = 0;

static unsigned char filename[30];

FILE *bmpFile;

unsigned char bmp_head_t[] = {

0x42,0x4d,0x42,0x58,0x02,0x00,0x00,0x00,0x00,0x00,

0x42,0x00,0x00,0x00,0x28,0x00,0x00,0x00,0xf0,0x00,

0x00,0x00,0x40,0x01,0x00,0x00,0x01,0x00,0x10,0x00,

0x03,0x00,0x00,0x00,0x00,0x58,0x02,0x00,0x00,0x00,

0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,

0x00,0x00,0x00,0x00,0x00,0xf8,0x00,0x00,0xe0,0x07,

0x00,0x00,0x1f,0x00,0x00,0x00

};

static int fb_bpp;

//14byte

typedef struct

{

char cfType[2]; /* 文件类型, 必须为 "BM" (0x4D42)*/

unsigned int cfSize; /* 文件的大小(字节) */

unsigned int cfReserved; /* 保留, 必须为 0 */

unsigned int cfoffBits; /* 位图阵列相对于文件头的偏移量(字节)*/

}__attribute__((packed)) BITMAPFILEHEADER; /* 文件头结构 */

//40byte

typedef struct

{

unsigned int ciSize; /* size of BITMAPINFOHEADER */

unsigned int ciWidth; /* 位图宽度(像素) */

unsigned int ciHeight; /* 位图高度(像素) */

unsigned short ciPlanes; /* 目标设备的位平面数, 必须置为1 */

unsigned short ciBitCount; /* 每个像素的位数, 1,4,8或24 */

unsigned int ciCompress; /* 位图阵列的压缩方法,0=不压缩 */

unsigned int ciSizeImage; /* 图像大小(字节) */

unsigned int ciXPelsPerMeter;/* 目标设备水平每米像素个数 */

unsigned int ciYPelsPerMeter;/* 目标设备垂直每米像素个数 */

unsigned int ciClrUsed; /* 位图实际使用的颜色表的颜色数 */

unsigned int ciClrImportant; /* 重要颜色索引的个数 */

}__attribute__((packed)) BITMAPINFOHEADER; /* 位图信息头结构 */

BITMAPFILEHEADER FileHead;

BITMAPINFOHEADER InfoHead;

unsigned char bmp_head[54];

static int fb_fp = -1;

static char *fb_addr = NULL;

int width=0;

int height=0;

static inline int fb_init(void)

{

int dev_fp = -1;

int fb_size;

struct fb_var_screeninfo vinfo;

dev_fp = open("/dev/fb0", O_RDWR);

if (dev_fp < 0) {

perror("/dev/fb0");

return -1;

}

if (ioctl(dev_fp, FBIOGET_VSCREENINFO, &vinfo)) {

printf("Error reading variable information.\n");

exit(1);

}

width=vinfo.xres;

height=vinfo.yres;

fb_bpp=vinfo.bits_per_pixel;

//if(fb_bpp==24) fb_bpp=32;

fb_size=width*height*fb_bpp/8;

if ((fb_addr = (char*)mmap(0, fb_size,

PROT_READ | PROT_WRITE, MAP_SHARED, dev_fp, 0)) < 0) {

perror("mmap()");

return -1;

}

printf("%dx%d bpp:%d mmaped 0x%08x\n",width,height,fb_bpp,fb_addr);

return dev_fp;

}

void writeImageToFile(unsigned int size)

{

sprintf(filename,"/mnt/sd/0%d.bmp",capframe);

bmpFile=fopen(filename, "w+");

if(fb_bpp == 16)

fwrite(bmp_head_t,1,66,bmpFile);

else

{

fwrite(&FileHead,1,14,bmpFile);

fwrite(&InfoHead,1,40,bmpFile);

}

//fwrite(fb_addr,1,size,bmpFile);

int h = 0;

for (h = height-1; h > 0; h--)

{

fwrite(fb_addr + h * width*fb_bpp/8, 1, width*fb_bpp/8, bmpFile);

}

fclose(bmpFile);

printf("%s\n", filename);

}

int main(int argc, char *argv[])

{

unsigned int i = 10;

unsigned long size = 0;

fb_fp = fb_init();

size=width*height*fb_bpp/8;

if (argc < 2)

{

printf("run like 'prntscr num', num is bmpname'\n");

return 0;

}

capframe = atoi(argv[1]);

if(fb_bpp==16){

*((unsigned int*)(bmp_head_t+18)) = width;

*((unsigned int*)(bmp_head_t+22)) = height;

*((unsigned short*)(bmp_head+28)) = 16;

}else{

FileHead.cfType[0] = 'B';

FileHead.cfType[1] = 'M';

unsigned int tmp = width*height*fb_bpp/8;+54;

FileHead.cfSize = tmp;

FileHead.cfoffBits = 54;

InfoHead.ciSize = 40;

InfoHead.ciWidth = width;

InfoHead.ciHeight = height;

InfoHead.ciBitCount = 32;

InfoHead.ciCompress = 0;

InfoHead.ciSizeImage = size;

}

//while(i--)

{

writeImageToFile(size);

}

return 0;

}