论坛 › 嵌入式开发 › 分享一个把framebuffer当前内容存储成BMP图片的小程序

icebreaker7 发表于 2011-02-28 13:01

分享一个把framebuffer当前内容存储成BMP图片的小程序

写操作手册的时候可能会用到，抓出来的图片肯定比拿相机对着显示器照的效果要真实:em06: :em06: :em06:
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <sys/ioctl.h>


typedef unsigned char BYTE;
typedef unsigned short WORD;
typedef unsigned int DWORD;
typedef long LONG;


typedef struct tagBITMAPFILEHEADER {
WORDbfType;
DWORD bfSize;
WORDbfReserved1;
WORDbfReserved2;
DWORD bfOffBits;
}__attribute__((packed)) BITMAPFILEHEADER, *PBITMAPFILEHEADER;

typedef struct tagBITMAPINFOHEADER {
DWORD biSize;
LONGbiWidth;
LONGbiHeight;
WORDbiPlanes;
WORDbiBitCount;
DWORD biCompression;
DWORD biSizeImage;
LONGbiXPelsPerMeter;
LONGbiYPelsPerMeter;
DWORD biClrUsed;
DWORD biClrImportant;
}__attribute__((packed)) BITMAPINFOHEADER, *PBITMAPINFOHEADER;

typedef struct tagRGBQUAD {
BYTE rgbBlue;
BYTE rgbGreen;
BYTE rgbRed;
BYTE rgbReserved;
}__attribute__((packed)) RGBQUAD;


#define FRAME_BUFFER_PATH                "/dev/fb0"


int main(int argc, char *argv[])
{
        int i;
        int img_fd, fb_fd;
        int data_size;
        char *img_buf;
        struct fb_var_screeninfo var_info;
        BITMAPFILEHEADER file_head;
        BITMAPINFOHEADER info_head;
        //RGBQUAD rgb_quad;
       
        if (argc != 2)
        {
                printf("usage %s bmp_file\n", argv);
                return -1;
        }       
       
        /*open files*/
        fb_fd = open(FRAME_BUFFER_PATH, O_RDWR);
        if (img_fd < 0)
        {
                perror("open framebuff");
                return -1;
        }
        if (ioctl(fb_fd, FBIOGET_VSCREENINFO, &var_info) < 0)
        {
                perror("ioctl FBIOGET_VSCREENINFO");
                close(img_fd);
                return 0;
        }
        printf("xres %d, yres %d\n", var_info.xres, var_info.yres);
       
        img_fd = open(argv, O_RDWR | O_CREAT, 0644);
        if (img_fd < 0)
        {
                perror("open image");
                close(img_fd);
                return -1;
        }
       
        data_size = var_info.xres*var_info.yres*(var_info.bits_per_pixel/8);
        /*initialize bmp structs*/
        file_head.bfType = 0x4d42;
        file_head.bfSize = sizeof(file_head) + sizeof(info_head) + data_size;
        file_head.bfReserved1 = file_head.bfReserved2 = 0;
        file_head.bfOffBits = sizeof(file_head) + sizeof(info_head);
       
        info_head.biSize = sizeof(info_head);
        info_head.biWidth = var_info.xres;
        info_head.biHeight = var_info.yres;
        info_head.biPlanes = 1;
        info_head.biBitCount = var_info.bits_per_pixel;
        info_head.biCompression = 0;
        info_head.biSizeImage = 0;
        info_head.biXPelsPerMeter = 0;
        info_head.biYPelsPerMeter = 0;
        info_head.biClrUsed = 0;
        info_head.biClrImportant = 0;
       
        img_buf = (char *)malloc(data_size);
        if (img_buf == NULL)
        {
                printf("malloc failed!\n");
                close(fb_fd);
                close(img_fd);
                return -1;
        }

/*read img data and */
read(fb_fd, img_buf, data_size);

write(img_fd, &file_head, sizeof(file_head));
write(img_fd, &info_head, sizeof(info_head));

/*revese img and write to file*/
for (i = 0; i < var_info.yres; i++)
{
        write(img_fd, img_buf + var_info.xres*(var_info.yres-i-1)*(var_info.bits_per_pixel/8),
                var_info.xres*(var_info.bits_per_pixel/8));
}

close(fb_fd);
        close(img_fd);
        return 0;
}

sugelawa 发表于 2013-10-03 18:05

为什么截图是模糊和错位的？

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