我想从中捕获屏幕截图FrameBuffer，Android我使用下面的代码，但只是得到了一个模糊的图像。我包含 3 个主要步骤。首先，从中读取数据和信息FrameBuffer，其次，将原始数据转换为 24 位，第三，构造 BITMAP 结构并写入bmp文件。但是我得到了模糊的图像，有人可以帮忙吗？我会很感激的。
#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 {
WORD bfType;
DWORD bfSize;
WORD bfReserved1;
WORD bfReserved2;
DWORD bfOffBits;
}__attribute__((packed)) BITMAPFILEHEADER, *PBITMAPFILEHEADER;
typedef struct tagBITMAPINFOHEADER {
DWORD biSize;
LONG biWidth;
LONG biHeight;
WORD biPlanes;
WORD biBitCount;
DWORD biCompression;
DWORD biSizeImage;
LONG biXPelsPerMeter;
LONG biYPelsPerMeter;
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/graphics/fb0"
int take_screenshot(char *path)
{
int i;
int img_fd, fb_fd;
int data_size;
char *img_buf;
struct fb_var_screeninfo var_info;
struct fb_fix_screeninfo fix_info;
BITMAPFILEHEADER file_head;
BITMAPINFOHEADER info_head;
//RGBQUAD rgb_quad;
/*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);
if (ioctl(fb_fd, FBIOGET_FSCREENINFO, &fix_info)){
debug("Error reading fixed information\n");
close(img_fd);
return 0;
}
img_fd = open(path, 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 = 0;
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 = 0;
info_head.biBitCount = 24;
info_head.biCompression = 0;
info_head.biSizeImage = data_size;
info_head.biXPelsPerMeter = 3780;
info_head.biYPelsPerMeter = 3780;
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));
/*********************/
int w, h;
int depth;
unsigned short *bits;
w = var_info.xres;
h = var_info.yres;
depth = var_info.bits_per_pixel;
uint8_t *rgb24;
if (depth == 16) {
rgb24 = (uint8_t *)malloc(w * h * 3);
int i = 0;
for ( ; i < w*h; i++) {
uint16_t pixel16 = ((uint16_t *)img_buf)[i];
// RRRRRGGGGGGBBBBBB -> RRRRRRRRGGGGGGGGBBBBBBBB
// in rgb24 color max is 2^8 per channel (*255/32 *255/64 *255/32)
rgb24[3*i+0] = (255*(pixel16 & 0x001F))/ 32; //Blue
rgb24[3*i+1] = (255*((pixel16 & 0x07E0) >> 5))/64; //Green
rgb24[3*i+2] = (255*((pixel16 & 0xF800) >> 11))/32; //Red
}
} else if (depth == 24) {
rgb24 = (uint8_t *)img_buf;
} else if (depth == 32) {
//skip transparency channel
rgb24 = (uint8_t *) malloc(w * h * 3);
int i=0;
for ( ; i <w*h; i++) {
uint32_t pixel32 = ((uint32_t *)img_buf)[i];
// in rgb24 color max is 2^8 per channel
rgb24[3*i+2] = pixel32 & 0x000000FF; //Blue
rgb24[3*i+1] = (pixel32 & 0x0000FF00) >> 8; //Green
rgb24[3*i+0] = (pixel32 & 0x00FF0000) >> 16; //Red
}
} else {
};
write(img_fd, rgb24, w*h*3);
close(fb_fd);
close(img_fd);
return 0;
}
