bmp_show_framebuffer
作者:互联网
bmp_show_framebuffer
bmp_show_framebuffer.c
#include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <string.h> #include <linux/fb.h> #include <sys/mman.h> #include <sys/ioctl.h> #include <arpa/inet.h> #include <errno.h> //14byte文件头 typedef struct { char cfType[2]; //文件类型,"BM"(0x4D42) int cfSize; //文件大小(字节) int cfReserved; //保留,值为0 int cfoffBits; //数据区相对于文件头的偏移量(字节) }__attribute__((packed)) BITMAPFILEHEADER; //__attribute__((packed))的作用是告诉编译器取消结构在编译过程中的优化对齐 //40byte信息头 typedef struct { char ciSize[4]; //BITMAPFILEHEADER所占的字节数 int ciWidth; //宽度 int ciHeight; //高度 char ciPlanes[2]; //目标设备的位平面数,值为1 int ciBitCount; //每个像素的位数 char ciCompress[4]; //压缩说明 char ciSizeImage[4]; //用字节表示的图像大小,该数据必须是4的倍数 char ciXPelsPerMeter[4]; //目标设备的水平像素数/米 char ciYPelsPerMeter[4]; //目标设备的垂直像素数/米 char ciClrUsed[4]; //位图使用调色板的颜色数 char ciClrImportant[4]; //指定重要的颜色数,当该域的值等于颜色数时(或者等于0时),表示所有颜色都一样重要 }__attribute__((packed)) BITMAPINFOHEADER; typedef struct { unsigned char blue; unsigned char green; unsigned char red; unsigned char reserved; }__attribute__((packed)) PIXEL; //颜色模式RGB typedef struct { int fbfd; char *fbp; unsigned int xres; unsigned int yres; unsigned int xres_virtual; unsigned int yres_virtual; unsigned int xoffset; unsigned int yoffset; unsigned int bpp; unsigned long line_length; unsigned long size; struct fb_bitfield red; struct fb_bitfield green; struct fb_bitfield blue; } FB_INFO; typedef struct { unsigned int width; unsigned int height; unsigned int bpp; unsigned long size; unsigned int data_offset; } IMG_INFO; FB_INFO fb_info; IMG_INFO img_info; int show_bmp(char *img_name); static int cursor_bitmap_format_convert(char *dst,char *src, unsigned long img_len_one_line) { int img_len ,fb_len ; char *p; __u32 val; PIXEL pix; p = (char *)&val; img_len = img_info.width; /*一行图片的长度*/ fb_len = fb_info.xres; /*一行显示屏的长度*/ /*进行x轴的偏移*/ dst += fb_info.xoffset * (fb_info.bpp / 8); fb_len -= fb_info.xoffset; /*bmp 数据是上下左右颠倒的,这里只进行左右的处理*/ /*先定位到图片的最后一个像素的地址,然后往第一个像素的方向处理,进行左右颠倒的处理*/ src += img_len_one_line - 1; /*处理一行要显示的数据*/ while(1) { if (img_info.bpp == 32) pix.reserved = *(src--); pix.red = *(src--); pix.green = *(src--); pix.blue = *(src--); val = 0x00; val |= (pix.red >> (8 - fb_info.red.length)) << fb_info.red.offset; val |= (pix.green >> (8 - fb_info.green.length)) << fb_info.green.offset; val |= (pix.blue >> (8 - fb_info.blue.length)) << fb_info.blue.offset; if (fb_info.bpp == 16) { *(dst++) = *(p + 0); *(dst++) = *(p + 1); } else if (fb_info.bpp == 24) { *(dst++) = *(p + 0); *(dst++) = *(p + 1); *(dst++) = *(p + 2); } else if (fb_info.bpp == 32) { *(dst++) = *(p + 0); *(dst++) = *(p + 1); *(dst++) = *(p + 2); *(dst++) = *(p + 3); } /*超过图片长度或显示屏长度认为一行处理完了*/ img_len--; fb_len--; if (img_len <= 0 || fb_len <= 0) break; } #if 0 printf("r = %d\n", pix.red); printf("g = %d\n", pix.green); printf("b = %d\n", pix.blue); #endif return 0; } int show_bmp(char *img_name) { FILE *fp; int ret = 0; BITMAPFILEHEADER FileHead; BITMAPINFOHEADER InfoHead; if(img_name == NULL) { printf("img_name is null\n"); return -1; } fp = fopen( img_name, "rb" ); if(fp == NULL) { printf("img[%s] open failed\n", img_name); ret = -1; goto err_showbmp; } /* 移位到文件头部 */ fseek(fp, 0, SEEK_SET); ret = fread(&FileHead, sizeof(BITMAPFILEHEADER), 1, fp); if ( ret != 1) { printf("img read failed\n"); ret = -1; goto err_showbmp; } //检测是否是bmp图像 if (memcmp(FileHead.cfType, "BM", 2) != 0) { printf("it's not a BMP file[%c%c]\n", FileHead.cfType[0], FileHead.cfType[1]); ret = -1; goto err_showbmp; } ret = fread( (char *)&InfoHead, sizeof(BITMAPINFOHEADER),1, fp ); if ( ret != 1) { printf("read infoheader error!\n"); ret = -1; goto err_showbmp; } img_info.width = InfoHead.ciWidth; img_info.height = InfoHead.ciHeight; img_info.bpp = InfoHead.ciBitCount; img_info.size = FileHead.cfSize; img_info.data_offset = FileHead.cfoffBits; printf("img info w[%d] h[%d] bpp[%d] size[%ld] offset[%d]\n", img_info.width, img_info.height, img_info.bpp, img_info.size, img_info.data_offset); if (img_info.bpp != 24 && img_info.bpp != 32) { printf("img bpp is not 24 or 32\n"); ret = -1; goto err_showbmp; } /* *一行行处理 */ char *buf_img_one_line; char *buf_fb_one_line; char *p; int fb_height; long img_len_one_line = img_info.width * (img_info.bpp / 8); long fb_len_one_line = fb_info.line_length; printf("img_len_one_line = %d\n", img_len_one_line); printf("fb_len_one_line = %d\n", fb_info.line_length); buf_img_one_line = (char *)calloc(1, img_len_one_line + 256); if(buf_img_one_line == NULL) { printf("alloc failed\n"); ret = -1; goto err_showbmp; } buf_fb_one_line = (char *)calloc(1, fb_len_one_line + 256); if(buf_fb_one_line == NULL) { printf("alloc failed\n"); ret = -1; goto err_showbmp; } fseek(fp, img_info.data_offset, SEEK_SET); p = fb_info.fbp + fb_info.yoffset * fb_info.line_length; /*进行y轴的偏移*/ fb_height = fb_info.yres; while (1) { memset(buf_img_one_line, 0, img_len_one_line); memset(buf_fb_one_line, 0, fb_len_one_line); ret = fread(buf_img_one_line, 1, img_len_one_line, fp); if (ret < img_len_one_line) { /*图片读取完成,则图片显示完成*/ printf("read to end of img file\n"); cursor_bitmap_format_convert(buf_fb_one_line, buf_img_one_line, img_len_one_line); /*数据转换*/ memcpy(fb_info.fbp, buf_fb_one_line, fb_len_one_line); break; } cursor_bitmap_format_convert(buf_fb_one_line, buf_img_one_line, img_len_one_line); /*数据转换*/ memcpy(p, buf_fb_one_line, fb_len_one_line); /*显示一行*/ p += fb_len_one_line; /*超过显示屏宽度认为图片显示完成*/ fb_height--; if (fb_height <= 0) break; } free(buf_img_one_line); free(buf_fb_one_line); fclose(fp); return ret; err_showbmp: if (fp) fclose(fp); return ret; } int show_picture(char *img_name) { struct fb_var_screeninfo vinfo; struct fb_fix_screeninfo finfo; if (fb_info.fbfd <= -1) { printf("fb open fialed\n"); return -1; } if (ioctl(fb_info.fbfd, FBIOGET_FSCREENINFO, &finfo)) { printf("fb ioctl fialed\n"); return -1; } if (ioctl(fb_info.fbfd, FBIOGET_VSCREENINFO, &vinfo)) { printf("fb ioctl fialed\n"); return -1; } fb_info.xres = vinfo.xres; fb_info.yres = vinfo.yres; fb_info.xres_virtual = vinfo.xres_virtual; fb_info.yres_virtual = vinfo.yres_virtual; fb_info.xoffset = vinfo.xoffset; fb_info.yoffset = vinfo.yoffset; fb_info.bpp = vinfo.bits_per_pixel; fb_info.line_length = finfo.line_length; fb_info.size = finfo.smem_len; memcpy(&fb_info.red, &vinfo.red, sizeof(struct fb_bitfield)); memcpy(&fb_info.green, &vinfo.green, sizeof(struct fb_bitfield)); memcpy(&fb_info.blue, &vinfo.blue, sizeof(struct fb_bitfield)); printf("fb info x[%d] y[%d] x_v[%d] y_v[%d] xoffset[%d] yoffset[%d] bpp[%d] line_length[%ld] size[%ld]\n", fb_info.xres, fb_info.yres, fb_info.xres_virtual, fb_info.yres_virtual, fb_info.xoffset, fb_info.yoffset, fb_info.bpp, fb_info.line_length, fb_info.size); printf("fb info red off[%d] len[%d] msb[%d]\n", fb_info.red.offset, fb_info.red.length, fb_info.red.msb_right); printf("fb info green off[%d] len[%d] msb[%d]\n", fb_info.green.offset, fb_info.green.length, fb_info.green.msb_right); printf("fb info blue off[%d] len[%d] msb[%d]\n", fb_info.blue.offset, fb_info.blue.length, fb_info.blue.msb_right); if (fb_info.bpp != 16 && fb_info.bpp != 24 && fb_info.bpp != 32) { printf("fb bpp is not 16,24 or 32\n"); return -1; } if (fb_info.red.length > 8 || fb_info.green.length > 8 || fb_info.blue.length > 8) { printf("fb red|green|blue length is invalid\n"); return -1; } // 内存映射 fb_info.fbp = (char *)mmap(0, fb_info.size, PROT_READ | PROT_WRITE, MAP_SHARED, fb_info.fbfd, 0); if (fb_info.fbp == (char *)-1) { printf("mmap fialed\n"); return -1; } show_bmp(img_name); //删除映射 munmap(fb_info.fbp, fb_info.size); return 0; } int main(int argc, char **argv) { char img_name[64]; if (argc != 2) { printf("arg error\n"); return 0; } snprintf(img_name, sizeof(img_name), "%s", argv[1]); printf("img_name = %s\n", img_name); fb_info.fbfd = open("/dev/fb0", O_RDWR); if (!fb_info.fbfd) { printf("Error: cannot open framebuffer device(/dev/fb0).\n"); return -1; } show_picture(img_name); close(fb_info.fbfd); return 0; }
标签:info,img,show,int,bmp,unsigned,char,fb,framebuffer 来源: https://www.cnblogs.com/panda-w/p/15893863.html