linux的bmp代码.docx

/bmp.c/* fbv - simple image viewer for the linux framebuffer Copyright (C) 2002 Tomasz Sterna This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.*/#include config.h#ifdef FBV_SUPPORT_BMP#include fbv.h#include #include #include #include #define BMP_TORASTER_OFFSET10#define BMP_SIZE_OFFSET18#define BMP_BPP_OFFSET28#define BMP_RLE_OFFSET30#define BMP_COLOR_OFFSET54#define fill4B(a)( ( 4 - ( (a) % 4 ) ) & 0x03)struct color unsigned char red;unsigned char green;unsigned char blue;int fh_bmp_id(char *name)/读取位图头信息，判断是否为BM int fd;char id2;fd = open(name, O_RDONLY);/打开文件if (fd = -1) return(0);read(fd, id, 2);close(fd);if ( id0=B & id1=M ) return(1);return(0);void fetch_pallete(int fd, struct color pallete, int count)/获取调色板信息unsigned char buff4;int i;lseek(fd, BMP_COLOR_OFFSET, SEEK_SET);/fd,28,SEEK_SET:参数28为新的读写位置for (i=0; icount; i+) read(fd, buff, 4);/将fd所指向的文件的4个字节传送给缓冲区（指针）buff所指内存中palletei.red = buff2;palletei.green = buff1;palletei.blue = buff0;return;int fh_bmp_load(char *name,unsigned char *buffer, unsigned char *alpha, int x,int y)#if 1int fd, bpp, raster, i, j, k, skip;unsigned char buff4;unsigned char *wr_buffer = buffer + x*(y-1)*3;struct color pallete256; fd = open(name, O_RDONLY); if (fd = -1) return(FH_ERROR_FILE);if (lseek(fd, BMP_TORASTER_OFFSET, SEEK_SET) = -1) /从文件10处开始读写return(FH_ERROR_FORMAT);read(fd, buff, 4);raster = buff0 + (buff18) + (buff216) + (buff324);/由上面可知：从bfOffBits/开始四个字节：每一行扫描的字节数？if (lseek(fd, BMP_BPP_OFFSET, SEEK_SET) = -1) return(FH_ERROR_FORMAT);read(fd, buff, 2);bpp = buff0 + (buff18);/可得biBitCount(从28开始2个字节)switch (bpp)case 1: /* monochrome 单色 */skip = fill4B(x/8+(x%8?1:0);/*#define fill4B(a)( ( 4 - ( (a) % 4 ) ) & 0x03)1.BMP文件记录一行图像是以字节为单位的。因此，就不存在一个字节中的数据位信息表示的点在不同的两行中。也就是说，设显示模式位16色，在每个字节分配两个点信息时，如果图像的宽度位奇数，那么最后一个像素点的信息将独占一个字节，这个字节的后4位将没有意义。接下来的一个字节将开始记录下一行的信息。2.为了显示的方便，除了真彩色外，其他的每中颜色模式的行字节数要用数据“00”补齐为4的整数倍。如果显示模式为16色，当图像宽为19时，存储时每行则要补充4-(19/2+1)%4=2个字节（加1是因为里面有一个像素点要独占了一字节）。如果显示模式为256色，当图像宽为19时，每行也要补充4-19%4=1个字节。*/lseek(fd, raster, SEEK_SET);for (i=0; iy; i+) for (j=0; jx/8; j+) read(fd, buff, 1);for (k=0; k8; k+) if (buff0 & 0x80) *wr_buffer+ = 0xff;*wr_buffer+ = 0xff;*wr_buffer+ = 0xff; else *wr_buffer+ = 0x00;*wr_buffer+ = 0x00;*wr_buffer+ = 0x00;buff0 = buff01;if (x%8) read(fd, buff, 1);for (k=0; kx%8; k+) if (buff0 & 0x80) *wr_buffer+ = 0xff;*wr_buffer+ = 0xff;*wr_buffer+ = 0xff; else *wr_buffer+ = 0x00;*wr_buffer+ = 0x00;*wr_buffer+ = 0x00;buff0 = buff01;if (skip) read(fd, buff, skip);wr_buffer -= x*6; /* backoff 2 lines - x*2 *3 */break;case 4: /* 4bit palletized */skip = fill4B(x/2+x%2);/#define fill4B(a)( ( 4 - ( (a) % 4 ) ) & 0x03)fetch_pallete(fd, pallete, 16);lseek(fd, raster, SEEK_SET);for (i=0; iy; i+) for (j=0; j4;buff2 = buff0 & 0x0f;*wr_buffer+ = palletebuff1.red;*wr_buffer+ = palletebuff1.green;*wr_buffer+ = palletebuff1.blue;*wr_buffer+ = palletebuff2.red;*wr_buffer+ = palletebuff2.green;*wr_buffer+ = palletebuff2.blue;if (x%2) read(fd, buff, 1);buff1 = buff04;*wr_buffer+ = palletebuff1.red;*wr_buffer+ = palletebuff1.green;*wr_buffer+ = palletebuff1.blue;if (skip) read(fd, buff, skip);wr_buffer -= x*6; /* backoff 2 lines - x*2 *3 */break;case 8: /* 8bit palletized */skip = fill4B(x);fetch_pallete(fd, pallete, 256);lseek(fd, raster, SEEK_SET);for (i=0; iy; i+) for (j=0; jx; j+) read(fd, buff, 1);*wr_buffer+ = palletebuff0.red;*wr_buffer+ = palletebuff0.green;*wr_buffer+ = palletebuff0.blue;if (skip) read(fd, buff, skip);wr_buffer -= x*6; /* backoff 2 lines - x*2 *3 */break;case 16: /* 16bit RGB */return(FH_ERROR_FORMAT);break;case 24: /* 24bit RGB */skip = fill4B(x*3);lseek(fd, raster, SEEK_SET);for (i=0; iy; i+) for (j=0; jx; j+) read(fd, buff, 3);*wr_buffer+ = buff2;*wr_buffer+ = buff1;*wr_buffer+ = buff0;if (skip) read(fd, buff, skip);wr_buffer -= x*6; /* backoff 2 lines - x*2 *3 */break;default:return(FH_ERROR_FORMAT);close(fd);return(FH_ERROR_OK);#endifint fh_bmp_getsize(char *name,int *x,int *y)int fd;unsigned char size4;fd = open(name, O_RDONLY);if (fd = -1) return(FH_ERROR_FILE);/宏定义FH_ERROR_FILE 1; 见fbv.hif (lseek(fd, BMP_SIZE_OFFSET, SEEK_SET) = -1) /BMP_SIZE_OFFSET :28return(FH_ERROR_FORMAT);/FH_ERROR_FORMAT:2read(fd, size, 4);*x = size0 + (size18) + (size216) + (size324);/*x-=1;read(fd, size, 4);*y = size0 + (size18) + (size216) + (size324);close(fd);return(FH_ERROR_OK);#endif/bmp.c/main.c/#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include config.h#include fbv.h#include #include #if 1#define UI_w 240 #define UI_h 320 /unsigned char *fbdis = 0; /static int opt_clear = 1, opt_alpha = 0, opt_hide_cursor = 1, opt_image_info = 1, opt_stretch = 0, opt_delay = 0, opt_enlarge = 0, opt_ignore_aspect = 0;int cmp;void display_rgb( unsigned char * dis_data,int W,int H) static int fbfd = 0; static int kh=0; int tfd=0; struct fb_var_screeninfo vinfo; struct fb_fix_screeninfo finfo; int blank=0; long int screensize = 0; unsigned char * buf; int x = 0, y = 0,z=0; / Open the file for reading and writing fbfd = open(/dev/fb0, O_RDWR);/打开显示设备 if (fbfd 0) printf(Error: cannot open framebuffer device.n); exit(1); / 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) /获取屏的显示信息 printf(Error reading variable information.n); exit(3); printf(%dx%d, %dbppn, vinfo.xres, vinfo.yres, vinfo.bits_per_pixel );/vinfo.bits_per_pixel:每个像素/所占比特，也就是biBitCount / Figure out the size of the screen in bytes:计算出屏幕大小，单位bit screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8; / Map the device to memory：映射设备到内存/*void *mmap(void *start, size_t length, int prot, int flags, int fd, off_t offsize);mmap（）建立内存映射:将某个文件内容映射到内存中，对该内存区域的存取即是对该文件内容的读写。参数start指向欲对应的内存起始地址，通常设为NULL,代表让系统自动选定地址，对应成功后该地址会返回。参数length代表将文件中多大的部分对应到内存。参数prot代表映射区域的保护方式有下列组合:PROT_EXEC 映射区域可被执行 PROT_READ 映射区域可读 PROT_WRITE 映射区域可写 PROT_NONE 映射区域不能存取 参数flags会影响映射区域的各种特性。其中，MAP_SHARED:对映射区域的写入数据会复制回文件中，而且允许其他映射该文件的进程共享 参数fd为open（）返回的文件描述符，代表欲映射到内存的文件。 参数offset为文件映射的偏移量，通常设置为0，代表从文件最前方开始对应返回值：成功：返回映射区的内存起始地址，否则返回MAP_FATLED(-1),错误原因在errno中*/ fbdis = (unsigned char *)mmap(0, screensize, PROT_READ | PROT_WRITE, MAP_SHARED, fbfd, 0); if (int)fbdis = -1) printf(Error: failed to map framebuffer device to memory.n); exit(4); int yy=0; if(dis_data)buf=fbdis;/往显示内存写入RBGfor ( y = 0; y H/2; y+ ) for ( x = 0; x 3)|(dis_datay*W*3+x*3+15)&0x07)|(dis_datay*W*3+x*3&0xf8);/dis_datay*W*3+x*3=0;/dis_datay*W*3+x*3+1=x;/dis_datay*W*3+x*3+2=0; buf y*UI_w*2+x*2 =(dis_datay*W*3+x*3+23)&0x1f)|(dis_datay*W*3+x*3+16)&0x07)|(dis_datay*W*3+x*32)&0x78);/ buf y*UI_w*2+x*2+1 = (dis_datay*W*3+x*31)&0x78); munmap(fbdis, screensize);/关闭设备 close(fbfd); printf(end of display rgbn); int disp_image(char *filename)/显示图片int (*load)(char *, unsigned char *, unsigned char *, int, int);/申明加载 static int k=1;unsigned char * image = NULL;unsigned char * alpha = NULL;int x_size, y_size, screen_width, screen_height;int x_pan, y_pan, x_offs, y_offs, refresh = 1, c, ret = 1;int delay = opt_delay, retransform = 1;int transform_stretch = opt_stretch, transform_enlarge = opt_enlarge, transform_cal = (opt_stretch = 2), transform_iaspect = opt_ignore_aspect, transform_rotation = 0;#ifdef FBV_SUPPORT_GIFif(fh_gif_id(filename)if(fh_gif_getsize(filename, &x_size, &y_size) = FH_ERROR_OK)load = fh_gif_load;goto identified1;#endif#ifdef FBV_SUPPORT_PNGif(fh_png_id(filename)if(fh_png_getsize(filename, &x_size, &y_size) = FH_ERROR_OK)load = fh_png_load;goto identified1;#endif#ifdef FBV_SUPPORT_JPEGif(fh_jpeg_id(filename)if(fh_jpeg_getsize(filename, &x_size, &y_size) = FH_ERROR_OK)load = fh_jpeg_load;goto identified1;#endif#ifdef FBV_SUPPORT_BMPif(fh_bmp_id(filename)/判断是否为bmp格式，见bmp.cif(fh_bmp_getsize(filename, &x_size, &y_size) = FH_ERROR_OK)/读取图片信息load = fh_bmp_load;goto identified1;#endifprintf(%s: Unable to access file or file format unknown.n, filename);return(1);identified1:if(!(image = (unsigned char*) malloc(x_size * y_size * 3)fprintf(stderr, %s: Out of memory.n, filename);goto error_mem;if(load(filename, image, &alpha, x_size, y_size) != FH_ERROR_OK)fprintf(stderr, %s: Image data is corrupt?n, filename);/goto error_mem;if(!opt_alpha)free(alpha);alpha = NULL; ret=0;printf(dx=%d,dy=%dn,x_size,y_size); display_rgb( image,x_size,y_size); done:if(opt_clear)/printf(033H033J);fflush(stdout);error_mem:free(image);free(alpha);return(ret);int main()/disp_image(1.bmp);printf(begin main 00n);#endif/main.c/config.h/#define IDSTRING fbv 1.0b, s-tech#define DEFAULT_FRAMEBUFFER /dev/fb0/#define FBV_SUPPORT_JPEG/#define FBV_SUPPORT_PNG#define FBV_SUPPORT_BMP/config.h/fbv.h/* fbv - simple image viewer for the linux framebuffer Copyright (C) 2000, 2001, 2003 Mateusz Golicz This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.*/#define FH_ERROR_OK 0#define FH_ERROR_FILE 1/* read/access error */#define FH_ERROR_FORMAT 2/* file format error */int dis_w,dis_h;int one_pic;void fb_display(unsigned char *rgbbuff, unsigned char * alpha, int x_size, int y_size, int x_pan, int y_pan, int x_offs, int y_offs);void getCurrentRes(int *x, int *y);int fh_bmp_id(char *name);int fh_bmp_load(char *name,unsigned char *buffer, unsigned char *alpha, int x,int y);int fh_bmp_getsize(char *name,int *x,int *y);int fh_jpeg_id(char *name);int fh_jpeg_load(char *name,unsigned char *buffer, unsigned char *alpha, int x,int y);int fh_jpeg_getsize(char *name,int *x,int *y);int fh_png_id(char *name);int fh_png_load(char *name,unsigned char *buffer, unsigned char *alpha, int x,int y);int fh_png_getsize(char *name,int *x,int *y);int fh_gif_id(char *name);int fh_gif_load(char *name,unsigned char *buffer, unsigned char *alpha, int x,int y);int fh_gif_getsize(char *name,int *x,int *y);struct imageint width, height;unsigned char *rgb;unsigned char *alpha;int do_free;#ifnde