[問題] 讀BMP檔頭與相關問題

看板C_and_CPP (C/C++)作者grabyou (77)時間16年前 (2009/02/15 22:08)推噓3(3推 0噓 2→)

留言5則, 3人參與討論串1/1

有一段來源碼 #include "stdio.h" #include "stdlib.h" #include "math.h" #include "paulslib.h" /* Sample program to read a limited number of BMP file types Write out lots of diagnostics Write out a 24 bit RAW image file */ typedef struct { unsigned short int type; /* Magic identifier */ unsigned int size; /* File size in bytes */ unsigned short int reserved1, reserved2; unsigned int offset; /* Offset to image data, bytes */ } HEADER; typedef struct { unsigned int size; /* Header size in bytes */ int width,height; /* Width and height of image */ unsigned short int planes; /* Number of colour planes */ unsigned short int bits; /* Bits per pixel */ unsigned int compression; /* Compression type */ unsigned int imagesize; /* Image size in bytes */ int xresolution,yresolution; /* Pixels per meter */ unsigned int ncolours; /* Number of colours */ unsigned int importantcolours; /* Important colours */ } INFOHEADER; typedef struct { unsigned char r,g,b,junk; } COLOURINDEX; int main(int argc,char **argv) { int i,j; int gotindex = FALSE; unsigned char grey,r,g,b; HEADER header; INFOHEADER infoheader; COLOURINDEX colourindex[256]; FILE *fptr; /* Check arguments */ if (argc < 2) { fprintf(stderr,"Usage: %s filename\n",argv[0]); exit(-1); } /* Open file */ if ((fptr = fopen(argv[1],"r")) == NULL) { fprintf(stderr,"Unable to open BMP file \"%s\"\n",argv[1]); exit(-1); } /* Read and check the header */ ReadUShort(fptr,&header.type,FALSE); fprintf(stderr,"ID is: %d, should be %d\n",header.type,'M'*256+'B'); ReadUInt(fptr,&header.size,FALSE); fprintf(stderr,"File size is %d bytes\n",header.size); ReadUShort(fptr,&header.reserved1,FALSE); ReadUShort(fptr,&header.reserved2,FALSE); ReadUInt(fptr,&header.offset,FALSE); fprintf(stderr,"Offset to image data is %d bytes\n",header.offset); /* Read and check the information header */ if (fread(&infoheader,sizeof(INFOHEADER),1,fptr) != 1) { fprintf(stderr,"Failed to read BMP info header\n"); exit(-1); } fprintf(stderr,"Image size = %d x %d\n",infoheader.width,infoheader.height); fprintf(stderr,"Number of colour planes is %d\n",infoheader.planes); fprintf(stderr,"Bits per pixel is %d\n",infoheader.bits); fprintf(stderr,"Compression type is %d\n",infoheader.compression); fprintf(stderr,"Number of colours is %d\n",infoheader.ncolours); fprintf(stderr,"Number of required colours is %d\n",infoheader.importantcolours); /* Read the lookup table if there is one */ for (i=0;i<255;i++) { colourindex[i].r = rand() % 256; colourindex[i].g = rand() % 256; colourindex[i].b = rand() % 256; colourindex[i].junk = rand() % 256; } if (infoheader.ncolours > 0) { for (i=0;i<infoheader.ncolours;i++) { if (fread(&colourindex[i].b,sizeof(unsigned char),1,fptr) != 1) { fprintf(stderr,"Image read failed\n"); exit(-1); } if (fread(&colourindex[i].g,sizeof(unsigned char),1,fptr) != 1) { fprintf(stderr,"Image read failed\n"); exit(-1); } if (fread(&colourindex[i].r,sizeof(unsigned char),1,fptr) != 1) { fprintf(stderr,"Image read failed\n"); exit(-1); } if (fread(&colourindex[i].junk,sizeof(unsigned char),1,fptr) != 1) { fprintf(stderr,"Image read failed\n"); exit(-1); } fprintf(stderr,"%3d\t%3d\t%3d\t%3d\n",i, colourindex[i].r,colourindex[i].g,colourindex[i].b); } gotindex = TRUE; } /* Seek to the start of the image data */ fseek(fptr,header.offset,SEEK_SET); /* Read the image */ for (j=0;j<infoheader.height;j++) { for (i=0;i<infoheader.width;i++) { switch (infoheader.bits) { case 1: break; case 4: break; case 8: if (fread(&grey,sizeof(unsigned char),1,fptr) != 1) { fprintf(stderr,"Image read failed\n"); exit(-1); } if (gotindex) { putchar(colourindex[grey].r); putchar(colourindex[grey].g); putchar(colourindex[grey].b); } else { putchar(grey); } break; case 24: if (fread(&b,sizeof(unsigned char),1,fptr) != 1) { fprintf(stderr,"Image read failed\n"); exit(-1); } if (fread(&g,sizeof(unsigned char),1,fptr) != 1) { fprintf(stderr,"Image read failed\n"); exit(-1); } if (fread(&r,sizeof(unsigned char),1,fptr) != 1) { fprintf(stderr,"Image read failed\n"); exit(-1); } putchar(r); putchar(g); putchar(b); break; } } /* i */ } /* j */ fclose(fptr); } 當COMPILE的時候一直有問題但是小弟不知道問題出在哪因為內容（沒錯的情況下）應該是可以顯示出來才對希望大大們能解惑還有在同一檔案夾裡有一張彩色的LENA圖要設為何檔名呢？？謝謝 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 220.134.181.169