c读取bmp图片文件像素值不符有关问题

2013-03-14

c读取bmp图片文件像素值不符问题读取bmp文件之后，查看读取后的像素值，发现和实际不符。读取的图片的位深度

c读取bmp图片文件像素值不符问题
读取bmp文件之后，查看读取后的像素值，发现和实际不符。读取的图片的位深度为8bit。
读和写图片都能成功运行，就是读取出来的数据不符。
用软件查看的图片像素值：11
c读取bmp图片文件像素值不符有关问题
在vs2010调试时查看的图片像素值：10

一下为读取图片和保存图片的代码：
#ifndef _DATA_H_
#define _DATA_H_
#pragma pack(1)

typedef struct BITMAPFILEHEADER
{
unsigned short bfType;
unsigned long bfSize;
unsigned short bfReserved1;
unsigned short bfReserved2;
unsigned long bfOffBits;
} BITMAPFILEHEADER;

typedef struct BITMAPINFOHEADER
{
unsigned long biSize;
long biWidth;
long biHeight;
unsigned short biPlanes;
unsigned short biBitCount;
unsigned long biCompression;
unsigned long biSizeImage;
long biXPelsPerMeter;
long biYPelsPerMeter;
unsigned long biClrUsed;
unsigned long biClrImportant;
}BITMAPINFOHEADER;

#pragma pack()

typedef struct RGBQUAD
{
unsigned char rgbBlue;
unsigned char rgbGreen;
unsigned char rgbRed;
unsigned char rgbReserved;
}RGBQUAD;

typedef struct BMP
{
int biWidth;
int biHeight;
unsigned short biBitCount;
RGBQUAD *pColorTable;
unsigned char *pBmpBuf;
}BMP;

#endif

#include "data_info.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>

int readBmp( char *bmpName,BMP * p);
int saveBmp( char *bmpName,BMP * p);
void main()
{
int a,b;
BMP *p;
     p=(BMP *)malloc(sizeof(BMP));
a=readBmp("peppers.bmp",p);
b=saveBmp("HAPPY.bmp",p);

system("pause");
}

int readBmp( char *bmpName,BMP * p_im){

BITMAPINFOHEADER head;
int bmpWidth;
int bmpHeight;
int lineByte;
int biBitCount;

FILE *fp=fopen(bmpName,"rb");
if(fp==0) return 0;

fseek(fp, sizeof(BITMAPFILEHEADER),0);
//fread(&fileHead, sizeof(BITMAPFILEHEADER), 1,fp);
fread(&head, sizeof(BITMAPINFOHEADER), 1,fp);

bmpWidth = head.biWidth;
bmpHeight= head.biHeight;
biBitCount = head.biBitCount;

lineByte=(bmpWidth * biBitCount/8+3)/4*4;

if(biBitCount==8){

p_im->pColorTable=(RGBQUAD *)malloc( sizeof(RGBQUAD)*256);
fread(p_im->pColorTable,sizeof(RGBQUAD),256,fp);
}

p_im->pBmpBuf=(unsigned char*)malloc(lineByte*bmpHeight*sizeof(unsigned char));
fread(p_im->pBmpBuf,1,lineByte * bmpHeight,fp);
p_im->biBitCount=biBitCount;
p_im->biHeight=bmpHeight;
p_im->biWidth=bmpWidth;

fclose(fp);
return 1;
}

int saveBmp( char *bmpName,BMP * p)

{
FILE *fw;
BITMAPFILEHEADER fileHead;
BITMAPINFOHEADER head;
int lineByte=0;
int colorTablesize=0;

if(!p->pBmpBuf)
return 0;

if(p->biBitCount==8) colorTablesize=1024;

lineByte=(p->biWidth * p->biBitCount/8+3)/4*4;

fw=fopen(bmpName,"wb");
if(fw==0) return 0;

fileHead.bfType = 0x4D42;
fileHead.bfSize= sizeof(BITMAPFILEHEADER)+ sizeof(BITMAPINFOHEADER)+ colorTablesize +lineByte*(p->biHeight);
fileHead.bfReserved1 = 0;
fileHead.bfReserved2 = 0;
fileHead.bfOffBits=54+colorTablesize;

fwrite(&fileHead, sizeof(BITMAPFILEHEADER),1, fw);

head.biBitCount=p->biBitCount;
head.biClrImportant=0;
head.biClrUsed=0;
head.biCompression=0;
head.biHeight=p->biHeight;
head.biPlanes=1;
head.biSize=40;
head.biSizeImage=lineByte*(p->biWidth);
head.biWidth=p->biWidth;
head.biXPelsPerMeter=0;
head.biYPelsPerMeter=0;

fwrite(&head, sizeof(BITMAPINFOHEADER),1, fw);

if(p->biBitCount==8)
fwrite(p->pColorTable, sizeof(RGBQUAD),256, fw);

fwrite(p->pBmpBuf, (p->biHeight)*lineByte, 1, fw);
fclose(fw);
return 1;
}

求教各位，先谢谢了。
bmp图片像素值不符 c
[解决办法]
BMP文件有一些是倒着来的。
也就是从左下角的数据在最开始。

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c读取bmp图片文件像素值不符有关问题