C++中依像素读取BMP文件并显示，显示的问题

[goldfrapp04]

在此先行谢谢帮助我的大侠了！
我在C++中用自定义的BITMAPFILEHEADER和BITMAPINFOHEADER读取BMP，然后用SetPixel()显示出来。为了清楚地解释我遇到的问题，请看下面的图：

这是256*256的lena.bmp。左边是原图，右边是我程序的输出。请您看最左边有一个长条矩形，本来这一条应该是图的最右侧才对。

还有另外一个问题，请看：


这个图是146*146的bmp，是我随便截屏来的。下面这幅图是程序输出，不仅仍是最右侧的一条跑到最左侧来了，而且颜色也变得很奇怪。这如果是程序的问题的话，为什么lena里没有出现呢？如果是图片本身的问题，那么应该是什么问题呢？
我的代码如下，可以直接跑的：

/*****BMP.h*****/
#include <fstream>
#include <Windows.h>
#define N 384
using namespace std;

typedef struct {
   WORD bfType;                 /* Magic identifier            */
   DWORD bfSize;                       /* File size in bytes          */
   WORD bfReserved1;
   WORD bfReserved2;
   DWORD bfOffBits;                     /* Offset to image data, bytes */
} HEADER;

typedef struct {
   DWORD biSize;               /* Header size in bytes      */
   LONG biWidth;                /* Width and height of image */
   LONG biHeight;
   WORD biPlanes;       /* Number of colour planes   */
   WORD biBitCount;         /* Bits per pixel            */
   DWORD biCompression;        /* Compression type          */
   DWORD biSizeImage;          /* Image size in bytes       */
   LONG biXPelsPerMeter;     /* Pixels per meter          */
   LONG biYPelsPerMeter;
   DWORD biClrUsed;           /* Number of colours         */
   DWORD biClrImportant;   /* Important colours         */
} INFOHEADER;

#include "BMP.h"

HEADER bmfh;		//bitmap file header
INFOHEADER bmih;	//bitmap info header
BYTE R[N][N], G[N][N], B[N][N];						//RGB value of every pixel
COLORREF color[N][N];	//color
extern "C" WINBASEAPI HWND WINAPI GetConsoleWindow ();	//initialize the screen
void ReadBmp(char *BmpFileName);
void GetColor(int i, int j);

void main()
{
	HWND hwnd;	//handlers HWND and HDC
	HDC hdc;
	char BmpFileName[10];
	int i, j;
	
	hwnd = GetConsoleWindow();	//initialize the screen
	hdc = GetDC(hwnd);  
	scanf("%s", BmpFileName);
	ReadBmp(BmpFileName);	//read the BMP file
	for(i = 0; i < bmih.biHeight; i++)
		for(j = 0; j < bmih.biWidth; j++)
			SetPixel(hdc, i, j, color[bmih.biWidth - j][i]);	//draw the BMP image
	ReleaseDC(hwnd,hdc);
}

void ReadBmp(char *BmpFileName)		//read the BMP file
{
	int patch;	//number of 0s for complement in every row
	ifstream in(BmpFileName, ios_base::binary);		//open the BMP file
	in.read((char *)(&bmfh), sizeof(bmfh) - 2);		//read in BITMAPFILEHEADER. Here sizeof returns a value larger than struct size, so "-2"
	if(bmfh.bfType != 0x4d42)						//if not BMP, exit
	{
		printf("File type is not BMP!\n");
		exit(1);
	}
	in.read((char *)(&bmih),sizeof(bmih));		//read in BITMAPINFOHEADER
	in.seekg(bmfh.bfOffBits, ios_base::beg);	//seek bitmap data
	patch = (4 - (bmih.biWidth * 3) % 4) % 4;	//calculate number of 0s for complement in every row
	for(int i = 0; i < abs(bmih.biHeight); i++)	
	{
		for(int j = 0; j < abs(bmih.biWidth); j++)
		{
			in.read((char *)(&R[i][j]), 1);		//read in data pixel by pixel
			in.read((char *)(&G[i][j]), 1);
			in.read((char *)(&B[i][j]), 1);
			GetColor(i, j);		//obtain the original and greyscaled color
		}
		in.seekg(patch, ios_base::cur);	//skip 0s for complement in every row
	}
}

void GetColor(int i, int j)		//obtain the original and greyscaled color
{
	int iB, iG, iR;
	iB = (int)(B[i][j]);
	iG = (int)(G[i][j]);
	iR = (int)(R[i][j]);
	color[i][j] = RGB(iB, iG, iR);	//original color
}

[goldfrapp04]

我已经在VS里解决了这个问题，是这句引起的

in.read((char *)(&bmfh), sizeof(bmfh) - 2);        //read in BITMAPFILEHEADER. Here sizeof returns a value larger than struct size, so "-2"

是一个structure packing的问题，通过把这个"-2"删掉，并在头文件里加上

#pragma pack(push)
#pragma pack(1)

#pragma pack(pop)

而解决了。
但是我最终是在Qt里实现这一程序，HEADER的定义、read这句的代码都是和这里一模一样的，那么Qt下应该怎么实现类似pragma的disable structure packing呢？

[xjtugong]

Qt可能用VS的编译器，也可能用QTSDK带的编译器。
编译时设置对其方式应该可以达到你的目的

[lxyppc]

Qt中也一样
#pragma pack(push)
#pragma pack(1)

//结构体定义

#pragma pack(pop)

[赵4老师]

提醒，BMP的每行数据似乎是按16字节对齐的。

[goldfrapp04]

[Quote=引用 3 楼 lxyppc 的回复:]

Qt中也一样
#pragma pack(push)
#pragma pack(1)

//结构体定义

#pragma pack(pop)
[/Quote]
我的Qt程序包含几个.h文件，是只在定义这个结构的那个头文件加就好了是吗？那具体应该加在哪里呢？我下面这样加在运行程序的时候会打开图片后无响应……

#pragma pack(push)
#pragma pack(1)
#ifndef BMP_H
#define BMP_H

#include "qstring.h"
#include <qmessagebox.h>
#include <qimage.h>
#include "qpainter.h"
#include <fstream>
#include <Windows.h>
#define N 384
#define n 8
using namespace std;

typedef struct{     //self-defined BITMAPFILEHEADER
    WORD bfType;
    DWORD bfSize;
    WORD bfReserved1;
    WORD bfReserved2;
    DWORD bfOffBits;
} HEADER;

typedef struct{     //self-defined BITMAPINFOHEADER
    DWORD biSize;
    LONG biWidth;
    LONG biHeight;
    WORD biPlanes;
    WORD biBitCount;
    DWORD biCompression;
    DWORD biSizeImage;
    LONG biXPelsPerMeter;
    LONG biYPelsPerMeter;
    DWORD biClrUsed;
    DWORD biClrImportant;
} INFOHEADER;


class BMP
{
public:
    BMP();
    ~BMP();
    void ReadBmp(QString fileName);
    //QImage ShowImage1(QString fileName);
    //QImage ShowImage2(QString fileName);
    //QImage ShowImage3(QString fileName);
    QImage ShowImage(QString fileName, int i);
private:
    QString fileName;
    HEADER bmfh;
    INFOHEADER bmih;
    BYTE R[N][N], G[N][N], B[N][N];
    COLORREF color[N][N], grey[N][N], dithered[N][N];
    int iGrey[N][N];
    void GetColor(int i, int j);
    int Round(double x);
    void OrderedDither();
};
#pragma pack(pop)
#endif // BMP_H

把pragma和if的顺序换一下也仍然无响应

[lxyppc]

#ifndef BMP_H
#define BMP_H

#include "qstring.h"
#include <qmessagebox.h>
#include <qimage.h>
#include "qpainter.h"
#include <fstream>
#include <Windows.h>
#define N 384
#define n 8
using namespace std;
#pragma pack(push)
#pragma pack(1)
typedef struct{     //self-defined BITMAPFILEHEADER
    WORD bfType;
    DWORD bfSize;
    WORD bfReserved1;
    WORD bfReserved2;
    DWORD bfOffBits;
} HEADER;

typedef struct{     //self-defined BITMAPINFOHEADER
    DWORD biSize;
    LONG biWidth;
    LONG biHeight;
    WORD biPlanes;
    WORD biBitCount;
    DWORD biCompression;
    DWORD biSizeImage;
    LONG biXPelsPerMeter;
    LONG biYPelsPerMeter;
    DWORD biClrUsed;
    DWORD biClrImportant;
} INFOHEADER;
#pragma pack(pop)

class BMP
{
public:
    BMP();
    ~BMP();
    void ReadBmp(QString fileName);
    //QImage ShowImage1(QString fileName);
    //QImage ShowImage2(QString fileName);
    //QImage ShowImage3(QString fileName);
    QImage ShowImage(QString fileName, int i);
private:
    QString fileName;
    HEADER bmfh;
    INFOHEADER bmih;
    BYTE R[N][N], G[N][N], B[N][N];
    COLORREF color[N][N], grey[N][N], dithered[N][N];
    int iGrey[N][N];
    void GetColor(int i, int j);
    int Round(double x);
    void OrderedDither();
};
#endif // BMP_H