读取bmp

参考这篇文章的讲解bitmap格式http://blog.csdn.net/pathuang68/article/details/4219681

我试了下，用了个bicount=24的bmp，最后读到一个二维数组打算用setpixel输出时发现显示不正确

去stackoverflow上问了下，得到了解答，bitmap每一row会对32bit对齐，

所有每行末尾可能有padding data，用

int rowbyte=(pixelbyte*width+3)&~3;

int skipdata=rowbyte-pixelbyte*width;（这个好聪明的算法...）

得出skipdata，末尾时跳过即可。

同时rgb在内存中存储的顺

#include<iostream>
#include<fstream>
#include<windows.h>


using namespace std;

struct BITMAPHEADER
{
    unsigned short btType;
    unsigned int bfSize;
    unsigned short bfReserved1;
    unsigned short bfReserved2;
    unsigned int bfoffBits;
};

//struct BITMAPINFOHEADER
//{
//    unsigned int biSize;
//    unsigned int biWith;
//    unsigned int biHeight;
//    unsigned short biPlanes;
//    unsigned short biBitCount;
//    unsigned int biCompression;
//    unsigned int biSizeImage;
//    unsigned int biXPelsPerMeter;
//    unsigned int biYPerlPerMeter;
//    unsigned int biClrused;
//    unsigned int biClrImportant;
//};
//
//struct RGBQUAD
//{
//    char rgbBlue;
//    char rgbGreen;
//    char rgbRed;
//    char rgbReserved;
//
//};
int main()
{
    tagBITMAPFILEHEADER bh;
    BITMAPINFOHEADER bih;
    char buf[3];
    unsigned char bmp[200][600];
    int width ,height;
    ifstream fin(L"D:\美图图库\3.bmp",ios::_Nocreate|ios::binary);
    fin.read((char*)&bh,sizeof(bh));
    fin.read((char*)&bih,sizeof(bih));
    

    width=bih.biWidth;
    height=bih.biHeight;
    HWND myconsole=GetConsoleWindow();
    HDC mydc=GetDC(myconsole);
    int rowdata=(width*3+3)&~3;
    int skipdata=rowdata-width*3;
    char skip[4];
    for(int i=height;i>=1;i--)
    {
        for(int j=1;j<=width;j++)
        {
            fin.read(buf,sizeof(buf));
            bmp[i][j*3]=buf[0];
            bmp[i][j*3+1]=buf[1];
            bmp[i][j*3+2]=buf[2];
        
        }
        fin.read(skip,skipdata);
    }
        for(int i=1;i<=height;i++)
        {
            for(int j=1;j<=width;j++)
            {

                COLORREF color;
                color=RGB(bmp[i][j*3+2],bmp[i][j*3+1],bmp[i][j*3]);
                SetPixel(mydc,j,i,color);
            }
    
        }
        ReleaseDC(myconsole,mydc);
    fin.close();
    return 0;
}

序从低到高是B G R的顺序，所有最后要反过来一下。