從位圖數據取得位圖句柄

#include <windows.h>
#include <fstream>
using namespace std;

void main()
{
	ifstream infile("bm.bmp", ios::in | ios::binary);
	
	BITMAPFILEHEADER bmpHeader;
	// 獲取文件大小
	infile.seekg(0, ios::end);
	long nfilelen = infile.tellg();
	infile.seekg(0, ios::beg);

	// 讀取文件頭
	infile.read((char*)&bmpHeader, sizeof(bmpHeader));
	if (bmpHeader.bfType != 0x4d42)
		return ;

	// 佔用一塊內存
	HGLOBAL hDIB = GlobalAlloc(GMEM_FIXED, nfilelen);
	if (hDIB == 0)
		return ;
	
	// 把文件寫入DIB
	infile.read((char*)hDIB, nfilelen - sizeof(BITMAPFILEHEADER));

	// 鎖定內存, 位圖信息指向該內存
	// BITMAPINFO == 位圖信息頭 + 調色板
	BITMAPINFO &bmpInfo = *(BITMAPINFO*)GlobalLock(hDIB);
	// 位圖信息頭指向該內存
	// BITMAPINFOHEADER *pInfoHead = (BITMAPINFOHEADER*)hDIB;

	// 位圖信息頭大小
	// int nHeadSize = sizeof(BITMAPINFOHEADER);
	// 獲取顏色數組
	BYTE *pBmpPixelBuffer=(BYTE *)&bmpInfo + bmpHeader.bfOffBits - sizeof(BITMAPFILEHEADER);
	
	HDC hDC = GetDC(NULL);
	HBITMAP hBitmap;
	hBitmap=CreateDIBitmap(hDC,(BITMAPINFOHEADER *)&bmpInfo,
		CBM_INIT,(VOID *)pBmpPixelBuffer,&bmpInfo,DIB_RGB_COLORS);
	
	HDC memDC;
	memDC = CreateCompatibleDC(hDC);
	SelectObject(memDC, hBitmap);
	BitBlt(hDC, 0, 0, 500, 500, memDC, 0, 0, SRCCOPY);
	
	
	DeleteDC(memDC);
	GlobalFree(hDIB);
	infile.close();
}