#include<windows.h>

#define WIDTH	197
#define HEIGHT	100

LRESULT CALLBACK WindowProc(HWND hWnd,UINT uMsg,WPARAM wParam,LPARAM lParam)
{
	HDC hdc;
	PAINTSTRUCT ps;
	static LPBYTE lpPixel;
	static LPBITMAPINFO lpBmpInfo;
	static HDC hMemDC;
	HBITMAP hBitmap,hOldBitmap;
	int x,y;
	static int length;

	switch(uMsg) {
		case WM_CREATE:
			//DDB作成
			hdc=GetDC(hWnd);
			hMemDC=CreateCompatibleDC(hdc);
			hBitmap=CreateCompatibleBitmap(hdc,WIDTH,HEIGHT);

			//グラデーションで塗りつぶす
			hOldBitmap=(HBITMAP)SelectObject(hMemDC,hBitmap);
			for(y=0;y<HEIGHT;y++){ 				for(x=0;x<WIDTH;x++){ 					SetPixel(hMemDC,x,y,RGB(x%256,0,0)); 				} 			} 			SelectObject(hMemDC,hOldBitmap);  			//4の倍数に補正 			if(WIDTH%4) length=WIDTH+(4-WIDTH%4); 			else length=WIDTH;  			//DIB作成 			lpPixel=(LPBYTE)HeapAlloc(GetProcessHeap(),HEAP_ZERO_MEMORY, 				length*HEIGHT+sizeof(BITMAPINFOHEADER)+256*4); 			lpBmpInfo=(LPBITMAPINFO)(lpPixel+length*HEIGHT); 			lpBmpInfo->bmiHeader.biSize=sizeof(BITMAPINFOHEADER);
			lpBmpInfo->bmiHeader.biWidth=WIDTH;
			lpBmpInfo->bmiHeader.biHeight=HEIGHT;
			lpBmpInfo->bmiHeader.biPlanes=1;
			lpBmpInfo->bmiHeader.biBitCount=8;
			lpBmpInfo->bmiHeader.biCompression=BI_RGB;

			//DDB→DIB変換
			GetDIBits(hdc,hBitmap,0,HEIGHT,lpPixel,lpBmpInfo,DIB_RGB_COLORS);
			SelectObject(hMemDC,hBitmap);
			DeleteObject(hBitmap);
			ReleaseDC(hWnd,hdc);

			for(y=25;y<50;y++){		//DIBに描画
				for(x=25;x<50;x++){
					lpPixel[x+y*length]=( (x-25)+(y-25)*25 )%256;
				}
			}
			Rectangle(hMemDC,25,25,50,50);		//DDBに描画
			return 0;
		case WM_DESTROY:
			DeleteDC(hMemDC);	//DDB削除
			HeapFree(GetProcessHeap(),0,lpPixel);	//DIB削除
			PostQuitMessage(0);
			return 0;
		case WM_PAINT:
			hdc=BeginPaint(hWnd,&ps);
			BitBlt(hdc,0,0,WIDTH,HEIGHT,hMemDC,0,0,SRCCOPY);	//DDBを表画面へ転送
			StretchDIBits(hdc,250,0,WIDTH,HEIGHT,	//DIBを表画面へ転送
				0,0,WIDTH,HEIGHT,lpPixel,lpBmpInfo,DIB_RGB_COLORS,SRCCOPY);
			EndPaint(hWnd,&ps);
			return 0;
	}
	return DefWindowProc(hWnd,uMsg,wParam,lParam);
}

int WINAPI WinMain(
	HINSTANCE hInstance,HINSTANCE hPrevInstance,PSTR lpCmdLine,int nCmdShow)
{
	WNDCLASS wc;
	MSG msg;

	wc.style		 = CS_HREDRAW | CS_VREDRAW;
	wc.lpfnWndProc	 = WindowProc;
	wc.cbClsExtra	 = 0;
	wc.cbWndExtra	 = 0;
	wc.hInstance	 = hInstance;
	wc.hIcon		 = LoadIcon(NULL,IDI_APPLICATION);
	wc.hCursor		 = LoadCursor(NULL,IDC_ARROW);
	wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
	wc.lpszMenuName	 = NULL;
	wc.lpszClassName = __FILE__;
	if(!RegisterClass(&wc)) return 0;

	HWND hWnd=CreateWindow(
		__FILE__,"DDB→8ビットDIB変換",
		WS_OVERLAPPEDWINDOW | WS_VISIBLE,
		CW_USEDEFAULT,CW_USEDEFAULT,
		CW_USEDEFAULT,CW_USEDEFAULT, 
		NULL,NULL,hInstance,NULL);
	if(hWnd==NULL) return 0;

	BOOL bRet;
	while((bRet=GetMessage(&msg,NULL,0,0))!=0){
		if(bRet==-1) break;
		DispatchMessage(&msg);
	}

	return (int)msg.wParam;
}