DIB とパレット

DIB パレットインデックス

#include <windows.h>

#define PAL_SIZE (1 << bmpInfo->bmiHeader.biBitCount)
BITMAPFILEHEADER bmpFileHeader;
BITMAPINFO * bmpInfo;
BYTE * bPixelBits;

LOGPALETTE * NewLogPal(const RGBQUAD *pColorTable , int iSize) {
	LOGPALETTE *lpPalette;
	int count;

	lpPalette = malloc(sizeof (LOGPALETTE) + iSize * sizeof (PALETTEENTRY));
	lpPalette->palVersion = 0x0300;
	lpPalette->palNumEntries = iSize;
	
	for (count = 0 ; count < iSize ; count++) {
		lpPalette->palPalEntry[count].peRed = pColorTable[count].rgbRed;
		lpPalette->palPalEntry[count].peGreen = pColorTable[count].rgbGreen;
		lpPalette->palPalEntry[count].peBlue = pColorTable[count].rgbBlue;
		lpPalette->palPalEntry[count].peFlags = NULL;
	}
	return lpPalette;
}

LRESULT CALLBACK WndProc(HWND hWnd , UINT msg , WPARAM wp , LPARAM lp) {
	HDC hdc;
	PAINTSTRUCT ps;
	int count;
	LOGPALETTE * lpPalette;
	static HPALETTE hPalette;

	switch (msg) {
	case WM_DESTROY:
		free(bmpInfo);
		free(bPixelBits);
		DeleteObject(hPalette);
		PostQuitMessage(0);
		return 0;
	case WM_CREATE:
		if (PAL_SIZE <= 256) {
			lpPalette = NewLogPal(bmpInfo->bmiColors , PAL_SIZE);
			hPalette = CreatePalette(lpPalette);
			free(lpPalette);

			for (count = 0 ; count < PAL_SIZE ; count++)
				*(((WORD *)bmpInfo->bmiColors) + count) = (WORD)count;
		}
		else {
			hdc = GetDC(hWnd);
			hPalette = CreateHalftonePalette(hdc);
			ReleaseDC(hWnd , hdc);
		}

		return 0;
	case WM_PAINT:
		hdc = BeginPaint(hWnd , &ps);

		SelectPalette(hdc , hPalette , FALSE);
		RealizePalette(hdc);

		if (PAL_SIZE <= 256) SetDIBitsToDevice(
			hdc , 0 , 0 , 
			bmpInfo->bmiHeader.biWidth , bmpInfo->bmiHeader.biHeight ,
			0 , 0 , 0 , bmpInfo->bmiHeader.biHeight ,
			bPixelBits , bmpInfo , DIB_PAL_COLORS
		);
		else SetDIBitsToDevice(
			hdc , 0 , 0 , 
			bmpInfo->bmiHeader.biWidth , bmpInfo->bmiHeader.biHeight ,
			0 , 0 , 0 , bmpInfo->bmiHeader.biHeight ,
			bPixelBits , bmpInfo , DIB_RGB_COLORS
		);
		EndPaint(hWnd , &ps);
		return 0;
	case WM_QUERYNEWPALETTE:
		if (!hPalette) return FALSE;
		hdc = GetDC(hWnd);

		SelectPalette(hdc , hPalette , FALSE);
		RealizePalette(hdc);
		InvalidateRect(hWnd , NULL , TRUE);

		ReleaseDC(hWnd , hdc);
		return TRUE;
	}
	return DefWindowProc(hWnd , msg , wp , lp);
}

int WINAPI WinMain(HINSTANCE hInstance , HINSTANCE hPrevInstance ,
			PSTR lpCmdLine , int nCmdShow) {
	HWND hWnd;
	MSG msg;
	WNDCLASS winc;
	HANDLE hFile;
	DWORD dwBytes;
	int iBmpInfoLength , iPixelBitLength;

	hFile = CreateFile(lpCmdLine , GENERIC_READ , 0 , NULL ,
		OPEN_EXISTING , FILE_ATTRIBUTE_NORMAL , NULL);
	if (hFile == INVALID_HANDLE_VALUE) return 1;

	ReadFile(hFile , &bmpFileHeader , sizeof (BITMAPFILEHEADER) , &dwBytes , NULL);
	if (bmpFileHeader.bfType != 0x4D42) {
		MessageBox(NULL , TEXT("This is not a bitmap file") , NULL , MB_OK);
		return 1;
	}

	iBmpInfoLength = bmpFileHeader.bfOffBits - sizeof (BITMAPFILEHEADER);
	bmpInfo = malloc(iBmpInfoLength);
	ReadFile(hFile , bmpInfo , iBmpInfoLength , &dwBytes , NULL);

	iPixelBitLength = bmpFileHeader.bfSize - bmpFileHeader.bfOffBits;

	bPixelBits = malloc (iPixelBitLength);
	ReadFile(hFile ,bPixelBits , iPixelBitLength , &dwBytes , NULL);
	CloseHandle(hFile);

	winc.style 		= CS_HREDRAW | CS_VREDRAW;
	winc.lpfnWndProc		= WndProc;
	winc.cbClsExtra		= winc.cbWndExtra	= 0;
	winc.hInstance		= hInstance;
	winc.hIcon		= LoadIcon(NULL , IDI_APPLICATION);
	winc.hCursor		= LoadCursor(NULL , IDC_ARROW);
	winc.hbrBackground	= (HBRUSH)GetStockObject(WHITE_BRUSH);
	winc.lpszMenuName	= NULL;
	winc.lpszClassName	= TEXT("KITTY");

	if (!RegisterClass(&winc)) return 1;

	hWnd = CreateWindow(
			TEXT("KITTY") , TEXT("Kitty on your lap") ,
			WS_OVERLAPPEDWINDOW | WS_VISIBLE ,
			CW_USEDEFAULT , CW_USEDEFAULT ,
			CW_USEDEFAULT , CW_USEDEFAULT ,
			NULL , NULL , hInstance , NULL
	);

	if (hWnd == NULL) return 1;

	while (GetMessage(&msg , NULL , 0 , 0 )) {
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}

	return msg.wParam;
}

if (PAL_SIZE <= 256) {
	lpPalette = NewLogPal(bmpInfo->bmiColors , PAL_SIZE);
	lpPalette = CreatePalette(lpPalette);
	free(lpPalette);

	for (count = 0 ; count < PAL_SIZE ; count++)
		*(((WORD *)bmpInfo->bmiColors) + count) = (WORD)count;
}