fadein.shtml

mfc资源大全包含MFC编程各个方面的源码

					1 << bmInfo.bmiHeader.biBitCount;
	int nWidth = bmInfo.bmiHeader.biWidth;
	int nHeight = bmInfo.bmiHeader.biHeight;

	// Obtain the original entries in the palette
	GetPaletteEntries(hPal, 0, nColors, (LPPALETTEENTRY)&peOriginal);

	// Change all the entries in the palette to the start color
	int clrRValue = GetRValue(clrStart);
	int clrGValue = GetGValue(clrStart);
	int clrBValue = GetBValue(clrStart);
	for (int j = 0; j < nColors; j++) 
	{  
		peAnimate[j].peRed = clrRValue;
		peAnimate[j].peGreen = clrGValue;
		peAnimate[j].peBlue = clrBValue;
		peAnimate[j].peFlags = PC_RESERVED;
	}

	// Select the palette
	CPalette *pOldPalette = pDC->SelectPalette(&pal, FALSE);
	pDC->RealizePalette();

	// We need to draw the image so that it appears as a rectangle
	// with the start color. At the same time we don't want the 
	// colors to be remapped, otherwise all the pixels would remain
	// the same color. We use a memory DC to achieve this.
	CDC memDC;
	memDC.CreateCompatibleDC( pDC );
	CBitmap bmp;
	bmp.CreateCompatibleBitmap( pDC, nWidth, nHeight );
	CBitmap *pOldBitmap = memDC.SelectObject( &bmp );
	CPalette *pOldMemPalette = memDC.SelectPalette(&pal, FALSE);
	memDC.RealizePalette();

	// Draw the image to memDC
	LPVOID lpDIBBits = (LPVOID)(bmInfo.bmiColors + nColors);
	
	::SetDIBitsToDevice(memDC.m_hDC,	// hDC
		0,				// XDest
		0,				// YDest
		nWidth,				// nDestWidth
		nHeight,			// nDestHeight
		0,				// XSrc
		0,				// YSrc
		0,				// nStartScan
		nHeight,			// nNumScans
		lpDIBBits,			// lpBits
		(LPBITMAPINFO)hDIB,		// lpBitsInfo
		DIB_RGB_COLORS);		// wUsage

	// Set the color to start color
	AnimatePalette(hPal, 0, nColors, (LPPALETTEENTRY)&peAnimate);

	// Now copy the image from the memory DC
	// Since the palettes in memDC and pDC are the same, no color mapping
	// takes place. The image will appear in the start color
	pDC->BitBlt(xDest, yDest, nWidth, nHeight, &memDC,0,0,SRCCOPY );

	// Fade in
	for( int i=1; i <= nLoops; i++ )
	{
		for (j = 0; j < nColors; j++) 
		{  
			peAnimate[j].peRed = clrRValue - 
					((clrRValue-peOriginal[j].peRed)*i)/nLoops;
			peAnimate[j].peGreen = clrGValue - 
					((clrGValue-peOriginal[j].peGreen)*i)/nLoops;
			peAnimate[j].peBlue = clrBValue - 
					((clrBValue-peOriginal[j].peBlue)*i)/nLoops;
		}

		pal.AnimatePalette(0, nColors, (LPPALETTEENTRY)&peAnimate);

		// Delay...
		Sleep(nDelay);
	}

	// Reselect old objects into DC
	memDC.SelectPalette(pOldMemPalette, FALSE);
	memDC.SelectObject( pOldBitmap );
	pDC->SelectPalette(pOldPalette, FALSE);
}
</FONT></TT></PRE>

<h4>Function 3: Fade out an image to a given color</h4>
Fading out an image is much simpler than fading it in. We don't have to bother with an identity palette. After creating the reserved palette, we can select it into the device context, realize and then draw the image onto the device context. Now we have the image on the target device and we need to animate the palette so that at the end the colors in the palette are all the same.

<PRE><TT><FONT COLOR="#990000">
// FadeOut	- Draws a bitmap and fades it out to the desired end color
// pDC		- Pointer to the device context to draw in
// hDIB		- Handle to a device-independent bitmap
// clrEnd	- The final color of the bitmap
// xDest	- x-coordinate of upper-left corner of dest. rect. 
// yDest	- y-coordinate of upper-left corner of dest. rect. 
// nLoops	- How many loops to fade the image out.
// nDelay	- Delay in milli-seconds between each loop
//
void FadeOut( CDC *pDC, HANDLE hDIB, COLORREF clrEnd, int xDest, int yDest, 
							int nLoops, int nDelay )
{
	HPALETTE hPal;
	PALETTEENTRY peAnimate[256];
	PALETTEENTRY peOriginal[256];
	CPalette pal;

	// Create a 236 colors or less logical palette with PC_RESERVED set
	if (!(hPal = CreateReservedPalette(hDIB)))
		return;

	// The palette will be deleted when the CPalette object is destroyed
	pal.Attach( hPal );

	BITMAPINFO &bmInfo = *(LPBITMAPINFO)hDIB ;
	
	int nColors = bmInfo.bmiHeader.biClrUsed ? bmInfo.bmiHeader.biClrUsed : 
					1 << bmInfo.bmiHeader.biBitCount;
	int nWidth = bmInfo.bmiHeader.biWidth;
	int nHeight = bmInfo.bmiHeader.biHeight;

	// Obtain the original entries in the palette 
	GetPaletteEntries(hPal, 0, nColors, (LPPALETTEENTRY)&peAnimate);
	GetPaletteEntries(hPal, 0, nColors, (LPPALETTEENTRY)&peOriginal);

	// Get end color values
	int clrRValue = GetRValue(clrEnd);
	int clrGValue = GetGValue(clrEnd);
	int clrBValue = GetBValue(clrEnd);

	// Select the palette
	CPalette *pOldPalette = pDC->SelectPalette(&pal, FALSE);
	pDC->RealizePalette();

	// Draw the image 
	LPVOID lpDIBBits = (LPVOID)(bmInfo.bmiColors + nColors);
	
	::SetDIBitsToDevice(pDC->m_hDC,	// hDC
		xDest,				// XDest
		yDest,				// YDest
		nWidth,				// nDestWidth
		nHeight,			// nDestHeight
		0,				// XSrc
		0,				// YSrc
		0,				// nStartScan
		nHeight,			// nNumScans
		lpDIBBits,			// lpBits
		(LPBITMAPINFO)hDIB,		// lpBitsInfo
		DIB_RGB_COLORS);		// wUsage


	// Fade out
	for( int i=1; i <= nLoops; i++ )
	{
		for (int j = 0; j < nColors; j++) 
		{  
			peAnimate[j].peRed = peOriginal[j].peRed - 
				((peOriginal[j].peRed - clrRValue)*i)/nLoops;
			peAnimate[j].peGreen = peOriginal[j].peGreen - 
				((peOriginal[j].peGreen - clrGValue)*i)/nLoops;
			peAnimate[j].peBlue = peOriginal[j].peBlue - 
				((peOriginal[j].peBlue - clrBValue)*i)/nLoops;
		}

		pal.AnimatePalette(0, nColors, (LPPALETTEENTRY)&peAnimate);

		// Delay...
		Sleep(nDelay);
	}

	// Reselect old objects into DC
	pDC->SelectPalette(pOldPalette, FALSE);
}
</FONT></TT></PRE>







<P>
<HR>
<TABLE BORDER=0 WIDTH="100%" >
<TR>
<TD WIDTH="33%"><FONT SIZE=-1><A HREF="http://www.codeguru.com">Goto HomePage</A></FONT></TD>

<TD WIDTH="33%">
<CENTER><FONT SIZE=-2>&copy; 1998 Zafir Anjum</FONT>&nbsp;</CENTER>
</TD>

<TD WIDTH="34%">
<DIV ALIGN=right><FONT SIZE=-1>Contact me: <A HREF="mailto:[e-mail]">[e-mail]</A>&nbsp;</FONT></DIV>
</TD>
</TR>
</TABLE>

</BODY>
</HTML>