学步园

灰度图像与彩色图像之间的淡入淡出与指定背景的淡入淡出相比，仅
要将指定的背景色改为经计算得到灰度值，可创建一个灰度调色板加以保存。
关于彩色位图灰度值的求法，前面曾有介绍，这里不再细说。

返回：位图的淡入淡出

具体创建过程请见源程序：

//参数说明：
//hDIB -位图句柄
//xDest -显示位图的左上角x坐标
//yDest -显示位图的左上角y坐标
//nLoops -循环次数
//nDelay -每次循环中的延时
//nFlag -淡入淡出标志 1--淡入 其它--淡出

void FadeInColorORFadeOutGray( CDC *pDC, HANDLE hDIB, int xDest, int yDest, int nLoops,</p> <p>int nDelay ,int nFlag)</p> <p>{</p> <p>CPalette pal;</p> <p>CPalette *pOldPalette;</p> <p>PALETTEENTRY pAnimate[256];</p> <p>PALETTEENTRY pGray[256];</p> <p>PALETTEENTRY pOriginal[256];</p> <p>BITMAPINFO &bmInfo = *(LPBITMAPINFO)hDIB ;</p> <p>　</p> <p>int nColors = bmInfo.bmiHeader.biClrUsed ? bmInfo.bmiHeader.biClrUsed :</p> <p>1 << bmInfo.bmiHeader.biBitCount;</p> <p>int nReservedColors = nColors > 236 ? 236 : nReservedColors;</p> <p>int nWidth = bmInfo.bmiHeader.biWidth;</p> <p>int nHeight = bmInfo.bmiHeader.biHeight;</p> <p>LPVOID lpDIBBits = (LPVOID)(bmInfo.bmiColors + nColors);</p> <p>if( pDC->GetDeviceCaps(RASTERCAPS) & RC_PALETTE && nColors <= 256 )</p> <p>{</p> <p>HPALETTE hPal = Create236Palette(hDIB);</p> <p>pal.Attach( hPal );</p> <p>//得到位图调色板</p> <p>pal.GetPaletteEntries(0, nReservedColors, (LPPALETTEENTRY)&pOriginal);</p> <p>for( int i=0; i < nReservedColors; i++)</p> <p>{//得到颜色对应灰度值</p> <p>int nGray = (pOriginal[i].peRed*299+ pOriginal[i].peGreen*587+ pOriginal[i].peBlue*114)/1000;</p> <p>pGray[i].peRed = nGray;</p> <p>pGray[i].peGreen = nGray;</p> <p>pGray[i].peBlue = nGray;</p> <p>pGray[i].peFlags=PC_RESERVED;</p> <p>}</p> <p>pOldPalette = pDC->SelectPalette(&pal, FALSE);</p> <p>pDC->RealizePalette();</p> <p>CDC memDC;</p> <p>memDC.CreateCompatibleDC( pDC );</p> <p>CBitmap bmp;</p> <p>bmp.CreateCompatibleBitmap( pDC, nWidth, nHeight );</p> <p>CBitmap *pOldBitmap = memDC.SelectObject( &bmp );</p> <p>CPalette *pOldMemPalette = memDC.SelectPalette(&pal, FALSE);</p> <p>memDC.RealizePalette();</p> <p>::SetDIBitsToDevice(memDC.m_hDC, 0, 0, nWidth, nHeight, 0, 0, 0,</p> <p>nHeight, lpDIBBits, (LPBITMAPINFO)hDIB, DIB_RGB_COLORS);</p> <p>if(nFlag==1)//设置灰度调色板</p> <p>AnimatePalette(hPal, 0, nColors, (LPPALETTEENTRY)&pGray);</p> <p>pDC->BitBlt(xDest, yDest, nWidth, nHeight, &memDC,0,0,SRCCOPY );</p> <p>//设置动态调色板初始值为当前调色板</p> <p>pal.GetPaletteEntries(0, nColors, (LPPALETTEENTRY)&pAnimate);</p> <p>　</p> <p>memDC.SelectPalette(pOldMemPalette, FALSE);</p> <p>memDC.SelectObject( pOldBitmap );</p> <p>//淡入淡出</p> <p>for( i=1; i <= nLoops; i++ )</p> <p>{</p> <p>for (int j = 0; j< nColors; j++)</p> <p>{</p> <p>if(nFlag==1)</p> <p>{</p> <p>pAnimate[j].peRed = pGray[j].peRed - ((pGray[j].peRed -pOriginal[j].peRed)*i)/nLoops;</p> <p>pAnimate[j].peGreen = pGray[j].peGreen - ((pGray[j].peGreen-pOriginal[j].peGreen)*i)/nLoops;</p> <p>pAnimate[j].peBlue = pGray[j].peBlue - ((pGray[j].peBlue -pOriginal[j].peBlue)*i)/nLoops;</p> <p>pAnimate[j].peFlags = pGray[j].peFlags;</p> <p>}</p> <p>else</p> <p>{</p> <p>pAnimate[j].peRed = pOriginal[j].peRed -((pOriginal[j].peRed -pGray[j].peRed)*i)/nLoops;</p> <p>pAnimate[j].peGreen = pOriginal[j].peGreen - ((pOriginal[j].peGreen-pGray[j].peGreen)*i)/nLoops;</p> <p>pAnimate[j].peBlue = pOriginal[j].peBlue - ((pOriginal[j].peBlue -pGray[j].peBlue)*i)/nLoops;</p> <p>pAnimate[j].peFlags = pOriginal[j].peFlags;</p> <p>}</p> <p>}</p> <p>pal.AnimatePalette(0, nColors, (LPPALETTEENTRY)&pAnimate);</p> <p>// Delay...</p> <p>Sleep(nDelay);</p> <p>}</p> <p>pDC->SelectPalette(pOldPalette, FALSE);</p> <p>}</p> <p>else if( (pDC->GetDeviceCaps(RASTERCAPS) & RC_PALETTE) == 0 && nColors <= 256 )</p> <p>{</p> <p>for( int i=0; i < nColors; i++)</p> <p>{</p> <p>pOriginal[i].peRed = bmInfo.bmiColors[i].rgbRed ;</p> <p>pOriginal[i].peGreen = bmInfo.bmiColors[i].rgbGreen;</p> <p>pOriginal[i].peBlue = bmInfo.bmiColors[i].rgbBlue ;</p> <p>int nGray = (bmInfo.bmiColors[i].rgbRed*299+ bmInfo.bmiColors[i].rgbGreen*587+ bmInfo.bmiColors[i].rgbBlue*114)/1000;</p> <p>if(nFlag==1)</p> <p>{</p> <p>bmInfo.bmiColors[i].rgbRed = nGray;</p> <p>bmInfo.bmiColors[i].rgbGreen = nGray;</p> <p>bmInfo.bmiColors[i].rgbBlue = nGray;</p> <p>}</p> <p>pGray[i].peRed = nGray;</p> <p>pGray[i].peGreen = nGray;</p> <p>pGray[i].peBlue = nGray;</p> <p>}</p> <p>::SetDIBitsToDevice(pDC->m_hDC, xDest, yDest, nWidth, nHeight, 0, 0, 0,</p> <p>nHeight, lpDIBBits, (LPBITMAPINFO)hDIB, DIB_RGB_COLORS);</p> <p>//淡入淡出</p> <p>for( i=1; i <= nLoops; i++ )</p> <p>{</p> <p>for (int j = 0; j< nColors; j++)</p> <p>{</p> <p>if(nFlag==1)</p> <p>{</p> <p>bmInfo.bmiColors[j].rgbRed = pGray[j].peRed - ((pGray[j].peRed -pOriginal[j].peRed)*i)/nLoops;</p> <p>bmInfo.bmiColors[j].rgbGreen = pGray[j].peGreen - ((pGray[j].peGreen-pOriginal[j].peGreen)*i)/nLoops;</p> <p>bmInfo.bmiColors[j].rgbBlue = pGray[j].peBlue - ((pGray[j].peBlue -pOriginal[j].peBlue)*i)/nLoops;</p> <p>}</p> <p>else</p> <p>{</p> <p>bmInfo.bmiColors[j].rgbRed = pOriginal[j].peRed - ((pOriginal[j].peRed -pGray[j].peRed)*i)/nLoops;</p> <p>bmInfo.bmiColors[j].rgbGreen = pOriginal[j].peGreen - ((pOriginal[j].peGreen-pGray[j].peGreen)*i)/nLoops;</p> <p>bmInfo.bmiColors[j].rgbBlue = pOriginal[j].peBlue - ((pOriginal[j].peBlue -pGray[j].peBlue)*i)/nLoops;</p> <p>}</p> <p>}</p> <p>::SetDIBitsToDevice(pDC->m_hDC, xDest, yDest, nWidth, nHeight, 0, 0, 0, nHeight, lpDIBBits, (LPBITMAPINFO)hDIB, DIB_RGB_COLORS);</p> <p>// Delay...</p> <p>Sleep(nDelay);</p> <p>}</p> <p>}</p> <p>else</p> <p>{</p> <p>::SetDIBitsToDevice(pDC->m_hDC, xDest, yDest, nWidth, nHeight, 0, 0, 0, nHeight, lpDIBBits, (LPBITMAPINFO)hDIB, DIB_RGB_COLORS);</p> <p>}</p> <p>}