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<P ALIGN=CENTER><EM>Posted by <STRONG><A HREF="mailto:zda01@engr.uky.edu">Z.J.Da</A></STRONG> on <STRONG>4/21/98 7:49a.m.</STRONG></EM></P>
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<P>Hi All,
<P>I tried to create a bitmap for a contour plot then display it as the folloeing:
<P>//derive CContourPlot from CMDIChildWnd
<BR>IMPLEMENT_DYNCREATE(CContourPlot, CMDIChildWnd)
<P>//in the constructor create a color palette with 48 entries
<BR>CContourPlot::CContourPlot()
<BR>{
<BR> RGBQUAD *pRGB = new RGBQUAD[48];
<BR>
<BR> UINT nSize = sizeof(LOGPALETTE) + (sizeof(PALETTEENTRY) * 48);
<BR> LOGPALETTE *pLP = (LOGPALETTE *) new BYTE[nSize];
<P> pLP->palVersion = 0x300;
<BR> pLP->palNumEntries = 48;
<P> for(int i=0; i<8; i++) {
<BR> pLP->palPalEntry[i].peRed = 255;
<BR> pLP->palPalEntry[i].peGreen = 0;
<BR> pLP->palPalEntry[i].peBlue = i*32;
<BR> pLP->palPalEntry[i].peFlags = 0;
<P> pLP->palPalEntry[i+8].peRed = 255-i*32;
<BR> pLP->palPalEntry[i+8].peGreen = 0;
<BR> pLP->palPalEntry[i+8].peBlue = 255;
<BR> pLP->palPalEntry[i+8].peFlags = 0;
<P> pLP->palPalEntry[i+16].peRed = 0;
<BR> pLP->palPalEntry[i+16].peGreen = i*32;
<BR> pLP->palPalEntry[i+16].peBlue = 255;
<BR> pLP->palPalEntry[i+16].peFlags = 0;
<P> pLP->palPalEntry[i+24].peRed = 0;
<BR> pLP->palPalEntry[i+24].peGreen = 255;
<BR> pLP->palPalEntry[i+24].peBlue = 255-i*32;
<BR> pLP->palPalEntry[i+24].peFlags = 0;
<P> pLP->palPalEntry[i+32].peRed = i*32;
<BR> pLP->palPalEntry[i+32].peGreen = 255;
<BR> pLP->palPalEntry[i+32].peBlue = 0;
<BR> pLP->palPalEntry[i+32].peFlags = 0;
<P> pLP->palPalEntry[i+40].peRed = 223;
<BR> pLP->palPalEntry[i+40].peGreen = 255-i*32;
<BR> pLP->palPalEntry[i+40].peBlue = 0;
<BR> pLP->palPalEntry[i+40].peFlags = 0;
<BR> }
<P> myPalette.CreatePalette( pLP );
<P> delete[] pLP;
<BR>}
<P>//create the bitmap using the same color as the palette
<BR>CContourPlot::CreatMyBitmap()
<BR>{
<BR> COLORREF NEAR colorArray[48];
<BR> for(i=0; i<8; i++) {
<BR> colorArray[i] = RGB(255, 0, i*32);
<BR> colorArray[i+8] = RGB(255-i*32, 0, 255);
<BR> colorArray[i+16] = RGB(0, i*32, 255);
<BR> colorArray[i+24] = RGB(0, 255, 255-i*32);
<BR> colorArray[i+32] = RGB(i*32, 255, 0);
<BR> colorArray[i+40] = RGB(223, 255-i*32, 0);
<BR> }
<BR>
<BR> if(m_myBitmap.m_hObject != NULL)
<BR> m_myBitmap.DeleteObject();
<P> CClientDC dc(this);
<BR> CDC dcMem;
<P> dcMem.CreateCompatibleDC(&dc);
<BR> m_myBitmap.CreateCompatibleBitmap(&dc, 600, 410);
<BR> ASSERT(m_myBitmap.m_hObject != NULL);
<P> CBitmap* pOldBitmap = dcMem.SelectObject(&m_myBitmap);
<P> //draw a rectangle in the backgorund window color
<BR> CBrush brBackground(::GetSysColor(COLOR_WINDOW));
<BR> dcMem.FillRect(rect, &brBackground);
<P> CBrush myBrush[48];
<BR> for(i=0; i<48; i++)
<BR> myBrush[i].CreateSolidBrush(colorArray[i]);
<P> // draw contour
<BR> RECT myRect;
<BR> for(x=1; x<100; x += 5)
<BR> {
<BR> for(y=1; y<100; y += 5)
<BR> {
<BR> myRect.left = (LONG)(x-1);
<BR> myRect.top = (LONG)(y-1);
<BR> myRect.right = (LONG)(x+4);
<BR> myRect.bottom = (LONG)(y+4);
<BR> z = x + y; //plot linera contours
<BR> dcMem.FillRect(&myRect, &myBrush[(int)48.0*z/200.0]);
<BR> }
<BR> }
<P> dcMem.SelectObject(pOldBitmap);
<BR> dcMem.DeleteDC();
<BR>}
<P>//display the bitmap
<BR>void CContourPlot::OnPaint()
<BR>{
<BR> if(m_myBitmap.m_hObject == NULL)
<BR> return;
<P> CPaintDC dc(this);
<BR> CBitmap* pbmOld = NULL;
<P> CDC dcMem;
<BR> dcMem.CreateCompatibleDC(&dc);
<BR> pbmOld = dcMem.SelectObject(&m_myBitmap);
<P> // Select and realize the palette
<BR> if( dc.GetDeviceCaps(RASTERCAPS) & RC_PALETTE && myPalette.m_hObject != NULL ) {
<BR> dc.SelectPalette( &myPalette, TRUE );
<BR> dc.RealizePalette();
<BR> }
<BR>
<BR> //dc.SetStretchBltMode(COLORONCOLOR);
<BR> dc.StretchBlt(0, 0, m_Width, m_Height,
<BR> &dcMem, 0, 0, 100, 100, SRCCOPY);
<P> dcMem.SelectObject(pbmOld);
<BR> dcMem.DeleteDC();
<BR>
<BR> return;
<BR>}
<P>The bitmap can be displayed but it does not use the colors that I expected. Instead, the dithered colors are used. Could anybody tell me what is wrong with my code in using bitmap and color palette?
<P>Thank you in advance.
<P>Z.J. Da
<BR>
</P>
<A NAME="Responses"><HR></A><P ALIGN=CENTER><BIG><BIG><STRONG>Responses</STRONG></BIG></BIG>
<P><UL><LI><STRONG><A HREF="read.cgi-read=10075.htm" tppabs="http://www.codeguru.com/mfc_bbs/read.cgi?read=10075">Re: Q: Why Cannot display a bitmap nicely?</A></STRONG> : Steve McAdams -- <EM>4/22/98 6:11a.m.</EM>
<UL>
<LI><STRONG><A HREF="read.cgi-read=10087.htm" tppabs="http://www.codeguru.com/mfc_bbs/read.cgi?read=10087">Re: Q: Why Cannot display a bitmap nicely?</A></STRONG> : Z.J. Da -- <EM>4/22/98 7:56a.m.</EM>
<UL>
</UL>
</UL>
</UL></P>
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