<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.6000.16705" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT face=Arial size=2>Am I right in guessing thas it is BitBlt that doesn't support alpha values, and if so is there a better alternative?</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Michael</FONT></DIV> <BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style="FONT: 10pt arial">----- Original Message ----- </DIV> <DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B> <A title=gurnett@glocalnet.net href="mailto:gurnett@glocalnet.net">Michael Gurnett</A> </DIV> <DIV style="FONT: 10pt arial"><B>To:</B> <A title=cairo@cairographics.org href="mailto:cairo@cairographics.org">cairo@cairographics.org</A> </DIV> <DIV style="FONT: 10pt arial"><B>Sent:</B> Sunday, August 31, 2008 2:27 AM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> [cairo] problem with BitBlt</DIV> <DIV><BR></DIV> <DIV><FONT face=Arial size=2>I have the following bit of code</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>bckgrnd = new Graphics::TBitmap;<BR>   bckgrnd->Width = ClientWidth;<BR>   bckgrnd->Height = ClientHeight;<BR> HDC hdc;<BR> hdc=bckgrnd->Canvas->Handle;<BR>  cairo_pattern_t *pat;<BR> cairo_surface_t *surface;<BR><BR> surface = cairo_win32_surface_create (hdc);<BR> background = cairo_create (surface);</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>....</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>The idea is the to draw on the background surface and BitBlt it on my paint routine. However, with the code above it appears that the initial drawing space is filled white (guessing rgba are all 1). Is there a way to get the initial drawing region to be transparant. </FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Thanks</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Michael</FONT></DIV> <P> <HR> <P></P>_______________________________________________<BR>cairo mailing list<BR>cairo@cairographics.org<BR>http://lists.cairographics.org/mailman/listinfo/cairo</BLOCKQUOTE></BODY></HTML>