<!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>Why would you want to paint the background red with and 100% opaque (no transparancy). What you explain later on is the problem I have. The background colour would not be unexpected if the correct procedure as used. It is just a question of the correct approach.</FONT></DIV> <BLOCKQUOTE dir=ltr 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=elitecoder.mukul@gmail.com href="mailto:elitecoder.mukul@gmail.com">Mukul Sharma</A> </DIV> <DIV style="FONT: 10pt arial"><B>To:</B> <A title=gurnett@glocalnet.net href="mailto:gurnett@glocalnet.net">Michael Gurnett</A> </DIV> <DIV style="FONT: 10pt arial"><B>Cc:</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 11:23 AM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [cairo] problem with BitBlt</DIV> <DIV><BR></DIV> <DIV dir=ltr>Ohk.<BR><BR>Use cairo_set_source_rgba(1,0,0,1);<BR>and then use cairo_paint();<BR><BR>I think, this would work. On a sidenote, having a transparent background can give you unexpected background color. I had tried doing the same thing, but eventually settled on having a known background color as compared to having a transparent background. For example, when I had a transparent background, I obtained a black background. Thus, I painted it all in white and then performed my drawings.<BR><BR>I cannot support your guess that BitBlt does not support Alpha values. Because, BitBlt is simply a method to transfer a value of colour. The value of color is calculated at Cairo's End and rendered at the Display end. Thus, if Alpha values are not supported somewhere, it would be your display and AFAK it cannot be BitBlt part or Cairo part.<BR><BR>Regards<BR>Mukul<BR><BR> <DIV class=gmail_quote>On Sun, Aug 31, 2008 at 2:10 AM, Michael Gurnett <SPAN dir=ltr><<A href="mailto:gurnett@glocalnet.net">gurnett@glocalnet.net</A>></SPAN> wrote:<BR> <BLOCKQUOTE class=gmail_quote style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid"> <DIV bgcolor="#ffffff"> <DIV><FONT face=Arial size=2>Tried with </FONT><FONT face=Arial size=2>cairo_paint_with_alpha, but that didn't seem to work.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: rgb(0,0,0) 2px solid; MARGIN-RIGHT: 0px"> <DIV> <DIV></DIV> <DIV class=Wj3C7c> <DIV style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal">----- Original Message ----- </DIV> <DIV style="BACKGROUND: rgb(228,228,228); FONT: 10pt arial; font-size-adjust: none; font-stretch: normal; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial"><B>From:</B> <A title=gurnett@glocalnet.net href="mailto:gurnett@glocalnet.net" target=_blank>Michael Gurnett</A> </DIV> <DIV style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal"><B>To:</B> <A title=cairo@cairographics.org href="mailto:cairo@cairographics.org" target=_blank>cairo@cairographics.org</A> </DIV> <DIV style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal"><B>Sent:</B> Sunday, August 31, 2008 2:27 AM</DIV> <DIV style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal"><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></DIV></DIV> <P></P> <HR> <DIV class=Ih2E3d> <P></P>_______________________________________________<BR>cairo mailing list<BR><A href="mailto:cairo@cairographics.org" target=_blank>cairo@cairographics.org</A><BR><A href="http://lists.cairographics.org/mailman/listinfo/cairo" target=_blank>http://lists.cairographics.org/mailman/listinfo/cairo</A></DIV></BLOCKQUOTE></DIV><BR>_______________________________________________<BR>cairo mailing list<BR><A href="mailto:cairo@cairographics.org">cairo@cairographics.org</A><BR><A href="http://lists.cairographics.org/mailman/listinfo/cairo" target=_blank>http://lists.cairographics.org/mailman/listinfo/cairo</A><BR></BLOCKQUOTE></DIV><BR><BR clear=all><BR>-- <BR>Thanks and Regards,<BR><BR>Mukul Sharma<BR>Centre for High Performance Embedded Systems<BR>Nanyang Technological University, Singapore<BR><BR>"A person who runs from responsibilities, runs from life."<BR><BR>"It is easy to hate and it is difficult to love. This is how the whole scheme of things works. All good things are difficult to achieve; and bad things are very easy to get."<BR></DIV></BLOCKQUOTE></BODY></HTML>