<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=iso-8859-1"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Consolas;
panose-1:2 11 6 9 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:#954F72;
text-decoration:underline;}
span.E-MailFormatvorlage17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:70.85pt 70.85pt 2.0cm 70.85pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=DE link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Hello,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-US>I have the following problem:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>I have to integrate cairo into an existing rendering application so I need to stick to the applications API as close as possible.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>It requires me to implement two functions which work on rectangles:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>The first gets a rectangle specification (x,y,width,height) and needs to save that exact area of the painted surface somehow, the second just restores the last saved rectangle.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>My (not working) implementation looks like this:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas;color:blue'>void</span><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> CairoEngine::SaveRegion(ptvlib::CRectI region)<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'>{<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_surface_t* saved_surface = cairo_image_surface_create(CAIRO_FORMAT_RGB24, region.Width(), region.Height());<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_t* saved_context = cairo_create(saved_surface);<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> <span style='color:green'><o:p></o:p></span></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas;color:green'> cairo_set_source_surface(saved_context, win32_surface, -region.left, -region.top);</span><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_set_operator(saved_context, CAIRO_OPERATOR_SOURCE);<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_paint(saved_context);<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_surface_flush(saved_surface);<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_destroy(saved_context);<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> saved_regions.push(std::make_pair(region, saved_surface));<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'>}<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas;color:blue'>void</span><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> CairoEngine::ReplayRegion()<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'>{<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> <span style='color:blue'>if</span>(saved_regions.empty()) <span style='color:blue'>return</span>;<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> ptvlib::CRectI region = saved_regions.top().first;<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_surface_t* saved_surface = saved_regions.top().second;<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_save(win32_context);<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_set_operator(win32_context, CAIRO_OPERATOR_SOURCE);<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_set_source_surface(win32_context, saved_surface, region.left, region.bottom);<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_paint(win32_context);<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_surface_flush(win32_surface);<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_surface_destroy(saved_surface);<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_restore(win32_context);<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> saved_regions.pop();<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:9.5pt;font-family:Consolas'>}<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Any hints what I’m doing wrong?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Cheers,<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'>--</span><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'>David Weiß</span><span lang=EN-US style='font-size:10.0pt;color:#E02129;mso-fareast-language:DE'> <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'>Logistics Geographic Components<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;color:#E02129;mso-fareast-language:DE'>PTV GROUP</span><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;color:black;mso-fareast-language:DE'>Haid-und-Neu-Str. 15, 76131 Karlsruhe, Germany<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;color:black;mso-fareast-language:DE'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'>Phone +49 (0</span><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'>) </span><span lang=EN-US style='font-size:10.0pt;mso-fareast-language:DE'>721 9651</span><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'>-7416<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;mso-fareast-language:DE'><a href="mailto:david.weiss@ptvgroup.com"><span lang=EN-US style='color:windowtext;text-decoration:none'>david.weiss</span><span lang=EN-US style='color:windowtext;text-decoration:none'>@ptvgroup.com</span></a></span><span lang=EN-US style='font-size:10.0pt;mso-fareast-language:DE'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;mso-fareast-language:DE'><a href="http://www.ptvgroup.com/"><span style='color:windowtext;text-decoration:none'>www.ptvgroup.com</span></a><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;mso-fareast-language:DE'><a href="http://www.facebook.com/pages/PTV-AG/308012842618"><span lang=EN-GB style='color:windowtext;text-decoration:none'>http://www.facebook.com/pages/PTV-AG/308012842618</span></a></span><span lang=EN-US style='font-size:10.0pt;mso-fareast-language:DE'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:7.0pt;color:black;mso-fareast-language:DE'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:7.0pt;color:black;mso-fareast-language:DE'>PTV Planung Transport Verkehr AG<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:7.0pt;color:black;mso-fareast-language:DE'>Headquarters: Karlsruhe<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:7.0pt;color:black;mso-fareast-language:DE'>Executive Board: Vincent Kobesen (CEO), Dr.-Ing. Thomas Schwerdtfeger<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:7.0pt;color:black;mso-fareast-language:DE'>Chairman of the Supervisory Board: Dr. h.c. Frank-Jürgen Weise<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:7.0pt;color:black;mso-fareast-language:DE'>Commercial Register (HRB-Nr): 109262<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:7.0pt;color:black;mso-fareast-language:DE'>Local Court: Mannheim</span><span lang=EN-US style='mso-fareast-language:DE'><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div></body></html>