rendertargetbitmap - RenderToBitmap trouble in WPF -

actually, have print view viewport3d, obviously, use rendertargetbitmap. problem if resolution of rendered image got high, triangles of scene don't appear on final image.

for example, viewport can 1024*768 , resolution use rendertargetbitmap 3 times viewport's resolution.

http://imgur.com/ps2f9d9

i solved problem in way... in fact, triangles don't appear when use big scale. if lower size of rendertargetbitmap, contain everything.

actually, have more or less 1024*768 @ 96dpi. if want impress @ 300dpi, need huge image avoid last solution.

some code :

public static rendertargetbitmap captureecran(viewport3d p_viewport, int p_scale)     {         rendertargetbitmap l_bmp;         p_scale = p_scale > 5 ? 5 : p_scale;         l_bmp = new rendertargetbitmap(p_scale * convert.toint32(p_viewport.actualwidth), p_scale * convert.toint32(p_viewport.actualheight), p_scale * 96.0, p_scale * 96.0, pixelformats.pbgra32);          drawingvisual vis = new drawingvisual();         drawingcontext dc = vis.renderopen();         dc.drawrectangle(system.windows.media.brushes.white, null, new rect(0, 0, p_scale * p_viewport.actualwidth, p_scale * p_viewport.actualheight));         dc.close();          l_bmp.render(vis);         p_viewport.updatelayout();         l_bmp.render(p_viewport);         return l_bmp;     }  public static void saveimage(rendertargetbitmap rendertargetbitmap, string m_impression)     {         system.windows.forms.folderbrowserdialog l_fbd = new system.windows.forms.folderbrowserdialog();         l_fbd.showdialog();         string l_path = l_fbd.selectedpath + "\\" + currentuser() + "__" + currentdate() + "__." + m_impression.tolower();         filestream stream = new filestream(l_path, filemode.create);          bitmapencoder l_encoder = null;         switch(m_impression){             case "png":                 pngbitmapencoder l_png = new pngbitmapencoder();                 l_encoder = l_png;                 break;             case "jpeg":                 jpegbitmapencoder l_jpeg = new jpegbitmapencoder();                 l_jpeg.qualitylevel = 30;                 l_encoder = l_jpeg;                 break;         }         l_encoder.frames.add(bitmapframe.create(rendertargetbitmap));         l_encoder.save(stream);         stream.close();     } 

my call :

saveimage(captureecran(m_viewportcourant.viewport3d,5), m_impression); 

where m_impression .png or .jpg

it works using visualbrush containing viewport , drawn drawingcontext.

drawingvisual vis = new drawingvisual(); drawingcontext dc = vis.renderopen();  visualbrush sourcebrush = new visualbrush(p_viewport);  dc.drawrectangle(system.windows.media.brushes.white, null, new rect(0, 0, p_viewport.actualwidth * p_scale, p_viewport.actualheight * p_scale)); dc.drawrectangle(sourcebrush, null, new rect(new system.windows.point(0, 0), new vector(p_viewport.actualwidth, p_viewport.actualheight))); dc.close();      l_bmp.render(vis);