On 04.02.2009, at 15:12, Fabio Bracci wrote: >> You need to have a window mapped before you can create your >> offscreen. >> So you need to show your aWin object, and wait until it has actually >> been established, before you can safely create the offscreen context. > > This is one of the points I don't get: I first create a window and > then I show it, isn't this just enough to have a window mapped?
To make sure that the window is actually mapped, this should work: while (!win-shown()) Fl::wait(0.01); > And a more fundamental remark is: why isnn't such a offscreen > totally independent of the widgets, visualized or not? Yes, it should work independently. I am afraid that this was never fully tested and fl_create_offscreen misses some minimal initialisation, maybe the connection to the X11 server (which is required for offscreen rendering). This would be worth looking into on every supported platform. >> You are probably best deriving a viewer widget of your own, say >> derived >> from Fl_Box or similar, and from within its draw method, the first >> time >> it is called, you can then safely create your offscreen. You can be >> sure, if the draw() method is called, that the object is mapped to >> the >> display. > > Aha, I see. well, this looks to me as a workaround. Is this the only > way to go? I already developed a quite complex system, It doesn't > feel right to manipulate again the callbacks of my already complex > widget structure ... This is mixed up a little. The offscreen code is not related or derived from any particular widget type. But, see above. >> I'm fairly sure I posted examples of this in the past - but I take it >> they were not found? >> If I can find the examples at home, I'll try and post them later on. > > I'm analyzing your example now, indeed there was just that example > from Lukasz in the general forum. This conversation remids me of the Fl_Canvas prototype for incremental drawing that I had lying around. Maybe I can patch something usable together using the example and my stuff and drop it into 1.3. Matthias ---- http://robowerk.com/ _______________________________________________ fltk mailing list [email protected] http://lists.easysw.com/mailman/listinfo/fltk
