[linux-audio-dev] FLTK/X11 question

mdeboer at iua.upf.es mdeboer at iua.upf.es
Thu Sep 26 05:26:01 UTC 2002

> No, I'm just draw()ing the bitmap to the widget, then using line draw
> to draw on the pointer. I dont think FLTK supports blits or offscreen
> drawing - at least I couldn't find any mention of it.

fltk certainly does! the easiest way is to use Fl_Double_Window,
which does everything inside the draw() method (including child
widgets) offscreen, and copies it afterwards. works like a charm.
Note that an Fl_Double_Window can be used inside a normal window!

A slightly more complicated (and not documented way) is to use the
fl_*_offscreen methods: fl_create_offscreen, fl_begin_offscreen,
fl_end_offscreen and fl_copy_offscreen. I´m not 100pct sure of the
names, but a grep offscreen /usr/include/FL/* should get you going.

i don´t think this will get rid of the problem you mentioned, though
maybe some X implementations v-sync calls to XCopyArea?


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