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Class >Hierarchy>
>Fl_Double_Window>
> |
> +---->Fl_Overlay_Window>
>
Include >Files>
>#include <FL/Fl_Overlay_Window.H>
>
Description>
This >window >provides >double >buffering >and >also >
the >ability >to >draw >the > "overlay" >which >is >
another >picture >placed >on >top >of >the >main >
image. >The > overlay >is >designed >to >be >a >
rapidly-changing >but >simple >graphic >such >as > a >
mouse >selection >box. >Fl_Overlay_Window> uses >the >
overlay > planes >provided >by >your >graphics >hardware >
if >they >are >available. >
If >no >hardware >support >is >found >the >overlay >
is >simulated >by >drawing > directly >into >the >
on-screen >copy >of >the >double-buffered >window, >and >
"erased" >by >copying >the >backbuffer >over >it >again. >
This >means >the > overlay >will >blink >if >you >
change >the >image >in >the >window. >
Methods>
Creates >a >new >Fl_Overlay_Window> widget >using >
the >given > position, >size, >and >label >(title) >
string. >
Destroys >the >window >and >all >child >widgets. >
You >must >subclass >Fl_Overlay_Window> and >
provide >this >method. > It >is >just >like >a >
draw()> method, >except >it >draws >the >overlay. >
The >overlay >will >have >already >been >"cleared" >when >
this >is >called. > You > can >use >any >of >the >
routines >described >in >
<FL/fl_draw.H>>. >
Call >this >to >indicate >that >the >overlay >data >
has >changed >and >needs >to > be >redrawn. > The >
overlay >will >be >clear >until >the >first >time >this >
is > called, >so >if >you >want >an >initial >display >
you >must >call >this >after > calling >show()>. >
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