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GUI Combo: How to control so it drops down not up  Topic is solved

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GUI Combo: How to control so it drops down not up

Postby mhab » Mon Nov 18, 2013 11:45 pm

Hello

I have searched all kinds of GUI combo examples but could not find a TAG which controls if it drops UP or DOWN ...
I have checked dialogs which have drop-downs and couldn't find why.
I created one which drops up unwantedly ...
How can I make it drop down ?

Thanks for any hint
Mike-DE
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Re: GUI Combo: How to control so it drops down not up  

Postby mhab » Mon Jan 02, 2017 7:48 pm

Hello

As nobody ever replied to this, here is what I found out.
The GUI I refer to here is PUI and in PUI it says that combo boxes are controlled automatically for the direction they popup to.

Well sad to say but the "automatic" in the combo boxes is 90%-100% wrong as I experienced it.

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Re: GUI Combo: How to control so it drops down not up

Postby Thorsten » Tue Jan 03, 2017 7:24 am

Yeah, the combo isn't the strongest PUI widget...
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Re: GUI Combo: How to control so it drops down not up

Postby Hooray » Wed Jan 04, 2017 7:08 pm

See $FG_ROOT/Docs/README.gui - for instance, you could use a select widget instead of the combo if the combo turns out to be problematic.
Apart from that, the pui2canvas effort is using Canvas to parse/render a subset of the PUI/XML markup used by FlightGear to render a handful of widgets - and given that a combo box is really just an input field (possibly readonly) with a corresponding button, it should be relatively straightforward to create a full combo widget - in fact, a few months ago I created a simple combo-equivalent by using the existing ScrollArea widget, adding one button widget to the scrollArea for each combo item - ultimately, this turned out to be working well enough actually:

http://wiki.flightgear.org/Howto:Proces ... ing_Canvas
Image

It would be trivial to tell the Canvas widget to align/layout this according to what people need.

In addition, it is worth noting that we don't really need a 1:1 mapping between PUI and Canvas, because we can usually emulate/approximate most PUI widgets rather easily using similar workarounds - as a matter of fact, the whole PUI widget set is rather archaic, and we really only need 2-3 widgets to approximate the full set of supported widgets without much of an effort.

For instance, there are a number of hard-coded widgets, such as the airport-list, waypoint.list or the property browser - under the hood however, all of these end up just being combo/select boxes with items that respond to clicks - the screenshow below is using the pui2/canvas "combo-workaround" (shown above) to simply turn the airport-list logic into a crude property-browser equivalent:

Image

Also note that these screenshots don't just show "static" buttons, but instead use the corresponding Nasal APIs to dynamically populate the ScrollArea with the proper widgets.
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