| Re: Some tricky prblems....... [message #14043] |
Mon, 18 January 1999 00:00 |
davidf
Messages: 2866
Registered: September 1996
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Senior Member |
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Philip Aldis (jmkimber@dera.gov.uk) writes:
> 1. The next ablility I would like to have for the compound widget is to
> have popup menus when you click the right mouse button. e.g. You click
> the right mouse button over a graph and a menu pops up which has move,
> properties.. things like that. [...]
> I just can't for the life think how to go about it, short of creating
> from base building blocks.
I've fooled around with this a bit. I can make the pull-down
menu pop up under the cursor by using a bulletin board base
and my mapping and unmapping my menu base after I change its
offsets to position it under my cursor. The problem is that
it takes *another* click to get the pull-down menu to come
down, so the user has to click twice to select an item from
the menu. I've given up on it because I just can't make it
work in an "unclunky" fashion. :-(
> 2. Can you change the cursor type while the user has a button pressed
> down.
No, I'm afraid not.
> 4. Finally when I am redrawing things, for example when the user is
> moving a graph around the screen, I am having to redraw the entire
> screen which is causing flashing. I've been trying to think of the best
> way to do it using pixmaps, but it's quite tricky, because it's quite
> possible that two graphs might be over each other or something. One
> thought I did have
> was that when an object is selected I could draw every object except the
> selected one and then Device, COPY that pixmap every time the object is
> moved. But I'm still not sure about the best way.
I've implemented a selection method like you describe. When an object
is selected I "freeze" all the other objects by copying them to a pixmap.
The movement is then a Device Copy of the pixmap followed by a draw
on the moving object. It worked satisfactorily for my purposes,
but I can imagine it depends on what the "objects" are. My "objects"
were quite small and could be drawn quickly.
I'm going to be over in England teaching some classes the end
of March, Philip. We should try to get together. I'd like to
see a demo of some of these programs of yours. :-)
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
Coyote's Guide to IDL Progamming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155
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