MacArthur, Ian (SELEX GALILEO, UK) wrote:
>> I tried to make an image browser with Fl_Scroll and Fl_Button.
>> My code : http://nopaste.info/2b8b92cf0c.html
>> When i choose a directory, i call the loadDirectory function
>>
>> gui->window is the Fl_Double_Window
>>
>>
>> My problem : the Fl_Scroll isn't redrawn when i click on the
>> scrollbar. I have to iconify the application to get redrawn.
>>
>> I tried to add a callback on change, but the callback isn't called.
>>
>> Do you have any idea?
>
> Maybe start by looking at the demos in the test folder, and at:
>
> http://www.seriss.com/people/erco/fltk/#ScrollableImage
>
> Also the other examples there (on Greg's page) can be very useful.
If you're having redraw problems with Fl_Scroll,
the common cause is often the background not having a box.
When you create the scroll, try setting the box() type to FL_FLAT_BOX
(I think the default is FL_NO_BOX). So eg:
scroll=new Fl_Scroll(x,y,w,h);
scroll->type(5);
scroll->box(FL_FLAT_BOX);
Setting it to FL_FLAT_BOX will ensure the background is drawn
'with something' instead of nothing.
The only reason for FL_NO_BOX is if your widgets fill the scroll area,
no time has to be wasted to calculate where to render a box that can't
be seen. But in your case you might have areas not filled with your
widget
that need to be drawn, so it's best to have an FL_FLAT_BOX there.
Also:
# scroll=new Fl_Scroll(x,y,w,h);
# scroll->type(5);
# gui->scrollImages=scroll;
# scroll->show();
# scroll->redraw();
# Fl::flush();
Those last two commands don't do anything useful; when you show() the
widget, that just /schedules/ it to be shown, it does not draw it right
away, and Fl::flush() won't make it happen any faster, since it hasn't
been drawn yet.
And in this section:
# if (nb > 0)
# scroll->end();
# gui->window->redraw();
# Fl::flush();
I would think you'd want to *always* end() the scroll, and not
just when nb > 0.
Curious too why you're deleting/recreating the scroll instead
of just creating one scroll, and then clear()ing it whenever you
want to change the contents. Might be easier/better.
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