Re: goocanvas 1.91.x releases?

[Damon Chaplin <damon karuna eclipse co uk>]

On Fri, 2010-11-05 at 14:42 +0900, Tristan Van Berkom wrote:

> This is definitely odd... I added some trace to gtkscrolledwindow and
> found that it seems scrolledwindow is not to blame for this particular
> case.
> 
> I then added some trace to the canvas code, it seems that the canvas
> code is loosing its canvas size and ends up setting the canvas
> size to the window allocation size (I have no idea how that is
> happening).
> 
> For scrollbars to appear, obviously the statement:
>    adjustment->upper - adjustment->lower > adjustment->page_size
> 
> Must be true... somehow it seems that the goocanvas invariably
> ends up setting adjustment->upper = allocation->width/height
> (causing no scrollbars to appear at all).

It seems to be setting up the adjustments OK here. If I zoom in I get
settings like this:

  vadjustment lower:0 upper:909 page size:449

But no scrollbars appear. But if I then resize the window both
scrollbars appear and it all works fine.


> I'm attaching a patch against goocanvas.c here just to point out
> what I'm talking about, apply it and run the main demo and you will
> see some startling numbers (i.e. what is set as the upper value
> of the adjustment seems inconsistent and sometimes an unreasonably
> large number).

The confusion is because there are several canvas widgets in the demo,
on different notebook pages. The large numbers are correct - that is the
"Large Items" page testing a very large canvas.

(If you go to the bottom of demo.c in create_window() you can change all
the "#if 1' to '#if 0' except for the first "Primitives" one, so you can
focus on the main demo page.)

Damon