Re: GNOME spreadsheet work in progress

[Havoc Pennington <rhpennin midway uchicago edu>]

On Sun, 19 Jul 1998, Federico Mena Quintero wrote:
> 
> I could add a "confine" parameter to the gnome_canvas_item_grab()
> option.  It would be a single boolean, not a window, since you want to
> confine to the canvas window anyway.  Does this sound right?
>

I was thinking of confining to the item's window, not the canvas window.
(Items can have windows, right?) 

I see now that the grabbed window is (item->canvas)->window, I was misled
by the name gnome_canvas_item_grab. 

The reason is that there could be multiple plots on the same canvas. Often
you want to have two plots that share one axis. However, you can only
select a region from one at a time. So right now I'm giving each plot a
window, and grabbing the pointer with confine on while rubberbanding. 

This might not be a canvas issue; it may be a feature to add to my
PlotItem.
 
> Please tell me if you need any help when writing your own items.  It
> is not hard; it's basically cut&paste from any of the existing item
> types.  I intend to write documentation for the canvas, soon.
>

Sounds great. Thanks for the offer to help.
 
> That's a very good idea.  I will look into the Computer Graphics
> Metafile (CGM) format, as it may provide just what we need.
> 

If there's an appropriate existing format that would be most excellent.

Havoc