Re: Grid Based Canvas

[Asad Jibran Ahmed <surfer a1 gmail com>]

Dov,
 Thanks for the info. I think that your GtkImageViewer might just be
what I needed. I'll see where I can get with it. I hope I can contact
you for help if I run into any problems, since you are the author of the
widget.
Again, thanks for the great info.

Regards,
Jibran

On Tue, 2010-05-25 at 22:43 +0300, Dov Grobgeld wrote:
> Why don't you just draw a grid with lines on the canvas, and then
> whenever you "select" a square you create a canvas rectangle item and
> put it in the grid between the grid lines? When you unselect, you just
> destroy the canvas item. You will still need 20000 items, which might
> still be too much...
>
> Another approach which uses a lot less memory but requires more work
> on your part is to use my GtkImageViewer widget which is a hybrid
> between an image viewer and a canvas. (In spite of its name it does
> not necessarily display images). The widget handles zooming, but you
> have to redraw the contents yourself on exposure events. See: 
>
> http://giv.sourceforge.net/gtk-image-viewer/
>
> Regards,
> Dov
>
> On Tue, May 25, 2010 at 22:02, Asad Jibran Ahmed <surfer a1 gmail com>
> wrote:
>         On Mon, 2010-05-24 at 23:21 -0400, Liam R E Quin wrote:
>         > On Tue, 2010-05-25 at 05:04 +0500, Asad Jibran Ahmed wrote:
>         > > [...]
>         >
>         > > The canvas will have grids, much like a graph paper.
>         Whenever
>         > > the user clicks on one of the grid squares, that square
>         will become
>         > > selected and the selection will be shown by highlighting
>         the square.
>         >
>         > It sounds like you really have a grid of squares, even if
>         the user
>         > doesn't think of it that way.
>         >
>         > I think all of the canvas APIs support scrolling and
>         zooming.
>         >
>         > Or take a peek at e.g. the minesweeper game?
>         >
>         > Liam
>         >
>         
>         
>         Liam,
>          Thanks for the info. I checked out the crcanvas widget and I
>         think that
>         it may just be what I need. I do however have one issue with
>         the square
>         approach that you have suggested.
>         
>         The grid I am trying to make needs to be quite large
>         (10000x10000), and
>         the memory requirements of keeping track of this large a
>         number of
>         rectangles is very problematic.
>         
>         Any advice on how to proceed from here? Again, thanks for your
>         earlier
>         reply.
>         Thanks
>         
>         --
>         JB :: http://www.asadjb.com
>         
>         
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--
JB :: http://www.asadjb.com