Re: Zooming a pinboard layout

Hi

I am still having problems with zooming the drawing in my 
pinboard-layout.  I got a response from Eduardo Munoz which helps, but 
does zooming centered at the origin which is not good enough.

I want the following:

1 - click at (x y)
2 - zoom the drawing using the layout as a viewport

with the following constraint

if (x1 y1) were the (x y) coordinates in the pre-zoomed drawing, (x2 
y2) = (x y) must be the coordinates in the post-zoomed drawing.

Essentially I do the drawing by

	(gp:with-graphics-translation (port viewport-x viewport-y)
	   (gp:with-graphics-scale (port zoomed-width zoomed-height)
                    ;; draw))

But, I have not figured out how to reliably compute VIEWPORT-X and 
VIEWPORT-Y.

I know this is basic CG stuff, but I am no good at this stuff.

I'd appreciate any help.

Thanks

Marco











On Aug 10, 2004, at 1:31 PM, Marco Antoniotti wrote:

> Hi
>
> I need help on CAPI and GP.
>
> I am writing a plotting application (which I plan to distribute) and I 
> have all the basics in, but I'd like to add zooming (think Matlab) of 
> the plot.
>
> I think I figured out how to do clipping by using a 
> simple-pinboard-layout enclosing my graph, but zooming is escaping me. 
>  Should I just go ahead and draw everything of a pixmap and then copy 
> out only the necessary area, or there is something magic about the 
> transforms handling that is escaping me?
>
> Thanks fro your help,  just answer in private if you do not feel to 
> bother the whole list with this.
>
> Cheers
>
> marco
>
>
>
>
> --
> Marco Antoniotti					http://bioinformatics.nyu.edu
> NYU Courant Bioinformatics Group		tel. +1 - 212 - 998 3488
> 715 Broadway 10th FL				fax. +1 - 212 - 998 3484
> New York, NY, 10003, U.S.A.
>
--
Marco Antoniotti					http://bioinformatics.nyu.edu
NYU Courant Bioinformatics Group		tel. +1 - 212 - 998 3488
715 Broadway 10th FL				fax. +1 - 212 - 998 3484
New York, NY, 10003, U.S.A.