From: Hidetoshi NAGAI <nagai@...>
Date: 2005-10-19T01:02:01+09:00
Subject: Re: tk - canvas accessing color for each pixel

From: Ed Redman <ed.redman@dal.ca>
Subject: tk - canvas accessing color for each pixel
Date: Tue, 18 Oct 2005 21:41:57 +0900
Message-ID: <pan.2005.10.18.12.39.32.394824@dal.ca>
> I would like to access and change the color of any pixel on a Tk/canvas.

A canvas widget doesn't support to access per pixel.
Although you can do that if each pixel is represented by a line item, 
that will be incredibly slow.

If you want to do that, I think, you'll have to use a PhotoImage object.
On a PhotoImage, you can access and change the color of any pixel.
Please use TkPhotoImage#get and TkPhotoImage#put. 
And please read "photo" manual of Tcl/Tk. 

Stadard Tcl/Tk libraries supports only GIF and PPM/PGM. 
If you want to treat other image formats, 
please use "Img" extesion of Tcl/Tk.
-- 
Hidetoshi NAGAI (nagai@ai.kyutech.ac.jp)