Re: GTK application scene drawing

[Stefan Salewski <mail ssalewski de>]

On Sun, 2014-08-03 at 11:20 +0530, Gurjot Singh Bhatti wrote:
> Your project looks nice. Is it open-source?

Sure. It started as a proof of concept, to test my user interface ideas,
and how fine Ruby, Cairo and GTK works together. 

Generally I am satisfied, but in the last years I have done mostly very
experimental coding to test thinks, so I generated really ugly code,
which I have to cleanup now...

> I have something similar in my mind in context to that Grid and
> drawing entities.
> But so far I am just able to draw points on my drawingArea and and now
> working on how to detect if there is already a point under mouse. This
> is because I want to draw line when 2 points are already drawn and I
> select them.

With zooming and panning there is some math involved.
I started with a simple test application:
http://ssalewski.de/PetEd-Demo.html.en

(Was written for Ruby 1.8, for 2.0 some fixes may be necessary)

A similar very basic "library" in C should be available somewhere -- I
really think someone told us about such thing on gtk or cairo mailing
lists. But I can not remember the name and I can not find it in the
mails...