[cells-gtk-devel] cells-gtk drawing-area widget

[Peter Hildebrandt]

On Mon, 04 Jun 2007 05:02:57 -0700, Peter Denno <peter.denno at nist.gov>  
wrote:

> On Sunday 03 June 2007 12:45, Martin Flack wrote:
>> Hi all,
>>
>> I'm writing some stock equities charting software in Common Lisp
>> for my own amusement and to learn the language. I'd like to start
>> by porting over a simple program I had in Perl to draw daily price
>> bars. I used Tk in Perl so I was planning to use LTK but cells-gtk
>> caught my eye and looks interesting.
>>
>> I noticed the drawing.lisp is commented out in the asdf file - is
>> anyone actively using this widget in their code? I uncommented it
>> and got it to compile on SBCL.
>
> I wrote it, but I'm not using it yet.

I am in a similar situation, so if you guys would like to collaborate on  
the issue, that'd be great.

I'm writing a little GUI app as a frontend for my research project.  I  
really like the way cells-gtk works, but I miss the drawing-area widget.

My approach so far is based on Cairo (exporting the graphs to svg or  
postscript would be awesome, given I'd like to use them in a paper).

I started with Warren Wilkinson's patch (posted here on May 22):

http://www3.telus.net/public/thomasw2/dl/cells-gtk-cairo-patch.diff

I have fixed the button handlers to work properly.  Now I am in the  
process of rewriting the drawing methods to use cairo internally.  My idea  
is to store all objects in a (hash-)table, which is a cells slot in the  
drawing-area.  draw-* functions will just drop new entries in the list,  
and return a unique handle for every object.  update functions can take  
this handle and update existing objects (move them, change color, etc.). A  
delete method can delete them.

The draw-fn function will iterate over the list to draw the current  
layout.  Later some export-to-svg or -ps can be implemented.

In a final version it might make sense to use a hash-table.  For now I am  
playing with a simple list, the entries of which are cons of an id and a  
struct like (defstruct circle center-x center-y radius color).

There are cairo bindings for lisp out there, and it might be useful to  
integrate them.  I am looking into them right now.
http://www.cliki.net/cl-cairo
http://cairographics.org/cl-cairo/

>>
>> Secondly, I can't seem to get the widget to come up. I lifted some
>> example code from Google, but something's wrong. What I'm trying is
>> below - what happens is the program runs fine but there is no
>> graphic element, just the text label and entry box.
>>
>> Tk does offer a canvas widget which might be helpful to my
>> application, but I'm thinking that since the objects I'd want to
>> handle will be conceptually higher than lines, rectangles, etc.
>> that I could program my own canvas-type abstraction anyway.
>>
>> Any comments would be appreciated. Thanks! ;-)

Same from my side.

Thanks,
Peter

> I've got a paper due today, so I can't comment now, but I did get
> things to work. I had some ideas for the design of this thing that
> I'll try to recall. Tomorrow.


>>
>> Martin
>>
>>
>> (require :cells)
>> (require :cells-gtk)
>>
>> (defpackage hello-world
>>   (:use :cl :cells :cells-gtk)
>>   (:export :main))
>>
>> (in-package :hello-world)
>>
>> (defmodel hello-world (gtk-app)
>>   ()
>>   (:default-initargs
>>
>>     :title "Test"
>>     :position :center
>>     :width 650 :height 550
>>     :kids (list
>>
>> 	   (mk-notebook
>>
>> 	    :tab-labels (list "Tab 1")
>> 	    :kids (list
>>
>> 		   (mk-vbox
>>
>> 		    :kids (list
>>
>> (mk-label :text (c? (md-value (fm^ :mytext))))
>> (mk-entry :md-name :mytext :auto-aupdate t :init "Hello, World.")
>> (mk-drawing-area :md-name :drawing-area :width 100 :height 100
>>
>>  :draw-fn
>>
>>    #'(lambda (self)
>>        (with-pixmap (p "demo" :widget self :width 100 :height 100)
>>          (with-gc (p :fg "red")
>>            (draw-line p 0 0 100 100))
>>          (draw-text p "this is text" 10 70)
>>          (draw-rectangle p 10 10 30 30)
>>          (draw-rectangle p 1 1 97 97)
>>          (insert-pixmap p 0 0)
>>          p))))))))))
>>
>> (defun main (&optional dbg)
>>   (cells-gtk-init)
>>   (start-app 'hello-world :debug dbg))
>>
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>



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