From graphics-request at octave dot org Tue Nov 30 10:49:45 2004
Subject: Re: Oplot
From: Shai Ayal <shaiay at yahoo dot com>
To: Ole Jacob Hagen <waterthrill at yahoo dot no>
Cc: graphics at octave dot org
Date: Tue, 30 Nov 2004 18:37:32 +0200

Ole,

looking through the code in oplot/props/octave I see you have already 
done what I have proposed in my previous email: mainly you have 
implemented a minimal set of "core functions" -- set, get, etc... on top 
of these you could in theory used my plot.m file instead of the oplot.cc 
you use now.

All this without going into elaborate explanations of callbacks etc..., 
using m-files only.

	Shai

Ole Jacob Hagen wrote:
> Hi, Shai.
> 
> 
> Yes, thanks to Shai, we have contour-plot in Oplot. ;-)
> 
> 
> Have you looked at Props-source? And it's usage in the following classes :
> OpFigureManager (Props::Root), OpFigureWindow (Props::Figure), 
> OpAxesObject (Props::Axes), OpLineObject (Props::Line)? These four 
> classes represents each a graphics object. And the virtual method 
> property_changed is run, when a property has changed. This is due to a 
> callback setup.
> 
> Actually, Prop-package is the heart in Oplot.
> 
> Root::instance().setRootCallbackInterface(this) inside ctor of 
> OpFigureManager says that every callbacks regarding a property change in 
> root-object is controlled to OpFigureManager.
> 
> In Octave: f = figure; will make this code run.
> % snip of code %
> 
>> int OpFigureManager::new_figure( Figure* fig) {
>>     OpFigureWindow* fw = new OpFigureWindow(fig, this);
>>     fig->setCallbackInterface(fw);
>>     this->addFigureWindow(fw, (int) fig->getHandle());
>>     return 0;
>> }
> 
> 
> % end snip of code %
> We create a new OpFigureWindows, and connects the Figure-callbacks to 
> our newly created OpFigureWindow instance.  And we adds this figure 
> window into a QPtrList.
> 
> When we create a line-object, by using h = plot(x,y) will run this code, 
> since Line is a child of Axes
> % snip of code %
> 
>> int OpAxesObject::new_child( Object* p,  Object* child) {
>>      if((*child->get_string("Type") == "Line")) {
>>         Line* line = static_cast<Line*>(child);
>>         OpLineObject *lineobject = new OpLineObject(line, this);
>>         line->setCallbackInterface(lineobject);
>>             }
>>  return 0;
>> }
>>
> % end snip of code %
> We create a OpLineObject and connects the callbacks of line-object into 
> our OpLineObject.
> So every change in a line-object in octave, e.g set(h, 'color',[0 1 0]) 
> will make property_change inside OpLineObject be executed.
> 
> 
> Could this be used by visualisation applications, if we convience Paul 
> Kienzle to merge it into octave-forge?
> This means that Octave has a common library for handling graphics 
> objects, which can be used by many visualisation applications. The 
> visualisation application will be responsible of communication interface 
> to and from Octave. And Props will be a layer that handles graphics 
> objects, and properties within the visualisation application. Octave 
> doesn't need duplicate copies of datas.
> 
> Can I test the possibility to use Props inside OctPlot? Or will you Shai?
> It would be interesting if it's feasible. ;-) It should be.
> 
> The code needs some refactoring, I guess. But refactoring is good, not 
> evil.
> 
> If more people are interested in Props-package and how it really works, 
> then send me an email, and I will send you some more documentation about 
> it.
> 
> Cheers,
> 
> Ole J.
> 
> 
> 
> 
> 
> 
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>