Re: Polar axes

[logari81]

On 07/24/2012 05:15 PM, Juan Pablo Carbajal wrote:
> On Tue, Jul 24, 2012 at 4:50 PM, Jordi Gutiérrez Hermoso
> <address@hidden> wrote:
> > On 24 July 2012 10:25, Juan Pablo Carbajal <address@hidden> wrote:
> > > On Tue, Jul 24, 2012 at 4:01 PM, Jordi Gutiérrez Hermoso
> > > <address@hidden> wrote:
> > > > Look at the differences in the axes for "demo plot" between gnuplot
> > > > and fltk. Is this easy to fix?
> > > >
> > > > How about using polar axes? Is that easy?
> > > My plot function seems not to have demos
> > >
> > > warning: no demo available for plot
> > Sorry, I meant "demo polar".
> >
> > - Jordi G. H.
> I see fltk is not plotting a pair of axes crossing at the origin, the
> rest looks the same to me.
> Definitely, polar axis would be the best. What is the difference
> between a axes object and a plot object? or How is the geometry of the
> axes defined?
Hi,

I have been considering to add support for polar plots in the OpenGL 
backend for long time but lately my free time is almost inexistent. It 
shouldn't be much work, I think not more than a few hours programming 
and the implementation should be quite straightforward. One would need 
to extend the opengl_renderer::draw_axes function in gl-render.cc for 
drawing a circular axes box/plane and a polar grid. For cartesian axes 
this drawing is split into several functions:

  draw_axes_planes (props);
  draw_axes_boxes (props);
  draw_axes_x_grid (props);
  draw_axes_y_grid (props);
  draw_axes_z_grid (props);

However, polar axes should be restricted to 2D, so all this drawing 
would be simple enough to fit in one function:

  draw_axes_polar (props);

I hope this hints can be helpful for anyone willing to add this 
important feature to the OpenGL backend.

Kostas