Re: [unclassified] Re: Moving functions from octave to octave-forge?

[David Bateman]

Kai Habel wrote:
> David Bateman schrieb:
>> Shai Ayal wrote:
>>  
>>> I'll just add what's available in octplot/high_level to this list.
>>> unless stated otherwise, they are matlab compatible with v6 graphics
>>> -- octplot has no group objects.
>>>
>>>    
>>>> Graphics Stuff:
>>>>   contourf fill fill3 gtext pareto patch pcolor peaks pie quiver
>>>> scatter
>>>>   surf surfc zoom meshc
>>>>
>>>> * contourf, fill, fill3, patch, pcolor, pie all need new graphics
>>>> objects for patches, the current code is just a hack to simulate it.
>>>>       
>>> We now have a working contourf and clabel in octplot/high_level thanks
>>> to work by Kai Habel. They rely on patch of course. I see now way to
>>> do this with gnuplot. To the best of my knowledge, nothing even
>>> approximating patch is not even planned for gnuplot
>>>     
>> I think patch is possible with gnuplot. What I meant is that all of
>> these should wait for patch to be implemented in octave core before
>> doing much with them.. If you have something working in octplot, perhaps
>> you can suggest patches to the core to and least get the front-end of
>> patch objects included in the core..
>>
>>   
> Hello David,
> are you sure that gnuplot supports patches? What I have learned from the
> website is that gnuplot supports arbitrary shaped rectangles and has
> some fill options for line plots ..., but polygons? Can you give me a
> pointer what you have in mind?
> 
> The contourf function in octplot (or in general) needs patch objects of
> arbitrary shape. This includes concave polygons, the octplot
> implementation uses the OpenGL utilities lib (GLU) for polygon
> tesselation and plotting.
> 
> Kai
> 
> ...
> 

Kai,

I have the impression that in 2D you could do a patch it gnuplot with
the "with filledcurve" options. For example try have a file with
something like

0  0
0.5 1
0.5 1.5
1 1.5
1 0.5
0.5 0
0 0

which is a pretty arbitrary polygon, and then I could plot it with

plot <file> with filledcurve

with no issue at all. However, in 3D I think you are right as I don't
know a way to do an arbitrary polygonal patch... Limiting, gnuplot to
2-D patched surfaces would be fine, and if the backend can also treat 3D
surfaces even if gnuplot can't, why not... Especially if octplot can
profit from the more complete backend..

Cheers
David