Re: Graphics Objects -> Line Lists?

[Michael Goffioul]

Try to insert NaN between each line segment. IIRC this is how "stem" function
is implemented.

Michael.


On Tue, Aug 23, 2011 at 12:34 PM, Martin Werner
<address@hidden> wrote:
> Hello all,
>
> I am working with octave on a simulation system which relies on external
> CAD-Data.
>
> For the time being, the CAD-Data is externally rendered down to a list of
> lines and imported in octave as a matrix, each row representing a lines
> starting and endpoint.
>
> LINES=[x1,y1,x2,y2;...]
>
> Now, if I want to transport this data into a plot, I have severe performance
> problems:
>
> For a small CAD file (~200m^2) containing ~4500 lines, rendering them all
> with a for loop using either plot or line command takes ~50 seconds.
>
> for i = 1:size(LINES)(1);
>   plot(LINES(...))
> endfor
>
> If I use a better type of plotting creating exactly one line object with
> 4500 lines, it is fast enough:
>
> line([A(:,1),A(:,3)],[A(:,2),A(:,4)])
>
> runs below 15ms. But of course, this does not what I want. It essentially
> renders a line strip. Is there a possibility to render a line list in a fast
> manner? Quickly diving into the code of plot,line and __do_line__
>  functions, it seems to me, that there is no possibility to do that, am I
> right?
>
> Wouldn't it be good to have a plotting primitive set similar to OpenGL
> rendering primitives:
>
> GL_LINES, GL_LINESTRIP,GL_TRIANGLES,...
>
>
> Am I missing something? The question in short:
>
> Given a list of (many) independent lines, how can I (quickly) draw them to a
> plot window?
>
> Best regards,
>  Martin Werner
>
>
>
>
> --
> Martin Werner
> Mobile and Distributed Systems Group
> Institute for Computer Science, Ludwig-Maximilians-Universität München
> Room E 011, Oettingenstraße 67, 80538 Munich, Germany
> Phone: +49 89 2180 9127
> http://www.mobile.ifi.lmu.de/
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