Re: Postscript and PM3D file size.

[Daniel J S. <dan...@ie...>]

Hans-Bernhard Broeker wrote:

>On Wed, 3 Mar 2004, Daniel J Sebald wrote:
>  
>
>>Oh yeah, I forgot about "matrix".  The issue there is that "matrix" is 
>>designed for 3d data, i.e., splot.  (List members, if anything I say 
>>here is incorrect, please correct me.)  
>>    
>>
>
>I was going to about 'matrix', but you seemed to be progressing so nicely,
>I though I'ld let you you find that one yourself ;->
>
>  
>
>>There is a routine in "datafile.c" called df_3dmatrix.  I think it only
>>get's called from "plot3d.c".  
>>    
>>
>
>Don't just think, check it.  Tools like "cscope" will let you answer such
>queries almost in an instant:
>
>gnuplot/src> cscope -L0 df_3dmatrix
>datafile.h <global> 100 int df_3dmatrix __PROTO((struct surface_points *, int ));
>datafile.c df_3dmatrix 1268 df_3dmatrix(this_plot, need_palette)
>plot3d.c get_3ddata 652 xdatum = df_3dmatrix(this_plot, NEED_PALETTE(this_plot));
>
>You can even let it show you only the calls to a function:
>
>gnuplot/src> cscope -L3 df_3dmatrix
>plot3d.c get_3ddata 652 xdatum = df_3dmatrix(this_plot, NEED_PALETTE(this_plot));
>

I must learn how to use this cscope.  (I've bookmarked the info page... 
hey, why the water jostling around in the magnifying glass guy's head? 
 Is he/she/it supposed to be half magnifying glass, half periscope, 
i.e., sea scope?)

>>not the mode is "splot" or "plot".  In other words, if I'm not mistaken,
>>Gnuplot should not allow "matrix" to be used in "plot" mode.  
>>    
>>
>
>The current official version probably shouldn't, right.  So let's try...
>
>gnuplot> p 'using.dat' matrix u ($0):2:3 w e
>
>No error, no warning, and a rather stupid plot. How's that for a rather
>surprising undocumented feature?
>

Yes...  As a temporary fix for 4.0, the following placed near the start 
of the eval_plots() routine inside plot2d.c will rule out using 'matrix' 
option with 'splot'.  (Patch attached.)

    /* Temporary hack to rule out 'matrix' for 2d plots.  'matrix' is 
currently
       tested for inside df_open() which doesn't know the option currently
       can't be used with 'plot'.  This should be cleaned up post 4.0 
and this
       chunk of code tossed out. */
    while (!END_OF_COMMAND) {
    if (almost_equals(c_token, "mat$rix"))
        int_error(c_token, "option 'matrix' not supported for 2d plots");
    c_token++;
    }
    c_token = begin_token;

    /* ** First Pass: Read through data files ***

>>Actually, in the image patch, I modified things so that a mode variable 
>>is passed into that routine so it is possible to identify whether 
>>"splot" or "plot" was issued.  I probably needed that information for 
>>something else, but it could be used to rule out "matrix" when issued 
>>with "plot".  
>>    
>>
>
>But it should only be ruled out if that was not a 'plot with pixels',
>right?
>

Correct.

>>in previous discussions, that 2d and 3d formats have diverged in some 
>>ways.  
>>    
>>
>
>I suspect they have never started off a common ground in the first place.
>After looking at all the code for prolonged times, you get the impression
>3D must have been grafted onto an existing 2D-only plotting program as an
>afterthought.
>

Yes, that is my impression as well.

>>I think the "datafile.c" and related routines could be cleaned up 
>>a great deal, focusing more on just getting data from a file into 
>>Gnuplot and not so much on what the eventually plotting mode will look like.
>>    
>>
>
>Agreed.  After 4.0 is out, we could split datafile.c into two: datafile.c
>and "using.c".  The latter would be in charge of all the translation from
>data records into gnuplot "points", i.e. treat options 'using', 'every',
>'index' and 'smooth' (which really should be renamed to 'filter' some
>time).
>

That should be good.

>>Do developers here agree that, for large files, binary data in "plot" 
>>mode is preferable to ascii matrix?
>>    
>>
>
>Preferrable: yes.  But not so much so that it would be a strong argument
>against allowing 'matrix' at least in those 2D plots that really are 3D
>(i.e. "plot with image").
>
>I think we actually should allow 'matrix' for such plots.  It's about
>equally sensible as allowing binary files for 2D plots.'
>

Sure.  I think 'matrix' should be valid whenever appropriate.  If 
someone has a small set of data, fine.  And if they have a large set of 
data, fine too.  But I think it is just a better habit to work with 
compact data and not 20 M ASCII files.

Dan