Re: Y limits in fplot

[John W. Eaton]

On  1-Aug-2007, Henry F. Mollet wrote:

| N.B. Y limits in fplot are working when using
| Octave-2.1.71/gnuplot-4.0.
| Therefore I don't understand why I have problems when trying the same using
| octave-2.9.13/gnuplot-4.2.0.

Perhaps there are bugs in the new graphics code?

| Similarly, I have difficulties with the default colors, default linewidth,
| and no default key when using plot in octave-2.9.13/gnuplot-4.2.0 rather
| than Octave-2.1.71/gnuplot-4.0  as per different posting.

>From the NEWS file that is distributed with 2.9.13 (and also available
by typing "news" at the Octave prompt):

 ** Compatibility with Matlab graphics is much better now.  We now
    have some graphics features that work like Matlab's Handle
    Graphics (tm):

    + You can make a subplot and then use the print function to
      generate file with the plot.

    + RGB line colors are supported if you use gnuplot 4.2.  Octave
      can still use gnuplot 4.0, but there is no way to set arbitrary
      line colors with it when using the Matlab-style plot functions.
      There never was any way to do this reliably with older versions
      of gnuplot (whether run from Octave or not) since it only
      provided a limited set to choose from, and they were terminal
      dependent, so choosing color 1 with the X11 terminal would be
      different from color 1 with the PostScript terminal.  Valid RGB
      colors for gnuplot 4.0 are the eight possible combinations of 0
      and 1 for the R, G and B values. Invalid values are all mapped
      to the same color.

    + You can control the width of lines using (for example):

        line (x, y, "linewidth", 4, "color", [1, 0, 0.5]);

      (this also shows the color feature).

    + With gnuplot 4.2, image data is plotted with gnuplot and may be
      combined with other 2-d plot data.

    + Lines for contour plots are generated with an Octave function, so
      contour plots are now 2-d plots instead of special 3-d plots, and
      this allows you to plot additional 2-d data on top of a contour
      plot.

    + It is no longer possible to mix Matlab-style plot commands with
      the old (and now considered obsolete) style of plot commands
      (__gnuplot_set__, etc.).  You can do one or the other, but not
      both for the same plot.

    + Plot property values are not extensively checked.  Specifying
      invalid property values may produce unpredictible results.


Perhaps we should revise the beginning of this statement to be
something like

  The graphics features of Octave have been completely rewritten.
  Compatibility with Matlab graphics is much better now.  Backward
  compatibility with previous versions of Octave has been retained
  when possible, but compatibility with Matlab is the
  primary goal of the new graphics system.

  Some of the new graphics features that work like Matlab's Handle
  Graphics (tm) are:

?

jwe