[Octave-cvsupdate] SF.net SVN: octave:[9365] trunk/octave-forge/main/control/inst

[<par...@us...>]

Revision: 9365
          http://octave.svn.sourceforge.net/octave/?rev=9365&view=rev
Author:   paramaniac
Date:     2011-12-11 15:37:14 +0000 (Sun, 11 Dec 2011)
Log Message:
-----------
control: rework axis limits of plotting

Modified Paths:
--------------
    trunk/octave-forge/main/control/inst/bode.m

Added Paths:
-----------
    trunk/octave-forge/main/control/inst/__plot_margin__.m

Added: trunk/octave-forge/main/control/inst/__plot_margin__.m
===================================================================
--- trunk/octave-forge/main/control/inst/__plot_margin__.m	                        (rev 0)
+++ trunk/octave-forge/main/control/inst/__plot_margin__.m	2011-12-11 15:37:14 UTC (rev 9365)
@@ -0,0 +1,61 @@
+## Copyright (C) 1998, 2000, 2004, 2005, 2007
+##               Auburn University.  All rights reserved.
+##
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} __plot_margin__ (@var{axdata})
+## Determine axis limits for 2-D data (column vectors); leaves a 10%
+## margin around the plots.
+## Inserts margins of +/- 0.1 if data is one-dimensional 
+## (or a single point).
+##
+## @strong{Input}
+## @table @var
+## @item axdata
+## @var{n} by 2 matrix of data [@var{x}, @var{y}].
+## @end table
+##
+## @strong{Output}
+## @table @var
+## @item axvec
+## Vector of axis limits appropriate for call to @command{axis} function.
+## @end table
+## @end deftypefn
+
+function axvec = __plot_margin__ (axdata)
+
+  ## compute axis limits
+  minv = axdata(1);
+  maxv = axdata(2);
+  delv = (maxv-minv)/2;             # breadth of the plot
+  midv = (minv + maxv)/2;           # midpoint of the plot
+  axmid = [midv, midv];
+  axdel = [-0.1, 0.1];              # default plot width (if less than 2-d data)
+  if (delv == 0)
+    if (midv != 0)
+      axdel = [-0.1*midv, 0.1*midv];
+    endif
+  else
+    ## they're at least one-dimensional
+    tolv = max(1e-8, 1e-8*abs(midv));
+    if (abs (delv) >= tolv)
+      axdel = 1.1*[-delv,delv];
+    endif
+  endif
+  axvec = axmid + axdel;
+
+endfunction

Modified: trunk/octave-forge/main/control/inst/bode.m
===================================================================
--- trunk/octave-forge/main/control/inst/bode.m	2011-12-11 15:04:33 UTC (rev 9364)
+++ trunk/octave-forge/main/control/inst/bode.m	2011-12-11 15:37:14 UTC (rev 9365)
@@ -64,12 +64,6 @@
   if (! nargout)
     mag_db = 20 * log10 (mag);
 
-    wv = [min(w), max(w)];
-    ax_vec_mag = __axis_limits__ ([reshape(w, [], 1), reshape(mag_db, [], 1)]);
-    ax_vec_mag(1:2) = wv;
-    ax_vec_pha = __axis_limits__ ([reshape(w, [], 1), reshape(pha, [], 1)]);
-    ax_vec_pha(1:2) = wv;
-
     if (isct (sys))
       xl_str = "Frequency [rad/s]";
     else
@@ -78,18 +72,16 @@
 
     subplot (2, 1, 1)
     semilogx (w, mag_db)
-    ax = axis;
-    if (any (isinf (ax_vec_mag)))  # catch case purely imaginary poles or zeros
-      ax_vec_mag(3:4) = ax(3:4);
-    endif
-    axis (ax_vec_mag)
+    axis ("tight")
+    ylim (__plot_margin__ (ylim));
     grid ("on")
     title (["Bode Diagram of ", inputname(1)])
     ylabel ("Magnitude [dB]")
 
     subplot (2, 1, 2)
     semilogx (w, pha)
-    axis (ax_vec_pha)
+    axis ("tight")
+    ylim (__plot_margin__ (ylim));
     grid ("on")
     xlabel (xl_str)
     ylabel ("Phase [deg]")

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