[Plplot-cvs] SF.net SVN: plplot:[11809] trunk/src/pllegend.c

[<ai...@us...>]

Revision: 11809
          http://plplot.svn.sourceforge.net/plplot/?rev=11809&view=rev
Author:   airwin
Date:     2011-07-12 01:47:09 +0000 (Tue, 12 Jul 2011)

Log Message:
-----------
For some reason, plgradient gives unreliable results when the x and y
world coordinates have vastly different magnitudes.  Work around this
issue, by changing the world coordinates of the direction perpendicular
to the plcolorbar from {0., 1.} to {0., max_abs} where max_abs is
the maximum of the absolute values of the minimum and maximum of
the world coordinate range being plotted by the colorbar.

Modified Paths:
--------------
    trunk/src/pllegend.c

Modified: trunk/src/pllegend.c
===================================================================
--- trunk/src/pllegend.c	2011-07-11 22:11:54 UTC (rev 11808)
+++ trunk/src/pllegend.c	2011-07-12 01:47:09 UTC (rev 11809)
@@ -1169,7 +1169,7 @@
     // Min and max values
     // Assumes that the values array is sorted from smallest to largest
     // OR from largest to smallest.
-    PLFLT min_value, max_value;
+    PLFLT min_value, max_value, max_abs;
     // Length of cap in orientation direction
     PLFLT cap_extent;
 
@@ -1336,6 +1336,7 @@
 
     min_value = values[0];
     max_value = values[ n_values - 1 ];
+    max_abs   = MAX( fabs(min_value), fabs(max_value));
 
     // Assumes that the colors array is sorted from smallest to largest.
     plgcmap1_range( &min_color, &max_color );
@@ -1364,12 +1365,12 @@
         wx_min = min_value;
         wx_max = max_value;
         wy_min = 0.0;
-        wy_max = 1.0;
+        wy_max = max_abs;
     }
     else if ( opt & PL_COLORBAR_ORIENT_TOP )
     {
         wx_min = 0.0;
-        wx_max = 1.0;
+        wx_max = max_abs;
         wy_min = min_value;
         wy_max = max_value;
     }
@@ -1378,12 +1379,12 @@
         wx_min = max_value;
         wx_max = min_value;
         wy_min = 0.0;
-        wy_max = 1.0;
+        wy_max = max_abs;
     }
     else if ( opt & PL_COLORBAR_ORIENT_BOTTOM )
     {
         wx_min = 0.0;
-        wx_max = 1.0;
+        wx_max = max_abs;
         wy_min = max_value;
         wy_max = min_value;
     }
@@ -1663,7 +1664,7 @@
         // makes up 10% of the scale and segment B makes up 20% of the scale
         // then segment B will be twice the length of segment A.
         PLcGrid grid;
-        PLFLT   grid_axis[2] = { 0.0, 1.0 };
+        PLFLT   grid_axis[2] = { 0.0, max_abs };
         n_steps = n_values;
         // Use the provided values.
         if ( opt & PL_COLORBAR_ORIENT_RIGHT )


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