[genius] Tue Nov 22 14:47:08 2016 Jiri (George) Lebl <jirka 5z com>

[George Lebl <jirka src gnome org>]

commit 31ab83e252ae7108adbb5a08b1177a9e592010b4
Author: Jiri (George) Lebl <jiri lebl gmail com>
Date:   Tue Nov 22 14:47:10 2016 -0600

    Tue Nov 22 14:47:08 2016  Jiri (George) Lebl <jirka 5z com>
    
        * src/complex-analysis-wandering-ball.gel: add "angle" mode to show
          what happens to angles.

 ChangeLog                                    |    5 ++
 examples/complex-analysis-wandering-ball.gel |   62 +++++++++++++++++--------
 2 files changed, 47 insertions(+), 20 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 9cb701a..5c54a75 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Nov 22 14:47:08 2016  Jiri (George) Lebl <jirka 5z com>
+
+       * src/complex-analysis-wandering-ball.gel: add "angle" mode to show
+         what happens to angles.
+
 Thu Sep 22 17:41:55 2016  Jiri (George) Lebl <jirka 5z com>
 
        * examples/riemann-integral-darboux.gel: Add an example for Darboux
diff --git a/examples/complex-analysis-wandering-ball.gel b/examples/complex-analysis-wandering-ball.gel
index f2162ba..ddbbc98 100644
--- a/examples/complex-analysis-wandering-ball.gel
+++ b/examples/complex-analysis-wandering-ball.gel
@@ -3,7 +3,9 @@
 #
 # Shows a bouncing wandering ball and its image under a complex map.
 # If the mouse is within the plot window, then the mouse location is
-# used for the ball location.
+# used for the ball location.  The ball has a cross inside it, but
+# this can be changed into an angle by setting draw_angle to true
+# below.
 # Source is in blue and the target is in red.
 #
 
@@ -40,6 +42,11 @@ radius = 0.3;
 #step = 0.025;
 step = 0.01;
 
+#draw angle instead of cross in the ball
+draw_angle = false;
+
+angle1 = 0.05*pi;
+angle2 = 0.3*pi;
 
 # precision multiplier.  Increasing this number increases the
 # number of points
@@ -49,9 +56,42 @@ mult = 3;
 
 
 circlepts = ApplyOverMatrix((0:(80*mult))',`(k)=radius*exp(k*1i*2*pi/(80*mult)));
+
+#cross are vertical and horizontal line
 line1pts = ApplyOverMatrix((0:(30*mult))',`(k)=radius*(2.0*k/(30*mult)-1));
 line2pts = ApplyOverMatrix((0:(30*mult))',`(k)=1i*radius*(2.0*k/(30*mult)-1));
 
+# angle has radius 3 times that of the ball
+line1anglepts = ApplyOverMatrix((0:(50*mult))',`(k)=(radius*3*k/(30*mult))*exp(1i*angle1));
+line2anglepts = ApplyOverMatrix((0:(50*mult))',`(k)=(radius*3*k/(30*mult))*exp(1i*angle2));
+
+
+
+function draw_ball(pt) = (
+       PlotCanvasFreeze ();
+       LinePlotClear ();
+
+       points1 = pt + circlepts;
+       if draw_angle then (
+               points2 = pt + line1anglepts;
+               points3 = pt + line2anglepts;
+       ) else (
+               points2 = pt + line1pts;
+               points3 = pt + line2pts;
+       );
+       LinePlotDrawLine (points1, "color", "blue");
+       LinePlotDrawLine (points2, "color", "blue");
+       LinePlotDrawLine (points3, "color", "blue");
+
+       LinePlotDrawLine (ApplyOverMatrix (points1, f),
+                         "color", "red");
+       LinePlotDrawLine (ApplyOverMatrix (points2, f),
+                         "color", "red");
+       LinePlotDrawLine (ApplyOverMatrix (points3, f),
+                         "color", "red");
+
+       PlotCanvasThaw ();
+);
 
 dir = exp(1i*rand()*2*pi);
 pt = 0;
@@ -71,25 +111,7 @@ while true do (
                lastp = pt
        );
 
-       PlotCanvasFreeze ();
-       LinePlotClear ();
-
-       points = pt + circlepts;
-       LinePlotDrawLine(points,"color","blue");
-       points = ApplyOverMatrix(points,f);
-       LinePlotDrawLine(points,"color","red");
-
-       points = pt + line1pts;
-       LinePlotDrawLine(points,"color","blue");
-       points = ApplyOverMatrix(points,f);
-       LinePlotDrawLine(points,"color","red");
-
-       points = pt + line2pts;
-       LinePlotDrawLine(points,"color","blue");
-       points = ApplyOverMatrix(points,f);
-       LinePlotDrawLine(points,"color","red");
-
-       PlotCanvasThaw ();
+       draw_ball(pt);
 
        # Now wander around