Update distance-measurement sections of doc/tutorial.txt and doc/gui.txt

[hooke.git] / doc / gui.txt

diff --git a/doc/gui.txt b/doc/gui.txt
index f8ee894e572a962e26e098900b5236c784ab641d..17ec5f44b755e768341c19e5451d7ea6f971ee22 100644 (file)
--- a/doc/gui.txt
+++ b/doc/gui.txt
@@ -43,6 +43,27 @@ the `y column(s)` button and checking interesting columns.  We suggest
 you stick to columns with a single unit, and not try and dispay, for
 example, both meters and newtons on the same y axis.
 
+You can move about the plot using its navigation toolbar.  See the
+`Matplotlib manual`_ for details.
+
+.. _Matplotlib manual:
+  http://matplotlib.sourceforge.net/users/navigation_toolbar.html
+
+You can measure distances and forces directly in the plot.  If you
+want to know the coordinates of a single point, left click on it.  The
+index and coordinates of the nearest data point will be displayed in
+the status bar along with the x and y coordinates of your click.
+
+To find the distance between two points, just issue the command
+``delta``.  You will be asked to click two points.  When you click a
+point, a blue dot should appear.  When you click the second point, the
+distances will appear in the output panel.  Hooke automatically
+adjusts the position of the clicked point to the nearest point in the
+graph, so you will be always measuring distances and forces between
+points in the graph.
+
+.. todo:: Implement blue dots and click handler.
+
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