Update distance-measurement sections of doc/tutorial.txt and 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.
+
 Folders
 =======
 Here you can navigate your file system and double click on a saved

diff --git a/doc/tutorial.txt b/doc/tutorial.txt
index 714c59716e60fc5c8d238e0c72bd78766525af81..89a1919a1e09ddcb7b21aca2ad2a37f047ac75c4 100644 (file)
--- a/doc/tutorial.txt
+++ b/doc/tutorial.txt
@@ -95,9 +95,9 @@ the end of the stdin stream, which is Ctrl-d in many shells).
 Creating a playlist
 -------------------
 
-To start analyzing your curves, you first have to build a playlist. The
-playlist is just an index of the force curve files you want to
-analyze. Imagine it as a music playlist (that’s why it is called a
+To start analyzing your curves, you first have to build a playlist.
+The playlist is just an index of the force curve files you want to
+analyze.  Imagine it as a music playlist (that’s why it is called a
 playlist), but with data files instead of audio files.
 
 Suppose you have 100 PicoForce curve files in your curves directory,
@@ -234,7 +234,7 @@ blank note string with ``set_note ''``.
 Exporting curves
 ----------------
 
-You can export Hooke curves as images and as text columns. To export
+You can export Hooke curves as images and as text columns.  To export
 as images or text, use the ``export_block`` command.  Supported
 formats are PNG (Portable Network Graphic, raster) and EPS
 (Encapsulated Postscript, vector).  The export format is determined by
@@ -260,23 +260,24 @@ Interacting with the plot
 Measuring distances and forces
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-You can move about the plot using its navigation toolbar.  See the
-`Matplotlib manual`_ for details.
+To measure the distance between points, use the ``delta`` command.
+For example,::
 
-.. _Matplotlib manual:
-  http://matplotlib.sourceforge.net/users/navigation_toolbar.html
+    hooke> delta 300 500
 
-You can measure distances and forces directly in the plot. 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.  If you
-want to know the coordinates of a single point, left click on it.
+will measure the distance between the 300th point and the 500th point.
+One difficulty with the command line interface is that is difficult
+to know which points you're interested without seeing the plot.  The
+two ways around this are:
 
-.. todo:: Add description of ``delta``'s command line interface.
+1) Export the block (with ``export_block``), and graph the exported
+   file with a program of your choice (e.g. Gnuplot_).  Use the
+   resulting graph to determine the indices of the points you are
+   interested in.
+2) Run Hooke's GUI instead of the command line when you need to make
+   manual measurements.  See :doc:`gui` for details.
 
-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.
+.. _Gnuplot: http://gnuplot.sourceforge.net/
 
 Worm like chain and freely jointed chain fitting
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -290,7 +291,7 @@ delimiting the portion to fit, and performs a two-variable fit, with
 contour length, persistence length, and their relative errors as
 output.  If desired, one can use the ``noauto`` option to manually
 click the contact point, and/or the ``pl=NUMBER`` options to impose a
-specific persistence or Kuhn length (in nanometers). You can choose
+specific persistence or Kuhn length (in nanometers).  You can choose
 which model to use with ``set fit_function wlc`` or ``set fit_function
 fjc``.  See the help of the ``fit`` command from the Hooke command
 line for details.
@@ -321,9 +322,9 @@ directory.
 Configuring Hooke
 -----------------
 
-You can set environment variables to influence the behaviour of
-Hooke. The command to use is ``set_config``.  Use ``get_config`` to
-read a particular option and ``print_config`` to display the entire
+You can set environment variables to influence the behaviour of Hooke.
+The command to use is ``set_config``.  Use ``get_config`` to read a
+particular option and ``print_config`` to display the entire
 configuration file.  To save changes, either run ``save_config`` or
 start Hooke with the ``--save-config`` option.  See :doc:`config` for
 details.