The following diagram edit commands are issued by using the mouse
and/or the keyboard in the drawing area. We have grouped them into 
creation commands, selection commands, text edit commands and movement 
commands.



CREATION COMMANDS.
==================

Create a node.
--------------
For creating a node, first choose the desired node type from the node 
tiles. Click button-1 in the background of the drawing area, at the 
desired position. A new node shape appears, having its center at the 
position where is clicked and having the shape as indicated by the 
selected node type in the tiles.

Create an edge.
---------------
To create a straight edge between two nodes, Drag with button-2 from 
a node to a node. This means you push and hold down button-2 somewhere 
inside the source node and move the mouse with button-2 still pushed 
down. 

To create a segmented edge, release button-2 in the background while 
you are dragging. Then the first intermediate point is created. After 
that, the line follows the mouse all by itself. Then you can add 
another intermediate point by clicking button-2 somewhere else in the 
background. You complete the edge by moving into the target node and 
clicking button-2.

To create a curved edge, set the Curve toggle in the tiled menu. The 
Bezier curve requires exactly two intermediate points, which makes four
edge points in total. These intermediate points are added in the same 
way as creating normal multiple line segments as described for 
segmented edges. When the four points are determined, a smooth curve is
drawn between the end points and the two intermediate points act as 
controlling points.



SELECTION COMMANDS.
==================

Select a single node or edge.
-----------------------------
Click button-1 on an unselected shape (node, edge). The selection will 
contain only this shape which will show black selection handles.

Select a part of the diagram.
-----------------------------
Drag button-1 starting in the background. The area that you are 
selecting, is enclosed by a stippled box, and its bottom-right corner 
is attached to the mouse. If you release button-1 then every shape 
that was (partly) inside the stippled box is selected and every other 
shape outside the box is unselected. One of these selected shapes will 
show black selection handles, the others will become grey.

Add a shape to the selection.
-----------------------------
Click button-2 on an unselected shape. The first selected shape will 
show black selection handles, the other selected shapes will show grey
selection handles.

Remove from the selection. 
--------------------------
Click button-2 on a selected shape. The selection handles disappear.

Empty the selection.
--------------------
Click button-2 somewhere in the background. All selection handles 
disappear.

Make selected shape first selected.
------------------------------------
You can enforce that a selected shape is the first selected by clicking
button-1 on an already selected (grey) shape. The selection handles of 
the old first selected shape will become grey and the handles
of the clicked shape will become black.



TEXT EDIT COMMANDS.
==================

Go into edit mode.
------------------
For getting into edit mode make sure that the shape with the label that
you want to edit is the only selected shape. When you move the mouse 
pointer into the single selected shape, the mouse pointer turns 
into I-shape. By clicking button-1 on the shape or typing the first
character you go into edit mode. 

There are two edit modes: in-line editing and out-line editing. In-line
editing takes place directly in the drawing area. Out-line editing 
takes place in a separate window with a text editor that is popped up 
when the edit mode is entered. You can indicate which of the two 
possible edit modes has to be used by a toggle button labeled in-line 
editor.

Edit text.
----------
In both in-line as the out-line editor you can type in any printable 
character as text and move the edit cursor around with the arrow 
buttons or by clicking with button-1 at the desired cursor position.
See the user manual for the more advanced text edit features.
 
Leave edit mode.
-----------------
From the in-line editor you leave edit mode by clicking button-1 
outside the shape that is being edited or by clicking button-2
at any position of the drawing area. The text that is edited will 
be updated, and when the autoresizing toggle is on, the shape will be
resized to make it fit the text that it contains. After the text is
updated, you can still undo the update including the autoresizing, 
by issuing the undo command from the Edit menu. 



MOVEMENT COMMANDS.
==================

Move one or more nodes.
-----------------------
You can move a node shape by positioning the mouse into that node and 
then drag it with button-1. The shape does not need to be selected. A 
grey node outline moves along with the mouse. If you release button-1 
then this node shape is redrawn at the new position and all its 
adjacent lines are redrawn too. You can also move the entire selection.
If you drag one of the selected node shapes, all other selected shapes 
are moved with over the same distance, including the line handles of 
the selected edges.
 
Moving an edge handle. 
----------------------
You can drag the individual handles of an edge. When an edge is 
selected and the mouse is in one of the handles, you can drag this 
handle with button-1 and a grey outline of the new line follows 
the mouse. You can move the intermediate handles of a line to an 
arbitrary place in the drawing area. When you drag and release one of 
the end point handles into the connected node or somewhere in the 
background, then the end point will be placed at the border of the 
connected node at a position that is the closest to the place where 
the handle was released.

Redirect an edge.
-----------------
When you drag an end point handle of an edge into a different node 
then the edge will be redirected to that node. The result is that the 
edge now connects to a different node.

Add an edge handle.
-------------------
You add an extra handle when you drag with button-1 from a segment
of an existing line. Where you release the button a new edge
handle is added to the line.

Remove an edge handle.
----------------------
You remove an intermediate handle when you click with button-2 on
a handle of a single-selected line.

Move the label of an edge.
--------------------------
You can move the label of an edge by dragging it with button-1. The 
edge need not be selected. You cannot move the label of a node; when 
you move or resize a node, the label positions inside the node are 
recalculated, as well as the labels of the adjacent edges.

Resize a node (from the center).
--------------------------------
Resizing a node shape is possible by dragging button-1 on one of the 
selection handles. The mouse pointer turns into one of the eight 
symbols that indicate to what direction the node shape can be resized.
With this operation the center of the node shape stays the same.

Resize a node (relocate its borders).
------------------------------------
Resizing a node shape is possible by dragging button-2 on one of the 
selection handles. The mouse pointer turns into one of the eight 
symbols that indicate to what direction the node shape can be resized.
With this operation the borders of node shape are moved.
