ArgoUML's broom alignment tool is specialized to
support the needs of designers in achieving the kind of
alignment used in UML diagrams. It is common for designers to
roughly align objects as they are created or by using simple
movement commands. The broom is an easy way to precisely align
objects that are already roughly aligned. Furthermore, the
broom's distribution options are suited to the needs of
UML designers: making related objects appear evenly spaced,
packing objects to save diagram space, and spreading objects
out to make room for new objects. The broom also makes it easy
to change from horizontal to vertical alignment or from
left-alignment to right-alignment.
The T-shaped icon in ArgoUML's diagram toolbar
invokes the broom alignment tool. When the mouse button 1 is
pressed while in broom-mode, the designer's initial mouse
movement orients the broom to face in one of four directions:
north, south, east, or west. After that, mouse drag events
cause the broom to advance in the chosen direction, withdraw,
or grow in a lateral direction. Like a real-world push broom,
the broom tool pushes diagram elements that come in contact
with it. This has the effect of aligning objects along the face
of the broom and provides immediate visual feedback (see the
figure below). Unlike a real-world broom, moving backwards
allows diagram elements to return to their original position.
Growing the broom makes it possible to align objects that are
not near each other. When the mouse button is released, the
broom disappears and the moved objects are selected to make it
easy to manipulate them further.
If the designer presses the space bar
while using the
broom, objects on the face of the broom are distributed (i.e.,
spaced evenly). ArgoUML's broom supports three
distribution modes: objects can be spaced evenly across the
space that they use, objects can be packed together with only a
small gap between them, or objects can be distributed evenly
over the entire length of the broom's face. Repeatedly
pressing the space bar cycles among these three distribution
modes and displays a brief message indicating the operation
just performed: Space evenly, Pack tightly, Spread out and
If the designer presses the Enter
key while using the broom,
the broom turns red (instead of the normal blue), and objects are not
picked up by the broom when moving forward.
It works like lifting up the broom.
Pressing Enter again returns to the normal mode.
Pressing the Tab
key works exactly like the Enter key.