term% cat index.txt MOUSE(9.4) MOUSE(9.4)
NAME
mouse - jerq mouse user interface
DESCRIPTION
Most jerq programs use the mouse for control, either by pointing at
things on the screen or by making selections from a menu. The mouse
buttons are different from keys on a keyboard in that events are re‐
ported when a button is released (let `up') as well as depressed
(pressed `down'). It therefore matters not only where and when a but‐
ton is pressed, but for how long. For example, menus are drawn when a
button is depressed, and remain displayed as long as the button is held
down. While the button is down, moving the cursor over the menu high‐
lights entries in the menu; the entry (possibly none) under the cursor
when the button is released is the selection returned to the program.
Large menus also present a scroll bar on the left side of the menu.
Moving the mouse inside the scroll bar chooses which subset of the
available entries are displayed and therefore selectable.
There is a convention about how the buttons are used. The left button
(button 1) is used to point: selecting which layer to work in, which
file inside the editor, some text in the file, etc. The middle button
(button 2) produces a menu of actions related to the selection: remove
the selected text, replace it, etc. The right button (button 3)
presents a menu of global, program-wide actions: pick up a new file,
rearrange the files on the screen, etc. Programs follow this conven‐
tion well enough that an unfamiliar program can often be learned simply
by trying it. The main violators of the convention are drawing pro‐
grams, which use button 1 to draw things and button 2 to undraw them,
but this is also a consistent convention.
The mouse cursor is usually an arrow pointing at a pixel, but programs
often change the cursor to an iconic representation of the program's
state. The most common cursors are:
arrow standard cursor
coffee cup
program will be busy for a while
rectangle and arrow
program expects a rectangle to be `swept out' by pressing a but‐
ton (usually 3) at one corner and releasing at the diagonally
opposite corner
gunsight
program expects an object to be selected by pointing at it and
pressing a button (usually 3)
upside-down mouse
program is thinking; the mouse is inoperative
BUGS
It's still necessary to use the keyboard sometimes.
MOUSE(9.4)