MOUSE(9.4)                                             MOUSE(9.4)

          mouse - jerq mouse user interface

          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 reported when a button is
          released (let `up') as well as depressed (pressed `down').
          It therefore matters not only where and when a button 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 highlights 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

          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 convention well enough that an unfamiliar program can
          often be learned simply by trying it.  The main violators of
          the convention are drawing programs, 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 represen-
          tation of the program's state.  The most common cursors are:

               standard cursor

          coffee cup
               program will be busy for a while

          rectangle and arrow
               program expects a rectangle to be `swept out' by press-
               ing a button (usually 3) at one corner and releasing at
               the diagonally opposite corner

     MOUSE(9.4)                                             MOUSE(9.4)

               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

          It's still necessary to use the keyboard sometimes.