A menu bar and pull-down menus are provided via extensions to the existing menu facility. Ten new menu sections are defined, named POP1 through POP10. If the display driver is capable of supporting the new user interface, and the status line is configured, AutoCAD scans the POP menu areas and assembles a menu bar consisting of the first lines of each of the pop-up menu sections. If no ***POPn sections are defined, or the display driver lacks the extended functions, or the status line is deconfigured, the menu bar and pop-up menu facility will be automatically disabled. Any POPn menu sections present will be ignored.
The menu bar is displayed by moving the pointer above the top of the graphics screen (exactly as the standard screen menu is activated by moving to the right of the graphics area). When the pointer moves off the top of the screen, the status line and first line of the standard screen menu are replaced by the menu bar. If the cursor is lowered back into the graphics area, the status line reappears. The menu bar may be accessed only with a physical pointing device--the arrow keys may not be used to display the menu bar.
When the cursor is moved over an item in the menu bar, it highlights by flipping to reverse video. If the pick button is pressed while a menu bar title is highlighted, a menu will appear on the screen below the title. Moving the cursor within a menu highlights items within it, and picking a highlighted menu item executes the commands associated with it. A pulled down menu remains down until either an item from it is picked, another menu is pulled down by picking it from the menu bar, the menu is removed by picking an unused section of the menu bar, or a point is selected by picking a point on the graphics screen, or a character is typed on the keyboard.
Pull down menus behave exactly as any other menu sections, and menu macros may be defined exactly as one would for the standard screen or tablet menus. Menu labels, which are limited to 8 characters for most display devices, may be of any length within POP menu sections.
Menu and submenu swapping via ``$'' commands may be used with pop-up menus. The pop-up menu areas are named P1 through P10 for menu swapping purposes. The following illustrates a menu swapping sequence.
***POP5 **P5A [Submarine] Ready Aim [Fire]$P5=P5B Ready [Steady]*^Credo Go [--] [Test Sonar]^Cgrid on [Raise periscope]^Csnap on [Lower periscope]^Csnap off [--] [Crash dive]^Cquit y **P5B 4 [Fire 2]$P5=P5C **P5C UpScope [Torpedos]$P5=P5D Running . . . [Ping]$P5=P5A **P5D 2 [~Empty]$P5=P5E **P5E 2 [Torpedos]$P5=P5D
Since the title which appears in the menu bar is simply the first line of the menu, the title may be changed by replacing that line of the menu with a $Pn= command. If the first line of the menu section is blank, no entry for it will appear in the menu bar. This allows you to turn whole menus on and off. This may not be a good idea in user interface design, but if you want to do it, you can.
If a menu item begins with a tilde (``~''), it will be displayed ``greyed out'', indicating that it is not a valid selection. The action taken when such a menu item is selected is up to the creator of the menu. If the item is a label with no commands, selecting it will have no effect. However, if you wish to have a greyed out menu item execute commands, you need only supply them. A menu item with a label of two minus signs is expanded to a separator line which fills the entire width of the menu. These items usually have no effect when picked, but again, if you supply commands to execute, AutoCAD will comply.
Editor: John Walker