C H A P T E R 7

Controls

Figure 7-10 Command pop-down menu specifications

Combination Boxes

A combination box (or combo box) is a text entry field combined with a drop-down scrolling list. Combo boxes are useful for displaying a list of likely choices while still allowing the user to type in an item not in the list.

Figure 7-11 Combo box with scrolling list open

The default state of the combo box is closed, with the text field empty or displaying a default selection. The default selection (not necessarily the first item in the list) should provide a meaningful clue to the hidden choices. The combo box should also have a useful label.

To create a combo box, Carbon developers can use the HIComboBoxCreate function and DrawThemeButton with the appropriate constant. Cocoa developers can use the NSComboBox class.

128Control Behavior and Appearance

Apple Computer, Inc. June 2002

C H A P T E R 7

Controls

Combo Box Specifications

■Height: 20 pixels. Small: 17 pixels.

■Width: Wide enough to accommodate the longest menu item.

■Spacing: Leave at least 12 pixels of space between stacked controls. Small: Leave at least 8 pixels of space.

■Menu item text: System font (13-point Lucida Grande Regular), 9 pixels from left edge and at least 9 pixels from the double-triangle section. Small: Small system font (11-point Lucida Grande Regular), 7 pixels from left edge and at least 7 pixels of space on the right.

■Menu label text: Emphasized system font (13-point Lucida Grande Bold), 8 pixels from text (colon) to left edge of menu. Small: Emphasized small system font (11-point Lucida Grande Bold), 6 pixels from text (colon) to left edge of menu.

The Text Entry Field

The user can type any appropriate characters into the text field. If the user types in an item already in the menu or list, or types in a few characters that match the first characters of an item in the list, the item is highlighted when the user opens the list. A user-typed item does not get added to the permanent list.

Apple Computer, Inc. June 2002