C H A P T E R 1 5

Controls

Controls are graphic objects that cause instant actions or visible results when users manipulate them with themouseorotherinputdevice. Standardcontrolsincludepushbuttons,scrollbars,radiobuttons,checkboxes, sliders, and pop-up menus.

This chapter discusses the behavior and appearance of controls available in Mac OS X. It also provides usage recommendations for each control so you can use them correctly in your application. When appropriate, this chapter also offers control dimensions, labeling guidelines, and recommended spacing metrics to help you lay out controls in your window (for more extensive window-layout guidelines, see “Layout Guidelines” (page 337)). Note that, in most cases, one dimension of a control (typically the height) is fixed and should not be changed. When this is the case, the description of the control may include the pixel measurement of the fixed dimension, but only to help you lay out your window, not because you need to use this measurement to create the control.

You are strongly encouraged to use standard, system-provided controls in your application. When you do this, you benefit in two important ways. First, these controls are automatically updated whenever the Mac OS X user interface is refreshed, which means that you don’t have to produce a new version of your application to take advantage of the new look. Second, the appropriate use of familiar controls allows users to predict how to operate your application and therefore spend more time discovering what it does.

In addition, you should strive to use only the standard control sizes, which are regular, small, and mini. Most applications look best with regular-size controls, although small and mini controls can work well when space is very limited, such as in a panel. In particular, take care to avoid vertically resizing controls. In Mac OS X v10.5 and later, vertically resizing a control can cause it to produce an undesirable look that does not harmonize with the window appearance.

Important: Every control described in this chapter is accompanied by at least one illustration that shows an example of the control. These illustrations show the appearance of the control, usually demonstrate a recommended usage, and sometimes show spacing metrics. However, the images of the controls themselves do not necessarily exhibit the precise measurements or colors you would observe in a running application. Therefore, you should never measure the images in this document and use those measurements to create controls or other user-interface elements. Note that when you use Interface Builder to create your user interface, you automatically get the proper control sizes.

Window-Frame Controls

As described in “Window Appearance” (page 188), the window frame consists of the title bar, toolbar, and bottom-bar areas, and the window body is between the toolbar–title bar area and the bottom bar (if there is one). A small subset of Mac OS X controls are intended for use only in the window-frame areas, because they have been specially designed to look good on the window-frame surface. These controls should not be used anywhere in the window body. Conversely, all other controls available in Mac OS X can be used in the window body, and most should not be used in the window-frame areas.

Window-Frame Controls

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