C H A P T E R 7
Controls
When you define dimensions, make sure that the list displays only full lines of text (don’t cut text off vertically), and make sure that the scrolling increment is one list element.
■Text: 12 points
■Frame: 3 pixels wide
Image Wells
Use an image well to display an icon or picture that serves as a drag-and-drop target. You could use a set of image wells to manage thumbnails in a clip-art catalog, for example. Don’t use image wells in place of push buttons or bevel buttons.
Figure 7-33 |
Image wells |
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Normal |
Selected |
Selected plus Drop target |
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dropped |
Some image wells (the user picture in the Edit User pane of Accounts preferences, for example) must always contain an image. If the user can clear an image well (leaving it empty) in your application, provide standard Edit menu commands and Clipboard support.
Control Behavior and Appearance |
147 |
Apple Computer, Inc. June 2002
C H A P T E R 7
Controls
Disclosure Triangles
A disclosure triangle allows the display, or disclosure, of information that elaborates on the primary information in a window. Disclosure triangles are used in the Finder’s list view, where clicking a triangle displays a folder’s contents.
Figure 7-34 Disclosure triangles in the Finder list view
Disclosure triangle in closed state
Disclosure triangle in open state
Disclosure triangles are available to Carbon developers through the Control Manager (CreateDisclosureTriangleControl) or the Appearance Manager (DrawThemeButton). Cocoa provides this control only as part of the NSOutlineView class.
148Control Behavior and Appearance
Apple Computer, Inc. June 2002