Cocoa in a Nutshell

Drawing Text

For many applications that use text, AppKit’s NSTextField or NSTextView classes are sufficient. However, when you need to draw text as part of some custom graphics, you may want to use Cocoa’s string drawing functionality, provided by AppKit’s extensions to the NSString and NSAttributedString.

The Application Kit adds three methods to the NSString class—drawAtPoint: withAttributes:, drawInRect:withAttributes:, and sizeWithAttributes:—that let you draw strings in views easily. The string being drawn is placed in the view to locate the upper-left corner of its bounding box at the point specified in drawAtPoint:withAttributes:. When using drawInRect:withAttributes:, the text is drawn within the rectangle. If the bounding box of the string is larger than the rectangle, then the string is clipped.

Attributed strings

Attributes are associated with a string by the Foundation class NSAttributedString. Table 4-2 enumerates these attributes.

Table 4-2. Standard Cocoa attributes for NSAttributedString

Attribute identifier	Type	Default value
NSAttachmentAttributeName	NSTextAttachment	No default
NSBackgroundColorAttributeName	NSColor	No default
NSBaselineOffsetAttributeName	NSNumber	0.0
NSFontAttributeName	NSFont	Helvetica 12 points
NSForegroundColorAttributeName	NSColor	Black
NSKernAttributeName	NSNumber	0.0
NSLigatureAttributeName	NSNumber	1
NSLinkAttributeName	id	No default
NSParagraphAttributeName	NSParagraphStyle	[NSParagraphStyle defaultParagraphStyle] ...