View source for Core Text

{{Use mdy dates|date=October 2013}}
{{Refimprove|date=September 2007}}
'''Core Text''' is a [[Core Foundation]] style [[API]] in [[macOS]], first introduced in [[Mac OS X v10.4|Mac OS X 10.4 Tiger]], made public in [[Mac OS X v10.5|Mac OS X 10.5 Leopard]], and introduced for the [[iPad]] with iPhone SDK 3.2. Exposing a [[C (programming language)|C]] [[application programming interface|API]], it replaces the text rendering abilities of the now-deprecated [[QuickDraw]] and [[ATSUI]] frameworks in previous versions of Mac OS X. According to Apple, Core Text is "designed for high performance and ease of use" and its layout API is "simple, consistent, and tightly integrated with Core Foundation, Core Graphics, and Cocoa."<ref>[https://developer.apple.com/library/archive/documentation/StringsTextFonts/Conceptual/CoreText_Programming/Introduction/Introduction.html#//apple_ref/doc/uid/TP40005533 Core Text Programming Guide: Core Text Overview<!-- Bot generated title -->]</ref>

== Features ==
Core Text provides the following opaque types:
* '''CTFramesetter''' - creates CTFrame objects from given attributed string object and CGPath object using CTTypesetter.
* '''CTTypesetter''' - performs line layouts; e.g., line breaking
* '''CTFrame''' - represents an array of lines (i.e., CTLine objects).
* '''CTLine''' - represents an array of glyph runs.
* '''CTRun''' - an ordered collection of glyphs sharing the same attribute.
* '''CTFont''' - represents a font.

== Example ==
The following code displays the text "Hello, World!" to the given graphics context in [[Objective-C]].
<syntaxhighlight lang="c">
// Prepare font
CTFontRef font = CTFontCreateWithName(CFSTR("Times"), 48, NULL);

// Create an attributed string
CFStringRef keys[] = { kCTFontAttributeName };
CFTypeRef values[] = { font };
CFDictionaryRef attr = CFDictionaryCreate(NULL, (const void **)&keys, (const void **)&values,
					  sizeof(keys) / sizeof(keys[0]), &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
CFAttributedStringRef attrString = CFAttributedStringCreate(NULL, CFSTR("Hello, World!"), attr);
CFRelease(attr);

// Draw the string
CTLineRef line = CTLineCreateWithAttributedString(attrString);
CGContextSetTextMatrix(context, CGAffineTransformIdentity);  //Use this one when using standard view coordinates
//CGContextSetTextMatrix(context, CGAffineTransformMakeScale(1.0, -1.0)); //Use this one if the view's coordinates are flipped

CGContextSetTextPosition(context, 10, 20);
CTLineDraw(line, context);

// Clean up
CFRelease(line);
CFRelease(attrString);
CFRelease(font);
</syntaxhighlight>

== References ==

<references/>

== External links ==
* [https://developer.apple.com/library/archive/documentation/StringsTextFonts/Conceptual/CoreText_Programming/Introduction/Introduction.html#//apple_ref/doc/uid/TP40005533 Core Text overview] at [[Apple Developer Connection]]

{{Apple}}
{{Core Foundation}}
{{macOS}}

{{Mac-stub}}

[[Category:Text rendering libraries]]
[[Category:macOS APIs]]