我可以在iOS的Core Text中使用NSAttributedString吗？ [英] Can I use NSAttributedString in Core Text in iOS?

问题描述

我正在尝试研究如何获取NSAttributedString并在iPad上的Core Text中使用它。我观看了其中一个有幻灯片（但没有源代码）的WWDC视频（110），它描述了如何创建NSAttributedString，然后将其放入CTFramesetterRef：

I'm trying to work out how to take an NSAttributedString and use it in Core Text on the iPad. I watched one of the WWDC videos (110) which has slides (but no source code) and it describes how to create an NSAttributedString, then just put it into a CTFramesetterRef:

CTFontRef helveticaBold = CTFontCreateWithName( CFSTR("Helvetica-Bold"), 24.0, NULL);

NSString* unicodeString = NSLocalizedString(@"TitleString", @"Window Title");
CGColorRef color = [UIColor blueColor].CGColor; NSNumber* underline = [NSNumber numberWithInt:kCTUnderlineStyleSingle|kCTUnderlinePatternDot];
NSDictionary* attributesDict = [NSDictionary dictionaryWithObjectsAndKeys:helveticaBold, (NSString*)kCTFontAttributeName, color, (NSString*)kCTForegroundColorAttributeName, underline, (NSString*)kCTUnderlineStyleAttributeName, nil];
NSAttributedString* stringToDraw = [[NSAttributedString alloc] initWithString:unicodeString attributes:attributesDict];

CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(stringToDraw);

CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), path, NULL);
CFRelease(framesetter);
CTFrameDraw(frame, context);
CFRelease(frame);

但是当我尝试这个时，会抛出错误：

But when I try this, it throws the error:

从不兼容的指针类型传递'CTFramesetterCreateWithAttributedString'的参数1

Passing argument 1 of 'CTFramesetterCreateWithAttributedString' from incompatible pointer type

是CFAttributedString和NSAttributedString '免费桥接'？我已经在某个地方读过，这只适用于OSX，但这就是Apple在他们的演示中的表现......

Are CFAttributedString and NSAttributedString 'toll-free bridged'? I've read somewhere that this is only true on OSX, but this is how Apple do it in their demo...

谢谢！

： - Joe

推荐答案

您可以下载WWDC10源代码此处。此外，使用免费桥接并将 stringToDraw 显式转换为 CFAttributedStringRef 。

You can download the WWDC10 source code here. In addition, use toll-free bridging and explicitly cast your stringToDraw to a CFAttributedStringRef.

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