How to use drawInRect:withAttributes: instead of drawAtPoint:forWidth:withFont:fontSize:lineBreakMode:baselineAdjustment: in iOS 7

寵の児 提交于 2019-12-02 17:02:01

You can use NSDictionary and apply attributes like this:

NSFont *font = [NSFont fontWithName:@"Palatino-Roman" size:14.0];

NSDictionary *attrsDictionary =

[NSDictionary dictionaryWithObjectsAndKeys:
                              font, NSFontAttributeName,
                              [NSNumber numberWithFloat:1.0], NSBaselineOffsetAttributeName, nil];

Use attrsDictionary as argument.

Refer: Attributed String Programming Guide

Refer: Standard Attributes

SWIFT: IN String drawInRect is not available but we can use NSString instead:

let font = UIFont(name: "Palatino-Roman", size: 14.0)
let baselineAdjust = 1.0
let attrsDictionary =  [NSFontAttributeName:font, NSBaselineOffsetAttributeName:baselineAdjust] as [NSObject : AnyObject]
let str:NSString = "Hello World"
str.drawInRect(CGRectZero, withAttributes: attrsDictionary)

It is a little more complicated than before and you cannot use a minimum font size, but have to use minimum font scale factor. There is also a bug in the iOS SDK, which breaks it for most use cases (see notes at the bottom). Here is what you have to do:

// Create text attributes
NSDictionary *textAttributes = @{NSFontAttributeName: [UIFont systemFontOfSize:18.0]};

// Create string drawing context
NSStringDrawingContext *drawingContext = [[NSStringDrawingContext alloc] init];
drawingContext.minimumScaleFactor = 0.5; // Half the font size

CGRect drawRect = CGRectMake(0.0, 0.0, 200.0, 100.0);
[string drawWithRect:drawRect
             options:NSStringDrawingUsesLineFragmentOrigin
          attributes:textAttributes
             context:drawingContext];

Notes:

  • There seems to be a bug in the iOS 7 SDK at least up to version 7.0.3: If you specify a custom font in the attributes, the miniumScaleFactor is ignored. If you pass nil for the attributes, the text is scaled correctly.

  • The NSStringDrawingUsesLineFragmentOrigin option is important. It tells the text drawing system, that the drawing rect's origin should be at the top left corner.

  • There is no way to set the baselineAdjustment using the new method. You would have to do that yourself by calling boundingRectWithSize:options:attributes:context: first and then adjusting the rect before you pass it to drawWithRect:options:attributes:context.

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