CODEWITHSUNDEEP
iosnsattributedstringtextkit
EthanB
EthanB

Reputation: 4289

NSAttributedString relative font-size custom attribute

In CSS, you have the font-size property that can be used to specify font sizes relative to the rest of the text.

What would it take to implement a custom relative font-size attribute in iOS (requiring only iOS 7 compatibility)? Are there any third-party solutions that already implement this?

(I would expect the solution to be useful for everything that supports attributed text: UILabel, UITextView, ... the titleLabel in a UIButton, etc.)

Upvotes: 0

Views: 765

Answers (1)

bilobatum
bilobatum

Reputation: 8918

Let's say you want to define attributes for your own custom headers that are relative to the user's preferred body font size (i.e, Dynamic Type).

UIFontDescriptor *bodyFontDescriptor = [UIFontDescriptor preferredFontDescriptorWithTextStyle:UIFontTextStyleBody];

NSNumber *bodyFontSize = bodyFont.fontAttributes[UIFontDescriptorSizeAttribute];

float bodyFontSizeValue = [bodyFontSize floatValue];

UIFont *headerOneFont = [UIFont fontWithDescriptor:bodyFontDescriptor size:bodyFontSizeValue * 3.0f];

NSDictionary *headerOneAttributes = @{NSFontAttributeName : headerOneFont};

UIFont *headerTwoFont = [UIFont fontWithDescriptor:bodyFontDescriptor size:bodyFontSizeValue * 2.0f];

NSDictionary *headerTwoAttributes = @{NSFontAttributeName : headerTwoFont};

This code is based on code from Chapters 4 and 5 of "iOS 7 by Tutorials", by raywenderlich.com.

The attribute dictionaries can be used to initialize attributed string objects, which in turn, can be displayed in UILabels, UITextViews, and UITextFields.

Upvotes: 1

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