Wrong bounding rect for some strings when using "FS Albert Pro" font #121
Comments
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Unfortunately CTFramesetter may return wrong results as well, but for height value. Playground code (you need to add FS Albert Pro font to your playground resources): import UIKit
func calculateSizes(string: NSAttributedString) {
let maxSize = CGSize(width: 180, height: CGFloat.max)
let stringSize = string.boundingRectWithSize(maxSize, options: [.UsesLineFragmentOrigin, .UsesFontLeading], context: nil).size
print("boundingRect: \(stringSize)")
let range = CFRangeMake(0, string.length)
let framesetter = CTFramesetterCreateWithAttributedString(string)
let framesetterSize = CTFramesetterSuggestFrameSizeWithConstraints(framesetter, range, nil, maxSize, nil)
print("framesetter: \(framesetterSize)")
}
let text = "Мруа паваЫотрПрпв."
// System Font
print("System font:")
let attributes = [NSFontAttributeName: UIFont.systemFontOfSize(16)]
calculateSizes(NSAttributedString(string: text, attributes: attributes))
// FS Albert Pro font
print()
print("FS Albert Pro font:")
let url = NSBundle.mainBundle().URLForResource("FS Albert Pro", withExtension: "otf")
CTFontManagerRegisterFontsForURL(url!, CTFontManagerScope.Process, nil)
calculateSizes(NSAttributedString(string: text, attributes: [NSFontAttributeName: UIFont(name: "FSAlbertPro", size: 16)!]))will produce next output: As you can see, using CTFramesetter will solve the issue for "FS Albert Pro" font (all values are bigger than values returned from |
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@AntonPalich I couldn't help myself investigating this interesting issue... Take a look at this rendering comparison between UILabel and UITextView. UITextView's text is wider, and the distance in between "р" and "у" is slightly bigger, which leads to text kerning: https://www.objc.io/issues/5-ios7/getting-to-know-textkit/ The following seems to solve the issue, although I didn't test it thoroughly with different font faces and sizes... @@ -237,7 +237,10 @@ private final class TextBubbleLayoutModel {
return self.layoutContext.text.boundingRectWithSize(
CGSize(width: width, height: CGFloat.max),
options: [.UsesLineFragmentOrigin, .UsesFontLeading],
- attributes: [NSFontAttributeName: self.layoutContext.font], context: nil
+ attributes: [
+ NSFontAttributeName: self.layoutContext.font,
+ NSKernAttributeName: 0,
+ ], context: nil
).size.bma_round()
}
}ps: our size calculation should match UITextView.sizeThatFits(_:) after rounding. We're using boundingRectWithSize because it's way faster and UITextView can't be used in the background. |
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@diegosanchezr Great! This solved the issue, i'll revert previous changes |
boundingRectWithSize(_:options:attributes:context:)returns wrong bounding rect for string "Мруа паваЫотрПрпв." with font FS Albert Pro of size 16.00AR: Width is equal 150
ER: Width is equal 151
A possible solution would be to use CTFramesetter to calculate string sizes because it returns correct width in this case
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