CODEWITHSUNDEEP
iosfonts
KudoCC
KudoCC

Reputation: 6952

Why is lineHeight of UIFont larger than font size?

I use the code below to calculate the number of lines of string with limited width.

NSString *text = @"abcdefgh";
UIFont *font = [UIFont systemFontOfSize:15.0];
CGFloat h = [text suggestHeightWithFont:font width:320.0];
NSInteger lines = (h > font.lineHeight) ? h/font.lineHeight+1 : h/font.lineHeight;
NSLog(@"height %f, %f, number lines:%ld", h, font.lineHeight, (unsigned long)lines);

But I found that font.lineHeight (log shows it is 17.900391) is larger than the font size which is set as 15.0.

The log message shows:

height 17.900391, 17.900391, number lines:1

Upvotes: 7

Views: 5553

Answers (1)

Daij-Djan
Daij-Djan

Reputation: 50109

lineHeight = a font's ascender (part of a letter that is above)
                  + a font's descender (so below baseline)
                  + a font's leading (vertical spacing)

e.g. for font size 10
A might have ascender=10, descender=0
g might have ascender=5, descender=4

lineHeight = 14 + leading ... 14,5 maybe

Note that the numbers here were random and only given to better illustrate the issue

Upvotes: 15

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