Font size in pixels

Question

On an iPhone how do I calculate the size of a character in pixels for a given point size?

Answer 1

The easiest way to get the pixel height for a given font and size is to use the boundingRect method on NSString. (I'm using @"Ap" here to make sure it contains a descender and an ascender.)

- (CGFloat)heightForFont:(UIFont *)font
{
    NSStringDrawingContext *context = [[NSStringDrawingContext alloc] init];
    CGRect boundingRect = [@"Ap" boundingRectWithSize:CGSizeMake(CGFLOAT_MAX, CGFLOAT_MAX) options:NSStringDrawingUsesFontLeading attributes:@{NSFontAttributeName:font} context:context];
    return boundingRect.size.height;
}