UITextField in iOS 8.1 have different vertical text alignment between editing and not editing mode when using some fonts

Originator:diogot
Number:rdar://19374610 Date Originated:2015/01/05
Status:Open Resolved:
Product:iOS Product Version:8.1.2
Classification:UI Reproducible:Always
 
Summary:
UITextField in iOS 8.1 have different vertical text alignment between editing and not editing mode when using some fonts like Helvetica Neue Light 17.

Steps to Reproduce:
- Add a UITextField
- Set the font to Helvetica Neue Light 17 or a text style like UIFontTextStyleBody or UIFontTextStyleHeadline. May happen with other fonts
- Run
- Tap on the text field

Expected Results:
The text don't moves

Actual Results:
When the text field becomes the first responder the text moves up a few pixels

Version:
iOS 8.1.2 (12B440)

Notes:
Example project https://github.com/diogot/UITextFieldBug

Configuration:
All tested devices (and simulator) with iOS 8.1, iOS 8.0 not tested. In iOS 7.1 the bug is not present.

Comments

Workaround

The following snippet in a UITextField subclass should fix the issue: 

- (CGRect)editingRectForBounds:(CGRect)bounds
{
    if (UIDevice.currentDevice.systemVersion.integerValue != 8) return [self textRectForBounds:bounds];

    CGFloat const scale = UIScreen.mainScreen.scale;
    CGFloat const preferred = self.attributedText.size.height;
    CGFloat const delta = ceil(preferred) - preferred;
    CGFloat const adjustment = floor(delta * scale) / scale;

    CGRect const textRect = [self textRectForBounds:bounds];
    CGRect const editingRect = CGRectOffset(textRect, 0.0, adjustment);

    return editingRect;
}

See http://stackoverflow.com/a/30676237/796103 for a detailed explanation.

By tmjenox at June 6, 2015, 2:24 p.m. (reply...)

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