lexrus/LTMorphingLabel

Morphing animation messes up San Francisco Display font

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#61 opened on Jul 25, 2016

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enhancementhelp wanted

Description

I really like how the colon character (:) is a little bit raised up and not touching the baseline in the San Francisco Display font introduced in WWDC 2015. Here is how it is supposed to look like:

However, once I changed the text of the label to something else with the .Fall animation, the colon dropped onto the baseline:

I believe that this is caused by the way you draw the text using Core Text. Can you fix it?

Contributor guide

Tech stack
swift
Domain
mobile
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
SwiftCore TextiOS development
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
35
Research direction
Investigate the Core Text drawing code in LTMorphingLabel, specifically the method that renders text. The issue is that the colon character drops to the baseline during morphing animation. Examine how font attributes like baseline offset are handled. Since the issue is old, verify it still occurs with current iOS versions and the latest library code. Check comments for any previous attempts or maintainer input.