MacDownApp/macdown

Polish: Reduce font style jitter, seen when typing

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#953 opened on Apr 2, 2018

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 (1 comment) (0 reactions) (0 assignees)Objective-C (7,686 stars) (930 forks)batch import
enhancementhelp wanted

Description

(Feature/polish suggestion, not a bug)

As you type in the editor pane of Macdown, it seems to follow behind slightly, changing each letter to the correct "style" milliseconds later.

When you type in a # heading or in a **bold section**, however, there is a "jitter" that is noticeable and a little distracting.

The effect feels like this, as it jitters each letter you type in to place:

## [M]
## M[y]
## My [h]
## My h[e]
## My he[a]
## My hea[d]
## My head[i]
## My headi[n]
## My headin[g]
## My heading

For paragraphs, quotes, and lists, there's (usually, depends on font) no jitter. This is because the default document type style and the correct local style is the same.

My question is:

  • What level of effort would this be to fix? (2 weeks rewrite the whole text style preview engine? 2 days Tweak the event that prompts the recalculation?)
  • What classes should I look at if I were going to poke around and try to work this out?
  • What are the correct names for these two concepts in the codebase (document default type and styled local type)?
  • Any unexpected side effects I should think about besides perf?

PS. I use this program all the time. Love it. Thanks for making it.

Contributor guide

Tech stack
objective c
Domain
desktop
Issue type
feature
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.
1-2 days
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
Objective CmacOS developmenttext rendering
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
45
Research direction
Investigate the text rendering pipeline in MacDown, specifically how markdown styles are applied as the user types. Look at the editor view controller and text storage classes to identify where style recalculations occur. Check if the delay can be reduced by optimizing the recalculation trigger. Review the issue comments for any additional guidance.