Code Folding

[thecoolwinter]

Description

Adds a code folding ribbon.

Note

For reviewers: Most of these changes have been reviewed individually in separate PRs. This shouldn't require a detailed combing over. If you can review a few things in particular like: architecture, naming, and bugs with real use I think those would be the best use of your limited time.

Detailed Changes

• Folding-related changes
  • Added FoldingRibbonView - A view that draws a set of folding ranges. This does all the drawing manually to avoid having to manage view reuse, it does the drawing in the regions macOS designates so it only draws a small part of the visible ribbon at a time.
  • Added LineFoldProvider - A protocol for classes to provide fold information to CodeEditSourceEditor. This takes a line number, range, depth, and a reference to the text controller and returns a list of 'line info' objects.
    • Added LineIndentationFoldProvider, an implementation of LineFoldProvider that calculates folds based on the user's indent setting.
  • Added LineFoldCalculator, which interfaces with the given LineFoldProvider to calculate new folds. This happens asynchronously and recalculates every so often. It's very fast but stays off the main thread to avoid ever gumming up the user's typing.
  • Added LineFoldingModel, which is the glue between the text view, calculator, and view.
  • To display folded folds, we display a LineFoldPlaceholder in the text view. This keeps a reference to the LineFoldingModel via a delegate protocol to tell the model when it's dismissed.

This is a slightly complicated object graph, so I've added a diagram here

flowchart TD
    TV["TextView"] -->|Text Updates| LFM["LineFoldingModel"]
    PL["LineFoldPlaceholder"] --> |Placeholder Removed| LFM
    LFM -->|Text Updates| LFC["LineFoldCalculator"]
    LFC -->|LineFoldStorage| LFM
    LFM -->|Storage Updated| FRV["FoldingRibbonView"]
    LFC <--> |Fold Info| LFP["any LineFoldProvider"]

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• Gutter View changes
  • New property showFoldingRibbon toggles the visibility of the folding ribbon view.
  • The gutter now manages the folding ribbon view as a subview.
  • Added an additional padding option on the gutter for the folding ribbon.
  • Makes a slight modification to how it draws line numbers by using a line iterator in the drawn lines, rather than the 'visible lines'. Uses less resources when macOS only requests a redraw for a specific rect rather than the whole gutter.
• Other, related changes
  • Modified the minimap. The minimap is now an attachment delegate to the text view's attachment object. It receives updates to the text view's attachments and adds a fake attachment to it's own layout manager. This effectively syncs the text view's attachments to the minimap.
  • Renamed DispatchQueue.syncMainIfNot to waitMainIfNot and updated it to use a better method for waiting for a dispatched work item.
  • Added an extension to NSBezierPath for rounding corners.
  • Added a new NSColor convenience initializer for creating light and dark mode colors more easily.
  • Moved the font character width calculation from TextViewController to an NSFont extension.

Related Issues

• ✨ Code Folding #43

Checklist

• Folds reflected in minimap.
• Double-click fold expands it.
• I read and understood the contributing guide as well as the code of conduct
• The issues this PR addresses are related to each other
• My changes generate no new warnings
• My code builds and runs on my machine
• My changes are all related to the related issue above
• I documented my code

Screenshots

Screen.Recording.2025-06-25.at.4.07.28.PM.mov