Default attributes (#34)

* apply default text view attributes

* always use stored properties, even with TK2

* opt into TextKit 2 on iOS, too

Circumvents #20

* adjust tests for permanent attributes

* fix pasting code from Xcode rendering oddly

* store defaultTextViewAttributes to fix applying outdated styles

Projects/NeonExample-iOS/ViewController.swift

@@ -19,25 +19,32 @@ final class ViewController: UIViewController {
  let boldFont = UIFont.monospacedSystemFont(ofSize: 16, weight: .bold)
  let italicFont = regularFont.fontDescriptor.withSymbolicTraits(.traitItalic).map { UIFont(descriptor: $0, size: 16) } ?? regularFont
 
+ // Set the default styles. This is applied by stock `NSTextStorage`s during
+ // so-called "attribute fixing" when you type, and we emulate that as
+ // part of the highlighting process in `TextViewSystemInterface`.
+ textView.font = regularFont
+ textView.textColor = .darkGray
+
  let provider: TextViewSystemInterface.AttributeProvider = { token in
  return switch token.name {
  case let keyword where keyword.hasPrefix("keyword"): [.foregroundColor: UIColor.red, .font: boldFont]
  case "comment": [.foregroundColor: UIColor.green, .font: italicFont]
- default: [.foregroundColor: UIColor.darkText, .font: regularFont]
+ // Note: Default is not actually applied to unstyled/untokenized text.
+ default: [.foregroundColor: UIColor.blue, .font: regularFont]
  }
  }
 
  return try! TextViewHighlighter(textView: textView,
  language: language,
  highlightQuery: query,
+ executionMode: .synchronous,
  attributeProvider: provider)
  }()
 
  override func viewDidLoad() {
  super.viewDidLoad()
 
  _ = highlighter.textView
- _ = textView.layoutManager
 
  textView.text = """
  // Example Code!

Projects/NeonExample/ViewController.swift

@@ -10,22 +10,26 @@ final class ViewController: NSViewController {
 
  init() {
  self.textView = NSTextView()
+ textView.isRichText = false // Discards any attributes when pasting.
 
  scrollView.documentView = textView
 
  let regularFont = NSFont.monospacedSystemFont(ofSize: 16, weight: .regular)
  let boldFont = NSFont.monospacedSystemFont(ofSize: 16, weight: .bold)
  let italicFont = NSFont(descriptor: regularFont.fontDescriptor.withSymbolicTraits(.italic), size: 16) ?? regularFont
 
- // Alternatively, set `textView.typingAttributes = [.font: regularFont, ...]`
- // if you want to customize other default (fallback) attributes.
+ // Set the default styles. This is applied by stock `NSTextStorage`s during
+ // so-called "attribute fixing" when you type, and we emulate that as
+ // part of the highlighting process in `TextViewSystemInterface`.
  textView.font = regularFont
+ textView.textColor = .darkGray
 
  let provider: TextViewSystemInterface.AttributeProvider = { token in
  return switch token.name {
  case let keyword where keyword.hasPrefix("keyword"): [.foregroundColor: NSColor.red, .font: boldFont]
  case "comment": [.foregroundColor: NSColor.green, .font: italicFont]
- default: [.foregroundColor: NSColor.textColor, .font: regularFont]
+ // Note: Default is not actually applied to unstyled/untokenized text.
+ default: [.foregroundColor: NSColor.blue, .font: regularFont]
  }
  }
 

Sources/Neon/TextViewSystemInterface.swift

@@ -14,9 +14,20 @@ public struct TextViewSystemInterface {
 
  public let textView: TextView
  public let attributeProvider: AttributeProvider
+ public var defaultTextViewAttributes: [NSAttributedString.Key: Any] = [:]
 
- public init(textView: TextView, attributeProvider: @escaping AttributeProvider) {
+ public init(
+ textView: TextView,
+ defaultTextViewAttributes: [NSAttributedString.Key: Any] = [:],
+ attributeProvider: @escaping AttributeProvider
+ ) {
  self.textView = textView
+ // Assume that the default styles used before enabling any highlighting
+ // should be retained, unless client code overrides this.
+ self.defaultTextViewAttributes = [
+ .font: textView.font as Any,
+ .foregroundColor: textView.textColor as Any,
+ ].merging(defaultTextViewAttributes) { _, override in override }
  self.attributeProvider = attributeProvider
  }
 
@@ -43,34 +54,28 @@ public struct TextViewSystemInterface {
 }
 
 extension TextViewSystemInterface: TextSystemInterface {
- private func setAttributes(_ attrs: [NSAttributedString.Key : Any], in range: NSRange) {
+ private func clamped(range: NSRange) -> NSRange {
  let endLocation = min(range.max, length)
 
  assert(endLocation == range.max, "range is out of bounds, is the text state being updated correctly?")
 
- let clampedRange = NSRange(range.location..<endLocation)
+ return NSRange(range.location..<endLocation)
+ }
 
- // try text kit 2 first
- if
- #available(macOS 12, iOS 15.0, tvOS 15.0, *),
- let textLayoutManager = textLayoutManager,
- let contentManager = textLayoutManager.textContentManager,
- let textRange = NSTextRange(clampedRange, provider: contentManager)
- {
- textLayoutManager.setRenderingAttributes(attrs, for: textRange)
- return
- }
+ private func setAttributes(_ attrs: [NSAttributedString.Key : Any]?, in range: NSRange) {
+ let clampedRange = clamped(range: range)
 
- // For TextKit 1: Fall back to applying styles directly to the storage.
+ // Both `NSTextLayoutManager.setRenderingAttributes` and
  // `NSLayoutManager.setTemporaryAttributes` is limited to attributes
  // that don't affect layout, like color. So it ignores fonts,
  // making font weight changes or italicizing text impossible.
  assert(textStorage != nil, "TextView's NSTextStorage cannot be nil")
+ let attrs = attrs ?? defaultTextViewAttributes
  textStorage?.setAttributes(attrs, range: clampedRange)
  }
 
  public func clearStyle(in range: NSRange) {
- setAttributes([:], in: range)
+ setAttributes(nil, in: range)
  }
 
  public func applyStyle(to token: Token) {

Tests/NeonTests/TextViewSystemInterfaceTests.swift

@@ -65,7 +65,6 @@ final class TextViewSystemInterfaceTests: XCTestCase {
  XCTAssertEqual(attrs.count, 1)
  XCTAssertEqual(attrs[.foregroundColor] as? PlatformColor, PlatformColor.red)
  XCTAssertEqual(effectiveRange, NSRange(0..<6))
-
  }
 #endif
 
@@ -91,15 +90,13 @@ final class TextViewSystemInterfaceTests: XCTestCase {
 
  system.applyStyle(to: Token(name: "test", range: NSRange(0..<6)))
 
- let documentRange = textLayoutManager.documentRange
-
- var attrRangePairs = [([NSAttributedString.Key: Any], NSTextRange)]()
+ let textStorage = try XCTUnwrap(system.textStorage)
+ let documentRange = NSRange(location: 0, length: textStorage.length)
 
- textLayoutManager.enumerateRenderingAttributes(from: documentRange.location, reverse: false, using: { _, attrs, range in
+ var attrRangePairs = [([NSAttributedString.Key: Any], NSRange)]()
+ textStorage.enumerateAttributes(in: documentRange) { attrs, range, _ in
  attrRangePairs.append((attrs, range))
-
- return true
- })
+ }
 
  XCTAssertEqual(attrRangePairs.count, 1)