Text Recipes Cookbook

Use when the user has a "how do I..." question about text views and you need a quick working recipe, or when they want a copy-paste snippet for a common text task rather than architecture guidance. Covers the 25 most common text tasks - background colors per paragraph, line numbers, character limits, text wrapping around images, clickable links, syntax highlighting, placeholder text, auto-growing text views, and more.

Workflow Skills

Use when the user has a “how do I…” question about text views and you need a quick working recipe, or when they want a copy-paste snippet for a common text task rather than architecture guidance. Covers the 25 most common text tasks - background colors per paragraph, line numbers, character limits, text wrapping around images, clickable links, syntax highlighting, placeholder text, auto-growing text views, and more.

Family: Front Door Skills

Quick, working solutions to the most common “how do I…” questions about Apple text views.

When to Use

User asks “how do I [specific text thing]?” and you need a direct answer.
You need a working code snippet, not architecture guidance.
The question maps to a common text task that doesn’t need a full skill.

Quick Index

#	Recipe	Framework
1	Background color behind a paragraph	TextKit 1 / TextKit 2
2	Line numbers in a text view	TextKit 1
3	Character/word limit on input	UITextView delegate
4	Text wrapping around an image	NSTextContainer
5	Clickable links (not editable)	UITextView
6	Clickable links (editable)	UITextView delegate
7	Placeholder text in UITextView	UITextView
8	Auto-growing text view (no scroll)	Auto Layout
9	Highlight search results	Temporary attributes
10	Strikethrough text	NSAttributedString
11	Letter spacing (tracking/kern)	NSAttributedString
12	Different line heights per paragraph	NSParagraphStyle
13	Indent first line of paragraphs	NSParagraphStyle
14	Bullet/numbered lists	NSTextList / manual
15	Read-only styled text	UITextView
16	Detect data (phones, URLs, dates)	UITextView
17	Custom cursor color	UITextView
18	Disable text selection	UITextView
19	Programmatically scroll to range	UITextView
20	Get current line number	TextKit 1

1. Background Color Behind a Paragraph

Using `.backgroundColor` attribute (simple)

let attrs: [NSAttributedString.Key: Any] = [
    .backgroundColor: UIColor.systemYellow.withAlphaComponent(0.3),
    .font: UIFont.systemFont(ofSize: 15)
]
let highlighted = NSAttributedString(string: "This paragraph has a background", attributes: attrs)

Limitation: Only colors the area directly behind glyphs, not full-width.

Full-width paragraph background (TextKit 1 subclass)

class ParagraphBackgroundLayoutManager: NSLayoutManager {
    override func drawBackground(forGlyphRange glyphsToShow: NSRange, at origin: CGPoint) {
        super.drawBackground(forGlyphRange: glyphsToShow, at: origin)

        guard let textStorage = textStorage else { return }

        textStorage.enumerateAttribute(.paragraphBackgroundColor,
                                        in: characterRange(forGlyphRange: glyphsToShow,
                                                           actualGlyphRange: nil)) { value, charRange, _ in
            guard let color = value as? UIColor else { return }
            let glyphRange = self.glyphRange(forCharacterRange: charRange, actualCharacterRange: nil)

            enumerateLineFragments(forGlyphRange: glyphRange) { rect, _, container, _, _ in
                guard let context = UIGraphicsGetCurrentContext() else { return }
                let fullWidthRect = CGRect(
                    x: 0,
                    y: rect.origin.y + origin.y,
                    width: container.size.width,
                    height: rect.height
                )
                context.setFillColor(color.cgColor)
                context.fill(fullWidthRect)
            }
        }
    }
}

// Register custom attribute
extension NSAttributedString.Key {
    static let paragraphBackgroundColor = NSAttributedString.Key("paragraphBackgroundColor")
}

2. Line Numbers in a Text View

class LineNumberGutter: UIView {
    weak var textView: UITextView?

    func updateLineNumbers() {
        guard let textView = textView,
              let layoutManager = textView.layoutManager else { return }

        setNeedsDisplay()
    }

    override func draw(_ rect: CGRect) {
        guard let textView = textView,
              let layoutManager = textView.layoutManager else { return }

        let font = UIFont.monospacedDigitSystemFont(ofSize: 12, weight: .regular)
        let attrs: [NSAttributedString.Key: Any] = [
            .font: font,
            .foregroundColor: UIColor.secondaryLabel
        ]

        let visibleGlyphRange = layoutManager.glyphRange(
            forBoundingRect: textView.bounds,
            in: textView.textContainer
        )

        var lineNumber = 1
        var previousLineY: CGFloat = -1
        let inset = textView.textContainerInset

        // Count lines before visible range
        let textBeforeVisible = (textView.text as NSString)
            .substring(to: layoutManager.characterRange(
                forGlyphRange: NSRange(location: visibleGlyphRange.location, length: 0),
                actualGlyphRange: nil).location)
        lineNumber = textBeforeVisible.components(separatedBy: "\n").count

        layoutManager.enumerateLineFragments(forGlyphRange: visibleGlyphRange) {
            rect, _, _, glyphRange, _ in

            let charRange = layoutManager.characterRange(forGlyphRange: glyphRange,
                                                          actualGlyphRange: nil)
            let lineY = rect.origin.y + inset.top - textView.contentOffset.y

            // Only number paragraph-starting lines
            if charRange.location == 0 ||
               (textView.text as NSString).character(at: charRange.location - 1) == 0x0A {
                let numStr = "\(lineNumber)" as NSString
                let size = numStr.size(withAttributes: attrs)
                numStr.draw(at: CGPoint(
                    x: self.bounds.width - size.width - 4,
                    y: lineY + (rect.height - size.height) / 2
                ), withAttributes: attrs)
                lineNumber += 1
            }
        }
    }
}

3. Character/Word Limit

// Character limit
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange,
              replacementText text: String) -> Bool {
    let currentLength = textView.text.count
    let replacementLength = text.count
    let rangeLength = range.length
    let newLength = currentLength - rangeLength + replacementLength
    return newLength <= 280  // Twitter-style limit
}

// Word limit
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange,
              replacementText text: String) -> Bool {
    let currentText = (textView.text as NSString).replacingCharacters(in: range, with: text)
    let wordCount = currentText.split(separator: " ").count
    return wordCount <= 500
}

4. Text Wrapping Around an Image

// Add image view as subview of text view
let imageView = UIImageView(image: myImage)
imageView.frame = CGRect(x: 16, y: 16, width: 120, height: 120)
textView.addSubview(imageView)

// Create exclusion path in text container coordinates
let inset = textView.textContainerInset
let exclusionRect = CGRect(
    x: imageView.frame.origin.x - inset.left + imageView.frame.width,
    y: imageView.frame.origin.y - inset.top,
    width: imageView.frame.width + 8,
    height: imageView.frame.height + 8
)

// Set right-aligned exclusion (text wraps on left side)
textView.textContainer.exclusionPaths = [UIBezierPath(rect: CGRect(
    x: textView.textContainer.size.width - 120 - 8,
    y: 0,
    width: 120 + 8,
    height: 120 + 8
))]

5. Clickable Links (Non-Editable)

textView.isEditable = false
textView.isSelectable = true
textView.dataDetectorTypes = [.link]  // Auto-detect URLs

// Or manual links via attributed string:
let text = NSMutableAttributedString(string: "Visit our website for details.")
text.addAttribute(.link, value: URL(string: "https://example.com")!,
                  range: NSRange(location: 10, length: 7))
textView.attributedText = text

// Handle taps:
func textView(_ textView: UITextView, shouldInteractWith URL: URL,
              in characterRange: NSRange,
              interaction: UITextItemInteraction) -> Bool {
    // Return true for default behavior, false to handle yourself
    return true
}

6. Clickable Links (Editable Text View)

// Links in editable text views don't respond to taps by default.
// Use UITextViewDelegate to detect taps on link-attributed ranges:
func textView(_ textView: UITextView, shouldInteractWith URL: URL,
              in characterRange: NSRange,
              interaction: UITextItemInteraction) -> Bool {
    if interaction == .invokeDefaultAction {
        UIApplication.shared.open(URL)
        return false
    }
    return true
}

7. Placeholder Text in UITextView

class PlaceholderTextView: UITextView {
    var placeholder: String = "" {
        didSet { setNeedsDisplay() }
    }

    var placeholderColor: UIColor = .placeholderText

    override var text: String! {
        didSet { setNeedsDisplay() }
    }

    override func draw(_ rect: CGRect) {
        super.draw(rect)
        guard text.isEmpty else { return }

        let attrs: [NSAttributedString.Key: Any] = [
            .font: font ?? .systemFont(ofSize: 17),
            .foregroundColor: placeholderColor
        ]
        let inset = textContainerInset
        let padding = textContainer.lineFragmentPadding
        let placeholderRect = CGRect(
            x: inset.left + padding,
            y: inset.top,
            width: bounds.width - inset.left - inset.right - 2 * padding,
            height: bounds.height - inset.top - inset.bottom
        )
        placeholder.draw(in: placeholderRect, withAttributes: attrs)
    }

    // Call setNeedsDisplay in textDidChange notification
}

8. Auto-Growing Text View

// The simplest approach: disable scrolling
textView.isScrollEnabled = false
// Auto Layout now uses intrinsicContentSize to grow the text view

// With a maximum height:
textView.isScrollEnabled = false

// In your constraint setup:
let heightConstraint = textView.heightAnchor.constraint(lessThanOrEqualToConstant: 200)
heightConstraint.isActive = true

// When content exceeds max height, enable scrolling:
func textViewDidChange(_ textView: UITextView) {
    let fittingSize = textView.sizeThatFits(
        CGSize(width: textView.bounds.width, height: .greatestFiniteMagnitude)
    )
    textView.isScrollEnabled = fittingSize.height > 200
}

9. Highlight Search Results

// TextKit 1 — temporary attributes (don't modify the model)
func highlightOccurrences(of searchText: String, in textView: UITextView) {
    guard let layoutManager = textView.layoutManager,
          let text = textView.text else { return }

    // Clear previous highlights
    let fullRange = NSRange(location: 0, length: (text as NSString).length)
    layoutManager.removeTemporaryAttribute(.backgroundColor, forCharacterRange: fullRange)

    // Add new highlights
    var searchRange = text.startIndex..<text.endIndex
    while let range = text.range(of: searchText, options: .caseInsensitive, range: searchRange) {
        let nsRange = NSRange(range, in: text)
        layoutManager.addTemporaryAttribute(.backgroundColor,
                                             value: UIColor.systemYellow,
                                             forCharacterRange: nsRange)
        searchRange = range.upperBound..<text.endIndex
    }
}

10. Strikethrough Text

// Single strikethrough
let attrs: [NSAttributedString.Key: Any] = [
    .strikethroughStyle: NSUnderlineStyle.single.rawValue,
    .strikethroughColor: UIColor.red
]

// Double strikethrough
let attrs: [NSAttributedString.Key: Any] = [
    .strikethroughStyle: NSUnderlineStyle.double.rawValue
]

// Thick strikethrough
let attrs: [NSAttributedString.Key: Any] = [
    .strikethroughStyle: NSUnderlineStyle.thick.rawValue
]

11. Letter Spacing

// Kern — fixed spacing in points (doesn't scale with font size)
let attrs: [NSAttributedString.Key: Any] = [
    .kern: 2.0  // 2pt between characters
]

// Tracking (iOS 14+) — scales with font size
let attrs: [NSAttributedString.Key: Any] = [
    .tracking: 0.5  // Proportional to font size
]

Use .tracking when possible — it produces consistent results across font sizes.

12. Different Line Heights Per Paragraph

func styledParagraph(_ text: String, lineHeight: CGFloat, font: UIFont) -> NSAttributedString {
    let style = NSMutableParagraphStyle()
    style.minimumLineHeight = lineHeight
    style.maximumLineHeight = lineHeight

    let baselineOffset = (lineHeight - font.lineHeight) / 2

    return NSAttributedString(string: text + "\n", attributes: [
        .font: font,
        .paragraphStyle: style,
        .baselineOffset: baselineOffset
    ])
}

let result = NSMutableAttributedString()
result.append(styledParagraph("Title", lineHeight: 36,
              font: .boldSystemFont(ofSize: 28)))
result.append(styledParagraph("Body text here...", lineHeight: 24,
              font: .systemFont(ofSize: 17)))

13. Indent First Line

let style = NSMutableParagraphStyle()
style.firstLineHeadIndent = 24  // Only first line indented

14. Bullet Lists (Manual, Cross-Platform)

func bulletList(_ items: [String], font: UIFont) -> NSAttributedString {
    let bullet = "\u{2022}"  // bullet character
    let indentWidth: CGFloat = 20

    let style = NSMutableParagraphStyle()
    style.headIndent = indentWidth
    style.tabStops = [NSTextTab(textAlignment: .left, location: indentWidth)]
    style.firstLineHeadIndent = 0

    let result = NSMutableAttributedString()
    for item in items {
        let line = "\(bullet)\t\(item)\n"
        result.append(NSAttributedString(string: line, attributes: [
            .font: font,
            .paragraphStyle: style
        ]))
    }
    return result
}

15. Read-Only Styled Text

textView.isEditable = false
textView.isSelectable = true  // Allow copy
textView.textContainerInset = UIEdgeInsets(top: 16, left: 16, bottom: 16, right: 16)
textView.attributedText = styledContent
textView.backgroundColor = .systemBackground

16. Auto-Detect Data

textView.isEditable = false
textView.dataDetectorTypes = [.link, .phoneNumber, .address, .calendarEvent]
// Text view automatically makes detected data tappable

Must be non-editable. Data detection is disabled when isEditable = true.

17. Custom Cursor Color

textView.tintColor = .systemPurple  // Changes cursor AND selection handles

18. Disable Text Selection

// Option 1: Subclass
class NonSelectableTextView: UITextView {
    override var canBecomeFirstResponder: Bool { false }
}

// Option 2: Disable interaction
textView.isSelectable = false
textView.isEditable = false

19. Scroll to Range

// Scroll to make a character range visible
let range = NSRange(location: 500, length: 0)
textView.scrollRangeToVisible(range)

// Scroll to bottom
let bottom = NSRange(location: textView.text.count - 1, length: 1)
textView.scrollRangeToVisible(bottom)

20. Get Current Line Number

func currentLineNumber(in textView: UITextView) -> Int {
    guard let layoutManager = textView.layoutManager else { return 1 }

    let cursorPosition = textView.selectedRange.location
    var lineNumber = 1
    let glyphIndex = layoutManager.glyphIndexForCharacter(at: cursorPosition)

    layoutManager.enumerateLineFragments(
        forGlyphRange: NSRange(location: 0, length: glyphIndex)
    ) { _, _, _, _, _ in
        lineNumber += 1
    }

    return lineNumber
}

For measurement, exclusion paths, or layout details -> launch textkit-reference agent
For paragraph style, line breaking, or formatting attributes -> launch rich-text-reference agent
For attachment views (tables, custom views) -> launch rich-text-reference agent
For find/replace or editor interaction details -> launch editor-reference agent

Documentation Scope

This page documents the apple-text-recipes workflow skill. Use it when the job is a guided review, implementation flow, or integration pass instead of a single API lookup.

apple-text: Use when the user clearly has an Apple text-system problem but the right specialist skill is not obvious yet, or when the request mixes TextKit, text views, storage, layout, parsing, and Writing Tools. Reach for this router when you need the next best Apple-text skill, not when the subsystem is already clear.
apple-text-measurement: Use when measuring text size, calculating bounding rects, sizing text views to fit content, or getting line-level metrics. Covers NSString/NSAttributedString measurement, NSStringDrawingOptions, NSStringDrawingContext, TextKit 1 glyph-range measurement, TextKit 2 layout fragment measurement, and common sizing mistakes.
apple-text-exclusion-paths: Use when wrapping text around images or shapes, creating multi-column text layout, linking text containers for magazine/book layout, configuring NSTextContainer exclusion paths, or building non-rectangular text regions. Covers exclusionPaths, linked containers, multi-container layout in TextKit 1 and 2, and NSTextBlock/NSTextTable for in-text tables.
apple-text-line-breaking: Use when configuring line break behavior, hyphenation, truncation, line height, paragraph spacing, or tab stops. Covers NSParagraphStyle line properties, NSLineBreakStrategy, truncation tokens, maximumNumberOfLines, line height calculation, and common mistakes with line height multipliers.

Full SKILL.md source

---
name: apple-text-recipes
description: >
  Use when the user has a "how do I..." question about text views and you need a
  quick working recipe, or when they want a copy-paste snippet for a common text
  task rather than architecture guidance. Covers the 25 most common text tasks -
  background colors per paragraph, line numbers, character limits, text wrapping
  around images, clickable links, syntax highlighting, placeholder text,
  auto-growing text views, and more.
license: MIT
---

# Text Recipes Cookbook

Quick, working solutions to the most common "how do I..." questions about Apple text views.

## When to Use

- User asks "how do I [specific text thing]?" and you need a direct answer.
- You need a working code snippet, not architecture guidance.
- The question maps to a common text task that doesn't need a full skill.

## Quick Index

| # | Recipe | Framework |
|---|--------|-----------|
| 1 | Background color behind a paragraph | TextKit 1 / TextKit 2 |
| 2 | Line numbers in a text view | TextKit 1 |
| 3 | Character/word limit on input | UITextView delegate |
| 4 | Text wrapping around an image | NSTextContainer |
| 5 | Clickable links (not editable) | UITextView |
| 6 | Clickable links (editable) | UITextView delegate |
| 7 | Placeholder text in UITextView | UITextView |
| 8 | Auto-growing text view (no scroll) | Auto Layout |
| 9 | Highlight search results | Temporary attributes |
| 10 | Strikethrough text | NSAttributedString |
| 11 | Letter spacing (tracking/kern) | NSAttributedString |
| 12 | Different line heights per paragraph | NSParagraphStyle |
| 13 | Indent first line of paragraphs | NSParagraphStyle |
| 14 | Bullet/numbered lists | NSTextList / manual |
| 15 | Read-only styled text | UITextView |
| 16 | Detect data (phones, URLs, dates) | UITextView |
| 17 | Custom cursor color | UITextView |
| 18 | Disable text selection | UITextView |
| 19 | Programmatically scroll to range | UITextView |
| 20 | Get current line number | TextKit 1 |

---

## 1. Background Color Behind a Paragraph

### Using `.backgroundColor` attribute (simple)

```swift
let attrs: [NSAttributedString.Key: Any] = [
    .backgroundColor: UIColor.systemYellow.withAlphaComponent(0.3),
    .font: UIFont.systemFont(ofSize: 15)
]
let highlighted = NSAttributedString(string: "This paragraph has a background", attributes: attrs)
```

**Limitation:** Only colors the area directly behind glyphs, not full-width.

### Full-width paragraph background (TextKit 1 subclass)

```swift
class ParagraphBackgroundLayoutManager: NSLayoutManager {
    override func drawBackground(forGlyphRange glyphsToShow: NSRange, at origin: CGPoint) {
        super.drawBackground(forGlyphRange: glyphsToShow, at: origin)

        guard let textStorage = textStorage else { return }

        textStorage.enumerateAttribute(.paragraphBackgroundColor,
                                        in: characterRange(forGlyphRange: glyphsToShow,
                                                           actualGlyphRange: nil)) { value, charRange, _ in
            guard let color = value as? UIColor else { return }
            let glyphRange = self.glyphRange(forCharacterRange: charRange, actualCharacterRange: nil)

            enumerateLineFragments(forGlyphRange: glyphRange) { rect, _, container, _, _ in
                guard let context = UIGraphicsGetCurrentContext() else { return }
                let fullWidthRect = CGRect(
                    x: 0,
                    y: rect.origin.y + origin.y,
                    width: container.size.width,
                    height: rect.height
                )
                context.setFillColor(color.cgColor)
                context.fill(fullWidthRect)
            }
        }
    }
}

// Register custom attribute
extension NSAttributedString.Key {
    static let paragraphBackgroundColor = NSAttributedString.Key("paragraphBackgroundColor")
}
```

## 2. Line Numbers in a Text View

```swift
class LineNumberGutter: UIView {
    weak var textView: UITextView?

    func updateLineNumbers() {
        guard let textView = textView,
              let layoutManager = textView.layoutManager else { return }

        setNeedsDisplay()
    }

    override func draw(_ rect: CGRect) {
        guard let textView = textView,
              let layoutManager = textView.layoutManager else { return }

        let font = UIFont.monospacedDigitSystemFont(ofSize: 12, weight: .regular)
        let attrs: [NSAttributedString.Key: Any] = [
            .font: font,
            .foregroundColor: UIColor.secondaryLabel
        ]

        let visibleGlyphRange = layoutManager.glyphRange(
            forBoundingRect: textView.bounds,
            in: textView.textContainer
        )

        var lineNumber = 1
        var previousLineY: CGFloat = -1
        let inset = textView.textContainerInset

        // Count lines before visible range
        let textBeforeVisible = (textView.text as NSString)
            .substring(to: layoutManager.characterRange(
                forGlyphRange: NSRange(location: visibleGlyphRange.location, length: 0),
                actualGlyphRange: nil).location)
        lineNumber = textBeforeVisible.components(separatedBy: "\n").count

        layoutManager.enumerateLineFragments(forGlyphRange: visibleGlyphRange) {
            rect, _, _, glyphRange, _ in

            let charRange = layoutManager.characterRange(forGlyphRange: glyphRange,
                                                          actualGlyphRange: nil)
            let lineY = rect.origin.y + inset.top - textView.contentOffset.y

            // Only number paragraph-starting lines
            if charRange.location == 0 ||
               (textView.text as NSString).character(at: charRange.location - 1) == 0x0A {
                let numStr = "\(lineNumber)" as NSString
                let size = numStr.size(withAttributes: attrs)
                numStr.draw(at: CGPoint(
                    x: self.bounds.width - size.width - 4,
                    y: lineY + (rect.height - size.height) / 2
                ), withAttributes: attrs)
                lineNumber += 1
            }
        }
    }
}
```

## 3. Character/Word Limit

```swift
// Character limit
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange,
              replacementText text: String) -> Bool {
    let currentLength = textView.text.count
    let replacementLength = text.count
    let rangeLength = range.length
    let newLength = currentLength - rangeLength + replacementLength
    return newLength <= 280  // Twitter-style limit
}

// Word limit
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange,
              replacementText text: String) -> Bool {
    let currentText = (textView.text as NSString).replacingCharacters(in: range, with: text)
    let wordCount = currentText.split(separator: " ").count
    return wordCount <= 500
}
```

## 4. Text Wrapping Around an Image

```swift
// Add image view as subview of text view
let imageView = UIImageView(image: myImage)
imageView.frame = CGRect(x: 16, y: 16, width: 120, height: 120)
textView.addSubview(imageView)

// Create exclusion path in text container coordinates
let inset = textView.textContainerInset
let exclusionRect = CGRect(
    x: imageView.frame.origin.x - inset.left + imageView.frame.width,
    y: imageView.frame.origin.y - inset.top,
    width: imageView.frame.width + 8,
    height: imageView.frame.height + 8
)

// Set right-aligned exclusion (text wraps on left side)
textView.textContainer.exclusionPaths = [UIBezierPath(rect: CGRect(
    x: textView.textContainer.size.width - 120 - 8,
    y: 0,
    width: 120 + 8,
    height: 120 + 8
))]
```

## 5. Clickable Links (Non-Editable)

```swift
textView.isEditable = false
textView.isSelectable = true
textView.dataDetectorTypes = [.link]  // Auto-detect URLs

// Or manual links via attributed string:
let text = NSMutableAttributedString(string: "Visit our website for details.")
text.addAttribute(.link, value: URL(string: "https://example.com")!,
                  range: NSRange(location: 10, length: 7))
textView.attributedText = text

// Handle taps:
func textView(_ textView: UITextView, shouldInteractWith URL: URL,
              in characterRange: NSRange,
              interaction: UITextItemInteraction) -> Bool {
    // Return true for default behavior, false to handle yourself
    return true
}
```

## 6. Clickable Links (Editable Text View)

```swift
// Links in editable text views don't respond to taps by default.
// Use UITextViewDelegate to detect taps on link-attributed ranges:
func textView(_ textView: UITextView, shouldInteractWith URL: URL,
              in characterRange: NSRange,
              interaction: UITextItemInteraction) -> Bool {
    if interaction == .invokeDefaultAction {
        UIApplication.shared.open(URL)
        return false
    }
    return true
}
```

## 7. Placeholder Text in UITextView

```swift
class PlaceholderTextView: UITextView {
    var placeholder: String = "" {
        didSet { setNeedsDisplay() }
    }

    var placeholderColor: UIColor = .placeholderText

    override var text: String! {
        didSet { setNeedsDisplay() }
    }

    override func draw(_ rect: CGRect) {
        super.draw(rect)
        guard text.isEmpty else { return }

        let attrs: [NSAttributedString.Key: Any] = [
            .font: font ?? .systemFont(ofSize: 17),
            .foregroundColor: placeholderColor
        ]
        let inset = textContainerInset
        let padding = textContainer.lineFragmentPadding
        let placeholderRect = CGRect(
            x: inset.left + padding,
            y: inset.top,
            width: bounds.width - inset.left - inset.right - 2 * padding,
            height: bounds.height - inset.top - inset.bottom
        )
        placeholder.draw(in: placeholderRect, withAttributes: attrs)
    }

    // Call setNeedsDisplay in textDidChange notification
}
```

## 8. Auto-Growing Text View

```swift
// The simplest approach: disable scrolling
textView.isScrollEnabled = false
// Auto Layout now uses intrinsicContentSize to grow the text view

// With a maximum height:
textView.isScrollEnabled = false

// In your constraint setup:
let heightConstraint = textView.heightAnchor.constraint(lessThanOrEqualToConstant: 200)
heightConstraint.isActive = true

// When content exceeds max height, enable scrolling:
func textViewDidChange(_ textView: UITextView) {
    let fittingSize = textView.sizeThatFits(
        CGSize(width: textView.bounds.width, height: .greatestFiniteMagnitude)
    )
    textView.isScrollEnabled = fittingSize.height > 200
}
```

## 9. Highlight Search Results

```swift
// TextKit 1 — temporary attributes (don't modify the model)
func highlightOccurrences(of searchText: String, in textView: UITextView) {
    guard let layoutManager = textView.layoutManager,
          let text = textView.text else { return }

    // Clear previous highlights
    let fullRange = NSRange(location: 0, length: (text as NSString).length)
    layoutManager.removeTemporaryAttribute(.backgroundColor, forCharacterRange: fullRange)

    // Add new highlights
    var searchRange = text.startIndex..<text.endIndex
    while let range = text.range(of: searchText, options: .caseInsensitive, range: searchRange) {
        let nsRange = NSRange(range, in: text)
        layoutManager.addTemporaryAttribute(.backgroundColor,
                                             value: UIColor.systemYellow,
                                             forCharacterRange: nsRange)
        searchRange = range.upperBound..<text.endIndex
    }
}
```

## 10. Strikethrough Text

```swift
// Single strikethrough
let attrs: [NSAttributedString.Key: Any] = [
    .strikethroughStyle: NSUnderlineStyle.single.rawValue,
    .strikethroughColor: UIColor.red
]

// Double strikethrough
let attrs: [NSAttributedString.Key: Any] = [
    .strikethroughStyle: NSUnderlineStyle.double.rawValue
]

// Thick strikethrough
let attrs: [NSAttributedString.Key: Any] = [
    .strikethroughStyle: NSUnderlineStyle.thick.rawValue
]
```

## 11. Letter Spacing

```swift
// Kern — fixed spacing in points (doesn't scale with font size)
let attrs: [NSAttributedString.Key: Any] = [
    .kern: 2.0  // 2pt between characters
]

// Tracking (iOS 14+) — scales with font size
let attrs: [NSAttributedString.Key: Any] = [
    .tracking: 0.5  // Proportional to font size
]
```

**Use `.tracking` when possible** — it produces consistent results across font sizes.

## 12. Different Line Heights Per Paragraph

```swift
func styledParagraph(_ text: String, lineHeight: CGFloat, font: UIFont) -> NSAttributedString {
    let style = NSMutableParagraphStyle()
    style.minimumLineHeight = lineHeight
    style.maximumLineHeight = lineHeight

    let baselineOffset = (lineHeight - font.lineHeight) / 2

    return NSAttributedString(string: text + "\n", attributes: [
        .font: font,
        .paragraphStyle: style,
        .baselineOffset: baselineOffset
    ])
}

let result = NSMutableAttributedString()
result.append(styledParagraph("Title", lineHeight: 36,
              font: .boldSystemFont(ofSize: 28)))
result.append(styledParagraph("Body text here...", lineHeight: 24,
              font: .systemFont(ofSize: 17)))
```

## 13. Indent First Line

```swift
let style = NSMutableParagraphStyle()
style.firstLineHeadIndent = 24  // Only first line indented
```

## 14. Bullet Lists (Manual, Cross-Platform)

```swift
func bulletList(_ items: [String], font: UIFont) -> NSAttributedString {
    let bullet = "\u{2022}"  // bullet character
    let indentWidth: CGFloat = 20

    let style = NSMutableParagraphStyle()
    style.headIndent = indentWidth
    style.tabStops = [NSTextTab(textAlignment: .left, location: indentWidth)]
    style.firstLineHeadIndent = 0

    let result = NSMutableAttributedString()
    for item in items {
        let line = "\(bullet)\t\(item)\n"
        result.append(NSAttributedString(string: line, attributes: [
            .font: font,
            .paragraphStyle: style
        ]))
    }
    return result
}
```

## 15. Read-Only Styled Text

```swift
textView.isEditable = false
textView.isSelectable = true  // Allow copy
textView.textContainerInset = UIEdgeInsets(top: 16, left: 16, bottom: 16, right: 16)
textView.attributedText = styledContent
textView.backgroundColor = .systemBackground
```

## 16. Auto-Detect Data

```swift
textView.isEditable = false
textView.dataDetectorTypes = [.link, .phoneNumber, .address, .calendarEvent]
// Text view automatically makes detected data tappable
```

**Must be non-editable.** Data detection is disabled when `isEditable = true`.

## 17. Custom Cursor Color

```swift
textView.tintColor = .systemPurple  // Changes cursor AND selection handles
```

## 18. Disable Text Selection

```swift
// Option 1: Subclass
class NonSelectableTextView: UITextView {
    override var canBecomeFirstResponder: Bool { false }
}

// Option 2: Disable interaction
textView.isSelectable = false
textView.isEditable = false
```

## 19. Scroll to Range

```swift
// Scroll to make a character range visible
let range = NSRange(location: 500, length: 0)
textView.scrollRangeToVisible(range)

// Scroll to bottom
let bottom = NSRange(location: textView.text.count - 1, length: 1)
textView.scrollRangeToVisible(bottom)
```

## 20. Get Current Line Number

```swift
func currentLineNumber(in textView: UITextView) -> Int {
    guard let layoutManager = textView.layoutManager else { return 1 }

    let cursorPosition = textView.selectedRange.location
    var lineNumber = 1
    let glyphIndex = layoutManager.glyphIndexForCharacter(at: cursorPosition)

    layoutManager.enumerateLineFragments(
        forGlyphRange: NSRange(location: 0, length: glyphIndex)
    ) { _, _, _, _, _ in
        lineNumber += 1
    }

    return lineNumber
}
```

## Related Skills and Agents

- For measurement, exclusion paths, or layout details -> launch **textkit-reference** agent
- For paragraph style, line breaking, or formatting attributes -> launch **rich-text-reference** agent
- For attachment views (tables, custom views) -> launch **rich-text-reference** agent
- For find/replace or editor interaction details -> launch **editor-reference** agent

Text Recipes Cookbook

When to Use

Quick Index

1. Background Color Behind a Paragraph

Using `.backgroundColor` attribute (simple)

Full-width paragraph background (TextKit 1 subclass)

2. Line Numbers in a Text View

3. Character/Word Limit

4. Text Wrapping Around an Image

5. Clickable Links (Non-Editable)

6. Clickable Links (Editable Text View)

7. Placeholder Text in UITextView

8. Auto-Growing Text View

9. Highlight Search Results

10. Strikethrough Text

11. Letter Spacing

12. Different Line Heights Per Paragraph

13. Indent First Line

14. Bullet Lists (Manual, Cross-Platform)

15. Read-Only Styled Text

16. Auto-Detect Data

17. Custom Cursor Color

18. Disable Text Selection

19. Scroll to Range

20. Get Current Line Number

Documentation Scope

Start Here

Guide

Skills

Text Recipes Cookbook

When to Use

Quick Index

1. Background Color Behind a Paragraph

Using .backgroundColor attribute (simple)

Full-width paragraph background (TextKit 1 subclass)

2. Line Numbers in a Text View

3. Character/Word Limit

4. Text Wrapping Around an Image

5. Clickable Links (Non-Editable)

6. Clickable Links (Editable Text View)

7. Placeholder Text in UITextView

8. Auto-Growing Text View

9. Highlight Search Results

10. Strikethrough Text

11. Letter Spacing

12. Different Line Heights Per Paragraph

13. Indent First Line

14. Bullet Lists (Manual, Cross-Platform)

15. Read-Only Styled Text

16. Auto-Detect Data

17. Custom Cursor Color

18. Disable Text Selection

19. Scroll to Range

20. Get Current Line Number

Related Skills and Agents

Documentation Scope

Related

Start Here

Guide

Skills

Using `.backgroundColor` attribute (simple)