Merge pull request #100 from yusufozgul/feature/editorOverScroll

Editor Overscroll

Author: lukepistrol

README.md

@@ -44,6 +44,7 @@ struct ContentView: View {
     @State var font = NSFont.monospacedSystemFont(ofSize: 11, weight: .regular)
     @State var tabWidth = 4
     @State var lineHeight = 1.2
+    @State var editorOverscroll = 0.3
 
     var body: some View { 
         CodeEditTextView(
@@ -52,7 +53,8 @@ struct ContentView: View {
             theme: $theme,
             font: $font,
             tabWidth: $tabWidth,
-            lineHeight: $lineHeight
+            lineHeight: $lineHeight,
+            editorOverscroll: $editorOverscroll
         )
     }
 }

Sources/CodeEditTextView/CodeEditTextView.swift

@@ -20,13 +20,15 @@ public struct CodeEditTextView: NSViewControllerRepresentable {
     ///   - font: The default font
     ///   - tabWidth: The tab width
     ///   - lineHeight: The line height multiplier (e.g. `1.2`)
+    ///   - editorOverscroll: The percentage for overscroll, between 0-1 (default: `0.0`)
     public init(
         _ text: Binding<String>,
         language: CodeLanguage,
         theme: Binding<EditorTheme>,
         font: Binding<NSFont>,
         tabWidth: Binding<Int>,
         lineHeight: Binding<Double>,
+        editorOverscroll: Binding<Double> = .constant(0.0),
         cursorPosition: Published<(Int, Int)>.Publisher? = nil
     ) {
         self._text = text
@@ -35,6 +37,7 @@ public struct CodeEditTextView: NSViewControllerRepresentable {
         self._font = font
         self._tabWidth = tabWidth
         self._lineHeight = lineHeight
+        self._editorOverscroll = editorOverscroll
         self.cursorPosition = cursorPosition
     }
 
@@ -44,6 +47,7 @@ public struct CodeEditTextView: NSViewControllerRepresentable {
     @Binding private var font: NSFont
     @Binding private var tabWidth: Int
     @Binding private var lineHeight: Double
+    @Binding private var editorOverscroll: Double
     private var cursorPosition: Published<(Int, Int)>.Publisher?
 
     public typealias NSViewControllerType = STTextViewController
@@ -55,7 +59,8 @@ public struct CodeEditTextView: NSViewControllerRepresentable {
             font: font,
             theme: theme,
             tabWidth: tabWidth,
-            cursorPosition: cursorPosition
+            cursorPosition: cursorPosition,
+            editorOverscroll: editorOverscroll
         )
         controller.lineHeightMultiple = lineHeight
         return controller
@@ -67,6 +72,7 @@ public struct CodeEditTextView: NSViewControllerRepresentable {
         controller.theme = theme
         controller.tabWidth = tabWidth
         controller.lineHeightMultiple = lineHeight
+        controller.editorOverscroll = editorOverscroll
         controller.reloadUI()
         return
     }

Sources/CodeEditTextView/Documentation.docc/CodeEditTextView.md

@@ -12,6 +12,7 @@ struct ContentView: View {
     @State var font = NSFont.monospacedSystemFont(ofSize: 11, weight: .regular)
     @State var tabWidth = 4
     @State var lineHeight = 1.2
+    @State var editorOverscroll = 0.3
 
     var body: some View { 
         CodeEditTextView(
@@ -20,7 +21,8 @@ struct ContentView: View {
             theme: $theme,
             font: $font,
             tabWidth: $tabWidth,
-            lineHeight: $lineHeight
+            lineHeight: $lineHeight,
+            editorOverscroll: $editorOverscroll
         )
     }
 }

Sources/CodeEditTextView/Documentation.docc/STTextViewController.md

@@ -10,3 +10,4 @@
 - ``font``
 - ``tabWidth``
 - ``lineHeightMultiple``
+- ``editorOverscroll``

Sources/CodeEditTextView/STTextViewController.swift

@@ -42,6 +42,9 @@ public class STTextViewController: NSViewController, STTextViewDelegate, ThemeAt
     /// The font to use in the `textView`
     public var font: NSFont
 
+    /// The editorOverscroll to use for the textView over scroll
+    public var editorOverscroll: Double
+
     // MARK: - Highlighting
 
     internal var highlighter: Highlighter?
@@ -55,14 +58,16 @@ public class STTextViewController: NSViewController, STTextViewDelegate, ThemeAt
         font: NSFont,
         theme: EditorTheme,
         tabWidth: Int,
-        cursorPosition: Published<(Int, Int)>.Publisher? = nil
+        cursorPosition: Published<(Int, Int)>.Publisher? = nil,
+        editorOverscroll: Double
     ) {
         self.text = text
         self.language = language
         self.font = font
         self.theme = theme
         self.tabWidth = tabWidth
         self.cursorPosition = cursorPosition
+        self.editorOverscroll = editorOverscroll
         super.init(nibName: nil, bundle: nil)
     }
 
@@ -152,6 +157,13 @@ public class STTextViewController: NSViewController, STTextViewDelegate, ThemeAt
 
     public override func viewDidLoad() {
         super.viewDidLoad()
+
+        NotificationCenter.default.addObserver(forName: NSWindow.didResizeNotification,
+                                               object: nil,
+                                               queue: .main) { [weak self] _ in
+            guard let self = self else { return }
+            (self.view as? NSScrollView)?.contentView.contentInsets.bottom = self.bottomContentInsets
+        }
     }
 
     public override func viewDidAppear() {
@@ -169,6 +181,18 @@ public class STTextViewController: NSViewController, STTextViewDelegate, ThemeAt
         return paragraph
     }
 
+    /// ScrollView's bottom inset using as editor overscroll
+    private var bottomContentInsets: CGFloat {
+        let height = view.frame.height
+        var inset = editorOverscroll * height
+
+        if height - inset < lineHeight {
+            inset = height - lineHeight
+        }
+
+        return max(inset, .zero)
+    }
+
     /// Reloads the UI to apply changes to ``STTextViewController/font``, ``STTextViewController/theme``, ...
     internal func reloadUI() {
         textView?.font = font
@@ -182,6 +206,8 @@ public class STTextViewController: NSViewController, STTextViewDelegate, ThemeAt
         rulerView?.separatorColor = theme.invisibles
         rulerView?.baselineOffset = baselineOffset
 
+        (view as? NSScrollView)?.contentView.contentInsets.bottom = bottomContentInsets
+
         setStandardAttributes()
     }
 

Tests/CodeEditTextViewTests/STTextViewControllerTests.swift

@@ -32,7 +32,8 @@ final class STTextViewControllerTests: XCTestCase {
             language: .default,
             font: .monospacedSystemFont(ofSize: 11, weight: .medium),
             theme: theme,
-            tabWidth: 4
+            tabWidth: 4,
+            editorOverscroll: 0.5
         )
     }
 
@@ -60,4 +61,34 @@ final class STTextViewControllerTests: XCTestCase {
         XCTAssertEqual(color4, NSColor.textColor)
     }
 
+    func test_editorOverScroll() throws {
+        let scrollView = try XCTUnwrap(controller.view as? NSScrollView)
+        scrollView.frame = .init(x: .zero,
+                                 y: .zero,
+                                 width: 100,
+                                 height: 100)
+
+        // editorOverscroll: 0
+        XCTAssertEqual(scrollView.contentView.contentInsets.bottom, 0)
+
+        controller.editorOverscroll = 0.5
+        controller.reloadUI()
+
+        // editorOverscroll: 0.5
+        XCTAssertEqual(scrollView.contentView.contentInsets.bottom, 50.0)
+
+        controller.editorOverscroll = 1.0
+        controller.reloadUI()
+
+        // editorOverscroll: 1.0
+        XCTAssertEqual(scrollView.contentView.contentInsets.bottom, 87.0)
+    }
+
+    func test_editorOverScroll_ZeroCondition() throws {
+        let scrollView = try XCTUnwrap(controller.view as? NSScrollView)
+        scrollView.frame = .zero
+
+        // editorOverscroll: 0
+        XCTAssertEqual(scrollView.contentView.contentInsets.bottom, 0)
+    }
 }