Scroll Syncing Done!

Author: thecoolwinter

Sources/CodeEditSourceEditor/Controller/TextViewController+StyleViews.swift

@@ -67,6 +67,10 @@ extension TextViewController {
         scrollView.hasVerticalScroller = true
         scrollView.hasHorizontalScroller = !wrapLines
 
+        updateContentInsets()
+    }
+
+    package func updateContentInsets() {
         scrollView.contentView.postsBoundsChangedNotifications = true
         if let contentInsets {
             scrollView.automaticallyAdjustsContentInsets = false
@@ -80,10 +84,14 @@ extension TextViewController {
 
         scrollView.contentInsets.top += additionalTextInsets?.top ?? 0
         scrollView.contentInsets.bottom += additionalTextInsets?.bottom ?? 0
+        minimapView.scrollView.contentInsets.top += additionalTextInsets?.top ?? 0
+        minimapView.scrollView.contentInsets.bottom += additionalTextInsets?.bottom ?? 0
+
+        let findInset = (findViewController?.isShowingFindPanel ?? false) ? FindPanel.height : 0
+        scrollView.contentInsets.top += findInset
+        minimapView.scrollView.contentInsets.top += findInset
 
-        scrollView.contentInsets.top += (findViewController?.isShowingFindPanel ?? false) ? FindPanel.height : 0
-        minimapView.scrollView.contentInsets.top += (
-            findViewController?.isShowingFindPanel ?? false
-        ) ? FindPanel.height : 0
+        scrollView.reflectScrolledClipView(scrollView.contentView)
+        minimapView.scrollView.reflectScrolledClipView(minimapView.scrollView.contentView)
     }
 }

Sources/CodeEditSourceEditor/Extensions/NSEdgeInsets+Helpers.swift

@@ -0,0 +1,18 @@
+//
+//  NSEdgeInsets+Helpers.swift
+//  CodeEditSourceEditor
+//
+//  Created by Khan Winter on 4/15/25.
+//
+
+import Foundation
+
+extension NSEdgeInsets {
+    var vertical: CGFloat {
+        top + bottom
+    }
+
+    var horizontal: CGFloat {
+        left + right
+    }
+}

Sources/CodeEditSourceEditor/Minimap/MinimapContentView.swift

@@ -7,26 +7,59 @@
 
 import AppKit
 
+extension NSScrollView {
+    var percentScrolled: CGFloat {
+        get {
+            let currentYPos = documentVisibleRect.origin.y + contentInsets.top
+            let totalHeight = (documentView?.frame.height ?? 0.0) + contentInsets.top
+            let goalYPos = totalHeight - (documentVisibleRect.height - contentInsets.top)
+
+            return currentYPos / goalYPos
+        }
+        set {
+            let totalHeight = (documentView?.frame.height ?? 0.0) + contentInsets.top
+            contentView.scroll(
+                to: NSPoint(
+                    x: contentView.frame.origin.x,
+                    y: (newValue * (totalHeight - (documentVisibleRect.height - contentInsets.top))) - contentInsets.top
+                )
+            )
+            reflectScrolledClipView(contentView)
+        }
+    }
+}
+
 extension MinimapView {
     func updateDocumentVisibleViewPosition() {
-        guard let textView = textView, let editorScrollView = textView.enclosingScrollView else { return }
-        layoutManager?.layoutLines(in: scrollView.documentVisibleRect)
-        let editorHeight = textView.frame.height
+        guard let textView = textView, let editorScrollView = textView.enclosingScrollView, let layoutManager else {
+            return
+        }
+
         let minimapHeight = contentView.frame.height
+        let editorHeight = textView.frame.height
+        let editorToMinimapHeightRatio = minimapHeight / editorHeight
+
+        let containerHeight = editorScrollView.visibleRect.height - editorScrollView.contentInsets.vertical
+        let availableHeight = min(minimapHeight, containerHeight)
+        let scrollPercentage = editorScrollView.percentScrolled
+
+        // Update Visible Pane, should scroll down slowly as the user scrolls the document, following the scroller.
+        // Visible pane's height   = scrollview visible height * (minimap line height / editor line height)
+        // Visible pane's position = (container height - visible pane height) * scrollPercentage
+        let visibleRectHeight = containerHeight * editorToMinimapHeightRatio
+        guard visibleRectHeight < 1e100 else { return }
+
+        let availableContainerHeight = (availableHeight - visibleRectHeight)
+        let visibleRectYPos = availableContainerHeight * scrollPercentage
 
-        let containerHeight = scrollView.documentVisibleRect.height
-        let scrollPercentage = (
-            editorScrollView.documentVisibleRect.origin.y + editorScrollView.contentInsets.top
-        ) / textView.frame.height
-//        let scrollOffset = editorScrollView.documentVisibleRect.origin.y
+        documentVisibleView.frame.origin.y = scrollView.contentInsets.top + visibleRectYPos
+        documentVisibleView.frame.size.height = visibleRectHeight
 
-//        let scrollMultiplier: CGFloat = if minimapHeight < containerHeight {
-//            1.0
-//        } else {
-//            1.0 - (minimapHeight - containerHeight) / (editorHeight - containerHeight)
-//        }
+        // Minimap scroll offset slowly scrolls down with the visible pane.
+        if minimapHeight > containerHeight {
+            scrollView.percentScrolled = scrollPercentage
+        }
 
-        let newMinimapOrigin = minimapHeight * scrollPercentage
-        scrollView.contentView.bounds.origin.y = newMinimapOrigin - editorScrollView.contentInsets.top
+        layoutManager.layoutLines()
     }
 }

Sources/CodeEditSourceEditor/Minimap/MinimapView+DocumentVisibleView.swift

@@ -8,13 +8,13 @@
 import AppKit
 import CodeEditTextView
 
-class MinimapView: NSView {
+class MinimapView: FlippedNSView {
     weak var textView: TextView?
 
     /// The container scrollview for the minimap contents.
     let scrollView: NSScrollView
     /// The view text lines are rendered into.
-    let contentView: MinimapContentView
+    let contentView: FlippedNSView
     /// The box displaying the visible region on the minimap.
     let documentVisibleView: NSView
 
@@ -26,7 +26,7 @@ class MinimapView: NSView {
 
     var theme: EditorTheme {
         didSet {
-            documentVisibleView.layer?.backgroundColor = theme.text.color.withAlphaComponent(0.1).cgColor
+            documentVisibleView.layer?.backgroundColor = theme.text.color.withAlphaComponent(0.05).cgColor
             layer?.backgroundColor = theme.background.cgColor
         }
     }
@@ -57,13 +57,13 @@ class MinimapView: NSView {
         scrollView.drawsBackground = false
         scrollView.verticalScrollElasticity = .none
 
-        self.contentView = MinimapContentView(frame: .zero)
+        self.contentView = FlippedNSView(frame: .zero)
         contentView.translatesAutoresizingMaskIntoConstraints = false
 
         self.documentVisibleView = NSView()
         documentVisibleView.translatesAutoresizingMaskIntoConstraints = false
         documentVisibleView.wantsLayer = true
-        documentVisibleView.layer?.backgroundColor = theme.text.color.withAlphaComponent(0.1).cgColor
+        documentVisibleView.layer?.backgroundColor = theme.text.color.withAlphaComponent(0.05).cgColor
 
         super.init(frame: .zero)
 
@@ -97,7 +97,8 @@ class MinimapView: NSView {
             scrollView.leadingAnchor.constraint(equalTo: leadingAnchor),
             scrollView.trailingAnchor.constraint(equalTo: trailingAnchor),
 
-            contentView.widthAnchor.constraint(equalTo: widthAnchor),
+            contentView.leadingAnchor.constraint(equalTo: leadingAnchor),
+            contentView.trailingAnchor.constraint(equalTo: trailingAnchor),
 
             documentVisibleView.leadingAnchor.constraint(equalTo: leadingAnchor),
             documentVisibleView.trailingAnchor.constraint(equalTo: trailingAnchor)
@@ -153,4 +154,16 @@ class MinimapView: NSView {
             return super.hitTest(point)
         }
     }
+
+    override func draw(_ dirtyRect: NSRect) {
+        guard let context = NSGraphicsContext.current?.cgContext else { return }
+        context.saveGState()
+
+        context.setFillColor(NSColor.separatorColor.cgColor)
+        context.fill([
+            CGRect(x: 0, y: 0, width: 1, height: frame.height)
+        ])
+
+        context.restoreGState()
+    }
 }