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Select Undone/Redone Text #105

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Jun 18, 2025
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Original file line number Diff line number Diff line change
@@ -14,26 +14,25 @@ extension TextView {

/// Scrolls the upmost selection to the visible rect if `scrollView` is not `nil`.
public func scrollSelectionToVisible() {
guard let scrollView, let selection = getSelection() else {
guard let scrollView else {
return
}

let offsetToScrollTo = offsetNotPivot(selection)

// There's a bit of a chicken-and-the-egg issue going on here. We need to know the rect to scroll to, but we
// can't know the exact rect to make visible without laying out the text. Then, once text is laid out the
// selection rect may be different again. To solve this, we loop until the frame doesn't change after a layout
// pass and scroll to that rect.

var lastFrame: CGRect = .zero
while let boundingRect = layoutManager.rectForOffset(offsetToScrollTo), lastFrame != boundingRect {
while let boundingRect = getSelection()?.boundingRect, lastFrame != boundingRect {
lastFrame = boundingRect
layoutManager.layoutLines()
selectionManager.updateSelectionViews()
selectionManager.drawSelections(in: visibleRect)
}
if lastFrame != .zero {
scrollView.contentView.scrollToVisible(lastFrame)
scrollView.reflectScrolledClipView(scrollView.contentView)
}
}

29 changes: 29 additions & 0 deletions Sources/CodeEditTextView/Utils/CEUndoManager.swift
Original file line number Diff line number Diff line change
@@ -83,6 +83,10 @@ public class CEUndoManager: UndoManager {
textView.replaceCharacters(in: mutation.inverse.range, with: mutation.inverse.string)
}
textView.textStorage.endEditing()

updateSelectionsForMutations(mutations: item.mutations.map { $0.mutation })
textView.scrollSelectionToVisible()

NotificationCenter.default.post(name: .NSUndoManagerDidUndoChange, object: self)
redoStack.append(item)
_isUndoing = false
@@ -101,16 +105,41 @@ public class CEUndoManager: UndoManager {

_isRedoing = true
NotificationCenter.default.post(name: .NSUndoManagerWillRedoChange, object: self)
textView.selectionManager.removeCursors()
textView.textStorage.beginEditing()
for mutation in item.mutations {
textView.replaceCharacters(in: mutation.mutation.range, with: mutation.mutation.string)
}
textView.textStorage.endEditing()

updateSelectionsForMutations(mutations: item.mutations.map { $0.inverse })
textView.scrollSelectionToVisible()

NotificationCenter.default.post(name: .NSUndoManagerDidRedoChange, object: self)
undoStack.append(item)
_isRedoing = false
}

/// We often undo/redo a group of mutations that contain updated ranges that are next to each other but for a user
/// should be one continuous range. This merges those ranges into a set of disjoint ranges before updating the
/// selection manager.
private func updateSelectionsForMutations(mutations: [TextMutation]) {
if mutations.reduce(0, { $0 + $1.range.length }) == 0 {
if let minimumMutation = mutations.min(by: { $0.range.location < $1.range.location }) {
// If the mutations are only deleting text (no replacement), we just place the cursor at the last range,
// since all the ranges are the same but the other method will return no ranges (empty range).
textView?.selectionManager.setSelectedRange(
NSRange(location: minimumMutation.range.location, length: 0)
)
}
} else {
let mergedRanges = mutations.reduce(into: IndexSet(), { set, mutation in
set.insert(range: mutation.range)
})
textView?.selectionManager.setSelectedRanges(mergedRanges.rangeView.map { NSRange($0) })
}
}

/// Clears the undo/redo stacks.
public func clearStack() {
undoStack.removeAll()