add resizable columns and rows to markdown table view

src/EditorView.swift

@@ -321,81 +321,129 @@ class MarkdownTableView: NSView, NSTextFieldDelegate {
     var onTableChanged: ((ParsedTable) -> Void)?
 
     private var cellFields: [[NSTextField]] = []
-    private let cellHeight: CGFloat = 26
+    private var columnWidths: [CGFloat] = []
-    private let cellPadding: CGFloat = 4
+    private var rowHeights: [CGFloat] = []
-    private let headerHeight: CGFloat = 28
+    private var tableWidth: CGFloat = 0
+
+    private let minColWidth: CGFloat = 40
+    private let minRowHeight: CGFloat = 24
+    private let defaultHeaderHeight: CGFloat = 28
+    private let defaultCellHeight: CGFloat = 26
+    private let dividerHitZone: CGFloat = 6
+
+    private enum DragMode { case none, column(Int), row(Int) }
+    private var dragMode: DragMode = .none
+    private var dragStartPoint: NSPoint = .zero
+    private var dragStartSize: CGFloat = 0
 
     init(table: ParsedTable, width: CGFloat) {
         self.table = table
+        self.tableWidth = width
         super.init(frame: .zero)
         wantsLayer = true
         layer?.backgroundColor = Theme.current.base.cgColor
         layer?.cornerRadius = 4
         layer?.borderWidth = 1
         layer?.borderColor = Theme.current.surface2.cgColor
-        buildGrid(width: width)
+        initSizes(width: width)
+        buildGrid()
+        setupTrackingArea()
     }
 
     required init?(coder: NSCoder) { fatalError() }
 
-    private func buildGrid(width: CGFloat) {
+    private func initSizes(width: CGFloat) {
+        let colCount = table.headers.count
+        guard colCount > 0 else { return }
+        let available = width - CGFloat(colCount + 1)
+        let colW = available / CGFloat(colCount)
+        columnWidths = Array(repeating: max(colW, minColWidth), count: colCount)
+
+        rowHeights = []
+        rowHeights.append(defaultHeaderHeight)
+        for _ in 0..<table.rows.count {
+            rowHeights.append(defaultCellHeight)
+        }
+    }
+
+    private var totalHeight: CGFloat {
+        rowHeights.reduce(0, +)
+    }
+
+    private func columnX(for col: Int) -> CGFloat {
+        var x: CGFloat = 1
+        for i in 0..<col {
+            x += columnWidths[i] + 1
+        }
+        return x
+    }
+
+    private func rowY(for row: Int) -> CGFloat {
+        let th = totalHeight
+        var y = th
+        for i in 0...row {
+            y -= rowHeights[i]
+        }
+        return y
+    }
+
+    private func buildGrid() {
         subviews.forEach { $0.removeFromSuperview() }
         cellFields = []
 
         let colCount = table.headers.count
         guard colCount > 0 else { return }
-        let colWidth = (width - CGFloat(colCount + 1)) / CGFloat(colCount)
+        let th = totalHeight
-        let totalRows = 1 + table.rows.count
+        let totalWidth = columnX(for: colCount) + 1
-        let totalHeight = headerHeight + CGFloat(table.rows.count) * cellHeight
 
-        frame.size = NSSize(width: width, height: totalHeight)
+        frame.size = NSSize(width: totalWidth, height: th)
 
-        // Header row
+        let headerBg = NSView(frame: NSRect(x: 0, y: th - rowHeights[0], width: totalWidth, height: rowHeights[0]))
-        let headerBg = NSView(frame: NSRect(x: 0, y: totalHeight - headerHeight, width: width, height: headerHeight))
         headerBg.wantsLayer = true
         headerBg.layer?.backgroundColor = Theme.current.surface0.cgColor
         addSubview(headerBg)
 
         var headerFields: [NSTextField] = []
         for (col, header) in table.headers.enumerated() {
-            let x = CGFloat(col) * colWidth + CGFloat(col + 1)
+            let x = columnX(for: col)
-            let field = makeCell(text: header, frame: NSRect(x: x, y: totalHeight - headerHeight + 2, width: colWidth, height: headerHeight - 4), isHeader: true, row: -1, col: col)
+            let h = rowHeights[0]
+            let field = makeCell(text: header, frame: NSRect(x: x, y: th - h + 2, width: columnWidths[col], height: h - 4), isHeader: true, row: -1, col: col)
             addSubview(field)
             headerFields.append(field)
         }
         cellFields.append(headerFields)
 
-        // Data rows
         for (rowIdx, row) in table.rows.enumerated() {
             var rowFields: [NSTextField] = []
-            let y = totalHeight - headerHeight - CGFloat(rowIdx + 1) * cellHeight
+            let y = rowY(for: rowIdx + 1)
+            let h = rowHeights[rowIdx + 1]
             for (col, cell) in row.enumerated() where col < colCount {
-                let x = CGFloat(col) * colWidth + CGFloat(col + 1)
+                let x = columnX(for: col)
-                let field = makeCell(text: cell, frame: NSRect(x: x, y: y + 2, width: colWidth, height: cellHeight - 4), isHeader: false, row: rowIdx, col: col)
+                let field = makeCell(text: cell, frame: NSRect(x: x, y: y + 2, width: columnWidths[col], height: h - 4), isHeader: false, row: rowIdx, col: col)
                 addSubview(field)
                 rowFields.append(field)
             }
             while rowFields.count < colCount {
                 let col = rowFields.count
-                let x = CGFloat(col) * colWidth + CGFloat(col + 1)
+                let x = columnX(for: col)
-                let field = makeCell(text: "", frame: NSRect(x: x, y: y + 2, width: colWidth, height: cellHeight - 4), isHeader: false, row: rowIdx, col: col)
+                let field = makeCell(text: "", frame: NSRect(x: x, y: y + 2, width: columnWidths[col], height: h - 4), isHeader: false, row: rowIdx, col: col)
                 addSubview(field)
                 rowFields.append(field)
             }
             cellFields.append(rowFields)
         }
 
-        // Grid lines
+        let totalRows = 1 + table.rows.count
         for i in 1..<colCount {
-            let x = CGFloat(i) * (colWidth + 1)
+            let x = columnX(for: i) - 1
-            let line = NSView(frame: NSRect(x: x, y: 0, width: 1, height: totalHeight))
+            let line = NSView(frame: NSRect(x: x, y: 0, width: 1, height: th))
             line.wantsLayer = true
             line.layer?.backgroundColor = Theme.current.surface2.cgColor
             addSubview(line)
         }
         for i in 0..<totalRows {
-            let y = totalHeight - headerHeight - CGFloat(i) * cellHeight
+            let lineY = (i == 0) ? th - rowHeights[0] : rowY(for: i)
-            let line = NSView(frame: NSRect(x: 0, y: y, width: width, height: 1))
+            let line = NSView(frame: NSRect(x: 0, y: lineY, width: totalWidth, height: 1))
             line.wantsLayer = true
             line.layer?.backgroundColor = Theme.current.surface2.cgColor
             addSubview(line)
@@ -426,6 +474,110 @@ class MarkdownTableView: NSView, NSTextFieldDelegate {
         return field
     }
 
+    // MARK: - Resize hit detection
+
+    private func columnDivider(at point: NSPoint) -> Int? {
+        let colCount = table.headers.count
+        for i in 1..<colCount {
+            let divX = columnX(for: i) - 1
+            if abs(point.x - divX) <= dividerHitZone {
+                return i - 1
+            }
+        }
+        let lastX = columnX(for: colCount)
+        if abs(point.x - lastX) <= dividerHitZone {
+            return colCount - 1
+        }
+        return nil
+    }
+
+    private func rowDivider(at point: NSPoint) -> Int? {
+        let totalRows = 1 + table.rows.count
+        for i in 0..<totalRows {
+            let divY: CGFloat
+            if i == 0 {
+                divY = totalHeight - rowHeights[0]
+            } else {
+                divY = rowY(for: i)
+            }
+            if abs(point.y - divY) <= dividerHitZone {
+                return i
+            }
+        }
+        return nil
+    }
+
+    // MARK: - Tracking area
+
+    private func setupTrackingArea() {
+        for area in trackingAreas { removeTrackingArea(area) }
+        let area = NSTrackingArea(
+            rect: bounds,
+            options: [.mouseMoved, .mouseEnteredAndExited, .activeInKeyWindow, .inVisibleRect],
+            owner: self,
+            userInfo: nil
+        )
+        addTrackingArea(area)
+    }
+
+    override func mouseMoved(with event: NSEvent) {
+        let pt = convert(event.locationInWindow, from: nil)
+        if columnDivider(at: pt) != nil {
+            NSCursor.resizeLeftRight.set()
+        } else if rowDivider(at: pt) != nil {
+            NSCursor.resizeUpDown.set()
+        } else {
+            NSCursor.arrow.set()
+        }
+    }
+
+    override func mouseExited(with event: NSEvent) {
+        NSCursor.arrow.set()
+    }
+
+    override func mouseDown(with event: NSEvent) {
+        let pt = convert(event.locationInWindow, from: nil)
+        if let col = columnDivider(at: pt) {
+            dragMode = .column(col)
+            dragStartPoint = pt
+            dragStartSize = columnWidths[col]
+            return
+        }
+        if let row = rowDivider(at: pt) {
+            dragMode = .row(row)
+            dragStartPoint = pt
+            dragStartSize = rowHeights[row]
+            return
+        }
+        dragMode = .none
+        super.mouseDown(with: event)
+    }
+
+    override func mouseDragged(with event: NSEvent) {
+        let pt = convert(event.locationInWindow, from: nil)
+        switch dragMode {
+        case .column(let col):
+            let delta = pt.x - dragStartPoint.x
+            columnWidths[col] = max(minColWidth, dragStartSize + delta)
+            buildGrid()
+        case .row(let row):
+            let delta = dragStartPoint.y - pt.y
+            rowHeights[row] = max(minRowHeight, dragStartSize + delta)
+            buildGrid()
+        case .none:
+            super.mouseDragged(with: event)
+        }
+    }
+
+    override func mouseUp(with event: NSEvent) {
+        if case .none = dragMode {
+            super.mouseUp(with: event)
+        }
+        dragMode = .none
+    }
+
+    // MARK: - Cell editing
+
     func controlTextDidEndEditing(_ obj: Notification) {
         guard let field = obj.object as? NSTextField else { return }
         let tag = field.tag
@@ -464,8 +616,8 @@ class MarkdownTableView: NSView, NSTextFieldDelegate {
             table.rows.append(Array(repeating: "", count: table.headers.count))
             onTableChanged?(table)
 
-            let width = frame.width
+            rowHeights.append(defaultCellHeight)
-            buildGrid(width: width)
+            buildGrid()
             needsLayout = true
             return true
         }