diff --git a/McBopomofo.xcodeproj/project.pbxproj b/McBopomofo.xcodeproj/project.pbxproj
index dd33b425..7f0a3aac 100644
--- a/McBopomofo.xcodeproj/project.pbxproj
+++ b/McBopomofo.xcodeproj/project.pbxproj
@@ -49,6 +49,8 @@
 		D47F7DD3278C1263002F9DD7 /* UserOverrideModel.cpp in Sources */ = {isa = PBXBuildFile; fileRef = D47F7DD2278C1263002F9DD7 /* UserOverrideModel.cpp */; };
 		D47F7DD5278C25A0002F9DD7 /* InputSourceHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = D47F7DD4278C25A0002F9DD7 /* InputSourceHelper.swift */; };
 		D47F7DD6278C3075002F9DD7 /* InputSourceHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = D47F7DD4278C25A0002F9DD7 /* InputSourceHelper.swift */; };
+		D47F7DDA278C32CD002F9DD7 /* CandidateController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D47F7DD9278C32CD002F9DD7 /* CandidateController.swift */; };
+		D47F7DDC278C39EC002F9DD7 /* HorizontalCandidateController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D47F7DDB278C39EC002F9DD7 /* HorizontalCandidateController.swift */; };
 		D48550A325EBE689006A204C /* OpenCC in Frameworks */ = {isa = PBXBuildFile; productRef = D48550A225EBE689006A204C /* OpenCC */; };
 /* End PBXBuildFile section */
 
@@ -181,6 +183,8 @@
 		D47F7DD1278C1263002F9DD7 /* UserOverrideModel.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = UserOverrideModel.h; sourceTree = "<group>"; };
 		D47F7DD2278C1263002F9DD7 /* UserOverrideModel.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = UserOverrideModel.cpp; sourceTree = "<group>"; };
 		D47F7DD4278C25A0002F9DD7 /* InputSourceHelper.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = InputSourceHelper.swift; sourceTree = "<group>"; };
+		D47F7DD9278C32CD002F9DD7 /* CandidateController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CandidateController.swift; sourceTree = "<group>"; };
+		D47F7DDB278C39EC002F9DD7 /* HorizontalCandidateController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = HorizontalCandidateController.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -260,6 +264,8 @@
 		6A0D4ED815FC0DA600ABF4B3 /* CandidateUI */ = {
 			isa = PBXGroup;
 			children = (
+				D47F7DD9278C32CD002F9DD7 /* CandidateController.swift */,
+				D47F7DDB278C39EC002F9DD7 /* HorizontalCandidateController.swift */,
 				6A0D4ED915FC0DA600ABF4B3 /* VTCandidateController.h */,
 				6A0D4EDA15FC0DA600ABF4B3 /* VTCandidateController.m */,
 				6A0D4EDB15FC0DA600ABF4B3 /* VTHorizontalCandidateController.h */,
@@ -575,11 +581,13 @@
 				6A0D4EFE15FC0DA600ABF4B3 /* VTCandidateController.m in Sources */,
 				6A0D4EFF15FC0DA600ABF4B3 /* VTHorizontalCandidateController.m in Sources */,
 				D47F7DD3278C1263002F9DD7 /* UserOverrideModel.cpp in Sources */,
+				D47F7DDC278C39EC002F9DD7 /* HorizontalCandidateController.swift in Sources */,
 				6A0D4F0015FC0DA600ABF4B3 /* VTHorizontalCandidateView.m in Sources */,
 				6A0D4F0115FC0DA600ABF4B3 /* VTVerticalCandidateController.m in Sources */,
 				6A0D4F0215FC0DA600ABF4B3 /* VTVerticalCandidateTableView.m in Sources */,
 				6A0D4F0315FC0DA600ABF4B3 /* VTVerticalKeyLabelStripView.m in Sources */,
 				D47F7DD0278C0897002F9DD7 /* NonModalAlertWindowController.swift in Sources */,
+				D47F7DDA278C32CD002F9DD7 /* CandidateController.swift in Sources */,
 				D427A9C125ED28CC005D43E0 /* OpenCCBridge.swift in Sources */,
 				D47F7DCE278BFB57002F9DD7 /* PreferencesWindowController.swift in Sources */,
 				6A0D4F4515FC0EB100ABF4B3 /* Mandarin.cpp in Sources */,
diff --git a/Source/CandidateUI/CandidateController.swift b/Source/CandidateUI/CandidateController.swift
new file mode 100644
index 00000000..f0595c7f
--- /dev/null
+++ b/Source/CandidateUI/CandidateController.swift
@@ -0,0 +1,105 @@
+import Cocoa
+
+@objc(CandidateControllerDelegate)
+public protocol CandidateControllerDelegate: AnyObject {
+    func candidateCountForController(_ controller: CandidateController) -> UInt
+    func candidateController(_ controller: CandidateController, candidateAtIndex index: UInt) -> String
+    func candidateController(_ controller: CandidateController, didSelectCandidateAtIndex index: UInt)
+}
+
+@objc(CandidateController)
+public class CandidateController: NSWindowController {
+    @objc public weak var delegate: CandidateControllerDelegate?
+    @objc public var selectedCandidateIndex: UInt = UInt.max
+    @objc public var visible: Bool = false {
+        didSet {
+            if visible {
+                window?.perform(#selector(NSWindow.orderFront(_:)), with: self, afterDelay: 0.0)
+            } else {
+                window?.perform(#selector(NSWindow.orderOut(_:)), with: self, afterDelay: 0.0)
+            }
+        }
+    }
+    @objc public var windowTopLeftPoint: NSPoint {
+        get {
+            guard let frameRect = window?.frame else {
+                return NSPoint.zero
+            }
+            return NSPoint(x: frameRect.minX, y: frameRect.maxY)
+        }
+        set {
+            DispatchQueue.main.asyncAfter(deadline: DispatchTime.now()) {
+                self.set(windowTopLeftPoint: newValue, bottomOutOfScreenAdjustmentHeight: 0)
+            }
+        }
+    }
+
+    @objc public var keyLabels: [String] = ["1", "2", "3", "4", "5", "6", "7", "8", "9"]
+    @objc public var keyLabelFont: NSFont = NSFont.systemFont(ofSize: 14)
+    @objc public var candidateFont: NSFont = NSFont.systemFont(ofSize: 18)
+
+    @objc public func reloadData() {
+    }
+
+    @objc public func showNextPage() -> Bool {
+        return false
+    }
+
+    @objc public func showPreviousPage() -> Bool {
+        return false
+    }
+
+    @objc public func highlightNextCandidate() -> Bool {
+        return false
+    }
+
+    @objc public func highlightPreviousCandidate() -> Bool {
+        return false
+    }
+
+    func set(windowTopLeftPoint: NSPoint, bottomOutOfScreenAdjustmentHeight height:CGFloat) {
+        var adjustedPoint = windowTopLeftPoint
+        var adjustedHeight = height
+
+        var screenFrame = NSScreen.main?.visibleFrame ?? NSRect.zero
+        for screen in NSScreen.screens {
+            let frame = screen.visibleFrame
+            if windowTopLeftPoint.x >= frame.minX &&
+                windowTopLeftPoint.x <= frame.maxX &&
+                windowTopLeftPoint.y >= frame.minY &&
+                windowTopLeftPoint.y <= frame.maxY {
+                screenFrame = frame
+                break
+            }
+        }
+
+        if adjustedHeight > screenFrame.size.height / 2.0 {
+            adjustedHeight = 0.0
+        }
+
+        let windowSize = window?.frame.size ?? NSSize.zero
+
+        // bottom beneath the screen?
+        if adjustedPoint.y - windowSize.height < screenFrame.maxY {
+            adjustedPoint.y = windowTopLeftPoint.y + adjustedHeight + windowSize.height
+        }
+
+        // top over the screen?
+        if adjustedPoint.y >= screenFrame.maxY {
+            adjustedPoint.y = screenFrame.maxY - 1.0
+        }
+
+        // right
+        if adjustedPoint.x + windowSize.width >= screenFrame.maxX {
+            adjustedPoint.x = NSMaxX(screenFrame) - windowSize.width
+        }
+
+        // left
+        if adjustedPoint.x < screenFrame.minX {
+            adjustedPoint.x = screenFrame.minX
+        }
+
+        window?.setFrameTopLeftPoint(adjustedPoint)
+    }
+
+}
diff --git a/Source/CandidateUI/HorizontalCandidateController.swift b/Source/CandidateUI/HorizontalCandidateController.swift
new file mode 100644
index 00000000..b6ce204e
--- /dev/null
+++ b/Source/CandidateUI/HorizontalCandidateController.swift
@@ -0,0 +1,382 @@
+import Cocoa
+
+class HorizontalCandidateView: NSView {
+    var highlightedIndex: UInt = 0
+    var action: Selector?
+    weak var target: AnyObject?
+
+    private var keyLabels: [String] = []
+    private var displayedCandidates: [String] = []
+    private var keyLabelHeight: CGFloat = 0
+    private var candidateTextHeight: CGFloat = 0
+    private var cellPadding: CGFloat = 0
+    private var keyLabelAttrDict: [NSAttributedString.Key:AnyObject] = [:]
+    private var candidateAttrDict: [NSAttributedString.Key:AnyObject] = [:]
+    private var elementWidths: [CGFloat] = []
+    private var trackingHighlightedIndex: UInt = UInt.max
+
+    override var isFlipped: Bool {
+        true
+    }
+
+    var sizeForView: NSSize {
+        var result = NSSize.zero
+
+        if !elementWidths.isEmpty {
+            result.width = elementWidths.reduce(0, +)
+            result.width += CGFloat(elementWidths.count)
+            result.height = keyLabelHeight + candidateTextHeight + 1.0
+
+        }
+        return result
+    }
+
+    @objc(setKeyLabels:displayedCandidates:)
+    func set(keyLabels labels: [String], displayedCandidates candidates: [String]) {
+        let count = min(labels.count, candidates.count)
+        keyLabels = Array(labels[0..<count])
+        displayedCandidates = Array(candidates[0..<count])
+
+        var newWidths = [CGFloat]()
+        let baseSize = NSSize(width: 10240.0, height: 10240.0)
+        for index in 0..<count {
+            let labelRect = (keyLabels[index] as NSString).boundingRect(with: baseSize, options: .usesLineFragmentOrigin, attributes: keyLabelAttrDict)
+            let candidateRect = (displayedCandidates[index] as NSString).boundingRect(with: baseSize, options: .usesLineFragmentOrigin, attributes: keyLabelAttrDict)
+            let cellWidth = max(labelRect.size.width, candidateRect.size.width)
+            newWidths.append(cellWidth)
+        }
+        elementWidths = newWidths
+    }
+
+    @objc(setKeyLabelFont:candidateFont:)
+    func set(keyLabelFont labelFont: NSFont, candidateFont: NSFont) {
+        let paraStyle = NSMutableParagraphStyle()
+        paraStyle.setParagraphStyle(NSParagraphStyle.default)
+        paraStyle.alignment = .center
+
+        keyLabelAttrDict = [.font: labelFont,
+                            .paragraphStyle: paraStyle,
+                            .foregroundColor: NSColor.black]
+        candidateAttrDict = [.font: candidateFont,
+                             .paragraphStyle: paraStyle,
+                             .foregroundColor: NSColor.textColor]
+
+        let labelFontSize = labelFont.pointSize
+        let candidateFontSize = candidateFont.pointSize
+        let biggestSize = max(labelFontSize, candidateFontSize)
+
+        keyLabelHeight = ceil(labelFontSize * 1.20)
+        candidateTextHeight = ceil(candidateFontSize * 1.20)
+        cellPadding = ceil(biggestSize / 2.0)
+    }
+
+    override func draw(_ dirtyRect: NSRect) {
+        let backgroundColor = NSColor.controlBackgroundColor
+        let darkGray = NSColor(deviceWhite: 0.7, alpha: 1.0)
+        let lightGray = NSColor(deviceWhite: 0.8, alpha: 1.0)
+
+        let bounds = self.bounds
+        backgroundColor.setFill()
+        NSBezierPath.fill(bounds)
+
+        if #available(macOS 10.14, *) {
+            NSColor.separatorColor.setStroke()
+        } else {
+            NSColor.darkGray.setStroke()
+        }
+
+        NSBezierPath.strokeLine(from: NSPoint(x: bounds.size.width, y: 0.0), to: NSPoint(x: bounds.size.width, y: bounds.size.height))
+
+        var accuWidth: CGFloat = 0
+        for index in 0..<elementWidths.count {
+            let currentWidth = elementWidths[index]
+            let labelRect = NSRect(x: accuWidth, y: 0.0, width: currentWidth, height: keyLabelHeight);
+            let candidateRect = NSRect(x: accuWidth, y: keyLabelHeight + 1.0, width: currentWidth, height: candidateTextHeight);
+            (index == highlightedIndex ? darkGray : lightGray).setFill()
+            NSBezierPath.fill(labelRect)
+            (keyLabels[index] as NSString).draw(in: labelRect, withAttributes: keyLabelAttrDict)
+
+            var activeCandidateAttr = candidateAttrDict
+            if index == highlightedIndex {
+                NSColor.selectedTextBackgroundColor.setFill()
+                activeCandidateAttr = candidateAttrDict
+                activeCandidateAttr[.foregroundColor] = NSColor.selectedTextColor
+            } else {
+                backgroundColor.setFill()
+            }
+
+            NSBezierPath.fill(candidateRect)
+            (displayedCandidates[index] as NSString).draw(in: candidateRect, withAttributes: activeCandidateAttr)
+            accuWidth += currentWidth + 1.0
+        }
+    }
+
+    private func findHitIndex(event: NSEvent) -> UInt? {
+        let location = convert(event.locationInWindow, to: nil)
+        if !NSPointInRect(location, self.bounds) {
+            return nil
+        }
+        var accuWidth: CGFloat = 0.0
+        for index in 0..<elementWidths.count {
+            let currentWidth = elementWidths[index]
+
+            if location.x >= accuWidth && location.x <= accuWidth + currentWidth {
+                return UInt(index)
+            }
+            accuWidth += currentWidth + 1.0
+        }
+        return nil
+
+    }
+
+    override func mouseUp(with event: NSEvent) {
+        trackingHighlightedIndex = highlightedIndex
+        guard let newIndex = findHitIndex(event: event) else {
+            return
+        }
+        highlightedIndex = newIndex
+        self.setNeedsDisplay(self.bounds)
+    }
+
+    override func mouseDown(with event: NSEvent) {
+        guard let newIndex = findHitIndex(event: event) else {
+            return
+        }
+        var triggerAction = false
+        if newIndex == highlightedIndex {
+            triggerAction = true
+        } else {
+            highlightedIndex = trackingHighlightedIndex;
+        }
+
+        trackingHighlightedIndex = 0
+        self.setNeedsDisplay(self.bounds)
+        if triggerAction {
+            if let target = target as? NSObject, let action = action {
+                target.perform(action, with: self)
+            }
+        }
+    }
+}
+
+public class HorizontalCandidateController : CandidateController {
+    private var candidateView: HorizontalCandidateView
+    private var prevPageButton: NSButton
+    private var nextPageButton: NSButton
+    private var currentPage: UInt = 0
+
+    public init() {
+        var contentRect = NSRect(x: 128.0, y: 128.0, width: 0.0, height: 0.0)
+        let styleMask: NSWindow.StyleMask = [.borderless, .nonactivatingPanel]
+        let panel = NSPanel(contentRect: contentRect, styleMask: styleMask, backing: .buffered, defer: false)
+
+        contentRect.origin = NSPoint.zero
+        candidateView = HorizontalCandidateView(frame: contentRect)
+        panel.contentView?.addSubview(candidateView)
+
+        contentRect.size = NSSize(width: 36.0, height: 20.0)
+        nextPageButton = NSButton(frame: contentRect)
+        prevPageButton = NSButton(frame: contentRect)
+
+        panel.contentView?.addSubview(nextPageButton)
+        panel.contentView?.addSubview(prevPageButton)
+
+        super.init(window: panel)
+
+        candidateView.target = self
+        candidateView.action = #selector(candidateViewMouseDidClick(_:))
+
+        nextPageButton.setButtonType(.momentaryLight)
+        nextPageButton.bezelStyle = .smallSquare
+        nextPageButton.title = "»"
+        nextPageButton.target = self
+        nextPageButton.action = #selector(pageButtonAction(_:))
+
+        prevPageButton.setButtonType(.momentaryLight)
+        prevPageButton.bezelStyle = .smallSquare
+        prevPageButton.title = "«"
+        prevPageButton.target = self
+        prevPageButton.action = #selector(pageButtonAction(_:))
+    }
+
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    public override func reloadData() {
+        candidateView.highlightedIndex = 0
+        currentPage = 0
+        layoutCandidateView()
+    }
+
+    public override func showNextPage() -> Bool {
+        guard delegate != nil else {
+            return false
+        }
+
+        if currentPage + 1 >= self.pageCount {
+            return false
+        }
+
+        currentPage += 1
+        candidateView.highlightedIndex = 0
+        layoutCandidateView();
+        return true;
+    }
+
+    public override func showPreviousPage() -> Bool {
+        guard delegate != nil else {
+            return false
+        }
+
+        if currentPage == 0 {
+            return false
+        }
+
+        currentPage -= 1
+        candidateView.highlightedIndex = 0
+        layoutCandidateView();
+        return true;
+    }
+
+    public override func highlightNextCandidate() -> Bool {
+        guard let delegate = delegate else {
+            return false
+        }
+
+        let currentIndex = selectedCandidateIndex
+        if currentIndex + 1 >= delegate.candidateCountForController(self) {
+            return false;
+        }
+        selectedCandidateIndex = currentIndex + 1
+        return true;
+    }
+
+    public override func highlightPreviousCandidate() -> Bool {
+        guard delegate != nil else {
+            return false
+        }
+
+        let currentIndex = self.selectedCandidateIndex;
+        if currentIndex == 0 {
+            return false
+        }
+
+        selectedCandidateIndex = currentIndex - 1
+        return true
+    }
+
+    @objc public func candidateIndexAtKeyLabelIndex(_ index: UInt) -> UInt {
+        guard let delegate = delegate else {
+            return UInt.max
+        }
+
+        let result = currentPage * UInt(keyLabels.count) + index;
+        return result < delegate.candidateCountForController(self) ? result : UInt.max;
+    }
+
+    @objc public override var selectedCandidateIndex: UInt {
+        get {
+            return currentPage * UInt(keyLabels.count) + candidateView.highlightedIndex
+        }
+        set {
+            guard let delegate = delegate else {
+                return
+            }
+            let keyLabelCount = UInt(keyLabels.count)
+            if newValue < delegate.candidateCountForController(self) {
+                currentPage = newValue / keyLabelCount;
+                candidateView.highlightedIndex = newValue % keyLabelCount;
+                layoutCandidateView()
+            }
+        }
+    }
+}
+
+extension HorizontalCandidateController {
+
+    var pageCount: UInt {
+        guard let delegate = delegate else {
+            return 0
+        }
+        let totalCount = delegate.candidateCountForController(self)
+        let keyLabelCount = UInt(keyLabels.count)
+        return totalCount / keyLabelCount + ((totalCount % keyLabelCount) != 0 ? 1 : 0)
+    }
+
+    func layoutCandidateView() {
+        guard let delegate = delegate else {
+            return
+        }
+
+        candidateView.set(keyLabelFont: keyLabelFont, candidateFont: candidateFont)
+        var candidates = [String]()
+        let count = delegate.candidateCountForController(self)
+        let keyLabelCount = UInt(keyLabels.count)
+
+        let begin = currentPage * keyLabelCount
+        for index in begin..<min(begin + keyLabelCount, count) {
+            let candidate = delegate.candidateController(self, candidateAtIndex: index)
+            candidates.append(candidate)
+        }
+        candidateView.set(keyLabels: keyLabels, displayedCandidates: candidates)
+        var newSize = candidateView.sizeForView
+        var frameRect = candidateView.frame
+        frameRect.size = newSize
+        candidateView.frame = frameRect
+
+        if self.pageCount > 1 {
+            var buttonRect = nextPageButton.frame
+            var spacing = 0.0
+
+            if newSize.height < 40.0 {
+                buttonRect.size.height = floor(newSize.height / 2)
+            } else {
+                buttonRect.size.height = 20.0
+            }
+
+            if newSize.height >= 60.0 {
+                spacing = ceil(newSize.height * 0.1)
+            }
+
+            let buttonOriginY = (newSize.height - (buttonRect.size.height * 2.0 + spacing)) / 2.0
+            buttonRect.origin = NSPoint(x: newSize.width + 8.0, y: buttonOriginY)
+            nextPageButton.frame = buttonRect
+
+            buttonRect.origin = NSPoint(x: newSize.width + 8.0, y: buttonOriginY + buttonRect.size.height + spacing)
+            prevPageButton.frame = buttonRect
+
+            newSize.width += 52.0
+            nextPageButton.isHidden = false
+            prevPageButton.isHidden = false
+        } else {
+            nextPageButton.isHidden = true
+            prevPageButton.isHidden = true
+        }
+
+        frameRect = window?.frame ?? NSRect.zero
+
+        let  topLeftPoint = NSMakePoint(frameRect.origin.x, frameRect.origin.y + frameRect.size.height)
+        frameRect.size = newSize
+        frameRect.origin = NSMakePoint(topLeftPoint.x, topLeftPoint.y - frameRect.size.height)
+        self.window?.setFrame(frameRect, display: false)
+        self.candidateView.setNeedsDisplay(candidateView.bounds)
+    }
+
+    @objc func pageButtonAction(_ sender: Any) {
+        guard let sender = sender as? NSButton else {
+            return
+        }
+        if sender == nextPageButton {
+            _ = showNextPage()
+        } else if sender == prevPageButton {
+            _ =  showPreviousPage()
+        }
+    }
+
+    @objc func candidateViewMouseDidClick(_ sender: Any) {
+        delegate?.candidateController(self, didSelectCandidateAtIndex: self.selectedCandidateIndex)
+    }
+
+}
+