horizontal scrollable candidates

patches/hallelujah.patch

@@ -1,12 +1,12 @@
 diff --git a/CMakeLists.txt b/CMakeLists.txt
-index 02daeea..bcc8397 100644
+index 7ffcf34..a57a061 100644
 --- a/CMakeLists.txt
 +++ b/CMakeLists.txt
 @@ -12,8 +12,6 @@ option(ENABLE_TEST "Build Test" On)
  option(BUILD_DATA "Build data" On)
 
  find_package(Gettext REQUIRED)
--find_package(Fcitx5Core 5.0.0 REQUIRED)
+-find_package(Fcitx5Core 5.1.9 REQUIRED)
 -find_package(Fcitx5Module REQUIRED COMPONENTS Spell TestFrontend)
  find_package(PkgConfig REQUIRED)
 
@@ -75,7 +75,7 @@ index dcbd627..6b0f00d 100644
 +    \"
 +)
 diff --git a/src/hallelujah.h b/src/hallelujah.h
-index 115ad79..c35bd7e 100644
+index ace78e7..2a371b8 100644
 --- a/src/hallelujah.h
 +++ b/src/hallelujah.h
 @@ -71,7 +71,6 @@ private:

uipanel/CMakeLists.txt

@@ -2,6 +2,8 @@ add_library(KeyboardUI STATIC
     keyboardui.swift
     Key.swift
     Keyboard.swift
+    Candidate.swift
+    CandidateBar.swift
 )
 set_target_properties(KeyboardUI PROPERTIES Swift_MODULE_NAME KeyboardUI)
 target_compile_options(KeyboardUI PUBLIC "$<$<COMPILE_LANGUAGE:Swift>:-cxx-interoperability-mode=default>")

uipanel/Candidate.swift

@@ -0,0 +1,34 @@
+import UIKit
+
+class CandidateView: UICollectionViewCell {
+  static let identifier = "CandidateView"
+
+  let wordLabel: UILabel = {
+    let label = UILabel()
+    label.textAlignment = .center
+    label.font = UIFont.systemFont(ofSize: 18)
+    label.translatesAutoresizingMaskIntoConstraints = false
+    return label
+  }()
+
+  override init(frame: CGRect) {
+    super.init(frame: frame)
+    contentView.addSubview(wordLabel)
+    setupConstraints()
+  }
+
+  required init?(coder: NSCoder) {
+    fatalError("init(coder:) has not been implemented")
+  }
+
+  private func setupConstraints() {
+    NSLayoutConstraint.activate([
+      wordLabel.centerXAnchor.constraint(equalTo: contentView.centerXAnchor),
+      wordLabel.centerYAnchor.constraint(equalTo: contentView.centerYAnchor),
+    ])
+  }
+
+  func configure(with word: String) {
+    wordLabel.text = word
+  }
+}

uipanel/CandidateBar.swift

@@ -0,0 +1,92 @@
+import UIKit
+
+class CandidateCollectionView: UIView {
+
+  var words = [String]()
+
+  private var collectionView: UICollectionView!
+
+  override init(frame: CGRect) {
+    super.init(frame: frame)
+    setupCollectionView()
+    setupConstraints()
+  }
+
+  required init?(coder: NSCoder) {
+    fatalError("init(coder:) has not been implemented")
+  }
+
+  private func setupCollectionView() {
+    let layout = UICollectionViewFlowLayout()
+    layout.scrollDirection = .horizontal
+
+    collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)
+    collectionView.translatesAutoresizingMaskIntoConstraints = false
+    collectionView.backgroundColor = UIColor.clear
+    collectionView.delegate = self
+    collectionView.dataSource = self
+    collectionView.register(
+      CandidateView.self, forCellWithReuseIdentifier: CandidateView.identifier)
+
+    addSubview(collectionView)
+  }
+
+  private func setupConstraints() {
+    NSLayoutConstraint.activate([
+      collectionView.leadingAnchor.constraint(equalTo: leadingAnchor),
+      collectionView.trailingAnchor.constraint(equalTo: trailingAnchor),
+      collectionView.topAnchor.constraint(equalTo: topAnchor),
+      collectionView.bottomAnchor.constraint(equalTo: bottomAnchor),
+      collectionView.heightAnchor.constraint(equalToConstant: 35),
+    ])
+  }
+
+  func updateCandidates(_ candidates: [String]) {
+    words = candidates
+    collectionView.reloadData()
+  }
+}
+
+extension CandidateCollectionView: UICollectionViewDataSource {
+  func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int)
+    -> Int
+  {
+    return words.count
+  }
+
+  func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath)
+    -> UICollectionViewCell
+  {
+    guard
+      let cell = collectionView.dequeueReusableCell(
+        withReuseIdentifier: CandidateView.identifier, for: indexPath) as? CandidateView
+    else {
+      return UICollectionViewCell()
+    }
+    cell.configure(with: words[indexPath.item])
+    return cell
+  }
+}
+
+extension CandidateCollectionView: UICollectionViewDelegate {
+  func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
+  }
+}
+
+extension CandidateCollectionView: UICollectionViewDelegateFlowLayout {
+  func collectionView(
+    _ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout,
+    sizeForItemAt indexPath: IndexPath
+  ) -> CGSize {
+    let word = words[indexPath.item]
+    let width = word.size(withAttributes: [.font: UIFont.systemFont(ofSize: 18)]).width + 20
+    return CGSize(width: width, height: 35)
+  }
+
+  func collectionView(
+    _ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout,
+    minimumLineSpacingForSectionAt section: Int
+  ) -> CGFloat {
+    return 10
+  }
+}

uipanel/keyboardui.swift

@@ -3,10 +3,14 @@ import OSLog
 import UIKit
 
 let logger = Logger(subsystem: "org.fcitx.Fcitx5", category: "FcitxLog")
+let candidateCollectionView = CandidateCollectionView()
 
 private func setupMainLayout(_ client: FcitxProtocol) {
   let mainStackView = client.getView()
 
+  candidateCollectionView.translatesAutoresizingMaskIntoConstraints = false
+  mainStackView.addArrangedSubview(candidateCollectionView)
+
   let keyboardView = Keyboard(client)
   keyboardView.translatesAutoresizingMaskIntoConstraints = false
   mainStackView.addArrangedSubview(keyboardView)
@@ -21,3 +25,9 @@ public func showKeyboardAsync(_ clientPtr: UnsafeMutableRawPointer) {
     setupMainLayout(client)
   }
 }
+
+public func setCandidatesAsync(_ candidates: [String]) {
+  DispatchQueue.main.async {
+    candidateCollectionView.updateCandidates(candidates)
+  }
+}

uipanel/uipanel.cpp

@@ -21,15 +21,17 @@ void UIPanel::update(UserInterfaceComponent component,
     case UserInterfaceComponent::InputPanel: {
         const InputPanel &inputPanel = inputContext->inputPanel();
         int size = 0;
+        auto candidates = swift::Array<swift::String>::init();
         if (const auto &list = inputPanel.candidateList()) {
             size = list->size();
             for (int i = 0; i < size; i++) {
                 const auto &candidate = list->candidate(i);
-                FCITX_INFO()
-                    << instance_->outputFilter(inputContext, candidate.text())
-                           .toString();
+                candidates.append(
+                    instance_->outputFilter(inputContext, candidate.text())
+                        .toString());
             }
         }
+        KeyboardUI::setCandidatesAsync(candidates);
         break;
     }
     case UserInterfaceComponent::StatusArea: