MessageSource Line Numbers

Create a model for getting line numbers from a QQuickTextDocument and then add them to the MessageSource page

src/CMakeLists.txt

@@ -148,6 +148,8 @@ add_library(neochat STATIC
     models/itinerarymodel.h
     proxycontroller.cpp
     proxycontroller.h
+    models/linemodel.cpp
+    models/linemodel.h
 )
 
 qt_add_qml_module(neochat URI org.kde.neochat NO_PLUGIN

src/models/linemodel.cpp

@@ -0,0 +1,64 @@
+// SPDX-FileCopyrightText: 2024 James Graham <james.h.graham@protonmail.com>
+// SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
+
+#include "linemodel.h"
+
+LineModel::LineModel(QObject *parent)
+    : QAbstractListModel(parent)
+{
+}
+
+QQuickTextDocument *LineModel::document() const
+{
+    return m_document;
+}
+
+void LineModel::setDocument(QQuickTextDocument *document)
+{
+    if (document == m_document) {
+        return;
+    }
+
+    m_document = document;
+    Q_EMIT documentChanged();
+
+    resetModel();
+}
+
+QVariant LineModel::data(const QModelIndex &index, int role) const
+{
+    if (!index.isValid()) {
+        return {};
+    }
+
+    const auto &row = index.row();
+    if (row < 0 || row > rowCount()) {
+        return {};
+    }
+
+    if (role == LineHeightRole) {
+        auto textDoc = m_document->textDocument();
+        return int(textDoc->documentLayout()->blockBoundingRect(textDoc->findBlockByNumber(row)).height());
+    }
+    return {};
+}
+
+int LineModel::rowCount(const QModelIndex &parent) const
+{
+    Q_UNUSED(parent);
+    if (m_document == nullptr) {
+        return 0;
+    }
+    return m_document->textDocument()->blockCount();
+}
+
+QHash<int, QByteArray> LineModel::roleNames() const
+{
+    return {{LineHeightRole, "docLineHeight"}};
+}
+
+void LineModel::resetModel()
+{
+    beginResetModel();
+    endResetModel();
+}

src/models/linemodel.h

@@ -0,0 +1,80 @@
+// SPDX-FileCopyrightText: 2024 James Graham <james.h.graham@protonmail.com>
+// SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
+
+#pragma once
+
+#include <QAbstractListModel>
+#include <QAbstractTextDocumentLayout>
+#include <QQmlEngine>
+#include <QQuickTextDocument>
+#include <QTextBlock>
+#include <qtmetamacros.h>
+
+/**
+ * @class LineModel
+ *
+ * A model to provide line info for a QQuickTextDocument.
+ *
+ * @sa QQuickTextDocument
+ */
+class LineModel : public QAbstractListModel
+{
+    Q_OBJECT
+    QML_ELEMENT
+
+    /**
+     * @brief The QQuickTextDocument that is being handled.
+     */
+    Q_PROPERTY(QQuickTextDocument *document READ document WRITE setDocument NOTIFY documentChanged)
+
+public:
+    /**
+     * @brief Defines the model roles.
+     */
+    enum Roles {
+        LineHeightRole = Qt::UserRole + 1, /**< The delegate type of the message. */
+    };
+    Q_ENUM(Roles)
+
+    explicit LineModel(QObject *parent = nullptr);
+
+    [[nodiscard]] QQuickTextDocument *document() const;
+    void setDocument(QQuickTextDocument *document);
+
+    /**
+     * @brief Get the given role value at the given index.
+     *
+     * @sa QAbstractItemModel::data
+     */
+    [[nodiscard]] QVariant data(const QModelIndex &index, int role) const override;
+
+    /**
+     * @brief Number of rows in the model.
+     *
+     * @sa QAbstractItemModel::rowCount
+     */
+    [[nodiscard]] int rowCount(const QModelIndex &parent = QModelIndex()) const override;
+
+    /**
+     * @brief Returns a mapping from Role enum values to role names.
+     *
+     * @sa Roles, QAbstractItemModel::roleNames()
+     */
+    [[nodiscard]] QHash<int, QByteArray> roleNames() const override;
+
+    /**
+     * @brief Reset the model.
+     *
+     * This needs to be called when the QQuickTextDocument container changes width
+     * or height as this may change line heights due to wrapping.
+     *
+     * @sa QQuickTextDocument
+     */
+    Q_INVOKABLE void resetModel();
+
+Q_SIGNALS:
+    void documentChanged();
+
+private:
+    QPointer<QQuickTextDocument> m_document = nullptr;
+};

src/qml/MessageSourceSheet.qml

@@ -4,6 +4,7 @@
 
 import QtQuick
 import QtQuick.Controls as QQC2
+import QtQuick.Layouts
 
 import org.kde.kirigami as Kirigami
 import org.kde.syntaxhighlighting
@@ -11,6 +12,7 @@ import org.kde.syntaxhighlighting
 import org.kde.neochat
 
 Kirigami.Page {
+    id: root
     property string sourceText
 
     topPadding: 0
@@ -21,6 +23,7 @@ Kirigami.Page {
     title: i18n("Event Source")
 
     QQC2.ScrollView {
+        id: scrollView
         anchors.fill: parent
         contentWidth: availableWidth
 
@@ -29,24 +32,71 @@ Kirigami.Page {
 
         QQC2.TextArea {
             id: sourceTextArea
-            text: sourceText
+            Layout.fillWidth: true
+
+            leftPadding: lineNumberColumn.width + lineNumberColumn.anchors.leftMargin + Kirigami.Units.smallSpacing * 2
+
+            text: root.sourceText
             readOnly: true
             textFormat: TextEdit.PlainText
             wrapMode: TextEdit.Wrap
-            background: Rectangle {
-                Kirigami.Theme.colorSet: Kirigami.Theme.View
-                Kirigami.Theme.inherit: false
-                color: Kirigami.Theme.backgroundColor
-            }
 
             // opt-out of whatever spell checker a styled TextArea might come with
             Kirigami.SpellCheck.enabled: false
 
+            onWidthChanged: lineModel.resetModel()
+            onHeightChanged: lineModel.resetModel()
+
             SyntaxHighlighter {
                 textEdit: sourceTextArea
                 definition: "JSON"
                 repository: Repository
             }
+
+            ColumnLayout {
+                id: lineNumberColumn
+
+                anchors {
+                    top: sourceTextArea.top
+                    topMargin: sourceTextArea.topPadding
+                    left: sourceTextArea.left
+                    leftMargin: Kirigami.Units.smallSpacing
+                }
+                spacing: 0
+                Repeater {
+                    id: repeater
+                    model: LineModel {
+                        id: lineModel
+                        document: sourceTextArea.textDocument
+                    }
+                    delegate: QQC2.Label {
+                        id: label
+                        required property int index
+                        required property int docLineHeight
+                        Layout.fillWidth: true
+                        Layout.preferredHeight: docLineHeight
+                        topPadding: 1
+                        horizontalAlignment: Text.AlignRight
+                        text: index + 1
+                        color: Kirigami.Theme.disabledTextColor
+                    }
+                }
+            }
+
+            background: Rectangle {
+                Kirigami.Theme.colorSet: Kirigami.Theme.View
+                Kirigami.Theme.inherit: false
+                color: Kirigami.Theme.backgroundColor
+            }
+        }
+    }
+
+    Kirigami.Separator {
+        anchors {
+            top: parent.top
+            bottom: parent.bottom
+            left: parent.left
+            leftMargin: lineNumberColumn.width + lineNumberColumn.anchors.leftMargin + Kirigami.Units.smallSpacing
         }
     }
 }