MessageSource Line Numbers

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

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;
+};