From a39c44e483e20e0ac30f92d2e0a6cdce15735974 Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@freecad.org>
Date: Sun, 18 May 2025 10:30:55 +0200
Subject: [PATCH] Tools: Add ExpressionLineEdit to QtDesigner plugin

---
 src/Tools/plugins/widget/customwidgets.cpp | 62 ++++++++++++++++++++++
 src/Tools/plugins/widget/customwidgets.h   | 28 ++++++++++
 src/Tools/plugins/widget/plugin.cpp        | 51 ++++++++++++++++++
 3 files changed, 141 insertions(+)

diff --git a/src/Tools/plugins/widget/customwidgets.cpp b/src/Tools/plugins/widget/customwidgets.cpp
index 79836644b2..2514dbc18f 100644
--- a/src/Tools/plugins/widget/customwidgets.cpp
+++ b/src/Tools/plugins/widget/customwidgets.cpp
@@ -22,11 +22,13 @@
 
 #include <limits>
 
+#include <QAction>
 #include <QApplication>
 #include <QColorDialog>
 #include <QCursor>
 #include <QFileDialog>
 #include <QHeaderView>
+#include <QMenu>
 #include <QMessageBox>
 #include <QRegularExpression>
 #include <QRegularExpressionMatch>
@@ -544,6 +546,66 @@ void InputField::setHistorySize(int i)
 
 // --------------------------------------------------------------------
 
+ExpressionLineEdit::ExpressionLineEdit(QWidget* parent)
+    : QLineEdit(parent)
+    , exactMatch {false}
+{
+    completer = new QCompleter(this);
+    connect(this, &QLineEdit::textEdited, this, &ExpressionLineEdit::slotTextChanged);
+}
+
+void ExpressionLineEdit::setExactMatch(bool enabled)
+{
+    exactMatch = enabled;
+    if (completer) {
+        completer->setFilterMode(exactMatch ? Qt::MatchStartsWith : Qt::MatchContains);
+    }
+}
+
+void ExpressionLineEdit::slotTextChanged(const QString& text)
+{
+    Q_EMIT textChanged2(text, cursorPosition());
+}
+
+void ExpressionLineEdit::slotCompleteText(const QString& completionPrefix, bool isActivated)
+{
+    Q_UNUSED(completionPrefix)
+    Q_UNUSED(isActivated)
+}
+
+void ExpressionLineEdit::slotCompleteTextHighlighted(const QString& completionPrefix)
+{
+    slotCompleteText(completionPrefix, false);
+}
+
+void ExpressionLineEdit::slotCompleteTextSelected(const QString& completionPrefix)
+{
+    slotCompleteText(completionPrefix, true);
+}
+
+void ExpressionLineEdit::keyPressEvent(QKeyEvent* e)
+{
+    QLineEdit::keyPressEvent(e);
+}
+
+void ExpressionLineEdit::contextMenuEvent(QContextMenuEvent* event)
+{
+    QMenu* menu = createStandardContextMenu();
+
+    if (completer) {
+        menu->addSeparator();
+        QAction* match = menu->addAction(tr("Exact match"));
+        match->setCheckable(true);
+        match->setChecked(completer->filterMode() == Qt::MatchStartsWith);
+        QObject::connect(match, &QAction::toggled, this, &Gui::ExpressionLineEdit::setExactMatch);
+    }
+    menu->setAttribute(Qt::WA_DeleteOnClose);
+
+    menu->popup(event->globalPos());
+}
+
+// --------------------------------------------------------------------
+
 namespace Base
 {
 
diff --git a/src/Tools/plugins/widget/customwidgets.h b/src/Tools/plugins/widget/customwidgets.h
index c80966b493..ed91cf2c24 100644
--- a/src/Tools/plugins/widget/customwidgets.h
+++ b/src/Tools/plugins/widget/customwidgets.h
@@ -27,6 +27,7 @@
 #include <QButtonGroup>
 #include <QCheckBox>
 #include <QComboBox>
+#include <QCompleter>
 #include <QDoubleSpinBox>
 #include <QFontComboBox>
 #include <QGridLayout>
@@ -386,6 +387,33 @@ private:
 
 // ------------------------------------------------------------------------------
 
+class ExpressionLineEdit: public QLineEdit
+{
+    Q_OBJECT
+public:
+    ExpressionLineEdit(QWidget* parent = nullptr);
+
+public Q_SLOTS:
+    void slotTextChanged(const QString& text);
+    void slotCompleteText(const QString& completionPrefix, bool isActivated);
+    void slotCompleteTextHighlighted(const QString& completionPrefix);
+    void slotCompleteTextSelected(const QString& completionPrefix);
+    void setExactMatch(bool enabled = true);
+
+protected:
+    void keyPressEvent(QKeyEvent* event) override;
+    void contextMenuEvent(QContextMenuEvent* event) override;
+
+Q_SIGNALS:
+    void textChanged2(QString text, int pos);
+
+private:
+    QCompleter* completer;
+    bool exactMatch;
+};
+
+// ------------------------------------------------------------------------------
+
 class QuantitySpinBoxPrivate;
 class QuantitySpinBox: public QAbstractSpinBox
 {
diff --git a/src/Tools/plugins/widget/plugin.cpp b/src/Tools/plugins/widget/plugin.cpp
index 62b9672fff..dee5844e13 100644
--- a/src/Tools/plugins/widget/plugin.cpp
+++ b/src/Tools/plugins/widget/plugin.cpp
@@ -523,6 +523,56 @@ public:
     }
 };
 
+class ExpressionLineEditPlugin: public QDesignerCustomWidgetInterface
+{
+    Q_INTERFACES(QDesignerCustomWidgetInterface)
+public:
+    ExpressionLineEditPlugin()
+    {}
+    QWidget* createWidget(QWidget* parent)
+    {
+        return new Gui::ExpressionLineEdit(parent);
+    }
+    QString group() const
+    {
+        return QLatin1String("Input Widgets");
+    }
+    QIcon icon() const
+    {
+        return QIcon(QPixmap(inputfield_pixmap));
+    }
+    QString includeFile() const
+    {
+        return QLatin1String("Gui/InputField.h");
+    }
+    QString toolTip() const
+    {
+        return QLatin1String("Expression line edit");
+    }
+    QString whatsThis() const
+    {
+        return QLatin1String("A widget to work with expressions.");
+    }
+    bool isContainer() const
+    {
+        return false;
+    }
+    QString domXml() const
+    {
+        return "<ui language=\"c++\">\n"
+               " <widget class=\"Gui::ExpressionLineEdit\" name=\"exprLineEdit\">\n"
+               "  <property name=\"unit\" stdset=\"0\">\n"
+               "   <string notr=\"true\"></string>\n"
+               "  </property>\n"
+               " </widget>\n"
+               "</ui>";
+    }
+    QString name() const
+    {
+        return QLatin1String("Gui::ExpressionLineEdit");
+    }
+};
+
 /* XPM */
 static const char* quantityspinbox_pixmap[] = {"22 22 6 1",
                                                "a c #000000",
@@ -1653,6 +1703,7 @@ QList<QDesignerCustomWidgetInterface*> CustomWidgetPlugin::customWidgets() const
     cw.append(new FileChooserPlugin);
     cw.append(new AccelLineEditPlugin);
     cw.append(new ActionSelectorPlugin);
+    cw.append(new ExpressionLineEditPlugin);
     cw.append(new InputFieldPlugin);
     cw.append(new QuantitySpinBoxPlugin);
     cw.append(new CommandIconViewPlugin);