From b9ca537fc72daafb91d11fbb7ec0fbfc8723c7a7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thorbj=C3=B8rn=20Lindeijer?= <bjorn@lindeijer.nl>
Date: Thu, 26 Sep 2024 18:02:32 +0200
Subject: [PATCH] Show inherited class name as placeholder text

For map objects, which can inherit their class from their tile or their
template.
---
 src/tiled/propertieswidget.cpp | 21 +++++++++++++++++++--
 src/tiled/textpropertyedit.h   |  2 ++
 src/tiled/varianteditor.cpp    | 15 +++++++++++++++
 src/tiled/varianteditor.h      | 16 ++++++++++++++--
 4 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/src/tiled/propertieswidget.cpp b/src/tiled/propertieswidget.cpp
index e65ab82234..2b6d695ed1 100644
--- a/src/tiled/propertieswidget.cpp
+++ b/src/tiled/propertieswidget.cpp
@@ -556,6 +556,8 @@ class ClassNameProperty : public StringProperty
         , mDocument(document)
         , mObject(object)
     {
+        updatePlaceholderText();
+
         connect(mDocument, &Document::changed,
                 this, &ClassNameProperty::onChanged);
     }
@@ -564,6 +566,7 @@ class ClassNameProperty : public StringProperty
     {
         auto editor = new QComboBox(parent);
         editor->setEditable(true);
+        editor->lineEdit()->setPlaceholderText(placeholderText());
         editor->addItems(classNamesFor(*mObject));
         auto syncEditor = [this, editor] {
             const QSignalBlocker blocker(editor);
@@ -571,11 +574,15 @@ class ClassNameProperty : public StringProperty
         };
         syncEditor();
         connect(this, &Property::valueChanged, editor, syncEditor);
+        connect(this, &StringProperty::placeholderTextChanged,
+                editor->lineEdit(), &QLineEdit::setPlaceholderText);
         connect(editor, &QComboBox::currentTextChanged, this, &StringProperty::setValue);
         connect(Preferences::instance(), &Preferences::propertyTypesChanged,
-                editor, [this,editor] {
+                editor, [=] {
+            const QSignalBlocker blocker(editor);
             editor->clear();
             editor->addItems(classNamesFor(*mObject));
+            syncEditor();
         });
         return editor;
     }
@@ -590,8 +597,18 @@ class ClassNameProperty : public StringProperty
         if (!objectsEvent.objects.contains(mObject))
             return;
 
-        if (objectsEvent.properties & ObjectsChangeEvent::ClassProperty)
+        if (objectsEvent.properties & ObjectsChangeEvent::ClassProperty) {
+            updatePlaceholderText();
             emit valueChanged();
+        }
+    }
+
+    void updatePlaceholderText()
+    {
+        if (mObject->typeId() == Object::MapObjectType && mObject->className().isEmpty())
+            setPlaceholderText(static_cast<MapObject*>(mObject)->effectiveClassName());
+        else
+            setPlaceholderText(QString());
     }
 
     Document *mDocument;
diff --git a/src/tiled/textpropertyedit.h b/src/tiled/textpropertyedit.h
index 4ef2c7360f..a509ab38fc 100644
--- a/src/tiled/textpropertyedit.h
+++ b/src/tiled/textpropertyedit.h
@@ -45,6 +45,8 @@ class TextPropertyEdit : public QWidget
 
     QString text() const;
 
+    QLineEdit *lineEdit() const { return mLineEdit; }
+
 public slots:
     void setText(const QString &text);
 
diff --git a/src/tiled/varianteditor.cpp b/src/tiled/varianteditor.cpp
index 580efa507f..d09e163f25 100644
--- a/src/tiled/varianteditor.cpp
+++ b/src/tiled/varianteditor.cpp
@@ -57,15 +57,26 @@ void Property::setEnabled(bool enabled)
     }
 }
 
+void StringProperty::setPlaceholderText(const QString &placeholderText)
+{
+    if (m_placeholderText != placeholderText) {
+        m_placeholderText = placeholderText;
+        emit placeholderTextChanged(placeholderText);
+    }
+}
+
 QWidget *StringProperty::createEditor(QWidget *parent)
 {
     auto editor = new QLineEdit(parent);
+    editor->setPlaceholderText(m_placeholderText);
+
     auto syncEditor = [=] {
         editor->setText(value());
     };
     syncEditor();
 
     connect(this, &Property::valueChanged, editor, syncEditor);
+    connect(this, &StringProperty::placeholderTextChanged, editor, &QLineEdit::setPlaceholderText);
     connect(editor, &QLineEdit::textEdited, this, &StringProperty::setValue);
 
     return editor;
@@ -74,6 +85,8 @@ QWidget *StringProperty::createEditor(QWidget *parent)
 QWidget *MultilineStringProperty::createEditor(QWidget *parent)
 {
     auto editor = new TextPropertyEdit(parent);
+    editor->lineEdit()->setPlaceholderText(placeholderText());
+
     auto syncEditor = [=] {
         const QSignalBlocker blocker(editor);
         editor->setText(value());
@@ -81,6 +94,8 @@ QWidget *MultilineStringProperty::createEditor(QWidget *parent)
     syncEditor();
 
     connect(this, &StringProperty::valueChanged, editor, syncEditor);
+    connect(this, &StringProperty::placeholderTextChanged,
+            editor->lineEdit(), &QLineEdit::setPlaceholderText);
     connect(editor, &TextPropertyEdit::textChanged, this, &StringProperty::setValue);
 
     return editor;
diff --git a/src/tiled/varianteditor.h b/src/tiled/varianteditor.h
index ce9098114b..a4e72d4130 100644
--- a/src/tiled/varianteditor.h
+++ b/src/tiled/varianteditor.h
@@ -168,13 +168,25 @@ class PropertyTemplate : public Property
 
 struct StringProperty : PropertyTemplate<QString>
 {
+    Q_OBJECT
+
+public:
     using PropertyTemplate::PropertyTemplate;
     QWidget *createEditor(QWidget *parent) override;
+
+    void setPlaceholderText(const QString &placeholderText);
+    const QString &placeholderText() const { return m_placeholderText; }
+
+signals:
+    void placeholderTextChanged(const QString &placeholderText);
+
+private:
+    QString m_placeholderText;
 };
 
-struct MultilineStringProperty : PropertyTemplate<QString>
+struct MultilineStringProperty : StringProperty
 {
-    using PropertyTemplate::PropertyTemplate;
+    using StringProperty::StringProperty;
     QWidget *createEditor(QWidget *parent) override;
 };