[PlasmaComponents Menu] Add maximumWidth property

This allows to limit the maximum width of a menu. It can be useful for instance
in task manager where long file names for recent documents will result in gigantic menus.

The property has a RESET method (which is called if you assign "undefined") which will
set it back to QWIDGETSIZE_MAX to remove the size restriction.

Differential Revision: https://phabricator.kde.org/D4257

src/declarativeimports/plasmacomponents/qmenu.cpp

@@ -153,6 +153,25 @@ void QMenuProxy::setMinimumWidth(int width)
     }
 }
 
+int QMenuProxy::maximumWidth() const
+{
+    return m_menu->maximumWidth();
+}
+
+void QMenuProxy::setMaximumWidth(int width)
+{
+    if (m_menu->maximumWidth() != width) {
+        m_menu->setMaximumWidth(width);
+
+        emit maximumWidthChanged();
+    }
+}
+
+void QMenuProxy::resetMaximumWidth()
+{
+    setMaximumWidth(QWIDGETSIZE_MAX);
+}
+
 bool QMenuProxy::event(QEvent *event)
 {
     switch (event->type()) {

src/declarativeimports/plasmacomponents/qmenu.h

@@ -93,6 +93,13 @@ class QMenuProxy : public QObject
      */
     Q_PROPERTY(int minimumWidth READ minimumWidth WRITE setMinimumWidth NOTIFY minimumWidthChanged)
 
+    /**
+     * A maximum width for the menu.
+     *
+     * @since 5.31
+     */
+    Q_PROPERTY(int maximumWidth READ maximumWidth WRITE setMaximumWidth RESET resetMaximumWidth NOTIFY maximumWidthChanged)
+
 public:
     QMenuProxy(QObject *parent = 0);
     ~QMenuProxy();
@@ -114,6 +121,10 @@ public:
     int minimumWidth() const;
     void setMinimumWidth(int width);
 
+    int maximumWidth() const;
+    void setMaximumWidth(int maximumWidth);
+    void resetMaximumWidth();
+
     /**
      * This opens the menu at position x,y on the given visualParent. By default x and y are set to 0
      */
@@ -163,6 +174,7 @@ Q_SIGNALS:
     void transientParentChanged();
     void placementChanged();
     void minimumWidthChanged();
+    void maximumWidthChanged();
     void triggered(QMenuItem *item);
     void triggeredIndex(int index);
 

tests/components/menu.qml

@@ -68,5 +68,36 @@ Rectangle {
                 PlasmaComponents.MenuItem { text: "Another item" }
             }
         }
+
+        Row {
+            spacing: units.smallSpacing
+
+            PlasmaComponents.Button {
+                id: minMaxButton
+                text: "Fixed minimum and maximum width"
+                onClicked: minMaxMenu.open(0, height)
+
+                PlasmaComponents.Menu {
+                    id: minMaxMenu
+
+                    minimumWidth: minMaxButton.width
+                    maximumWidth: limitMenuMaxWidth.checked ? minMaxButton.width : undefined // has a RESET property
+
+                    PlasmaComponents.MenuItem { text: "Hello" }
+                    PlasmaComponents.MenuItem { text: "This is just a simple" }
+                    PlasmaComponents.MenuItem { text: "Menu" }
+                    PlasmaComponents.MenuItem { text: "with some very very long text in one item that will "
+                                                    + "make the menu super huge if you don't do anything about it" }
+                    PlasmaComponents.MenuItem { text: "and other stuff" }
+                }
+            }
+
+            PlasmaComponents.CheckBox {
+                id: limitMenuMaxWidth
+                anchors.verticalCenter: parent.verticalCenter
+                text: "Limit maximum width"
+                checked: true
+            }
+        }
     }
 }