Issue #801: place holder for hint in input fields

[modules/shaper.git] / src / ModuleBase / ModuleBase_WidgetLineEdit.cpp

diff --git a/src/ModuleBase/ModuleBase_WidgetLineEdit.cpp b/src/ModuleBase/ModuleBase_WidgetLineEdit.cpp
index f2f5034b8c380051a6055b77eddcb92b51353656..273cc902016246860653d4168e7fa0b56e0fc197 100644 (file)
--- a/src/ModuleBase/ModuleBase_WidgetLineEdit.cpp
+++ b/src/ModuleBase/ModuleBase_WidgetLineEdit.cpp
@@ -22,13 +22,53 @@
 #include <QLineEdit>
 #include <QObject>
 #include <QString>
+#include <QPainter>
+#include <QResizeEvent>
 
 #include <memory>
 #include <string>
 
+class CustomLineEdit : public QLineEdit
+{
+public:
+  CustomLineEdit( QWidget* theParent, const QString& thePlaceHolder )
+    : QLineEdit( theParent ), myPlaceHolder( thePlaceHolder )
+  {
+  }
+
+  virtual ~CustomLineEdit()
+  {
+  }
+
+  virtual void paintEvent( QPaintEvent* theEvent )
+  {
+    QLineEdit::paintEvent( theEvent );
+    if( text().isEmpty() && !myPlaceHolder.isEmpty() )
+    {
+      QPainter aPainter( this );
+      QRect aRect = rect();
+      int aHorMargin = 5;
+      aRect.adjust( aHorMargin, 0, 0, 0 );
+
+      QColor aColor = palette().text().color();
+      aColor.setAlpha( 128 );
+      QPen anOldpen = aPainter.pen();
+      aPainter.setPen( aColor );
+      QFontMetrics aFontMetrics = fontMetrics();
+      QString elidedText = aFontMetrics.elidedText( myPlaceHolder, Qt::ElideRight, aRect.width() );
+      aPainter.drawText( aRect, Qt::AlignLeft | Qt::AlignVCenter, elidedText );
+      aPainter.setPen( anOldpen );
+    }
+  }
+
+private:
+  QString myPlaceHolder;
+};
+
 ModuleBase_WidgetLineEdit::ModuleBase_WidgetLineEdit(QWidget* theParent,
                                                      const Config_WidgetAPI* theData,
-                                                     const std::string& theParentId)
+                                                     const std::string& theParentId,
+                                                     const std::string& thePlaceHolder )
     : ModuleBase_ModelWidget(theParent, theData, theParentId)
 {
   QFormLayout* aMainLay = new QFormLayout(this);
@@ -39,8 +79,15 @@ ModuleBase_WidgetLineEdit::ModuleBase_WidgetLineEdit(QWidget* theParent,
   if (!aLabelIcon.isEmpty())
     aLabel->setPixmap(QPixmap(aLabelIcon));
 
-  myLineEdit = new QLineEdit(this);
+  myLineEdit = new CustomLineEdit( this, QString::fromStdString( thePlaceHolder ) );
+  // Here we do not use the Qt's standard method setPlaceHolderText() since it
+  // draws the place holder only if there is no focus on widget;
+  // we would like to see the place holder in the case of empty text
+  // even if the widget is focused.
+  // The corresponding patch appears in Qt only since version 5.x
+
   myLineEdit->setMinimumHeight(20);
+
   aMainLay->addRow(aLabel, myLineEdit);
   this->setLayout(aMainLay);