diff --git a/src/TerminalDisplay.cpp b/src/TerminalDisplay.cpp
--- a/src/TerminalDisplay.cpp
+++ b/src/TerminalDisplay.cpp
@@ -45,6 +45,8 @@
 #include <QDrag>
 #include <QDesktopServices>
 #include <QAccessible>
+#include <QWindow>
+#include <QScreen>
 
 // KDE
 #include <KShell>
@@ -793,20 +795,28 @@
 
     // shift rectangle top down one pixel to leave some space
     // between top and bottom
-    QRect cursorRect = rect.adjusted(0, 1, 0, 0);
+    QRectF cursorRect = rect.adjusted(0, 1, 0, 0);
 
     QColor cursorColor = _cursorColor.isValid() ? _cursorColor : foregroundColor;
-    painter.setPen(cursorColor);
+    QPen pen(cursorColor);
+    //scale only integer factors
+    pen.setWidth(qRound(window()->windowHandle()->screen()->devicePixelRatio()));
+    pen.setCosmetic(true);
+    //don't round corners
+    pen.setJoinStyle(Qt::MiterJoin);
+    painter.setPen(pen);
 
     if (_cursorShape == Enum::BlockCursor) {
         // draw the cursor outline, adjusting the area so that
         // it is draw entirely inside 'rect'
-        int penWidth = qMax(1, painter.pen().width());
-        painter.drawRect(cursorRect.adjusted(penWidth / 2,
+        qreal penWidth = painter.pen().widthF();
+        painter.drawRect((int)penWidth % 2 == 0
+                         ? cursorRect
+                         : cursorRect.adjusted(penWidth / 2,
                                              penWidth / 2,
-                                             - penWidth / 2 - penWidth % 2,
-                                             - penWidth / 2 - penWidth % 2));
-
+                                             - penWidth / 2,
+                                             - penWidth / 2));
+        if(window()->windowHandle()&&window()->windowHandle()->screen())
         // draw the cursor body only when the widget has focus
         if (hasFocus()) {
             painter.fillRect(cursorRect, cursorColor);
@@ -831,6 +841,7 @@
     }
 }
 
+
 void TerminalDisplay::drawCharacters(QPainter& painter,
                                      const QRect& rect,
                                      const QString& text,
@@ -1253,10 +1264,15 @@
 
             // add the area occupied by this line to the region which needs to be
             // repainted
-            QRect dirtyRect = QRect(_contentRect.left() + tLx ,
-                                    _contentRect.top() + tLy + _fontHeight * y ,
-                                    _fontWidth * columnsToUpdate ,
-                                    _fontHeight);
+            //with fractional scaling (ie QT_SCREEN_SCALE_FACTORS=1.3
+            //there can be rounding errors due to the painting code being all based on QRects instead of QRectF (not easily
+            //fixable, because the rects arrive fromthe paintevent's
+            //QRegion which doesn't have a qreal based alternative
+            //so grow the dirty region by one pixel to make sure every dirty pixel is cleaned up
+            QRect dirtyRect = QRect(_contentRect.left() + tLx,
+                                    _contentRect.top() + tLy + _fontHeight * y,
+                                    _fontWidth * columnsToUpdate,
+                                    _fontHeight).adjusted(-1, -1, 1, 1);
 
             dirtyRegion |= dirtyRect;
         }
@@ -1269,18 +1285,18 @@
     // if the new _image is smaller than the previous _image, then ensure that the area
     // outside the new _image is cleared
     if (linesToUpdate < _usedLines) {
-        dirtyRegion |= QRect(_contentRect.left() + tLx ,
-                             _contentRect.top() + tLy + _fontHeight * linesToUpdate ,
-                             _fontWidth * this->_columns ,
-                             _fontHeight * (_usedLines - linesToUpdate));
+        dirtyRegion |= QRect(_contentRect.left() + tLx,
+                             _contentRect.top() + tLy + _fontHeight * linesToUpdate,
+                             _fontWidth * this->_columns,
+                             _fontHeight * (_usedLines - linesToUpdate)).adjusted(-1, -1, 1, 1);
     }
     _usedLines = linesToUpdate;
 
     if (columnsToUpdate < _usedColumns) {
-        dirtyRegion |= QRect(_contentRect.left() + tLx + columnsToUpdate * _fontWidth ,
-                             _contentRect.top() + tLy ,
-                             _fontWidth * (_usedColumns - columnsToUpdate) ,
-                             _fontHeight * this->_lines);
+        dirtyRegion |= QRect(_contentRect.left() + tLx + columnsToUpdate * _fontWidth,
+                             _contentRect.top() + tLy,
+                             _fontWidth * (_usedColumns - columnsToUpdate),
+                             _fontHeight * this->_lines).adjusted(-1, -1, 1, 1);
     }
     _usedColumns = columnsToUpdate;