Keep completion popup on the screen

Pop it upwards when it would otherwise go below the screen and shift it
to the left when it would otherwise exit the screen on the right.

src/plugins/texteditor/basetexteditor.cpp

@@ -1603,7 +1603,6 @@ namespace TextEditor {
             int firstColumn;
             int lastColumn;
         };
-
     }
 }
 

src/plugins/texteditor/completionwidget.cpp

@@ -39,8 +39,9 @@
 #include <utils/qtcassert.h>
 
 #include <QtCore/QEvent>
-#include <QtGui/QKeyEvent>
 #include <QtGui/QApplication>
+#include <QtGui/QDesktopWidget>
+#include <QtGui/QKeyEvent>
 #include <QtGui/QVBoxLayout>
 
 #include <limits.h>
@@ -130,6 +131,8 @@ CompletionWidget::CompletionWidget(CompletionSupport *support, ITextEditable *ed
     layout->addWidget(this);
 
     setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    m_popupFrame->setMinimumSize(1, 1);
+    setMinimumSize(1, 1);
 }
 
 bool CompletionWidget::event(QEvent *e)
@@ -227,20 +230,15 @@ void CompletionWidget::setCompletionItems(const QList<TextEditor::CompletionItem
 
 void CompletionWidget::showCompletions(int startPos)
 {
-    const QPoint &pos = m_editor->cursorRect(startPos).bottomLeft();
-    m_popupFrame->move(pos.x() - 16, pos.y());
-    m_popupFrame->setMinimumSize(1, 1);
-    setMinimumSize(1, 1);
-
-    updateSize();
-
+    updatePositionAndSize(startPos);
     m_popupFrame->show();
     show();
     setFocus();
 }
 
-void CompletionWidget::updateSize()
+void CompletionWidget::updatePositionAndSize(int startPos)
 {
+    // Determine size by calculating the space of the visible items
     int visibleItems = m_model->rowCount();
     if (visibleItems > NUMBER_OF_VISIBLE_ITEMS)
         visibleItems = NUMBER_OF_VISIBLE_ITEMS;
@@ -254,10 +252,25 @@ void CompletionWidget::updateSize()
             shint = tmp;
     }
 
-    const int width = (shint.width() + (m_popupFrame->frameWidth() * 2) + 30);
-    const int height = (shint.height() * visibleItems) + m_popupFrame->frameWidth() * 2;
+    const int frameWidth = m_popupFrame->frameWidth();
+    const int width = shint.width() + frameWidth * 2 + 30;
+    const int height = shint.height() * visibleItems + frameWidth * 2;
 
-    m_popupFrame->resize(width, height);
+    // Determine the position, keeping the popup on the screen
+    const QRect cursorRect = m_editor->cursorRect(startPos);
+    const QDesktopWidget *desktop = QApplication::desktop();
+    const QRect screen = desktop->availableGeometry(desktop->screenNumber(this));
+
+    QPoint pos = cursorRect.bottomLeft();
+    pos.rx() -= 16 + frameWidth;    // Space for the icons
+
+    if (pos.y() + height > screen.bottom())
+        pos.setY(cursorRect.top() - height);
+
+    if (pos.x() + width > screen.right())
+        pos.setX(screen.right() - width);
+
+    m_popupFrame->setGeometry(pos.x(), pos.y(), width, height);
 }
 
 void CompletionWidget::completionActivated(const QModelIndex &index)

src/plugins/texteditor/completionwidget.h

@@ -74,7 +74,7 @@ private slots:
     void completionActivated(const QModelIndex &index);
 
 private:
-    void updateSize();
+    void updatePositionAndSize(int startPos);
 
     QPointer<QFrame> m_popupFrame;
     bool m_blockFocusOut;