Fix for text items' buttons overflowing from frame

This was observed in some cases on low-resolution screens, at least on
Linux and Windows.

The previously hardcoded value for the width of the text items' titlebar
(consisting of the buttons for formatting text) was replaced by a
method calculating its width (which varies based on screen resolution).

src/board/UBBoardView.cpp

@@ -1335,6 +1335,7 @@ void UBBoardView::mouseReleaseEvent (QMouseEvent *event)
 
                 textItem->setTextInteractionFlags(Qt::TextEditorInteraction);
                 textItem->setSelected (true);
+                textItem->setTextWidth(0);
                 textItem->setFocus();
             }
         }

src/domain/UBGraphicsTextItem.cpp

@@ -306,8 +306,12 @@ QPainterPath UBGraphicsTextItem::shape() const
 
 void UBGraphicsTextItem::setTextWidth(qreal width)
 {
-    qreal strictMin = 155; // the size of the font customization panel
-    qreal newWidth = qMax(strictMin, width);
+    qreal titleBarWidth = 0;
+    UBGraphicsTextItemDelegate * del = dynamic_cast<UBGraphicsTextItemDelegate*>(Delegate());
+    if (del)
+        titleBarWidth = del->titleBarWidth();
+
+    qreal newWidth = qMax(titleBarWidth, width);
 
     QGraphicsTextItem::setTextWidth(newWidth);
 }

src/domain/UBGraphicsTextItemDelegate.cpp

@@ -204,6 +204,31 @@ void UBGraphicsTextItemDelegate::createControls()
 
 }
 
+/**
+ * @brief Calculate the width of the toolbar containing the text item-related buttons
+ * @return The space between the left-most and right-most buttons in pixels
+ */
+qreal UBGraphicsTextItemDelegate::titleBarWidth()
+{
+    if (!mFontButton)
+        return 0;
+
+    // refresh the frame and buttons' positions
+    positionHandles();
+
+    qreal titleBarWidth(0);
+    qreal frameLeftCoordinate = mFontButton->pos().x();
+    qreal frameRightCoordinate = frameLeftCoordinate;
+
+    foreach(DelegateButton* button, mButtons) {
+        if (button->getSection() == Qt::TitleBarArea) {
+            frameLeftCoordinate = qMin(button->pos().x(), frameLeftCoordinate);
+            frameRightCoordinate = qMax(button->pos().x() + button->boundingRect().width(), frameRightCoordinate);
+        }
+    }
+
+    return frameRightCoordinate - frameLeftCoordinate;
+}
 
 void UBGraphicsTextItemDelegate::freeButtons()
 {

src/domain/UBGraphicsTextItemDelegate.h

@@ -114,6 +114,7 @@ class UBGraphicsTextItemDelegate : public UBGraphicsItemDelegate
         void scaleTextSize(qreal multiplyer);
         virtual QVariant itemChange(QGraphicsItem::GraphicsItemChange change, const QVariant &value);
         virtual void createControls();
+        qreal titleBarWidth();
 
     public slots:
         void contentsChanged();