struts calculations at screen_edge coordinates

--as it appears in wayland the struts calculations must be
applied for exact screen_edge coordinates and use only the
view shown thickness. During the process floating panels
struts were not accurate at all cases and as such they
were fixed also for x11.

app/view/visibilitymanager.cpp

@@ -372,23 +372,23 @@ QRect VisibilityManager::acceptableStruts()
 
     switch (m_latteView->location()) {
     case Plasma::Types::TopEdge: {
-        calcs = QRect(m_latteView->x(), m_latteView->y(), m_latteView->width(), shownThickness);
+        calcs = QRect(m_latteView->x(), m_latteView->screenGeometry().top(), m_latteView->width(), shownThickness);
         break;
     }
 
     case Plasma::Types::BottomEdge: {
-        int y = m_latteView->y() + m_latteView->height() - shownThickness;
+        int y = m_latteView->screenGeometry().bottom() - shownThickness + 1 /* +1, is needed in order to not leave a gap at screen_edge*/;
         calcs = QRect(m_latteView->x(), y, m_latteView->width(), shownThickness);
         break;
     }
 
     case Plasma::Types::LeftEdge: {
-        calcs = QRect(m_latteView->x(), m_latteView->y(), shownThickness, m_latteView->height());
+        calcs = QRect(m_latteView->screenGeometry().left(), m_latteView->y(), shownThickness, m_latteView->height());
         break;
     }
 
     case Plasma::Types::RightEdge: {
-        int x = m_latteView->x() + m_latteView->width() - shownThickness;
+        int x = m_latteView->screenGeometry().right() - shownThickness + 1 /* +1, is needed in order to not leave a gap at screen_edge*/;
         calcs = QRect(x, m_latteView->y(), shownThickness, m_latteView->height());
         break;
     }