sc lok: Always provide a reasonable document size.

With an empty document, GetPrintArea() returned false, causing nothing visible
on the screen.

Also increase the values when I'm touching this.

Change-Id: Iee7544a428d5d4d5d5931230a51e605302557f41

sc/source/core/data/documen2.cxx

@@ -708,15 +708,14 @@ bool ScDocument::GetDataStart( SCTAB nTab, SCCOL& rStartCol, SCROW& rStartRow )
 
 bool ScDocument::GetTiledRenderingArea(SCTAB nTab, SCCOL& rEndCol, SCROW& rEndRow) const
 {
-    if (!GetPrintArea(nTab, rEndCol, rEndRow, false))
-        return false;
+    bool bHasPrintArea = GetPrintArea(nTab, rEndCol, rEndRow, false);
 
     // we need some reasonable minimal document size
-    if (rEndCol < 12)
-        rEndCol = 12;
+    if (!bHasPrintArea || rEndCol < 20)
+        rEndCol = 20;
 
-    if (rEndRow < 36)
-        rEndRow = 36;
+    if (!bHasPrintArea || rEndRow < 50)
+        rEndRow = 50;
 
     return true;
 }