merged

--- a/src/Pure/General/swing_thread.scala	Tue Dec 08 23:05:23 2009 +0100
+++ b/src/Pure/General/swing_thread.scala	Wed Dec 09 11:53:51 2009 +0100
@@ -10,6 +10,8 @@
 import javax.swing.{SwingUtilities, Timer}
 import java.awt.event.{ActionListener, ActionEvent}
 
+import scala.actors.{Future, Futures}
+
 
 object Swing_Thread
 {
@@ -21,13 +23,17 @@
 
   /* main dispatch queue */
 
-  def now[A](body: => A): A = {
+  def now[A](body: => A): A =
+  {
     var result: Option[A] = None
     if (SwingUtilities.isEventDispatchThread()) { result = Some(body) }
     else SwingUtilities.invokeAndWait(new Runnable { def run = { result = Some(body) } })
     result.get
   }
 
+  def future[A](body: => A): Future[A] =
+    Futures.future(now(body))
+
   def later(body: => Unit) {
     if (SwingUtilities.isEventDispatchThread()) body
     else SwingUtilities.invokeLater(new Runnable { def run = body })

--- a/src/Pure/System/isabelle_system.scala	Tue Dec 08 23:05:23 2009 +0100
+++ b/src/Pure/System/isabelle_system.scala	Wed Dec 09 11:53:51 2009 +0100
@@ -341,11 +341,11 @@
   private def create_font(name: String) =
     Font.createFont(Font.TRUETYPE_FONT, platform_file(name))
 
-  def register_fonts(): Boolean =
-  {
+  def register_fonts() {
     val ge = GraphicsEnvironment.getLocalGraphicsEnvironment()
     val ok1 = ge.registerFont(create_font("~~/lib/fonts/IsabelleText.ttf"))
     val ok2 = ge.registerFont(create_font("~~/lib/fonts/IsabelleTextBold.ttf"))
-    ok1 && ok2
+    if (!(ok1 && ok2) && !ge.getAvailableFontFamilyNames.contains(font_family))
+      error("Font family " + font_family + " unavailable")
   }
 }