--- a/Image.st	Mon Nov 20 20:11:24 2017 +0100
+++ b/Image.st	Tue Nov 21 16:28:57 2017 +0100
@@ -9901,14 +9901,18 @@
      yI "{ Class: SmallInteger }"
      wI "{ Class: SmallInteger }"
      hI "{ Class: SmallInteger }" 
-     tempImage lw|
+     tempImage lw display|
+
+    (display := Screen current) isNil ifTrue:[
+        self error:'No display - cannot draw ellipse'
+    ].    
 
     lw := lineWidthOrNil ? 1.
      
     wI := aRectangle width.
     hI := aRectangle height.
 
-    tempForm := Form width:wI+lw height:hI+lw depth:1 onDevice:Screen current.
+    tempForm := Form width:wI+lw height:hI+lw depth:1 onDevice:display.
     tempForm
         paint:(Color colorId:1) on:(Color colorId:0);
         clear.
@@ -9946,6 +9950,7 @@
     "
 
     "Created: / 26-02-2017 / 17:13:16 / cg"
+    "Modified: / 21-11-2017 / 16:27:54 / cg"
 !
 
 drawLineFrom:startPoint to:endPoint with:aColorOrPixelValue
@@ -10171,12 +10176,16 @@
 
     |tempForm wI "{ Class: SmallInteger }"
      hI "{ Class: SmallInteger }"
-     colorValue tempImage|
+     colorValue tempImage display|
+
+    (display := Screen current) isNil ifTrue:[
+        self error:'No display - cannot draw arc'
+    ].    
 
     wI := self width.
     hI := self height.
 
-    tempForm := Form width:wI height:hI depth:1 onDevice:Screen current.
+    tempForm := Form width:wI height:hI depth:1 onDevice:display.
     tempForm
         paint:(Color colorId:1) on:(Color colorId:0);
         clear.
@@ -10218,7 +10227,7 @@
         aaImgArray last inspect.
     "
 
-    "Modified (comment): / 16-02-2017 / 20:12:59 / cg"
+    "Modified: / 21-11-2017 / 16:28:05 / cg"
 !
 
 fillArc:origin radius:r from:startAngle angle:angle withColor:aColorOrIndex
@@ -10228,12 +10237,16 @@
     |tempForm tempImage
      wI "{ Class: SmallInteger }"
      hI "{ Class: SmallInteger }"
-     colorValue|
-
+     colorValue display|
+
+    (display := Screen current) isNil ifTrue:[
+        self error:'No display - cannot fill arc'
+    ].    
+    
     wI := self width.
     hI := self height.
 
-    tempForm := Form width:wI height:hI depth:1 onDevice:Screen current.
+    tempForm := Form width:wI height:hI depth:1 onDevice:display.
     tempForm
         paint:(Color colorId:1) on:(Color colorId:0);
         clear.
@@ -10266,7 +10279,7 @@
      i inspect.
     "
 
-    "Modified (comment): / 16-02-2017 / 20:12:37 / cg"
+    "Modified: / 21-11-2017 / 16:28:15 / cg"
 !
 
 fillEllipse:aRectangle with:aColorOrPixelValue
@@ -10309,12 +10322,16 @@
     |tempForm xI "{ Class: SmallInteger }"
      yI "{ Class: SmallInteger }"
      wI "{ Class: SmallInteger }"
-     hI "{ Class: SmallInteger }" tempImage|
+     hI "{ Class: SmallInteger }" tempImage display|
+
+    (display := Screen current) isNil ifTrue:[
+        self error:'No display - cannot fill ellipse'
+    ].    
 
     wI := aRectangle width.
     hI := aRectangle height.
 
-    tempForm := Form width:wI height:hI depth:1 onDevice:Screen current.
+    tempForm := Form width:wI height:hI depth:1 onDevice:display.
     tempForm
         paint:(Color colorId:1) on:(Color colorId:0);
         clear.
@@ -10343,7 +10360,7 @@
      i inspect.
     "
 
-    "Modified (comment): / 05-09-2017 / 14:51:59 / cg"
+    "Modified: / 21-11-2017 / 16:28:25 / cg"
 !
 
 fillRectangle:aRectangle with:aColorOrPixelValue