--- a/Image.st	Thu Oct 12 14:17:22 2017 +0200
+++ b/Image.st	Thu Oct 12 16:45:16 2017 +0200
@@ -10008,7 +10008,7 @@
     "draw a line with some pixel value.
      This is in no way tuned, as normally, display-forms are used to draw.
      The only use for this is when we have to generate images in a headless webService
-     (such as the HumanReadableImageGenerator).
+     (such as the HumanReadableImageGenerator) or in the image editor.
      If aPixelValueOrNil is nil, the mask pixel will be set to 0 (transparent),
      otherwise to 1. (used by the bitmap editor)"
 
@@ -10019,6 +10019,19 @@
     x1 := endPoint x.
     y1 := endPoint y.
 
+    (x1 - x0) == 0 ifTrue:[
+        y0 to: y1 do:[:y |
+            self atImageAndMask:x0@y putValue:aPixelValueOrNil.
+        ].
+        ^ self.
+    ].
+    (y1 - y0) == 0 ifTrue:[
+        x0 to: x1 do:[:x |
+            self atImageAndMask:x@y0 putValue:aPixelValueOrNil.
+        ].
+        ^ self.
+    ].
+
     steep := (y1 - y0) abs > (x1 - x0) abs.
     steep ifTrue:[
         t := x0. x0 := y0. y0 := t.
@@ -10032,19 +10045,6 @@
     deltax := x1 - x0.
     deltay := (y1 - y0) abs.
 
-    deltax == 0 ifTrue:[
-        y0 to: y1 do:[:y |
-            self atImageAndMask:x0@y putValue:aPixelValueOrNil.
-        ].
-        ^ self.
-    ].
-    deltay == 0 ifTrue:[
-        x0 to: x1 do:[:x |
-            self atImageAndMask:x@y0 putValue:aPixelValueOrNil.
-        ].
-        ^ self.
-    ].
-
     error := 0.
     deltaerr := deltay / deltax.
     y := y0.
@@ -10417,11 +10417,20 @@
     hI := h.
     p := Point new.
 
-    yI to:yI+hI-1 do:[:yRun |
-        xI to:xI+wI-1 do:[:xRun |
-            p x:xRun y:yRun.
-            self atImageAndMask:p putValue:aPixelValueOrNil.
-        ]
+    mask isNil ifTrue:[
+        yI to:yI+hI-1 do:[:yRun |
+            xI to:xI+wI-1 do:[:xRun |
+                p x:xRun y:yRun.
+                self pixelAt:p put:(aPixelValueOrNil ? 0).
+            ]
+        ].
+    ] ifFalse:[
+        yI to:yI+hI-1 do:[:yRun |
+            xI to:xI+wI-1 do:[:xRun |
+                p x:xRun y:yRun.
+                self atImageAndMask:p putValue:aPixelValueOrNil.
+            ]
+        ].
     ].
     self release. "/ device-image is no longer valid
 
@@ -13477,6 +13486,8 @@
 !Image methodsFor:'initialization'!
 
 createPixelStore
+    "instantiate the underlying pixel storage (a byteArray)"
+
     |bytesPerRow|
 
     bytesPerRow := self bytesPerRow.