--- a/Depth24Image.st	Tue Aug 30 18:53:27 2016 +0200
+++ b/Depth24Image.st	Wed Aug 31 10:57:46 2016 +0200
@@ -1,3 +1,5 @@
+"{ Encoding: utf8 }"
+
 "
  COPYRIGHT (c) 1993 by Claus Gittinger
 	      All Rights Reserved
@@ -2680,6 +2682,52 @@
     ]
 
     "Created: 7.6.1996 / 19:09:40 / cg"
+!
+
+valuesFromX:xStart y:yStart toX:xEnd y:yEnd do:aBlock
+    "perform aBlock for each pixel in the rectangle
+     yStart..yEnd / xStart..xEnd.
+     The block is passed the pixelValue at each pixel.
+     This method allows slighly faster processing of an
+     image than using individual valueAtX:y: accesses,
+     since some processing can be avoided when going from pixel to pixel..
+     However, for real high performance image processing, specialized methods
+     should be written which know how to deal with specific photometric interpretations."
+
+    |srcIndex    "{ Class: SmallInteger }"
+     srcNext     "{ Class: SmallInteger }"
+     bytesPerRow "{ Class: SmallInteger }"
+     value    "{ Class: SmallInteger }"
+     x1       "{ Class: SmallInteger }"
+     x2       "{ Class: SmallInteger }"
+     y1       "{ Class: SmallInteger }"
+     y2       "{ Class: SmallInteger }"
+     bytes|
+
+    x1 := xStart.
+    x2 := xEnd.
+    y1 := yStart.
+    y2 := yEnd.
+
+    srcIndex := (width * 3 * y1) + (x1 * 3) + 1 .
+    bytesPerRow := self bytesPerRow.
+    bytes := self bits.
+
+    y1 to:y2 do:[:y |
+        srcNext := srcIndex + bytesPerRow.
+        x1 to:x2 do:[:x |
+            value := bytes at:srcIndex.
+            value := (value bitShift:8) + (bytes at:srcIndex+1).
+            value := (value bitShift:8) + (bytes at:srcIndex+2).
+            srcIndex := srcIndex + 3.
+
+            aBlock value:x value:y value:value
+        ].
+        srcIndex := srcNext.
+    ].
+
+    "Modified: 11.7.1996 / 20:06:47 / cg"
+    "Created: 11.7.1996 / 20:08:11 / cg"
 ! !
 
 !Depth24Image methodsFor:'image manipulations'!