diff --git a/Headers/gnustep/gui/NSAffineTransform.h b/Headers/gnustep/gui/NSAffineTransform.h
index fe71ce543..d395954a9 100644
--- a/Headers/gnustep/gui/NSAffineTransform.h
+++ b/Headers/gnustep/gui/NSAffineTransform.h
@@ -86,8 +86,10 @@ typedef	struct {
 
 /* Returns anotherMatrix * self */
 - (void) concatenateWith: (NSAffineTransform*)anotherMatrix;
+- (void) concatenateWithMatrix: (const float[6])anotherMatrix;
 
 - (NSPoint) pointInMatrixSpace: (NSPoint)point;
+- (NSPoint) deltaPointInMatrixSpace: (NSPoint)point;
 - (NSSize) sizeInMatrixSpace: (NSSize)size;
 - (NSRect) rectInMatrixSpace: (NSRect)rect;
 
diff --git a/Source/NSAffineTransform.m b/Source/NSAffineTransform.m
index 2bde2eaff..a6b7634f0 100644
--- a/Source/NSAffineTransform.m
+++ b/Source/NSAffineTransform.m
@@ -438,6 +438,24 @@ static NSAffineTransformStruct identityTransform = {
   [self appendTransform: other];
 }
 
+- (void) concatenateWithMatrix: (const float[6])concat
+{
+  float newA, newB, newC, newD, newTX, newTY;
+
+  newA = concat[0] * A + concat[1] * C;
+  newB = concat[0] * B + concat[1] * D;
+  newC = concat[2] * A + concat[3] * C;
+  newD = concat[2] * B + concat[3] * D;
+  newTX = concat[4] * A + concat[5] * C + TX;
+  newTY = concat[4] * B + concat[5] * D + TY;
+
+  A = newA; B = newB;
+  C = newC; D = newD;
+  TX = newTX; TY = newTY;
+
+  rotationAngle = -1;
+}
+
 - (void)inverse
 {
   [self invert];
@@ -515,6 +533,16 @@ static NSAffineTransformStruct identityTransform = {
   return new;
 }
 
+- (NSPoint) deltaPointInMatrixSpace: (NSPoint)point
+{
+  NSPoint new;
+
+  new.x = A * point.x + C * point.y;
+  new.y = B * point.x + D * point.y;
+
+  return new;
+}
+
 - (NSSize) sizeInMatrixSpace: (NSSize)size
 {
   NSSize new;