diff --git a/headers/os/interface/AffineTransform.h b/headers/os/interface/AffineTransform.h
index b84dee957d3..c296c00c500 100644
--- a/headers/os/interface/AffineTransform.h
+++ b/headers/os/interface/AffineTransform.h
@@ -82,6 +82,8 @@ class BAffineTransform : public BFlattenable {
 	inline	const BAffineTransform&	TranslateBy(double x, double y);
 			const BAffineTransform&	TranslateBy(const BPoint& delta);
 
+	inline	const BAffineTransform&	PreTranslateBy(double x, double y);
+
 			BAffineTransform		TranslateByCopy(double x, double y) const;
 			BAffineTransform		TranslateByCopy(const BPoint& delta) const;
 
@@ -92,6 +94,8 @@ class BAffineTransform : public BFlattenable {
 			const BAffineTransform&	RotateBy(const BPoint& center,
 										double angle);
 
+	inline	const BAffineTransform&	PreRotateBy(double angleRadians);
+
 			BAffineTransform		RotateByCopy(double angle) const;
 			BAffineTransform		RotateByCopy(const BPoint& center,
 										double angle) const;
@@ -109,6 +113,8 @@ class BAffineTransform : public BFlattenable {
 			const BAffineTransform&	ScaleBy(const BPoint& center,
 										const BPoint& scale);
 
+	inline	const BAffineTransform&	PreScaleBy(double x, double y);
+
 			BAffineTransform		ScaleByCopy(double scale) const;
 			BAffineTransform		ScaleByCopy(const BPoint& center,
 										double scale) const;
@@ -244,6 +250,15 @@ BAffineTransform::TranslateBy(double x, double y)
 }
 
 
+inline const BAffineTransform&
+BAffineTransform::PreTranslateBy(double x, double y)
+{
+	tx += x * sx + y * shx;
+	ty += x * shy + y * sy;
+	return *this;
+}
+
+
 inline const BAffineTransform&
 BAffineTransform::RotateBy(double angle)
 {
@@ -262,6 +277,21 @@ BAffineTransform::RotateBy(double angle)
 }
 
 
+inline const BAffineTransform&
+BAffineTransform::PreRotateBy(double angle)
+{
+	double ca = cos(angle);
+	double sa = sin(angle);
+	double newSx = sx * ca + shx * sa;
+	double newSy = -shy * sa + sy * ca;
+	shy = shy * ca + sy * sa;
+	shx = -sx * sa + shx * ca;
+	sx = newSx;
+	sy = newSy;
+	return *this;
+}
+
+
 inline const BAffineTransform&
 BAffineTransform::ScaleBy(double x, double y)
 {
@@ -293,6 +323,17 @@ BAffineTransform::ScaleBy(double s)
 }
 
 
+inline const BAffineTransform&
+BAffineTransform::PreScaleBy(double x, double y)
+{
+	sx *= x;
+	shx *= y;
+	shy *= x;
+	sy *= y;
+	return *this;
+}
+
+
 inline const BAffineTransform&
 BAffineTransform::ShearBy(double x, double y)
 {