diff --git a/draw/draw.go b/draw/draw.go
index b92e3c7..dfaa7fc 100644
--- a/draw/draw.go
+++ b/draw/draw.go
@@ -11,12 +11,12 @@
 // package in the standard library.
 package draw
 
-// This file just contains the API exported by the image/draw package in the
-// standard library. Other files in this package provide additional features.
+// This file, and the go1_*.go files, just contains the API exported by the
+// image/draw package in the standard library. Other files in this package
+// provide additional features.
 
 import (
 	"image"
-	"image/color"
 	"image/draw"
 )
 
@@ -32,13 +32,6 @@ func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mas
 	draw.DrawMask(dst, r, src, sp, mask, mp, draw.Op(op))
 }
 
-// Drawer contains the Draw method.
-type Drawer interface {
-	// Draw aligns r.Min in dst with sp in src and then replaces the
-	// rectangle r in dst with the result of drawing src on dst.
-	Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point)
-}
-
 // FloydSteinberg is a Drawer that is the Src Op with Floyd-Steinberg error
 // diffusion.
 var FloydSteinberg Drawer = floydSteinberg{}
@@ -48,32 +41,3 @@ type floydSteinberg struct{}
 func (floydSteinberg) Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point) {
 	draw.FloydSteinberg.Draw(dst, r, src, sp)
 }
-
-// Image is an image.Image with a Set method to change a single pixel.
-type Image interface {
-	image.Image
-	Set(x, y int, c color.Color)
-}
-
-// Op is a Porter-Duff compositing operator.
-type Op int
-
-const (
-	// Over specifies ``(src in mask) over dst''.
-	Over Op = Op(draw.Over)
-	// Src specifies ``src in mask''.
-	Src Op = Op(draw.Src)
-)
-
-// Draw implements the Drawer interface by calling the Draw function with
-// this Op.
-func (op Op) Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point) {
-	(draw.Op(op)).Draw(dst, r, src, sp)
-}
-
-// Quantizer produces a palette for an image.
-type Quantizer interface {
-	// Quantize appends up to cap(p) - len(p) colors to p and returns the
-	// updated palette suitable for converting m to a paletted image.
-	Quantize(p color.Palette, m image.Image) color.Palette
-}
diff --git a/draw/go1_8.go b/draw/go1_8.go
new file mode 100644
index 0000000..95db46f
--- /dev/null
+++ b/draw/go1_8.go
@@ -0,0 +1,49 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !go1.9
+
+package draw
+
+import (
+	"image"
+	"image/color"
+	"image/draw"
+)
+
+// Drawer contains the Draw method.
+type Drawer interface {
+	// Draw aligns r.Min in dst with sp in src and then replaces the
+	// rectangle r in dst with the result of drawing src on dst.
+	Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point)
+}
+
+// Image is an image.Image with a Set method to change a single pixel.
+type Image interface {
+	image.Image
+	Set(x, y int, c color.Color)
+}
+
+// Op is a Porter-Duff compositing operator.
+type Op int
+
+const (
+	// Over specifies ``(src in mask) over dst''.
+	Over Op = Op(draw.Over)
+	// Src specifies ``src in mask''.
+	Src Op = Op(draw.Src)
+)
+
+// Draw implements the Drawer interface by calling the Draw function with
+// this Op.
+func (op Op) Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point) {
+	(draw.Op(op)).Draw(dst, r, src, sp)
+}
+
+// Quantizer produces a palette for an image.
+type Quantizer interface {
+	// Quantize appends up to cap(p) - len(p) colors to p and returns the
+	// updated palette suitable for converting m to a paletted image.
+	Quantize(p color.Palette, m image.Image) color.Palette
+}
diff --git a/draw/go1_9.go b/draw/go1_9.go
new file mode 100644
index 0000000..1e878e1
--- /dev/null
+++ b/draw/go1_9.go
@@ -0,0 +1,57 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.9
+
+package draw
+
+import (
+	"image/draw"
+)
+
+// We use type aliases (new in Go 1.9) for the exported names from the standard
+// library's image/draw package. This is not merely syntactic sugar for
+//
+//	type Drawer draw.Drawer
+//
+// as aliasing means that the types in this package, such as draw.Image and
+// draw.Op, are identical to the corresponding draw.Image and draw.Op types in
+// the standard library. In comparison, prior to Go 1.9, the code in go1_8.go
+// defines new types that mimic the old but are different types.
+//
+// The package documentation, in draw.go, explicitly gives the intent of this
+// package:
+//
+//	This package is a superset of and a drop-in replacement for the
+//	image/draw package in the standard library.
+//
+// Drop-in replacement means that I can replace all of my "image/draw" imports
+// with "golang.org/x/image/draw", to access additional features in this
+// package, and no further changes are required. That's mostly true, but not
+// completely true unless we use type aliases.
+//
+// Without type aliases, users might need to import both "image/draw" and
+// "golang.org/x/image/draw" in order to convert from two conceptually
+// equivalent but different (from the compiler's point of view) types, such as
+// from one draw.Op type to another draw.Op type, to satisfy some other
+// interface or function signature.
+
+// Drawer contains the Draw method.
+type Drawer = draw.Drawer
+
+// Image is an image.Image with a Set method to change a single pixel.
+type Image = draw.Image
+
+// Op is a Porter-Duff compositing operator.
+type Op = draw.Op
+
+const (
+	// Over specifies ``(src in mask) over dst''.
+	Over Op = draw.Over
+	// Src specifies ``src in mask''.
+	Src Op = draw.Src
+)
+
+// Quantizer produces a palette for an image.
+type Quantizer = draw.Quantizer