aboutsummaryrefslogtreecommitdiff
path: root/vendor/golang.org/x/image/draw/go1_9.go
diff options
context:
space:
mode:
Diffstat (limited to 'vendor/golang.org/x/image/draw/go1_9.go')
-rw-r--r--vendor/golang.org/x/image/draw/go1_9.go57
1 files changed, 57 insertions, 0 deletions
diff --git a/vendor/golang.org/x/image/draw/go1_9.go b/vendor/golang.org/x/image/draw/go1_9.go
new file mode 100644
index 0000000..fc548e9
--- /dev/null
+++ b/vendor/golang.org/x/image/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 go1.8.typealias
+
+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