draw: remove Go 1.8 support

This change removes support for Go 1.8 and older, as they're no longer
supported per release policy¹.

This brings back a simpler file layout that was here prior to CL 36730,
but keeps using type aliases for the exported names from the standard
library's image/draw package.

Don't keep the comment motivating type alias use, since that feature is
no longer new, and commonly understood by now.

¹ https://tip.golang.org/doc/devel/release.html#policy

Change-Id: I5fab71162cf6daa5985a048ed06011efacddf886
Reviewed-on: https://go-review.googlesource.com/c/148567
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
master
Dmitri Shuralyov 2018-11-08 15:15:35 -05:00
parent 36ab2409c1
commit a3f9a0009f
5 changed files with 22 additions and 132 deletions

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@ -11,9 +11,8 @@
// package in the standard library.
package draw
// 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.
// This file just contains the API exported by the image/draw package in the
// standard library. Other files in this package provide additional features.
import (
"image"
@ -32,6 +31,9 @@ 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 = draw.Drawer
// FloydSteinberg is a Drawer that is the Src Op with Floyd-Steinberg error
// diffusion.
var FloydSteinberg Drawer = floydSteinberg{}
@ -41,3 +43,19 @@ 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 = 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

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@ -1,49 +0,0 @@
// 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,!go1.8.typealias
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
}

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@ -1,57 +0,0 @@
// 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

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@ -519,9 +519,7 @@ func TestRectDstMask(t *testing.T) {
for _, dstMaskP := range dstMaskPs {
dstInside := mk(q, nil, image.Point{})
for _, wrap := range []bool{false, true} {
// TODO: replace "rectImage(rect)" with "rect" once Go 1.5 is
// released, where an image.Rectangle implements image.Image.
dstMask := image.Image(rectImage(rect))
dstMask := image.Image(rect)
if wrap {
dstMask = srcWrapper{dstMask}
}
@ -562,19 +560,6 @@ func TestDstMaskSameSizeCopy(t *testing.T) {
})
}
// TODO: delete this wrapper type once Go 1.5 is released, where an
// image.Rectangle implements image.Image.
type rectImage image.Rectangle
func (r rectImage) ColorModel() color.Model { return color.Alpha16Model }
func (r rectImage) Bounds() image.Rectangle { return image.Rectangle(r) }
func (r rectImage) At(x, y int) color.Color {
if (image.Point{x, y}).In(image.Rectangle(r)) {
return color.Opaque
}
return color.Transparent
}
// The fooWrapper types wrap the dst or src image to avoid triggering the
// type-specific fast path implementations.
type (

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@ -2,15 +2,8 @@
// 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
// This file contains tests that depend on the exact behavior of the
// image/color package in the standard library. The color conversion formula
// from YCbCr to RGBA changed between Go 1.4 and Go 1.5, and between Go 1.8 and
// Go 1.9, so this file's tests are only enabled for Go 1.9 and above.
import (
"bytes"
"image"