Update to dither v2.2.0 to support transparent images

MANPAGE.md

@@ -3,8 +3,8 @@
 title: DIDDER
 section: 1
 header: User Manual
-footer: didder 
-date: May 01, 2021
+footer: didder v1.0.0-3-g2404e20
+date: May 09, 2021
 ---
 
 # NAME
@@ -22,7 +22,7 @@ The most important parts of this manual are highlighted in the **TIPS** section,
 
 Homepage: <https://github.com/makeworld-the-better-one/didder>
 
-# GLOBAL OPTIONS
+# OPTIONS
 **-i**, **\--in** *PATH*
 
 Set the input file. This flag can be used multiple times to dither multiple images with the same palette and method. A *PATH* of \'**\-**' stands for standard input.

README.md

@@ -10,7 +10,6 @@
 didder is an extensive, fast, and accurate command-line image dithering tool. It is designed to work well for both power users as well as pipeline scripting.
 It is backed by my [dithering library](https://github.com/makeworld-the-better-one/dither), and is unique in its correctness and variety of dithering algorithms. No online or offline tool I know of provides as many options, while being correct (linearizing the image).
 
-It does not support images that make use of the alpha channel (transparency), but it will in the future.
 
 ## Types of dithering supported
 
@@ -48,6 +47,7 @@ More methods of dithering are being worked on, such as Riemersma, Yuliluoma, and
 - Process multiple images with one command
 - Combine multiple images into an animated GIF
 - Uses all CPU cores when possible
+- Support images with transparency (alpha channel is kept the same)
 
 ## Installation
 

didder.1

@@ -1,6 +1,6 @@
 .\" Automatically generated by Pandoc 2.13
 .\"
-.TH "DIDDER" "1" "May 01, 2021" "didder " "User Manual"
+.TH "DIDDER" "1" "May 09, 2021" "didder v1.0.0-3-g2404e20" "User Manual"
 .hy
 .SH NAME
 .PP
@@ -22,7 +22,7 @@ The most important parts of this manual are highlighted in the
 \f[B]TIPS\f[R] section, make sure you check it out!
 .PP
 Homepage: <https://github.com/makeworld-the-better-one/didder>
-.SH GLOBAL OPTIONS
+.SH OPTIONS
 .TP
 \f[B]-i\f[R], \f[B]--in\f[R] \f[I]PATH\f[R]
 Set the input file.

didder.1.md

@@ -21,7 +21,7 @@ The most important parts of this manual are highlighted in the **TIPS** section,
 
 Homepage: <https://github.com/makeworld-the-better-one/didder>
 
-# GLOBAL OPTIONS
+# OPTIONS
 **-i**, **\--in** *PATH*
 :   Set the input file. This flag can be used multiple times to dither multiple images with the same palette and method. A *PATH* of \'**\-**' stands for standard input.
 

go.mod

@@ -4,7 +4,7 @@ go 1.16
 
 require (
 	github.com/disintegration/imaging v1.6.2
-	github.com/makeworld-the-better-one/dither/v2 v2.1.0
+	github.com/makeworld-the-better-one/dither/v2 v2.2.0
 	github.com/urfave/cli/v2 v2.3.0
 	golang.org/x/image v0.0.0-20210220032944-ac19c3e999fb
 )

go.sum

@@ -5,8 +5,8 @@ github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/disintegration/imaging v1.6.2 h1:w1LecBlG2Lnp8B3jk5zSuNqd7b4DXhcjwek1ei82L+c=
 github.com/disintegration/imaging v1.6.2/go.mod h1:44/5580QXChDfwIclfc/PCwrr44amcmDAg8hxG0Ewe4=
-github.com/makeworld-the-better-one/dither/v2 v2.1.0 h1:ihYRtKQDkZwZutaCeRf1vYaq1Jqoy2mZGZR8BNZZK2I=
-github.com/makeworld-the-better-one/dither/v2 v2.1.0/go.mod h1:VBtN8DXO7SNtyGmLiGA7IsFeKrBkQPze1/iAeM95arc=
+github.com/makeworld-the-better-one/dither/v2 v2.2.0 h1:VTMAiyyO1YIO07fZwuLNZZasJgKUmvsIA48ze3ALHPQ=
+github.com/makeworld-the-better-one/dither/v2 v2.2.0/go.mod h1:VBtN8DXO7SNtyGmLiGA7IsFeKrBkQPze1/iAeM95arc=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/russross/blackfriday/v2 v2.0.1 h1:lPqVAte+HuHNfhJ/0LC98ESWRz8afy9tM/0RK8m9o+Q=

subcommand_helpers.go

@@ -257,8 +257,8 @@ func recolor(src image.Image) image.Image {
 	b := img.Bounds()
 	for y := b.Min.Y; y < b.Max.Y; y++ {
 		for x := b.Min.X; x < b.Max.X; x++ {
-			// Image pixel -> convert to RGBA -> find palette index using `m`
-			// -> find recolor palette color using index -> set color
+			// Image pixel -> convert to RGBA -> find recolor palette color using map
+			// -> set color
 			img.Set(x, y, paletteToRecolor[color.RGBAModel.Convert(img.At(x, y))])
 		}
 	}

subcommands.go

@@ -100,6 +100,7 @@ func preProcess(c *cli.Context) error {
 			r, g, b, _ := c.RGBA()
 			if r != g || g != b {
 				grayscale = false
+				break
 			}
 		}
 	}