/
dither.go
168 lines (138 loc) · 3.37 KB
/
dither.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
package main
import (
"flag"
"fmt"
"image"
_ "image/jpeg"
"image/png"
"log"
"os"
"path/filepath"
"strings"
"sync"
dither "github.com/alkazarix/go-dither"
)
var (
inputDir string
outputDir string
monochrome bool
multiplier float64
filterNames string
)
const helper = `
Usage:
go run <image>
Options:
-filters string
name of the filters to apply, options: 'floydSteinberg', 'burkes', 'sierra', 'sierra2', 'sierra3', 'stucki', 'atkinson' (default floydSteinberg)
-multiplier float
Error multiplier (default 1.18)
-outputdir string
Directory name, where to save the generated images (default "output")
`
func usage() {
fmt.Fprint(os.Stderr, helper)
os.Exit(1)
}
func main() {
if err := process(); err != nil {
log.Printf("%s", err)
usage()
}
log.Println("DONE")
}
func process() error {
command := flag.NewFlagSet("command", flag.ExitOnError)
command.StringVar(&outputDir, "outputDir", "output", "directory where to saved generated image")
command.BoolVar(&monochrome, "monochrome", false, "generate color or greyscale dithered images")
command.Float64Var(&multiplier, "multiplier", 1.18, "error factor")
command.StringVar(&filterNames, "filters", "floydSteinberg", "filters to apply (comma separated)")
command.Usage = usage
if len(os.Args) < 2 {
usage()
}
command.Parse(os.Args[2:])
filename := os.Args[1]
img, err := openImage(filename)
if err != nil {
return err
}
filters, err := filters(filterNames)
if err != nil {
return err
}
monochromeDir, colorDir := filepath.Join(outputDir, "mono"), filepath.Join(outputDir, "color")
if monochrome {
_ = os.Mkdir(monochromeDir, os.ModePerm)
} else {
_ = os.Mkdir(colorDir, os.ModePerm)
}
var wg sync.WaitGroup
for _, filter := range filters {
wg.Add(1)
go func(filter *dither.Filter) {
defer wg.Done()
var outImg image.Image
var directory string
if monochrome {
outImg = dither.Monochrome(img, *filter, float32(multiplier))
directory = monochromeDir
} else {
outImg = dither.Color(img, *filter, float32(multiplier))
directory = colorDir
}
writePNG(outImg, filepath.Join(directory, filter.Name+".png"))
}(filter)
}
wg.Wait()
return nil
}
func openImage(filename string) (image.Image, error) {
file, err := os.Open(filename)
if err != nil {
return nil, err
}
defer file.Close()
img, _, err := image.Decode(file)
if err != nil {
return nil, err
}
return img, nil
}
func filters(filterNames string) ([]*dither.Filter, error) {
var filters []*dither.Filter
for _, name := range strings.Split(filterNames, ",") {
switch strings.TrimSpace(name) {
case "floydSteinberg":
filters = append(filters, dither.FloydSteinberg)
case "burkes":
filters = append(filters, dither.Burkes)
case "sierra":
filters = append(filters, dither.SierraLite)
case "sierra2":
filters = append(filters, dither.Sierra2)
case "sierra3":
filters = append(filters, dither.Sierra3)
case "stucki":
filters = append(filters, dither.Stucki)
case "atkinson":
filters = append(filters, dither.Atkinson)
}
}
if filters == nil {
return nil, fmt.Errorf("invalid filter options %s", filterNames)
}
return filters, nil
}
func writePNG(img image.Image, fn string) {
f, err := os.Create(fn)
if err != nil {
log.Fatal(err)
} else {
if err := png.Encode(f, img); err != nil {
log.Fatal(err)
usage()
}
}
defer f.Close()
}