/
shitpic.go
146 lines (119 loc) · 2.51 KB
/
shitpic.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
package main
import (
"bytes"
"flag"
"fmt"
"image"
"image/gif"
"image/jpeg"
"image/png"
"io"
"math/rand"
"os"
"strings"
)
func recompress(in io.Reader, out io.Writer, quality int) error {
img, _, err := image.Decode(in)
if err != nil {
return err
}
return jpeg.Encode(out, img, &jpeg.Options{Quality: quality})
}
func gifize(in io.Reader, out io.Writer) error {
img, _, err := image.Decode(in)
if err != nil {
return err
}
return gif.Encode(out, img, nil)
}
func pngerate(in io.Reader, out io.Writer) error {
img, _, err := image.Decode(in)
if err != nil {
return err
}
return png.Encode(out, img)
}
func uglify(in io.Reader, cycles, lowerBound int) (io.Reader, error) {
randRange := 100 - lowerBound
var rbuf, wbuf bytes.Buffer
_, err := io.Copy(&rbuf, in)
if err != nil {
return nil, err
}
for i := 0; i < cycles; i++ {
fmt.Fprint(os.Stderr, ".")
quality := lowerBound + rand.Intn(randRange)
if err = recompress(&rbuf, &wbuf, quality); err != nil {
return nil, err
}
// Prevent allocations by reseting and swapping
rbuf.Reset()
rbuf, wbuf = wbuf, rbuf
}
fmt.Fprintln(os.Stderr)
return &rbuf, nil
}
func die(err error) {
if err != nil {
fmt.Fprintf(os.Stderr, "Error: %v\n", err)
os.Exit(1)
}
}
func main() {
flag.Usage = func() {
usage := `Usage of shitpic:
shitpic [options] input output
Shitpic accepts and can output JPEG, GIF, and PNG files.
`
fmt.Fprintln(os.Stderr, usage)
flag.PrintDefaults()
}
cycles := flag.Uint("cycles", 100, "How many times to reprocess input")
lowerBound := flag.Int("quality", 75, "Lower bound of quality (0–100)")
reduceColor := flag.Bool("reduce-colors", false, "Reduce to 256 colors")
flag.Parse()
if flag.NArg() != 2 {
flag.Usage()
os.Exit(2)
}
infilename := flag.Arg(0)
outfilename := flag.Arg(1)
if *lowerBound < 0 || *lowerBound > 100 {
flag.Usage()
os.Exit(2)
}
var r io.Reader = os.Stdin
if infilename != "-" {
f, err := os.Open(infilename)
die(err)
defer f.Close()
r = f
}
if *reduceColor {
var buf bytes.Buffer
die(gifize(r, &buf))
r = &buf
}
var err error
r, err = uglify(r, int(*cycles), *lowerBound)
die(err)
if strings.HasSuffix(outfilename, ".png") {
var buf bytes.Buffer
die(pngerate(r, &buf))
r = &buf
}
if strings.HasSuffix(outfilename, ".gif") {
var buf bytes.Buffer
die(gifize(r, &buf))
r = &buf
}
var outf = os.Stdout
if outfilename != "-" {
f, err := os.Create(outfilename)
die(err)
defer f.Close()
outf = f
}
_, err = io.Copy(outf, r)
die(err)
}