forked from nickalie/go-mozjpegbin
-
Notifications
You must be signed in to change notification settings - Fork 0
/
cjpeg.go
184 lines (151 loc) · 3.75 KB
/
cjpeg.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
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
package mozjpegbin
import (
"errors"
"fmt"
"image"
"io"
"github.com/Munchpass/go-mozjpegbin/embedbinwrapper"
)
// CJpeg wraps cjpeg tool from mozjpeg
type CJpeg struct {
BinWrapper *embedbinwrapper.EmbedBinWrapper
inputFile string
inputImage image.Image
input io.Reader
outputFile string
output io.Writer
quality int
optimize bool
}
// NewCJpeg creates new CJpeg instance
func NewCJpeg() (*CJpeg, error) {
binWrapper, err := createBinWrapper("cjpeg")
if err != nil {
return nil, fmt.Errorf("failed to create bin wrapper: %v", err)
}
bin := &CJpeg{
BinWrapper: binWrapper,
quality: -1,
}
return bin, nil
}
// InputFile sets image file to convert.
// Input or InputImage called before will be ignored.
func (c *CJpeg) InputFile(file string) *CJpeg {
c.input = nil
c.inputImage = nil
c.inputFile = file
return c
}
// Input sets reader to convert.
// InputFile or InputImage called before will be ignored.
func (c *CJpeg) Input(reader io.Reader) *CJpeg {
c.inputFile = ""
c.inputImage = nil
c.input = reader
return c
}
// InputImage sets image to convert.
// InputFile or Input called before will be ignored.
func (c *CJpeg) InputImage(img image.Image) *CJpeg {
c.inputFile = ""
c.input = nil
c.inputImage = img
return c
}
// OutputFile specify the name of the output jpeg file.
// Output called before will be ignored.
func (c *CJpeg) OutputFile(file string) *CJpeg {
c.output = nil
c.outputFile = file
return c
}
// Output specify writer to write jpeg file content.
// OutputFile called before will be ignored.
func (c *CJpeg) Output(writer io.Writer) *CJpeg {
c.outputFile = ""
c.output = writer
return c
}
// Quality specify the compression factor for RGB channels between 0 and 100. The default is 75.
//
// A small factor produces a smaller file with lower quality. Best quality is achieved by using a value of 100.
func (c *CJpeg) Quality(quality uint) *CJpeg {
if quality > 100 {
quality = 100
}
c.quality = int(quality)
return c
}
// Optimize perform optimization of entropy encoding parameters.
// Without this, default encoding parameters are used.
// Optimize usually makes the JPEG file a little smaller, but cjpeg runs somewhat slower and needs much more memory.
// Image quality and speed of decompression are unaffected by Optimize.
func (c *CJpeg) Optimize(optimize bool) *CJpeg {
c.optimize = optimize
return c
}
// Run starts cjpeg with specified parameters.
func (c *CJpeg) Run() error {
defer c.BinWrapper.Reset()
if c.quality > -1 {
c.BinWrapper.Arg("-quality", fmt.Sprintf("%d", c.quality))
}
if c.optimize {
c.BinWrapper.Arg("-optimize")
}
output, err := c.getOutput()
if err != nil {
return err
}
if output != "" {
c.BinWrapper.Arg("-outfile", output)
}
err = c.setInput()
if err != nil {
return err
}
if c.output != nil {
c.BinWrapper.SetStdOut(c.output)
}
err = c.BinWrapper.Run()
if err != nil {
return errors.New(err.Error() + ". " + string(c.BinWrapper.StdErr()))
}
return nil
}
// Version returns cjpeg version.
func (c *CJpeg) Version() (string, error) {
return version(c.BinWrapper)
}
// Reset resets all parameters to default values
func (c *CJpeg) Reset() *CJpeg {
c.quality = -1
c.optimize = false
return c
}
func (c *CJpeg) setInput() error {
if c.input != nil {
c.BinWrapper.StdIn(c.input)
} else if c.inputImage != nil {
r, err := createReaderFromImage(c.inputImage)
if err != nil {
return err
}
c.BinWrapper.StdIn(r)
} else if c.inputFile != "" {
c.BinWrapper.Arg(c.inputFile)
} else {
return errors.New("undefined input")
}
return nil
}
func (c *CJpeg) getOutput() (string, error) {
if c.output != nil {
return "", nil
} else if c.outputFile != "" {
return c.outputFile, nil
} else {
return "", errors.New("undefined output")
}
}