/
image.go
75 lines (66 loc) · 1.27 KB
/
image.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
package main
import (
"image"
"image/gif"
"image/jpeg"
"image/png"
"io"
"net/http"
"os"
"github.com/nfnt/resize"
)
const (
imageGIF = "image/gif"
imagePNG = "image/png"
imageJPG = "image/jpeg"
)
func getContentType(r io.Reader) string {
buff := make([]byte, 512)
r.Read(buff)
return http.DetectContentType(buff)
}
func isSupported(contentType string) bool {
return contentType == imageGIF || contentType == imageJPG || contentType == imagePNG
}
func copyFile(source, destination string) error {
fr, err := os.Open(source)
if err != nil {
return err
}
defer fr.Close()
fw, err := os.Create(destination)
if err != nil {
return err
}
defer fw.Close()
_, err = io.Copy(fw, fr)
return err
}
func generateThumbnail(source, destination string) error {
file, err := os.Open(source)
if err != nil {
return err
}
var img image.Image
var imageType string
img, imageType, err = image.Decode(file)
if err != nil {
return err
}
file.Close()
m := resize.Thumbnail(maxWidth, maxHeight, img, resize.Lanczos3)
out, err := os.Create(destination)
if err != nil {
return err
}
defer out.Close()
switch imageType {
case "gif":
return gif.Encode(out, m, nil)
case "jpeg":
return jpeg.Encode(out, m, nil)
case "png":
return png.Encode(out, m)
}
return nil
}