golang image 智能合并图片，自动识别图片类型，合并后缩放。
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
package util
import (
"fmt"
"image"
"image/draw"
"image/gif"
"image/jpeg"
"image/png"
"net/http"
"os"
"github.com/nfnt/resize"
)
func CheckImageType2(filePath string) (string, error) {
file, err := os.Open(filePath)
if err != nil {
return "", err
}
defer file.Close()
buff := make([]byte, 512) // why 512 bytes ? see http://golang.org/pkg/net/http/#DetectContentType
_, err = file.Read(buff)
if err != nil {
return "", err
}
filetype := http.DetectContentType(buff)
fmt.Println(filetype)
switch filetype {
case "image/jpeg", "image/jpg":
fmt.Println(filetype)
return "jpg", nil
case "image/gif":
fmt.Println(filetype)
case "image/png":
fmt.Println(filetype)
case "application/pdf": // not image, but application !
fmt.Println(filetype)
default:
fmt.Println("unknown file type uploaded")
}
return "aa", nil
}
func GetImageObj(filePath string) (img image.Image, err error) {
f1Src, err := os.Open(filePath)
if err != nil {
return nil, err
}
defer f1Src.Close()
buff := make([]byte, 512) // why 512 bytes ? see http://golang.org/pkg/net/http/#DetectContentType
_, err = f1Src.Read(buff)
if err != nil {
return nil, err
}
filetype := http.DetectContentType(buff)
fmt.Println(filetype)
fSrc, err := os.Open(filePath)
defer fSrc.Close()
switch filetype {
case "image/jpeg", "image/jpg":
img, err = jpeg.Decode(fSrc)
if err != nil {
fmt.Println("jpeg error")
return nil, err
}
case "image/gif":
img, err = gif.Decode(fSrc)
if err != nil {
return nil, err
}
case "image/png":
img, err = png.Decode(fSrc)
if err != nil {
return nil, err
}
default:
return nil, err
}
return img, nil
}
func MergeImage(worksDir string, file1 string, file2 string, newName string) (string, error) {
src, err := GetImageObj(worksDir + file1)
if err != nil {
return "", err
}
srcB := src.Bounds().Max
src1, err := GetImageObj(worksDir + file2)
if err != nil {
return "", err
}
src1B := src.Bounds().Max
newWidth := srcB.X + src1B.X
newHeight := srcB.Y
if src1B.Y > newHeight {
newHeight = src1B.Y
}
des := image.NewRGBA(image.Rect(0, 0, newWidth, newHeight)) // 底板
draw.Draw(des, des.Bounds(), src, src.Bounds().Min, draw.Over) //首先将一个图片信息存入jpg
draw.Draw(des, image.Rect(srcB.X, 0, newWidth, src1B.Y), src1, image.ZP, draw.Over) //将另外一张图片信息存入jpg
fSave, err := os.Create(worksDir + newName)
if err != nil {
return "", err
}
defer fSave.Close()
var opt jpeg.Options
opt.Quality = 80
newImage := resize.Resize(1024, 0, des, resize.Lanczos3)
err = jpeg.Encode(fSave, newImage, &opt) // put quality to 80%
if err != nil {
return "", err
}
return newName, nil
}
本文网址: https://golangnote.com/topic/149.html 转摘请注明来源