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
|
/*
* Copyright (C) 2014 ~ 2018 Deepin Technology Co., Ltd.
*
* Author: jouyouyun <jouyouwen717@gmail.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package graphic
import (
"fmt"
"image"
)
// ScaleImage returns a new image file with the given width and
// height created by resizing the given image.
func ScaleImage(srcfile, dstfile string, newWidth, newHeight int, f Format) (err error) {
srcimg, err := LoadImage(srcfile)
if err != nil {
return
}
dstimg := Scale(srcimg, newWidth, newHeight)
err = SaveImage(dstfile, dstimg, f)
dstimg.Pix = nil
return
}
// ScaleImagePrefer resize image file to new width and heigh, and
// maintain the original proportions unchanged.
func ScaleImagePrefer(srcfile, dstfile string, newWidth, newHeight int, f Format) (err error) {
srcimg, err := LoadImage(srcfile)
if err != nil {
return
}
dstimg, err := ScalePrefer(srcimg, newWidth, newHeight)
if err != nil {
return
}
err = SaveImage(dstfile, dstimg, f)
dstimg.Pix = nil
return
}
// ScaleImageCache resize any recognized format image file and save to cache
// directory, if already exists, just return it.
func ScaleImageCache(srcfile string, newWidth, newHeight int, f Format) (dstfile string, useCache bool, err error) {
dstfile = generateCacheFilePath(fmt.Sprintf("ScaleImageCache%s%d%d%s", srcfile, newWidth, newHeight, f))
if isFileExists(dstfile) {
useCache = true
return
}
err = ScaleImage(srcfile, dstfile, newWidth, newHeight, f)
return
}
// ThumbnailImage resize target image file with limited maximum width and height.
func ThumbnailImage(srcfile, dstfile string, maxWidth, maxHeight int, f Format) (err error) {
srcimg, err := LoadImage(srcfile)
if err != nil {
return
}
dstimg := Thumbnail(srcimg, maxWidth, maxHeight)
err = SaveImage(dstfile, dstimg, f)
dstimg.Pix = nil
return
}
// ThumbnailImageCache resize target image file with limited maximum width
// and height, and save to cache directory, if already exists, just
// return it.
func ThumbnailImageCache(srcfile string, maxWidth, maxHeight int, f Format) (dstfile string, useCache bool, err error) {
dstfile = generateCacheFilePath(fmt.Sprintf("ThumbnailImageCache%s%d%d%s", srcfile, maxWidth, maxHeight, f))
if isFileExists(dstfile) {
useCache = true
return
}
err = ThumbnailImage(srcfile, dstfile, maxWidth, maxHeight, f)
return
}
// Scale resize image object to new width and height.
func Scale(srcimg image.Image, newWidth, newHeight int) (dstimg *image.RGBA) {
dstimg = doScaleNearestNeighbor(srcimg, newWidth, newHeight)
return
}
// Thumbnail resize image object with limited maximum width and height.
func Thumbnail(srcimg image.Image, maxWidth, maxHeight int) (dstimg *image.RGBA) {
// get new width and heigh
var newWidth, newHeight int
w, h := GetSize(srcimg)
scale := float32(w) / float32(h)
newWidth = maxWidth
newHeight = int(float32(newWidth) / scale)
if newHeight > maxHeight {
newHeight = maxHeight
newWidth = int(float32(newHeight) * scale)
}
return Scale(srcimg, newWidth, newHeight)
}
// ScalePrefer resize image object to new width and heigh, and
// maintain the original proportions unchanged.
func ScalePrefer(srcimg image.Image, newWidth, newHeight int) (dstimg *image.RGBA, err error) {
iw, ih := GetSize(srcimg)
x, y, w, h, err := GetPreferScaleClipRect(newWidth, newHeight, iw, ih)
if err != nil {
return
}
dstimg = Clip(srcimg, x, y, w, h)
dstimg = Scale(dstimg, newWidth, newHeight)
return
}
// TODO doScaleNearestNeighbor returns a new RGBA image with the given width and
// height created by resizing the given image using the nearest neighbor
// algorithm.
func doScaleNearestNeighbor(img image.Image, newWidth, newHeight int) (newimg *image.RGBA) {
w := img.Bounds().Max.X
h := img.Bounds().Max.Y
newimg = image.NewRGBA(image.Rect(0, 0, newWidth, newHeight))
xr := (w<<16)/newWidth + 1
yr := (h<<16)/newHeight + 1
for yo := 0; yo < newHeight; yo++ {
y2 := (yo * yr) >> 16
for xo := 0; xo < newWidth; xo++ {
x2 := (xo * xr) >> 16
newimg.Set(xo, yo, img.At(x2, y2))
//Much faster, but requires some image type.
//newimg.Pix[offset] = img.Pix[y2*w+x2]
//offset++
}
}
return newimg
}
// GetPreferScaleClipRect get the maximum rectangle in center of
// image which with the same scale to reference width/heigh.
func GetPreferScaleClipRect(refWidth, refHeight, imgWidth, imgHeight int) (x, y, w, h int, err error) {
if refWidth*refHeight == 0 || imgWidth*imgHeight == 0 {
err = fmt.Errorf("argument is invalid: %d, %d, %d, %d", refWidth, refHeight, imgWidth, imgHeight)
return
}
scale := float32(refWidth) / float32(refHeight)
w = imgWidth
h = int(float32(w) / scale)
if h < imgHeight {
offsetY := (imgHeight - h) / 2
x = 0
y = 0 + offsetY
} else {
h = imgHeight
w = int(float32(h) * scale)
offsetX := (imgWidth - w) / 2
x = 0 + offsetX
y = 0
}
return
}
|
