想用RMagick，但据说内存泄露的问题比较厉害，作为替代品MiniMagick不存在内存泄露的问题。而二者都是使用ImageMagick的，所以需要下载并安装ImageMagick。
下面安装ImageMagick：
|
1 |
sudo apt-get install imagemagick |
安装gem··「mini_magick」
|
1 |
gem install mini_magick --no-ri --no-rdoc |
引入gem MiniMagick :
|
1 |
require "mini_magick" |
MiniMagick中的Image对象
MiniMagick::Image
|
1 |
img=MiniMagick::Image.open("./pic1.jpg") |
[](value)
A rather low-level way to interact with the “identify” command. No nice API here, just the crazy stuff you find in ImageMagick. See the examples listed!
@example
|
1
2
3
4
5
6
7 |
image["format"] #=> "TIFF"image["height"] #=> 41 (pixels)image["width"] #=> 50 (pixels)image["dimensions"] #=> [50, 41]image["size"] #=> 2050 (bits)image["original_at"] #=> 2005-02-23 23:17:24 +0000 (Read from Exif data)image["EXIF:ExifVersion"] #=> "0220" (Can read anything from Exif) |
@param format [String] A format for the “identify” command @see For reference seewww.imagemagick.org/script/command-line-options.php#format @return [String, Numeric, Array, Time, Object] Depends on the method called! Defaults to String for unknown commands
write(output_to)
Writes the temporary file out to either a file location (by passing in a String) or by passing in a Stream that you can write(chunk) to repeatedly
@param output_to [IOStream, String] Some kind of stream object that needs to be read or a file path as a String @return [IOStream, Boolean] If you pass in a file location [String] then you get a success boolean. If its a stream, you get it back. Writes the temporary image that we are using for processing to the output path
shave("宽x高")
|
1
2
3
4
5
6
7
8 |
require ‘mini_magick’img = MiniMagick::Image.from_file “1.jpg”w,h = img[:width],img[:height] #=> [2048, 1536]#取得宽度和高度shaved_off = ((w-h)/2).round #=> 256img.shave “#{shaved_off}x0″ #此处表示宽度上左右各截取256个像素，高度上截取0像素img.write “2.jpg” |
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17 |
#!/usr/bin/rubyrequire "mini_magick"def
resize_and_crop(image, square_size) if
image[:width]<image[:height] shave_off=((image[:height]-image[:width])/2).round image.shave("0x#{shave_off}") elsif
image[:width]>image[:height] shave_off=((image[:width]-image[:height])/2).round end geometry=to_geometry(square_size,square_size) image.resize(geometry return
imageendnew_image=resize_and_crop(MiniMagick::Image.from_file("1.jpg")) |
「ruby/MiniMagick」用MiniMagick处理图片,布布扣,bubuko.com
「ruby/MiniMagick」用MiniMagick处理图片
原文：http://www.cnblogs.com/lizunicon/p/3674605.html