windows下安装rmagick比较麻烦
安装 DevKit,这个DevKit就是Ruby在windows下调用的编译器 : https://github.com/oneclick/rubyinstaller/wiki/Development-Kit
安装 ImageMagick,勾选安装头文件,目录不要带空格。 http://www.imagemagick.org/script/binary-releases.php/#windows
设置到环境变量
set DFImageMagick ImageMagick的安装目录 set PATH=%DFImageMagick%;%PATH% set CPATH=%DFImageMagick%\include;%CPATH% set LIBRARY_PATH=%DFImageMagick%\lib;%LIBRARY_PATH%安装 RMagick : gem install rmagick
校验一下安装的结果:
A. convert -version 显示ImageMagick的版本
B. gem list –local 输出中应该包含 rmagick 2.13.1
进入irb 测试 require ‘rmagick’ 应该输出 ‘true’
使用RMagick,重要会用到两个对象:Image和Draw。
#encoding : UTF-8 require 'rmagick' img = Magick::Image.read('D:\\demo4.jpg').first thumb = img.resize_to_fit(1280) thumb.write('D:\\demo4.thumb.jpg') {self.quality = 50} puts 'down'Magick::Image的resize有数种方法
#resize ⇒ Object Scale an image to the desired dimensions using the specified filter and blur factor. #resize_to_fill(ncols, nrows = nil, gravity = CenterGravity) ⇒ Object (also: #crop_resized) Force an image to exact dimensions without changing the aspect ratio. #resize_to_fit(cols, rows = nil) ⇒ Object Convenience method to resize retaining the aspect ratio.更多用法:http://www.rubydoc.info/gems/rmagick/2.15.4/Magick