使用附件调整Flickr样式的大小

要设置100x100缩略图,请将以下内容添加到模型中:

  has_attachment :content_type => :image,
                 :storage => IMAGE_STORAGE,
                 :max_size => 20.megabytes,
                 :thumbnails => {
                   :thumb  => '100x100>',
                   :large  => '800x600>',
                 }

(在本例中,我创建了一个100x100的缩略图,以及一个800x600的“大”尺寸,以保持原始尺寸。)

另外,请记住,缩略图可能不完全是100x100;最大尺寸为100x100。这意味着如果原稿的纵横比为4:3,缩略图将为100x75。我不太确定这是否就是你所说的“完全100x100,任何多余的裁剪,以便保持纵横比。”

将此添加到您的模型中

protected  

  # Override image resizing method  
  def resize_image(img, size)  
    # resize_image take size in a number of formats, we just want  
    # Strings in the form of "crop: WxH"  
    if (size.is_a?(String) && size =~ /^crop: (\d*)x(\d*)/i) ||  
        (size.is_a?(Array) && size.first.is_a?(String) &&  
          size.first =~ /^crop: (\d*)x(\d*)/i)  
      img.crop_resized!($1.to_i, $2.to_i)  
      # We need to save the resized image in the same way the  
      # orignal does.  
      self.temp_path = write_to_temp_file(img.to_blob)  
    else  
      super # Otherwise let attachment_fu handle it  
    end  
  end

并将缩略图大小更改为:

:thumbnails => {:thumb => 'crop: 100x100' }

资料来源:

http://stuff-things.net/2008/02/21/quick-and-dirty-cropping-images-with-attachment_fu/

规范中有一个裁剪指令:

has_attachment :content_type => :image,
  :thumbnails => {
    :thumb  => '100x100#'
}

编辑:

has_attachment :content_type => :image,
  :thumbnails => {
    :thumb  => '100x100!'
}

  def resize_image(img, size)  
    # resize_image take size in a number of formats, we just want  
    # Strings in the form of "square: WxH"  
    if (size.is_a?(String) && size =~ /^square: (\d*)x(\d*)/i) ||  
        (size.is_a?(Array) && size.first.is_a?(String) &&  
          size.first =~ /^square: (\d*)x(\d*)/i)  
        iw, ih = img.columns, img.rows
        aspect = iw.to_f / ih.to_f
        if aspect > 1
            shave_off = (iw - ih) / 2
            img.shave!(shave_off, 0)
        else
            shave_off = (ih-iw) / 2
            img.shave!(0, shave_off)
        end
        resize_image_internal(img, "#{$1}x#{$2}!")
    else  
      resize_image_internal(img, size) # Otherwise let attachment_fu handle it  
    end  
  end

我现在可以使用“square:100x100”作为几何字符串。注意,上面的代码假设所需的输出是正方形的。