Carrierwave crop specific version

I am working on the ability to crop images using carrierwave and Jcrop. Its a combination of Railscasts episode 182 and 253. I have cropping working but it crops the original. Is there anyway to force manupulate! to use a different version?

def crop_image(x,y,w,h)
  manipulate! do |img|
    img.crop(x.to_i, y.to_i, w.to_i, h.to_i)
  end
end

or is there a way to set the version from the model call?

attr_accessor :crop_x, :crop_y, :crop_w, :crop_h
attr_accessible :description, :image, :crop_x, :crop_y, :crop_w, :crop_h
after_update :reprocess_image, :if => :cropping?

def cropping?
  !crop_x.blank? && !crop_y.blank? && !crop_w.blank? && !crop_h.blank?
end


def reprocess_image
  image.crop_image(crop_x, crop_y, crop_w, crop_h)
end

回答1:

In the railscast, Ryan's solution was to convert the coords to work with the original image by finding the ratio between the large version and the original version. I was able to get it to work with Carrierwave and jCrop by following the same logic. Interesting enough Carrierwave does not store the dimensions of the images. I was able to hack together something from this post: http://code.dblock.org/ShowPost.aspx?Id=194.

Here is my solution.

user.rb

class User < ActiveRecord::Base

  attr_accessor :password, :crop_x, :crop_y, :crop_h, :crop_w
  after_update :reprocess_profile, :if => :cropping?

  mount_uploader :profile, ProfileUploader

  def cropping?
    !crop_x.blank? && !crop_y.blank? && !crop_w.blank? && !crop_h.blank?
  end

  def profile_geometry
    img = Magick::Image::read(self.profile.current_path).first
    @geometry = {:width => img.columns, :height => img.rows }
  end

  private

  def reprocess_profile
    self.profile.recreate_versions!
  end

end

account_controller.rb

class AccountController < ApplicationController

  def crop
    @account = current_user
  end

  def crop_update
    @account = current_user
    @account.crop_x = params[:account]["crop_x"]
    @account.crop_y = params[:account]["crop_y"]
    @account.crop_h = params[:account]["crop_h"]
    @account.crop_w = params[:account]["crop_w"]
    @account.save
    redirect_to account_path
  end

end

profile_uploader.rb

class ProfileUploader < CarrierWave::Uploader::Base

  def extension_white_list
    %w(jpg jpeg gif png)
  end

  version :large do
    process :resize_to_fit => [500, 500]
  end

  version :thumb do
    process :manualcrop
    process :resize_to_fill => [100, 100]
  end

  def manualcrop
    return unless model.cropping?
    manipulate! do |img| 
      img = img.crop(model.crop_x.to_i,model.crop_y.to_i,model.crop_h.to_i,model.crop_w.to_i) 
    end 
  end

end

crop.html.erb

<% content_for :head do %>
<%= stylesheet_link_tag "jquery.Jcrop" %>
<%= javascript_include_tag "jquery.Jcrop.min" %>
<script type="text/javascript" charset="utf-8">
$(function() {
  $('#cropbox').Jcrop({
    onChange: update_crop,
    onSelect: update_crop,
    setSelect: [0, 0, 500, 500],
    aspectRatio: 1
  });
});

function update_crop(coords) {
    var rx = 100/coords.w;
    var ry = 100/coords.h;
    var lw = $('#cropbox').width();
    var lh = $('#cropbox').height();
    var ratio = <%= @account.profile_geometry[:width] %> / lw ;

  $('#preview').css({
    width: Math.round(rx * lw) + 'px',
    height: Math.round(ry * lh) + 'px',
    marginLeft: '-' + Math.round(rx * coords.x) + 'px',
    marginTop: '-' + Math.round(ry * coords.y) + 'px'
  });
  $("#crop_x").val(Math.round(coords.x * ratio));
  $("#crop_y").val(Math.round(coords.y * ratio));
  $("#crop_w").val(Math.round(coords.w * ratio));
  $("#crop_h").val(Math.round(coords.h * ratio));
}
</script>
<% end %>

<%= image_tag @account.profile_url(:large), :id => "cropbox" %>

<h3>Preview</h3>
<div class="preview">
    <%= image_tag @account.profile_url(:large), :id => "preview" %>
</div>

<%= form_for @account, :as => :account, :url => { :action => "crop_update" } do |f| %>
    <% for attribute in [:crop_x, :crop_y, :crop_h, :crop_w] %>
        <%= f.hidden_field attribute, :id => attribute %>
    <% end %>
    <p><%= f.submit "Crop" %></p>
<% end %>

style.css

.preview {
    width:100px;
    height:100px;
    overflow:hidden;
}

回答2:

If I correctly understand the problem more simple way is to send trueSize option to the Jcrop.

<% geo = @item.image_geometry %>
$('#cropbox').Jcrop({boxWidth:656,boxHeight:350,onChange:update_crop,onSelect: update_crop,aspectRatio:656/350,trueSize:[<%= "#{geo[0]}, #{geo[1]}"%>]});

回答3:

Ryan just updated railscasts #182, it uses CarrierWave now

http://railscasts.com/episodes/182-cropping-images-revised