wanderwort

One might want to set up dynamic attachment dimensions (or other styles) when generating images with thoughtbot’s paperclip. Styles in paperclip are basically represented in the :styles hash of has_attached_file:

class File
  has_attached_file(
    :attachment,
    :styles => { :thumb => "100x100" }
  )
end

Building a related size model in rails might look the following:

class File < ActiveRecord::Base
  has_many :sizes, :class_name => "FileSize", :dependent => :destroy
 
  has_attached_file(
    :attachment,
    :styles => # styles through FileSize model
  )
 
  def styles
   self.sizes.inject({ :thumb => "100x100" }) do |sizes, size|
      sizes[:"#{size.id}"] = "#{size.width}x#{size.height}"; sizes
    end
  end
end
 
class FileSize < ActiveRecord::Base
  belongs_to :file
end

Using a Proc we can fetch sizes from our FileSize model:

  has_attached_file(
    :attachment,
    :styles => Proc.new { |clip| clip.instance.styles }
  )

Clip is the Paperclip instance which holds an instance-method to get back to the calling Class.

As a last issue one might want to reprocess / regenerated images after creating or destroying sizes:

class FileSize < ActiveRecord::Base
  belongs_to :file
 
  after_create  :reprocess
  after_destroy :reprocess
 
  private
 
  def reprocess
    self.file.attachment.reprocess!
  end
end

Again I had to learn how much magento e-commerce documentation sucks or better to say the lack of it. After reading several tutorials and part-conclusions, i found following working solution
First of all it’s important to have one default category as a root category. Then you can use the following code in “magento/app/design/frontend/<#your template#>/<#your layout#>/template/catalog/navigation/top.phtml”.

<div id="navi">
  <ul>
  <?php
  foreach ($this->getStoreCategories() as $key => $cat):
      if ($this->isCategoryActive($cat)) { 
        echo '<li class="active">
          <a href="'.$this->getCategoryUrl($cat).'">
          <span>'.$cat->getName()."</span></a>
        </li>\n";
      } else {
        echo '<li class="normal">
          <a href="'.$this->getCategoryUrl($cat).'">
          <span>'.$cat->getName()."</span></a>
        </li>\n";
      }
  endforeach; ?>
  </ul>
</div>

Be sure to use $this->isCategoryActive() instead of finding out the current category first and compare it with the active one. This wouldn’t work for sub-categories so that an active sub-category wouldn’t mark it’s parent active. Actually many tutorials seem to have that mistake in their code.

A more or less good resource for magento developers is magetips.com.
I found the adressed function there as well.