Get the inverse of a hex color in Ruby

georgehotelling (George Hotelling) — Wed, 17 Aug 2005 23:32:43 GMT

This method will return the inverse of a hex color, which is useful if you want to make sure that your text will show up on a colored background.

def invert_color(color)

  color.gsub!(/^#/, '')

  sprintf("%X", color.hex ^ 0xFFFFFF)

end

Example:

invert_color('#c0c0c0') #=> "3F3F3F"

Limitations:

Doesn't handle named colors or 3 digit colors (i.e. #FFF == #FFFFFF)

Check that a user has permission on all parents in Zope

georgehotelling (George Hotelling) — Tue, 19 Jul 2005 22:41:19 GMT

If you need to be sure that a user can view an object, you need to check the View permission not only on the object but also all of its parents. To do this, I slightly modified the script at http://zopelabs.com/cookbook/1018022911 so that it uses the context object and specified the View permission.

Create a Python script in your acquisition path (I used portal_skins/custom) named can_view and paste in this code:

permission = "View"

try:

  object=context

  if not object.acquiredRolesAreUsedBy( permission ):

    for p in object.rolesOfPermission( permission ):

      if p['selected']:

        if p['name'] in user.getRoles():

          return 1

  else:

   return 1

except:

    pass

return 0

Then you can check the permission in TAL like this:

...

DZone Snippets: Georgehotelling's Code Snippets

Get the inverse of a hex color in Ruby

Check that a user has permission on all parents in Zope