doc/refactoring-the-css-with-uiprops.rst
author Sylvain Thénault <sylvain.thenault@logilab.fr>
Fri, 20 Dec 2013 08:39:03 +0100
changeset 9518 54ead5f372bb
parent 5492 da983679fab5
child 10121 23af005426bf
permissions -rw-r--r--
[rql2sql] remove special behaviour of symmetric relation vs DISTINCT 0542a85fe667 replacing SQL OR by hooks for symmetric relations allows that. This involve a single test value change for a border case: when querying a symmetric relation without specifying the subject nor the object, you may get some duplicated result. IMO this is fine to let the user explicitly use DISTINCT or not and to remove the dedicated handling we had which didn't let any choice. Related to #3259713

=========================================
Refactoring the CSSs with UI properties
=========================================

Overview
=========

Managing styles progressively became difficult in CubicWeb. The
introduction of uiprops is an attempt to fix this problem.

The goal is to make it possible to use variables in our CSSs.

These variables are defined or computed in the uiprops.py python file
and inserted in the CSS using the Python string interpolation syntax.

A quick example, put in ``uiprops.py``::

  defaultBgColor = '#eee'

and in your css::

  body { background-color: %(defaultBgColor)s; }


The good practices are:

- define a variable in uiprops to avoid repetitions in the CSS
  (colors, borders, fonts, etc.)

- define a variable in uiprops when you need to compute values
  (compute a color palette, etc.)

The algorithm implemented in CubicWeb is the following:

- read uiprops file while walk up the chain of cube dependencies: if
  cube myblog depends on cube comment, the variables defined in myblog
  will have precedence over the ones in comment

- replace the %(varname)s in all the CSSs of all the cubes

Keep in mind that the browser will then interpret the CSSs and apply
the standard cascading mechanism.

FAQ
====

- How do I keep the old style?

  Put ``STYLESHEET = [data('cubicweb.old.css')]`` in your uiprops.py
  file and think about something else.

- What are the changes in cubicweb.css?

  Version 3.9.0 of cubicweb changed the following in the default html
  markup and css:

  ===============  ==================================
   old              new
  ===============  ==================================
   .navcol          #navColumnLeft, #navColumnRight
   #contentcol      #contentColumn
   .footer          #footer
   .logo	    #logo
   .simpleMessage   .loginMessage
   .appMsg	    (styles are removed from css)
   .searchMessage   (styles are removed from css)
  ===============  ==================================

  Introduction of the new cubicweb.reset.css based on Eric Meyer's
  reset css.

  Lots of margin, padding, etc.