doc/dev/refactoring-the-css-with-uiprops.rst
author Julien Cristau <julien.cristau@logilab.fr>
Fri, 18 Dec 2015 17:49:45 +0100
changeset 11047 bfd11ffa79f7
parent 10492 68c13e0c0fc5
permissions -rw-r--r--
[entity] don't look at fetch order recursively If fetch_attrs includes relations, stop including the entities on the other side in our sorting. Fixes regression from 73ea636a5562 where we would sort on the target entity before the attribute we wanted if the relation's name sorted before the attribute's. This showed up in the forge/tracker cubes with Version entities being sorted by their State's name in preference to their version number.

=========================================
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.