doc/dev/refactoring-the-css-with-uiprops.rst
author David Douard <david.douard@logilab.fr>
Wed, 02 Nov 2016 10:15:42 +0100
changeset 11803 9f7949b63ab2
parent 10492 68c13e0c0fc5
permissions -rw-r--r--
[views] simplify and fix the TreeView (closes #16055814) Simplify the (internal) TreeView._init_params() method to get rid of the useless 'initial_thru_ajax' argument. The ajax tree view was not working properly when loaded via ajax, for instance from a lazy tab. This was due to the buggy protection against double javascript/ css inclusion, which is no more needed server-side as it is now implemented client-side. Deprecate use of the initial_thru_ajax argument of the TreeView.call() method.

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