doc/refactoring-the-css-with-uiprops.rst
author Alexandre Fayolle <alexandre.fayolle@logilab.fr>
Thu, 21 Apr 2011 16:33:55 +0200
branchstable
changeset 7341 c419c2d0d13e
parent 5492 da983679fab5
child 10121 23af005426bf
permissions -rw-r--r--
add a new method iter_process_result which does the same as proces_result but is a generator (closes #1625374) process_result is reimplemented using the new method, and the two helper methods are turned into generators. These generators use cursor.fetchmany instead of cursor.fetchall after setting cursor.arraysize to 100. This means that the whole result set should never loaded in memory when using the iter_process_result method. This is used in the "portable" database dump implementation when we typically to 'SELECT * FROM table', but could probably be used too in other parts of cubicweb.

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