This is part of http://docs.moodle.org/en/Development:Theme_engines_for_Moodle%3F
$THEME is now initialised at the same time as $OUTPUT. Old functions like
theme_setup are deprecated in favour of methods on $PAGE. There is a new
theme_config class in outputlib.php that deals with loading the theme config.php file.
CSS used to be served by themes styles.php files calling a function in weblib.php.
Now it works by each theme's styles.php file doing
$themename = basename(dirname(__FILE__));
require_once(dirname(__FILE__) . '/../../theme/styles.php');
which is less code to be copied into each theme. (Old-style styles.php files still
work thanks to some code in deprecatedlib.php.)
Admin UI for choosing a theme cleaned up.
A couple of theme-specific hard-coded hacks like $THEME->cssconstants and
$THEME->CSSEdit have been replaced by a more generic $THEME->customcssoutputfunction
hook. See examples at the end of outputlib.php
Also:
* Fix setting the theme in the URL, which seems to have been broken since 1.9.
* Fix up errors on a few pages caused by the new initialisation order.
* MDL-19097 moodle_page::set_course should not set $COURSE unless it is $PAGE.
* httpsrequired() from moodlelib.php moved to $PAGE->https_required().
* Move has_started() method to the renderer base class.
* Further fixes to display of early errors.
* Remove print_header/footer_old from weblib. I did not mean to commit them before.
New option on Administration -> Server -> Debugging called
'Show origin of languages strings' ($CFG->debugstringids).
If this is set, get_string will add the name of the lang file and the id of the string
to each string it gets, so instead of returning 'No', it will return '{No admin/checkboxno}'.
The custom-corners-specific code now in theme/customcornser/renderers.php
and lib/deprecatedlib.php.
Also, $CFG->pixpath is now causing more problems than ever. If it is
giving your problems, please call $OUTPUT->initialise_deprecated_cfg_pixpath()
as a temporary fix. As you can imagine, we are thinking about a better
long-term fix, which is why that method as a silly, and easy to grep name.
