NAME

       Prima::Themes - object themes management

DESCRIPTION

       Provides layer for theme registration in Prima. Themes are loosely grouped alternations of
       default class properties and behavior, by default stored in "Prima/themes" subdirectory.
       The theme realization is implemented as interception of object profile during its
       creation, inside "::profile_add". Various themes apply various alterations, one way only -
       once an object is applied a theme, it cannot be neither changed nor revoked thereafter.

       Theme configuration can be stored in an rc file, ~/.prima/themes, and is loaded
       automatically, unless $Prima::Themes::load_rc_file explicitly set to 0 before loading the
       "Prima::Themes" module. In effect, any Prima application not aware of themes can be
       coupled with themes in the rc file by the following:

               perl -MPrima::Themes program

       "Prima::Themes" namespace provides registration and execution functionality.
       "Prima::Themes::Proxy" is a class for overriding certain methods, for internal realization
       of a theme.

       For interactive theme selection use examples/theme.pl sample program.

SYNOPSIS

               # register a theme file
               use Prima::Themes qw(color);
               # or
               use Prima::Themes; load('color');
               # list registered themes
               print Prima::Themes::list;

               # install a theme
               Prima::Themes::install('cyan');
               # list installed themes
               print Prima::Themes::list_active;
               # create object with another theme while 'cyan' is active
               Class->create( theme => 'yellow');
               # remove a theme
               Prima::Themes::uninstall('cyan');

Prima::Themes

       load @THEME_MODULES
           Load THEME_MODULES from files via "use" clause, dies on error.  Can be used instead of
           explicit "use".

           A loaded theme file may register one or more themes.

       register $FILE, $THEME, $MATCH, $CALLBACK, $INSTALLER
           Registers a previously loaded theme. $THEME is a unique string identifier.  $MATCH is
           an array of pairs, where the first item is a class name, and the second is an
           arbitrary scalar parameter. When a new object is created, its class is matched via
           "isa" to each given class name, and if matched, the $CALLBACK routine is called with
           the following parameters: object, default profile, user profile, second item of the
           matched pair.

           If $CALLBACK is "undef", the default merger routine is called, which treats the second
           items of the pairs as hashes of the same format as the default and user profiles.

           The theme is inactive until "install" is called. If $INSTALLER subroutine is passed,
           it is called during install and uninstall, with two parameters, the name of the theme
           and boolean install/uninstall flag. When install flag is 1, the theme is about to be
           installed; the subroutine is expected to return a boolean success flag. Otherwise,
           subroutine return value is not used.

           $FILE is used to indicate the file in which the theme is stored.

       deregister $THEME
           Un-registers $THEME.

       install @THEMES
           Installs previosuly loaded and registered loaded THEMES; the installed themes are now
           used to match new objects.

       uninstall @THEMES
           Uninstalls loaded THEMES.

       list
           Returns the list of registered themes.

       list_active
           Returns the list of installed themes.

       loaded $THEME
           Return 1 if $THEME is registered, 0 otherwise.

       active $THEME
           Return 1 if $THEME is installed, 0 otherwise.

       select @THEMES
           Uninstalls all currently installed themes, and installs THEMES instead.

       merger $OBJECT, $PROFILE_DEFAULT, $PROFILE_USER, $PROFILE_THEME
           Default profile merging routine, merges $PROFILE_THEME into $PROFILE_USER by keys from
           $PROFILE_DEFAULT.

       load_rc [ $INSTALL = 1 ]
           Reads data ~/.prima/themes and loads listed modules.  If $INSTALL = 1, installs the
           themes from the rc file.

       save_rc
           Writes configuration of currently installed themes into rc file, returns success flag.
           If success flag is 0, $! contains the error.

Prima::Themes::Proxy

       An instance of "Prima::Themes::Proxy", created as

       Prima::Themes::Proxy-> new( $OBJECT)

       is a non-functional wrapper for any Perl object $OBJECT. All methods of $OBJECT, except
       "AUTOLOAD", "DESTROY", and "new", are forwarded to $OBJECT itself transparently. The class
       can be used, for example, to deny all changes to "lineWidth" inside object's painting
       routine:

               package ConstLineWidth;
               use vars qw(@ISA);
               @ISA = qw(Prima::Themes::Proxy);

               sub lineWidth { 1 } # line width is always 1 now!

               Prima::Themes::register( '~/lib/constlinewidth.pm', 'constlinewidth',
                       [ 'Prima::Widget' => {
                               onPaint => sub {
                                       my ( $object, $canvas) = @_;
                                       $object-> on_paint( ConstLineWidth-> new( $canvas));
                               },
                       } ]
               );

AUTHOR

       Dmitry Karasik, <dmitry@karasik.eu.org>.

FILES

       ~/.prima/themes

SEE ALSO

       Prima, Prima::Object, examples/themes.pl