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