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Section: User Contributed Perl Documentation (3) Updated: 2009-02-24
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Prima::Themes - object themes management  


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/ sample program.  


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



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.

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


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', 
                [ 'Prima::Widget' => {
                        onPaint => sub {
                                my ( $object, $canvas) = @_;
                                $object-> on_paint( ConstLineWidth-> new( $canvas));
                } ]



Dmitry Karasik, <>.  




Prima, Prima::Object, examples/




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Time: 21:53:01 GMT, April 16, 2011