Display Settings

part of the ArsDigita Community System by Tarik Alatovic and Sarah Ahmed

Site Administrator directory: /admin/display/
data model: /doc/sql/display.sql
procedures: base in /tcl/display-defs.tcl

The Big Picture

This module allows the site administrator to set the most commonly used CSS ( Cascaded Style Sheet) properties and the Logo for the site. It currently employs a simple version of CSS that supports only the options to choose fonts, background color, font color, link color and link underline status. Although it limits how much one can do with css, it should suffice for most practical purposes. As explained in the future improvement section, we are working on a data model to support a more complete version of CSS.

The Medium-Sized Picture

This system consists of two tables. css_simple table holds the css_properties of the site that can be set by the administrators together with the scope information.Using this table makes writing user friendly css forms possible.


create table css_simple (
        css_id  		  integer primary key,
        -- if scope=public, this is the css for the whole system
        -- if scope=group, this is the css for a particular group
        -- is scope=user this is the css for particular user
        scope   	          varchar(20) not null,
        user_id			  references users,
        group_id		  references user_groups,
	css_bgcolor		  varchar(40),
	css_textcolor		  varchar(40),
	css_unvisited_link	  varchar(40),
	css_visited_link	  varchar(40),
	css_link_text_decoration  varchar(40),
	css_font_type		  varchar(40)
);

alter table css_simple add constraint css_simple_scope_unique 
unique(scope, user_id, group_id);

alter table css_simple add constraint css_simple_data_scope_check check (
	(scope='group' and group_id is not null and user_id is null) or
        (scope='user' and user_id is not null and group_id is null) or
        (scope='public'));

page_logos table stores the log that can be displayed on every page


create sequence page_logos_id_sequence;
create table page_logos (
	logo_id 		integer primary key,
       	-- if scope=public, this is the system-wide logo
        -- if scope=group, this is the logo for a particular group
        -- is scope=user this is the logo for a particular user
        scope           	varchar(20) not null,
        user_id			references users,
        group_id		references user_groups,
	logo_enabled_p		char(1) default 'f' check(logo_enabled_p in ('t', 'f')),
	logo_file_type          varchar(100) not null,
        logo_file_extension     varchar(50) not null,    -- e.g., "jpg"
	logo			blob not null
);

alter table page_logos add constraint page_logos_scope_check check (
	(scope='group' and group_id is not null and user_id is null) or
        (scope='user' and user_id is not null and group_id is null) or
        (scope='public'));

alter table page_logos add constraint page_logos_scope_unique 
unique(scope, user_id, group_id);

Legal Transactions

From the Site Administration pages at /admin/display the site-wide administrator can go to

/admin/display/edit-simple-css.tcl in order to set

Body Background Color
Body Text Color
Links Color
Visited Links Color
Choose Font
Set Links Underlined / Not Underlined

/admin/display/upload-logo.tcl in order to

Upload a New Logo
View Current Logo
Change Current Logo if it exists
Enable/Disable Current Logo

Future Improvements

Right now, the system only supports a simple version of CSS which restricts the administrator to set style selectors for his/her site. It will be augmented by a more complete version of CSS module which will allow the administrator to set any selector-property-value combination for the site. We are working on a unified version of a data model which will provide the flexibility of the complete version and the easy interface of the simple version.

tarik@arsdigita.com