NAME

Prima::Widget::Link - routines for interactive links

DESCRIPTION

The class can be used in widgets that need to feature links, i e a highlighted rectangle, usually of text. When the user moves mouse or click on a link, depending on the link type, various action can be executed. A "tooltip" link type can display a hint with (rich) text, and a "hyperlink" link can open a browser or pod viewer. The programmer can also customize these actions.

SYNOPSIS

  use Prima qw(Label Application);
  my $main_window = Prima::MainWindow->new( size => [400, 100] );
  $main_window->insert( Label =>
    centered => 1,
    text   => \ "L<tip://$0/ttt|tip>, L<pod://Prima/|podviewer>, L<http://google.com/|browser>, L<id|custom>",
    onLink => sub { print "$_[2]\n" },
  );
  run Prima;
  =pod
  =head1 ttt
  this is a tooltip
  =for podview <img src="data:base64">
  R0lGODdhFgAVAIAAAAAAAP///ywAAAAAFgAVAIAAAAD///8CLIyPqcutsKALQKI6qT11R69lWDJm
  5omm6jqBjucycEx+bVOSNNf1+/NjCREFADs=

Link types

Link types can be set with the url syntax. There are four recognized link types that behave differently.

Tooltips

These are not really links in the strict sense, as clicking on them doesn't cause any action, however when the user hovers mouse over a tooltip, the module loads the pod content from the url, and displays it as a hint.

The idea behind this feature is to collect all tootip cards in a pod section, and referencing them in a text like in the example code in SYNOPSIS above.

Syntax: "L<tip://FILEPATH_OR_MODULE/SECTION>" or "L<tip://FILEPATH_OR_MODULE>" where "FILEPATH_OR_MODULE" can refer either to a file (path with slashes/backslashes) or a perl module (with "::"s ).

Tooltip text, when selected, is underscored by a dashed line, vs all other link types that draw solid line.

Pod sections

These links both diplay a pod section preview, like the toolkip, but also open a pod viewer with the referred section when clicked on.

Syntax: "L<pod://FILEPATH_OR_MODULE/SECTION>" or "L<pod://FILEPATH_OR_MODULE>" where "FILEPATH_OR_MODULE" can refer either to a file (path with slashes/backslashes) or a perl module (with "::"s ).

Hyperlinks

Links with schemes "ftp://", "http://", and "https://" open a browser when clicked on.

Custom links

All other urls, not matched by either scheme above, are expected to be handled programmatically. The preview, if any is handled by the "LinkPreview" event, and click by "Link" event.

See Events below.

Usage

Since "Prima::Widget::Link" is not a widget by itself but a collection of routines in a class, an object of such class should be instantiated programmatically and attached to a widget that needs to display links, an owner widget.

The owner needs to call mouse and paint methods from inside its "on_mousedown" etc relevant events. The owner might also want to overload link events, see below.

Markup

Prima::Drawable::Markup understands the "L<..|..>" command, which is, unlike perlpod, is formatted with its arguments reversed, to stay consistent with the other markup commands (i e it is "L<http://google.com|search>", not "L<search|http://google.com>" .

The simple way to incorporate rich text in both widget and link handler is to use "Prima::Drawable::Markup" to handle the markup parsing, and use the resulting object from the same class both for widget drawing and for the link reactions. One just needs to add " markup =" $markup_object > to " Prima::Widget::Link-"new() >.

API

Properties

rectangles: Contains array of rectangles in arbitrary coordinates that could be used to map screen coordinates to a url. Filled automatically.
references: An array of URLs

Methods

add_positions_from_blocks LINK_ID, BLOCKS, %DEFAULTS: To be used when the link object is not bound to a markup object and link rectangle recalculation is needed due to formatting change, f ex widget size, font size etc. %DEFAULTS is sent internally to "tb::block_walk" that might need eventual default parameters.
Scans BLOCKS and add monotonically increasing LINK_ID to new link rectanges. Return new LINK_ID.
clear_positions: Clears the content of "rectangles"
id2rectangles ID: Returns rectangles mapped to a link id. There can be more than 1 rectangle bound to a single link ID since link text could be, f ex, wrapped.
open_podview URL: Opens a pod viewer with the URL
open_browser URL: Opens a web browser with the URL
reset_positions_markup BLOCKS, %DEFAULTS: To be used when the link object is bound to a markup object and link rectangle recalculation is needed due to formatting change, f ex widget size, font size etc. %DEFAULTS is sent internally to "tb::block_walk" that might need eventual default parameters.

Events

All events are send to the owner, not to the link object itself, however the "SELF" parameter is sent and contains the link object.

Link SELF, URL, BUTTON, MOD: Send to the owner, if any, from within "on_mousedown" event, to indicate that a link as pressed on.
LinkPreview SELF, URL_REF: Send to the owner, if any, from within "on_mousemove" event. The owner might want to fill URL_REF with (rich) text that will be displayed as a link preview
LinkAdjustRect SELF, RECT_REF: Since the owner might implement a scrollable view, or any other view that has a coordinate system that is no necessary consistent with the rectangles stored in the link object, this event will be called when a link rectangle needs to be mapped to the owner coordinates.

AUTHOR

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