Section: User Contributed Perl Documentation (3)Updated: 2009-02-24Local indexUp
NAME
Prima::PodView - POD browser widget
SYNOPSIS
use Prima qw(Application);
use Prima::PodView;
my $window = Prima::MainWindow-> create;
my $podview = $window-> insert( 'Prima::PodView',
pack => { fill => 'both', expand => 1 }
);
$podview-> open_read;
$podview-> read("=head1 NAME\n\nI'm also a pod!\n\n");
$podview-> close_read;
run Prima;
DESCRIPTION
Prima::PodView contains a formatter ( in terms of perlpod ) and viewer of
POD content. It heavily employs its ascendant class Prima::TextView,
and is in turn base for the toolkit's default help viewer Prima::HelpViewer.
USAGE
The package consists of the several logically separated parts. These include
file locating and loading, formatting and navigation.
Content methods
The basic access to the content is not bound to the file system. The POD
content can be supplied without any file to the viewer. Indeed, the file
loading routine "load_file" is a mere wrapper to the content loading
functions:
open_read
Clears the current content and enters the reading mode. In this mode
the content can be appended by calling read that pushes the raw POD
content to the parser.
read TEXT
Supplies TEXT string to the parser. Manages basic indentation,
but the main formatting is performed inside add and add_formatted
Must be called only within open_read/close_read brackets
add TEXT, STYLE, INDENT
Formats TEXT string of a given STYLE ( one of "STYLE_XXX" constants) with
INDENT space.
Must be called only within open_read/close_read brackets.
add_formatted FORMAT, TEXT
Adds a pre-formatted TEXT with a given FORMAT, supplied by "=begin" or "=for"
POD directives. Prima::PodView understands 'text' and 'podview' FORMATs;
the latter format is for Prima::PodView itself and contains small number
of commands, aimed at inclusion of images into the document.
The 'podview' commands are:
cut
Example:
=for podview <cut>
=for text just text-formatter info
....
text-only info
...
=for podview </cut>
The <cut<gt> clause skips all POD input until cancelled.
It is used in conjunction with the following command, img, to allow
a POD manpage provide both graphic ('podview', 'html', etc ) and text ( 'text' )
content.
An image inclusion command, where src is a relative or an absolute path to
an image file. In case if scaling is required, "width" and "height" options
can be set. When the image is a multiframe image, the frame index can be
set by "frame" option. Special "cut" option, if set to a true value, activates the
cut behavior if ( and only if ) the image load operation was unsuccessful.
This make possible simultaneous use of 'podview' and 'text' :
=for podview <img src="graphic.gif" cut=1 >
=begin text
y .
| .
|.
+----- x
=end text
=for podview </cut>
In the example above 'graphic.gif' will be shown if it can be found and loaded,
otherwise the poor-man-drawings would be selected.
close_read
Closes the reading mode and starts the text rendering by calling "format".
Returns "undef" if there is no POD context, 1 otherwise.
Rendering
The rendering is started by "format" call, which returns ( almost ) immediately,
initiating the mechanism of delayed rendering, which is often time-consuming.
"format"'s only parameter KEEP_OFFSET is a boolean flag, which, if set to 1,
remembers the current location on a page, and when the rendered text approaches
the location, scrolls the document automatically.
The rendering is based an a document model, generated by open_read/close_read session.
The model is a set of same text blocks defined by Prima::TextView, except
that the header length is only three integers:
M_INDENT - the block X-axis indent
M_TEXT_OFFSET - same as BLK_TEXT_OFFSET
M_FONT_ID - 0 or 1, because PodView's fontPalette contains only two fonts -
variable ( 0 ) and fixed ( 1 ).
The actual rendering is performed in "format_chunks", where model blocks are
transformed to the full text blocks, wrapped and pushed into TextView-provided
storage. In parallel, links and the corresponding event rectangles are calculated
on this stage.
Topics
Prima::PodView provides the "::topicView" property, which governs whether
the man page is viewed by topics or as a whole. When it is viewed as topics,
"{modelRange}" array selects the model blocks that include the topic.
Thus, having a single model loaded, text blocks change dynamically.
Topics contained in "{topics}" array, each is an array with indices of "T_XXX"
constants:
T_MODEL_START - beginning of topic
T_MODEL_END - length of a topic
T_DESCRIPTION - topic name
T_STYLE - STYLE_XXX constant
T_ITEM_DEPTH - depth of =item recursion
T_LINK_OFFSET - offset in links array, started in the topic
Styles
"::styles" property provides access to the styles, applied to different pod
text parts. These styles are:
STYLE_CODE - style for pre-formatted text and C<>
STYLE_TEXT - normal text
STYLE_HEAD_1 - =head1
STYLE_HEAD_2 - =head2
STYLE_ITEM - =item
STYLE_LINK - style for L<> text
Each style is a hash with the following keys: "fontId", "fontSize", "fontStyle",
"color", "backColor", fully analogous to the tb::BLK_DATA_XXX options.
This functionality provides another layer of accessibility to the pod formatter.
In addition to styles, Prima::PodView defined "colormap" entries for
"STYLE_LINK" and "STYLE_CODE":
The default colors in the styles are mapped into these entries.
Link and navigation methods
Prima::PodView provides a hand-icon mouse pointer highlight for the link
entries and as an interactive part, the link documents or topics are loaded
when the user presses the mouse button on the link. The mechanics below that
is as follows. "{contents}" of event rectangles, ( see Prima::TextView )
is responsible for distinguishing whether a mouse is inside a link or not.
When the link is activated, "link_click" is called, which, in turn, calls
"load_link" method. If the page is loaded successfully, depending on "::topicView"
property value, either "select_topic" or "select_text_offset" method is called.
The family of file and link access functions consists of the following methods:
load_file MANPAGE
Loads a manpage, if it can be found in the PATH or perl installation directories.
If unsuccessful, displays an error.
load_link LINK
LINK is a text in format of perlpod "L<>" link: ``manpage/section''.
Loads the manpage, if necessary, and selects the section.
load_bookmark BOOKMARK
Loads a bookmark string, prepared by make_bookmark function.
Used internally.
load_content CONTENT
Loads content into the viewer. Returns "undef" is there is no POD
context, 1 otherwise.
make_bookmark [ WHERE ]
Combines the information about the currently viewing manpage, topic and text offset
into a storable string. WHERE, an optional string parameter, can be either omitted,
in such case the current settings are used, or be one of 'up', 'next' or 'prev' strings.
The 'up' string returns a bookmark to the upper level of the manpage.
The 'next' and 'prev' return a bookmark to the next or the previous topics in a manpage.
If the location cannot be stored or defined, "undef" is returned.