-This plugin has not yet been written; this page is an experiment in
-design-by-documentation :-)
-
-## Requirements
-
-This plugin formats a collection of images into a photo gallery,
-in the same way as many websites: good examples include the
-PHP application [Gallery](http://gallery.menalto.com/), Flickr,
-and Facebook's Photos "application".
-
-The web UI I'm trying to achieve consists of one
-[HTML page of thumbnails](http://www.pseudorandom.co.uk/2008/2008-03-08-panic-cell-gig/)
-as an entry point to the gallery, where each thumbnail links to
-[a "viewer" HTML page](http://www.pseudorandom.co.uk/2008/2008-03-08-panic-cell-gig/img_0068/)
-with a full size image, next/previous thumbnail links, and
-[[plugins/comments]].
-
-(The Summer of Code [[plugins/contrib/gallery]] plugin does the
-next/previous UI in Javascript using Lightbox, which means that
-individual photos can't be bookmarked in a meaningful way, and
-the best it can do as a fallback for non-Javascript browsers
-is to provide a direct link to the image.)
-
-Other features that would be good to have:
-
-* minimizing the number of separate operations needed to make a gallery -
- editing one source file per gallery is acceptable, editing one
- source file per photo is not
-
-* keeping photos outside source code control, for instance in an
- underlay
-
-* assigning [[tags|ikiwiki/directive/tag]] to photos, providing a
- superset of Facebook's "show tagged photos of this person" functionality
-
-* constructing galleries entirely via the web by uploading attachments
-
-* inserting grouping (section headings) within a gallery; as in the example
- linked above, I'd like this to split up the thumbnails but not the
- next/previous trail
-
-* rendering an `<object>/<embed>` arrangement to display videos, and possibly
- thumbnailing them in the same way as totem-video-thumbnailer
- (my camera can record short videos, so some of my web photo galleries
- contain them)
-
-My plan is to have these directives:
-
-* \[[!gallery]] registers the page it's on as a gallery, and displays all
- photos that are part of this gallery but not part of a \[[!gallerysection]]
- (below).
-
- All images (i.e. `*.png *.jpg *.gif`) that are attachments to the gallery page
- or its subpages are considered to be part of the gallery.
-
- Optional arguments:
-
- * filter="[[ikiwiki/PageSpec]]": only consider images to be part of the
- gallery if they also match this filter
-
- * sort="date|filename": order in which to sort the images
-
-* \[[!gallerysection filter="[[ikiwiki/PageSpec]]"]] displays all photos in the
- gallery that match the filter
-
-So,
-[the gallery I'm using as an example](http://www.pseudorandom.co.uk/2008/2008-03-08-panic-cell-gig/)
-could look something like this:
-
- \[[!gallery]]
- <!-- replaced with one uncategorized photo -->
-
- # Gamarra
-
- \[[!gallerysection filter="link(sometag)"]]
- <!-- all the Gamarra photos -->
-
- # Smokescreen
-
- \[[!gallerysection filter="link(someothertag)"]]
- <!-- all the Smokescreen photos -->
-
- <!-- ... -->
-
-## Implementation ideas
-
-The next/previous part this plugin overlaps with [[todo/wikitrails]].
-
-A \[[!galleryimg]] directive to assign metadata to images might be necessary, so
-the gallery page can contain something like:
-
- \[[!galleryimg p1010001.jpg title="..." caption="..." tags="foo"]]
- \[[!galleryimg p1010002.jpg title="..." caption="..." tags="foo bar"]]
-
-However, allowing other pages to push in metadata like that will make
-dependency tracking difficult.
-
-Making the viewer pages could be rather tricky. Here are some options:
-"synthesize source pages for viewers" is the one I'm leaning towards at the
-moment.
-
-### Viewers' source page is the gallery
-
-One possibility is to write out the viewer pages as a side-effect of
-preprocessing the \[[!gallery]] directive. The proof-of-concept implementation
-below does this. However, this does mean the viewer pages can't have tags or
-metadata of their own and can't be matched by [[pagespecs|ikiwiki/pagespec]] or
-[[wikilinks|ikiwiki/wikilink]].
-
-It might be possible to implement tagging by using \[[!galleryimg]] to assign
-the metadata to the *images* instead of their viewers; however, that would
-require hacking up both `IkiWiki::htmllink` and `IkiWiki::urlto` to redirect
-links to the image (e.g. from the \[[!map]] on a tag page) to become links to
-the viewer page.
-
-Modifications to the comments plugin would also be required, to make it allow
-comments written to `foo/bar/comment_1._comment` even though the page foo/bar
-does not really exist, and display comments on the viewer pages even though
-they're not real pages. (Writing comments to `foo/bar.jpg/*._comment` is not
-an option!)
-
-### Synthesize source pages for viewers
-
-Another is to synthesize source pages for the viewers. This means they can have
-tags and metadata, but trying to arrange for them to be scanned etc. correctly
-without needing another refresh run is somewhat terrifying.
-[[plugins/autoindex]] can safely create source pages because it runs in
-the refresh hook, but I don't really like the idea of a refresh hook that scans
-all source pages to see if they contain \[[!gallery]]...
-
-The photo galleries I have at the moment, like the Panic Cell example above,
-are made by using an external script to parse XML gallery descriptions (lists
-of image filenames, with metadata such as titles), and using this to write
-IkiWiki markup into a directory which is then used as an underlay. This is a
-hack, but it works. The use of XML is left over from a previous attempt at
-solving the same problem using Django.
-
-Perhaps a better approach would be to have a setupfile option that names a
-particular underlay directory (meeting the objective of not having large
-photos under source code control) and generates a source page for each file
-in that directory during the refresh hook. The source pages could be in the
-underlay until they are edited (e.g. tagged), at which point they would be
-copied into the source-code-controlled version in the usual way.
-
-The synthetic source pages can be very simple, using the same trick as my
-[[plugins/comments]] plugin (a dedicated [[directive|ikiwiki/directives]]
-encapsulating everything the plugin needs). If the plugin automatically
-gathers information like file size, pixel size, date etc. from the images, then
-only the human-edited information and a filename reference need to be present
-in the source page; with some clever lookup rules based on the filename of
-the source page, not even the photo's filename is necessarily needed.
-
- \[[!meta title="..."]]
- \[[!meta date="..."]]
- \[[!meta copyright="..."]]
- \[[!tag ...]]
-
- \[[!galleryimageviewer p1010001.jpg]]
-
-However, this would mean that editing tags and other metadata would require
-editing pages individually. Rather than trying to "fix" that, perhaps it would
-be better to have a special CGI interface for bulk tagging/metadata editing.
-This could even be combined with a bulk upload form (a reasonable number of
-file upload controls - maybe 20 - with metadata alongside each).
-
-Uploading multiple images is necessarily awkward due to restrictions placed on
-file upload controls by browsers for security reasons - sites like Facebook
-allow whole directories to be uploaded at the same time, but they achieve this
-by using a signed Java applet with privileged access to the user's filesystem.
-
-I've found that it's often useful to be able to force the creation time of
-photos (my camera's battery isn't very reliable, and it frequently decides that
-the date is 0000-00-00 00:00:00), so treating the \[[!meta date]] of the source
-page and the creation date of the photo as synonymous would be useful.
-
-### Images are the viewer's source - special filename extension
-
-Making the image be the source page (and generate HTML itself) would be
-possible, but I wouldn't want to generate a HTML viewer for every `.jpg` on a
-site, so either the images would have to have a special extension (awkward for
-uploads from Windows users) or the plugin would have to be able to change
-whether HTML was generated in some way (not currently possible).
-
-### Images are the viewer's source - alter `ispage()`
-
-It might be possible to hack up `ispage()` so some, but not all, images are
-considered to "be a page":
-
-* srcdir/not-a-photo.jpg → destdir/not-a-photo.jpg
-* srcdir/gallery/photo.jpg → destdir/gallery/photo/index.html
-
-Perhaps one way to do this would be for the photos to appear in a particular
-underlay directory, which would also fulfil the objective of having photos not
-be version-controlled:
-
-* srcdir/not-a-photo.jpg → destdir/not-a-photo.jpg
-* underlay/gallery/photo.jpg → destdir/gallery/photo/index.html
-
-## Proof-of-concept implementation of "viewers' source page is the gallery"
-
- #!/usr/bin/perl
- package IkiWiki::Plugin::gallery;
-
- use warnings;
- use strict;
- use IkiWiki 2.00;
-
- sub import {
- hook(type => "getsetup", id => "gallery", call => \&getsetup);
- hook(type => "checkconfig", id => "gallery", call => \&checkconfig);
- hook(type => "preprocess", id => "gallery",
- call => \&preprocess_gallery, scan => 1);
- hook(type => "preprocess", id => "gallerysection",
- call => \&preprocess_gallerysection, scan => 1);
- hook(type => "preprocess", id => "galleryimg",
- call => \&preprocess_galleryimg, scan => 1);
- }
-
- sub getsetup () {
- return
- plugin => {
- safe => 1,
- rebuild => undef,
- },
- }
-
- sub checkconfig () {
- }
-
- # page that is a gallery => array of images
- my %galleries;
- # page that is a gallery => array of filters
- my %sections;
- # page that is an image => page name of generated "viewer"
- my %viewers;
-
- sub preprocess_gallery {
- # \[[!gallery filter="!*/cover.jpg"]]
- my %params=@_;
-
- my $subpage = qr/^\Q$params{page}\E\//;
-
- my @images;
-
- foreach my $page (keys %pagesources) {
- # Reject anything not a subpage or attachment of this page
- next unless $page =~ $subpage;
-
- # Reject non-images
- # FIXME: hard-coded list of extensions
- next unless $page =~ /\.(jpg|gif|png|mov)$/;
-
- # Reject according to the filter, if any
- next if (exists $params{filter} &&
- !pagespec_match($page, $params{filter},
- location => $params{page}));
-
- # OK, we'll have that one
- push @images, $page;
-
- my $viewername = $page;
- $viewername =~ s/\.[^.]+$//;
- $viewers{$page} = $viewername;
-
- my $filename = htmlpage($viewername);
- will_render($params{page}, $filename);
- }
-
- $galleries{$params{page}} = \@images;
-
- # If we're just scanning, don't bother producing output
- return unless defined wantarray;
-
- # actually render the viewers
- foreach my $img (@images) {
- my $filename = htmlpage($viewers{$img});
- debug("rendering image viewer $filename for $img");
- writefile($filename, $config{destdir}, "# placeholder");
- }
-
- # display a list of "loose" images (those that are in no section);
- # this works because we collected the sections' filters during the
- # scan stage
-
- my @loose = @images;
-
- foreach my $filter (@{$sections{$params{page}}}) {
- my $_;
- @loose = grep { !pagespec_match($_, $filter,
- location => $params{page}) } @loose;
- }
-
- my $_;
- my $ret = "<ul>\n";
- foreach my $img (@loose) {
- $ret .= "<li>";
- $ret .= "<a href=\"" . urlto($viewers{$img}, $params{page});
- $ret .= "\">$img</a></li>\n"
- }
- return "$ret</ul>\n";
- }
-
- sub preprocess_gallerysection {
- # \[[!gallerysection filter="friday/*"]]
- my %params=@_;
-
- # remember the filter for this section so the "loose images" section
- # won't include these images
- push @{$sections{$params{page}}}, $params{filter};
-
- # If we're just scanning, don't bother producing output
- return unless defined wantarray;
-
- # this relies on the fact that we ran preprocess_gallery once
- # already, during the scan stage
- my @images = @{$galleries{$params{page}}};
- @images = grep { pagespec_match($_, $params{filter},
- location => $params{page}) } @images;
-
- my $_;
- my $ret = "<ul>\n";
- foreach my $img (@images) {
- $ret .= "<li>";
- $ret .= htmllink($params{page}, $params{destpage},
- $viewers{$img});
- $ret .= "</li>";
- }
- return "$ret</ul>\n";
- }
-
- sub preprocess_galleryimg {
- # \[[!galleryimg p1010001.jpg title="" caption="" tags=""]]
- my $file = $_[0];
- my %params=@_;
-
- return "";
- }
-
- 1