X-Git-Url: http://git.vanrenterghem.biz/git.ikiwiki.info.git/blobdiff_plain/be47e501c32cec7660129f430a4f93ee7fe8d3ff..4afe2d1170e85a09d43460045b5825fce081c469:/doc/plugins/contrib/album/discussion.mdwn diff --git a/doc/plugins/contrib/album/discussion.mdwn b/doc/plugins/contrib/album/discussion.mdwn index 7a3c19cf6..9720589b4 100644 --- a/doc/plugins/contrib/album/discussion.mdwn +++ b/doc/plugins/contrib/album/discussion.mdwn @@ -51,3 +51,323 @@ i'm new to ikiwiki, apologies if this is dealt with elsewhere. -brush > This plugin is pretty ambitious, and is unfinished, so I'd recommend > playing with a normal IkiWiki installation for a bit, then trying > out this plugin when you've mastered the basics of IkiWiki. --[[smcv]] + +---- + +You had wanted my feedback on the design of this. I have not looked at the +code or tried it yet, but here goes. --[[Joey]] + +* Needing to create the albumimage "viewer" pages for each photo + seems like it will become a pain. Everyone will need to come up + with their own automation for it, and then there's the question + of how to automate it when uploading attachments. -J + +> There's already a script (ikiwiki-album) to populate a git +> checkout with skeleton "viewer" pages; I was planning to make a +> specialized CGI interface for albums after getting feedback from +> you (since the requirements for that CGI interface change depending +> on the implementation). I agree that this is ugly, though. -s + +>> Would you accept a version where the albumimage "viewer" pages +>> could be 0 bytes long, at least until metadata gets added? +>> +>> The more I think about the "binaries as first-class pages" approach, +>> the more subtle interactions I notice with other plugins. I +>> think I'm up to needing changes to editpage, comments, attachment +>> and recentchanges, plus adjustments to img and Render (to reduce +>> duplication when thumbnailing an image with a strange extension +>> while simultaneously changing the extension, and to hardlink/copy +>> an image with a strange extension to a differing target filename +>> with the normal extension, respectively). -s + +* With each viewer page having next/prev links, I can see how you + were having the scalability issues with ikiwiki's data structures + earlier! -J + +> Yeah, I think they're a basic requirement from a UI point of view +> though (although they don't necessarily have to be full wikilinks). +> -s + +>> I think that with the new dependency types system, the dependencies for +>> these can be presence dependencies, which will probably help with +>> avoiding rebuilds of a page if the next/prev page is changed. +>> (Unless you use img to make the thumbnails for those links, then it +>> would rebuild the thumbnails anyway. Have not looked at the code.) --[[Joey]] + +* And doesn't each viewer page really depend on every other page in the + same albumsection? If a new page is added, the next/prev links + may need to be updated, for example. If so, there will be much + unnecessary rebuilding. -J + +> albumsections are just a way to insert headings into the flow of +> photos, so they don't actually affect dependencies. +> +> One non-obvious constraint of ikiwiki's current design is that +> everything "off-page" necessary to build any page has to happen +> at scan time, which has caused a few strange design decisions, +> like the fact that each viewer controls what album it's in. +> +> It's difficult for the contents of the album to just be a +> pagespec, like for inline, because pagespecs can depend on +> metadata, which is gathered in arbitrary order at scan time; +> so the earliest you can safely apply a pagespec to the wiki +> contents to get a concrete list of pages is at rebuild time. +> +> (This stalled my attempt at a trail plugin, too.) -s + +>> Not sure I understand why these need to look at pagespecs at scan time? +>> Also, note that it is fairly doable to detect if a pagespec uses such +>> metadata. Er, I mean, I have a cheezy hack in `add_depends` now that does +>> it to deal with a similar case. --[[Joey]] + +>>> I think I was misunderstanding how early you have to call `add_depends`? +>>> The critical thing I missed was that if you're scanning a page, you're +>>> going to rebuild it in a moment anyway, so it doesn't matter if you +>>> have no idea what it depends on until the rebuild phase. -s + +* One thing I do like about having individual pages per image is + that they can each have their own comments, etc. -J + +> Yes; also, they can be wikilinked. I consider those to be +> UI requirements. -s + +* Seems possibly backwards that the albumimage controls what album + an image appears in. Two use cases -- 1: I may want to make a locked + album, but then anyone who can write to any other page on the wiki can + add an image to it. 2: I may want an image to appear in more than one + album. Think tags. So it seems it would be better to have the album + directive control what pages it includes (a la inline). -J + +> I'm inclined to fix this by constraining images to be subpages of exactly +> one album: if they're subpages of 2+ nested albums then they're only +> considered to be in the deepest-nested one (i.e. longest URL), and if +> they're not in any album then that's a usage error. This would +> also make prev/next links sane. +> +> If you want to reference images from elsewhere in the wiki and display +> them as if in an album, then you can use an ordinary inline with +> the same template that the album would use, and I'll make sure the +> templates are set up so this works. +> +> (Implementation detail: this means that an image X/Y/Z/W/V, where X and +> Y are albums, Z does not exist and W exists but is not an album, +> would have a content dependency on Y, a presence dependency on Z +> and a content dependency on W.) +> +> Perhaps I should just restrict to having the album images be direct +> subpages of the album, although that would mean breaking some URLs +> on the existing website I'm doing all this work for... -s + +* Putting a few of the above thoughts together, my ideal album system + seems to be one where I can just drop the images into a directory and + have them appear in the album index, as well as each generate their own wiki + page. Plus some way I can, later, edit metadata for captions, + etc. (Real pity we can't just put arbitrary metadata into the images + themselves.) This is almost pointing toward making the images first-class + wiki page sources. Hey, it worked for po! :) But the metadata and editing + problems probably don't really allow that. -J + +> Putting a JPEG in the web form is not an option from my point of +> view :-) but perhaps there could just be a "web-editable" flag supplied +> by plugins, and things could be changed to respect it. + +>> Replying to myself: would you accept patches to support +>> `hook(type => 'htmlize', editable => 0, ...)` in editpage? This would +>> essentially mean "this is an opaque binary: you can delete it +>> or rename it, and it might have its own special editing UI, but you +>> can never get it in a web form". +>> +>> On the other hand, that essentially means we need to reimplement +>> editpage in order to edit the sidecar files that contain the metadata. +>> Having already done one partial reimplementation of editpage (for +>> comments) I'm in no hurry to do another. +>> +>> I suppose another possibility would be to register hook +>> functions to be called by editpage when it loads and saves the +>> file. In this case, the loading hook would be to discard +>> the binary and use filter() instead, and the saving conversion +>> would be to write the edited content into the metadata sidecar +>> (creating it if necessary). +>> +>> I'd also need to make editpage (and also comments!) not allow the +>> creation of a file of type albumjpg, albumgif etc., which is something +>> I previously missed; and I'd need to make attachment able to +>> upload-and-rename. +>> -s + +> In a way, what you really want for metadata is to have it in the album +> page, so you can batch-edit the whole lot by editing one file (this +> does mean that editing the album necessarily causes each of its viewers +> to be rebuilt, but in practice that happens anyway). -s + +>> Replying to myself: in practice that *doesn't* happen anyway. Having +>> the metadata in the album page is somewhat harmful because it means +>> that changing the title of one image causes every viewer in the album +>> to be rebuilt, whereas if you have a metadata file per image, only +>> the album itself, plus the next and previous viewers, need +>> rebuilding. So, I think a file per image is the way to go. +>> +>> Ideally we'd have some way to "batch-edit" the metadata of all +>> images in an album at once, except that would make conflict +>> resolution much more complicated to deal with; maybe just +>> give up and scream about mid-air collisions in that case? +>> (That's apparently good enough for Bugzilla, but not really +>> for ikiwiki). -s + +>> Yes, [all metadata in one file] would make some sense.. It also allows putting one image in +>> two albums, with different caption etc. (Maybe for different audiences.) +>> --[[Joey]] + +>>> Eek. No, that's not what I had in mind at all; the metadata ends up +>>> in the "viewer" page, so it's necessarily the same for all albums. -s + +>> It would probably be possible to add a new dependency type, and thus +>> make ikiwiki smart about noticing whether the metadata has actually +>> changed, and only update those viewers where it has. But the dependency +>> type stuff is still very new, and not plugin friendly .. so only just +>> possible, --[[Joey]] + +---- + +Trying to use the "special extension" design: + +Suppose that each viewer is a JPEG-or-GIF-or-something, with extension +".albumimage". We have a gallery "memes" with three images, badger, +mushroom and snake. + +> An alternative might be to use ".album.jpg", and ".album.gif" +> etc as the htmlize extensions. May need some fixes to ikiwiki to support +> that. --[[Joey]] + +>> foo.albumjpg (etc.) for images, and foo._albummeta (with +>> `keepextension => 1`) for sidecar metadata files, seems viable. -s + +Files in git repo: + +* index.mdwn +* memes.mdwn +* memes/badger.albumjpg (a renamed JPEG) +* memes/badger/comment_1._comment +* memes/badger/comment_2._comment +* memes/mushroom.albumgif (a renamed GIF) +* memes/mushroom._albummeta (sidecar file with metadata) +* memes/snake.albummov (a renamed video) + +Files in web content: + +* index.html +* memes/index.html +* memes/96x96-badger.jpg (from img) +* memes/96x96-mushroom.gif (from img) +* memes/96x96-snake.jpg (from img, hacked up to use totem-video-thumbnailer :-) ) +* memes/badger/index.html (including comments) +* memes/badger.jpg +* memes/mushroom/index.html +* memes/mushroom.gif +* memes/snake/index.html +* memes/snake.mov + +ispage("memes/badger") (etc.) must be true, to make the above rendering +happen, so albumimage needs to be a "page" extension. + +To not confuse other plugins, album should probably have a filter() hook +that turns .albumimage files into HTML? That'd probably be a reasonable +way to get them rendered anyway. + +> I guess that is needed to avoid preprocess, scan, etc trying to process +> the image, as well as eg, smiley trying to munge it in sanitize. +> --[[Joey]] + +>> As long as nothing has a filter() hook that assumes it's already +>> text... filters are run in arbitrary order. We seem to be OK so far +>> though. +>> +>> If this is the route I take, I propose to have the result of filter() +>> be the contents of the sidecar metadata file (empty string if none), +>> with the `\[[!albumimage]]` directive (which no longer requires +>> arguments) prepended if not already present. This would mean that +>> meta directives in the metadata file would work as normal, and it +>> would be possible to insert text both before and after the viewer +>> if desired. The result of filter() would also be a sensible starting +>> point for editing, and the result of editing could be diverted into +>> the metadata file. -s + +do=edit&page=memes/badger needs to not put the JPG in a text box: somehow +divert or override the normal edit CGI by telling it that .albumimage +files are not editable in the usual way? + +> Something I missed here is that editpage also needs to be told that +> creating new files of type albumjpg, albumgif etc. is not allowed +> either! -s + +Every image needs to depend on, and link to, the next and previous images, +which is a bit tricky. In previous thinking about this I'd been applying +the overly strict constraint that the ordered sequence of pages in each +album must be known at scan time. However, that's not *necessarily* needed: +the album and each photo could collect an unordered superset of dependencies +at scan time, and at rebuild time that could be refined to be the exact set, +in order. + +> Why do you need to collect this info at scan time? You can determine it +> at build time via `pagespec_match_list`, surely .. maybe with some +> memoization to avoid each image in an album building the same list. +> I sense that I may be missing a subtelty though. --[[Joey]] + +>> I think I was misunderstanding how early you have to call `add_depends` +>> as mentioned above. -s + +Perhaps restricting to "the images in an album A must match A/*" +would be useful; then the unordered superset could just be "A/*". Your +"albums via tags" idea would be nice too though, particularly for feature +parity with e.g. Facebook: "photos of Joey" -> "tags/joey and albumimage()" +maybe? + +If images are allowed to be considered to be part of more than one album, +then a pretty and usable UI becomes harder - "next/previous" expands into +"next photo in holidays/2009/germany / next photo in tagged/smcv / ..." +and it could get quite hard to navigate. Perhaps next/previous links could +be displayed only for the closest ancestor (in URL space) that is an +album, or something? + +> Ugh, yeah, that is a problem. Perhaps wanting to support that was just +> too ambitious. --[[Joey]] + +>> I propose to restrict to having images be subpages of albums, as +>> described above. -s + +Requiring renaming is awkward for non-technical Windows/Mac users, with both +platforms' defaults being to hide extensions; however, this could be +circumvented by adding some sort of hook in attachment to turn things into +a .albumimage at upload time, and declaring that using git/svn/... without +extensions visible is a "don't do that then" situation :-) + +> Or extend `pagetype` so it can do the necessary matching without +> renaming. Maybe by allowing a subdirectory to be specified along +> with an extension. (Or allow specifying a full pagespec, +> but I hesitate to seriously suggest that.) --[[Joey]] + +>> I think that might be a terrifying idea for another day. If we can +>> mutate the extension during the `attach` upload, that'd be enough; +>> I don't think people who are skilled enough to use git/svn/..., +>> but not skilled enough to tell Explorer to show file extensions, +>> represent a major use case. -s + +Ideally attachment could also be configured to upload into a specified +underlay, so that photos don't have to be in your source-code control +(you might want that, but I don't!). + +> Replying to myself: perhaps best done as an orthogonal extension +> to attach? -s + +> Yet another non-obvious thing this design would need to do is to find +> some way to have each change to memes/badger._albummeta show up as a +> change to memes/badger in `recentchanges`. -s + +Things that would be nice, and are probably possible: + +* make the "Edit page" link on viewers divert to album-specific CGI instead + of just failing or not appearing (probably possible via pagetemplate) + +* some way to deep-link to memes/badger.jpg with a wikilink, without knowing a + priori that it's secretly a JPEG (probably harder than it looks - you'd + have to make a directive for it and it's probably not worth it)