Posts and files

Uploading from a link

…or a link to it on the upload form downloads a file from the web. Give it the file itself, or a work’s page on a site Moekura can read:

Moekura asks the site for the work’s best (original) file and downloads that, and the page, not the file, becomes the post’s source. Any other page whose preview tags (OpenGraph) name an image works the same way. What the site says is used as well:

• The artist: beside the tags box, the tag of the artist whose artist entry lists their profile there; an artist without one gets a link to start it, filled in with their name and profiles.
• Tags: the Related tags panel’s From Pixiv (or the site’s name) group lists the site’s tags as this site’s: tags whose wiki pages list one as an other name, and tags named like one or its English translation.
• Commentary: the work’s title and description become the post’s artist’s commentary, unless you wrote one in the form.

The same happens with a file and a Source that is such a page, and for uploads through the APIs. When a site can’t be reached or has changed, the link is downloaded as it is, without extras.

Ugoira

Pixiv’s animations (ugoira) are a zip of JPEG or PNG frames. Upload the zip like any file, or link to the work on Pixiv, which downloads the zip and keeps each frame’s time in it. A zip you upload yourself can say how long each frame shows in an animation.json beside the frames, in Pixiv’s form:

{"frames": [{"file": "000000.jpg", "delay": 100}, {"file": "000001.jpg", "delay": 80}]}

Without one, every frame shows for a tenth of a second. Once it’s processed, the post plays the animation as a video made from its frames (a WebM), and Download the frames gets the zip. filetype:ugoira (or filetype:zip) finds them, and the Danbooru API gives the video as the post’s large file.

Replacing a post’s file

Staff with Replace posts’ files (moderators and admins, by default) can swap a post’s file for a better one: a higher resolution, an uncropped version, a fixed scan. Replace the file, below the picture, takes a file or a link, a reason, and whether to move and resize the notes to the new size (on by default). The post keeps its id, tags, comments, notes, pools and favourites; its thumbnails and metadata are made again from the new file, and the file can’t be one another post already has.

Replacements, under the picture, lists a post’s replacements: when, by whom and why, and the file before (still downloadable, until the post is purged) and after. Replacements are recorded in the moderation log, and Danbooru clients can read them at /post_replacements.json.

Square thumbnails

Square thumbnails, under Settings, makes grids show every post as a square: the part of the picture libvips finds most interesting, which is usually the face or the subject rather than the middle. Staff who review posts can choose the square themselves under Square thumbnail on a post’s page: give its left and top edges and its side in the picture’s pixels, or with scripts, click the picture where it should be centred. Back to automatic undoes the choice. Squares are made when a file is processed; for older posts, moekura admin regenerate-media --all makes them, and until then grids show their usual thumbnails.

File metadata

When a file is processed, its metadata is read and kept: the image’s make-up (colour components, bit depth, colour space, frames), EXIF (the camera, the software, comments), XMP (title, creator tool, keywords), PNG text chunks, and for videos the container and each stream (codec, frame rate, bit rate, audio channels). Metadata, under the picture on a post’s page, lists it by group, with names like exiftool’s: EXIF:Make, PNG:Software, File:ColorComponents.

Where a photo was taken and whose camera took it stay private: GPS and other location fields, serial numbers and owners’ names are never read into it. The original file itself is kept as it was uploaded, so Download original still has whatever it contained.

Posts uploaded before metadata was read get it when their files are processed again: moekura admin regenerate-media --all.