Triiiceratops Image download

Image Download

Download the current IIIF canvas as a raster image, handling canvases painted with more than one image correctly.

Downloads the current canvas (or the current multi-canvas view) as a raster image, correctly handling IIIF canvases painted with more than one image. It renders as a panel with three modes:

  • Composite canvas — every image on the current canvas, composited together at their annotated positions.

  • Single image — one image from the current canvas, with a picker shown when the canvas has more than one.

  • Current view — everything currently laid out together in the viewer (e.g. a two-page spread in paged viewing mode), matching the on-screen layout.

Each mode offers a resolution picker. IIIF level0 image services can only be requested at a fixed list of sizes declared in their info.json, so those are enumerated exactly; other services offer an Original/50%/25% ladder based on native dimensions. Output is always capped to a size browsers can reliably render to a canvas.

Audiovisual Canvases

A canvas whose painting annotations place only non-image content — audio, video, a 3D model — has no raster to export. It is the canvas the viewer itself gives the unsupported presentation to, and this plugin leaves it out silently. That is a contract, not an accident:

  • The single image picker lists only canvases an image can be produced from. On a spread of one page and one video, the video is not offered — the reader never picks it and never meets a resolution list with nothing in it.

  • Current view composites exactly the image canvases in the view, at the shape those canvases make on their own; the video leaves no empty column behind. As everywhere else, the mode is offered only when more than one canvas remains to combine, so that same page-and-video spread offers single image instead.

  • On such a canvas alone, every mode is empty: no images to composite and no resolution ladder to pick from.

  • Nothing is ever substituted for the missing image. A poster thumbnail, a placeholderCanvas, or an accompanyingCanvas describes the media; none of them is the canvas, and exporting one would hand the reader a picture the manifest never said was the content.

A canvas claim makes no difference. A claim is about what is rendered on screen; whether a raster can be produced is decided by the canvas's own painting bodies, so the answer is the same whether or not a media plugin has taken the canvas over.

Setup

pnpm add @triiiceratops/plugin-image-export

ImageDownloadPlugin is exported ready to use with no configuration required. Add it like any plugin — see using plugins.

Examples