Canvases are not upgraded from Presi 2 when isolated in upgrader

[cubap]

I encountered this when using Vault to load "https://t-pen.org/TPEN/canvas/13250383", a Presi 2 Canvas, as a test for my interface. It landed here:

Error: Resource type is not known
    at Ye (chunk-W3DWL6UZ.js:1:781)
    at e.traverseUnknown (chunk-W3DWL6UZ.js:1:7350)
    at Ut (chunk-HF3WYIOE.js:1:9547)
    at chunk-EIMQCVDV.js:18:43
    at u (chunk-EIMQCVDV.js:162:26)
    at chunk-EIMQCVDV.js:171:20
    at async AnnotoriousAnnotator.processCanvas (line-parser.js:366:24)

The upgrader sees "sc:Canvas" and strips the prefix

parser/src/presentation-2/upgrader.ts

Lines 157 to 165 in dcbb102

	function removePrefix(str: string) {
	for (const prefix of ['sc', 'oa', 'dcterms', 'dctypes', 'iiif']) {
	if (str.startsWith(`${prefix}:`)) {
	return str.slice(prefix.length + 1);
	}
	}
	return str;
	}

At

parser/src/presentation-2/upgrader.ts

Line 167 in dcbb102

const knownTypes = ['Collection', 'Manifest', 'Annotation', 'AnnotationPage', 'Range', 'Service'];

the knownTypes do not include "Canvas" so I am led to believe that a either a Presi 2 Canvas can only be upgraded within the processing of a Manifest or that (because it tends to be forwards-compatible) it is just not handled and has tended to work.

I can put some time against this, but not immediately. If there are any intellects that can shorten the path to success with bits of advice, I'd ratehr contribute back to iiif-helpers than just get it working on my machine.

[stephenwf]

Ah yeah, I think we can add support for that. At the moment it only supports resources that are typically dereferenced.

You may be able to get around it by using:

const p3Canvas = presentation2to3.traverseCanvas(p2canvas);