pdf.js Mobile: onSelectAnnotations is not triggered

[Dima-Android]

For HTML/EPUB mobile side receives onSelectAnnotations event when annotation is being tapped on with finger or mouse click in the document.
For some reason this event is not sent for PDF. Also the annotation is not getting visibly selected with dotted lines.
The only thing that works is if user were to tap on the annotation in the sidebar's list (sidebar list is implemented on Android side), which triggers Android side to call a JS function to select an annotation with a given ID, which does lead to that annotation being selected with dotted lines.

[mrtcode]

@Dima-Android I can't yet reproduce the issue as I haven't tested on a real Android device, but could you check if #224 potentially fixes the issue or not?

[Dima-Android]

@mrtcode I've tried the #224 but nothing changes. Interesting thing is that any annotation that was just created in the document can be selected! But if I leave the document and return none of the annotations are tapable, except for freedrawing ones.

Also after adding underline, highlight, square annotations one by one, the underline and highlight ones becomes unselectable even without leaving and returning to document

[mrtcode]

Thanks for the extra info, that changes everything.

I think the real issue is the Android annotation rect round-trip, not the pointer event path.

In the new JS reader path, AnnotationConverterV2 parses reader rects as [left, top, right, bottom]:
https://github.com/zotero/zotero-android/blob/7b85cec05c567fcff228c7fddb84acbeaa8c4e26/app/src/main/java/org/zotero/android/sync/AnnotationConverterV2.kt#L110-L147

But CreatePDFAnnotationsDbRequestV2 stores those rects with swapped y values:
https://github.com/zotero/zotero-android/blob/7b85cec05c567fcff228c7fddb84acbeaa8c4e26/app/src/main/java/org/zotero/android/database/requests/CreatePDFAnnotationsDbRequestV2.kt#L49-L52

Then RItem.pdfAnnotation sends them back to the JS reader as [minX, minY, maxX, maxY]:
https://github.com/zotero/zotero-android/blob/7b85cec05c567fcff228c7fddb84acbeaa8c4e26/app/src/main/java/org/zotero/android/database/objects/RItem.kt#L371-L375

This is also the order used when storing rects from sync responses:
https://github.com/zotero/zotero-android/blob/7b85cec05c567fcff228c7fddb84acbeaa8c4e26/app/src/main/java/org/zotero/android/database/requests/StoreItemsDbResponseRequest.kt#L390-L393

So a rect created as [x1, y1, x2, y2] becomes [x1, y2, x2, y1]. The reader hit-test expects y1 <= y <= y2, so persisted highlight/underline/etc. annotations are not tappable:

reader/src/pdf/lib/utilities.js

Lines 91 to 123 in b9b4884

	export function intersectAnnotationWithPoint(selectionPosition, pointPosition) {
	let [x, y] = pointPosition.rects[0];
	if (selectionPosition.nextPageRects && selectionPosition.pageIndex + 1 === pointPosition.pageIndex) {
	for (let i = 0; i < selectionPosition.nextPageRects.length; i++) {
	let [r1, r2] = selectionPosition.nextPageRects.slice(i, i + 2);
	if (!(x > r1[2]
	|| x < r1[0]
	|| y > r1[3]
	|| y < r1[1])) {
	return true;
	}
	if (!r2) {
	continue;
	}
	if (x > r1[0] && x > r2[0]
	&& x < r1[2] && x < r2[2]
	&& y < r1[3] && y > r2[1]
	&& r1[1] - r2[3] < Math.min(r1[3] - r1[1], r2[3] - r2[1])) {
	return true;
	}
	}
	}
	else if (selectionPosition.pageIndex === pointPosition.pageIndex) {
	if (selectionPosition.rects) {
	for (let i = 0; i < selectionPosition.rects.length; i++) {
	let [r1, r2] = selectionPosition.rects.slice(i, i + 2);
	if (!(x > r1[2]
	|| x < r1[0]
	|| y > r1[3]
	|| y < r1[1])) {
	return true;

Minimal fix should be in CreatePDFAnnotationsDbRequestV2: store minY = rect.top and maxY = rect.bottom for the new JS reader path.

Let me know if that fixes the issue.

[Dima-Android]

This did fix the issue! Thank you for thoroughly looking through Android code!

[mrtcode]

Thank you for thoroughly looking through Android code!

No, it's just my coding agent tracking down the issue.