Android beta: freehand drawing in PDF slows down, occasionally crashes app

jhimmelreich
edited May 15, 2025
A follow up on this issue (https://forums.zotero.org/discussion/comment/483290/#Comment_483290)

In using the freehand tool annotating a PDF that already has a lot of annotations, the app tends to hang/crash. If there are no annotations, the freehand draw is very slow.
See here: https://streamable.com/dtte0o
Another example: https://streamable.com/u5cd98

This has been a problem on all Zotero versions since January, including Zotero 1.0.0-169

This is on a Daylight computer (https://daylightcomputer.com/product). The drawing works fine in other apps on the device.

let me know if I can help with more information.


[Edit: fixed linkes, added another example]
  • malev
    Same. Too slow to be used.
  • jhimmelreich
    @malev: also on a DC-1?
  • malev
    Boox 10.3
  • jhimmelreich
    ah, so not a DC-1 specific problem...
  • rdiaz02
    edited August 31, 2025
    The slow freehand drawing/annotation is also a problem in the current stable Android app (1.0.0-186) on a Samsung Galaxy Tab S7 FE, using S-Pen and Staedtler Noris digital jumbo. Letters after the first are rendered with considerable delay, and often curves are turned into straight lines, which makes the letters unrecognizable. The only way to avoid the problem is to write very, very slowly (about a letter every second or second and a half).

    This does not happen in other PDF annotation apps. It also does not happen if I edit the PDF using the Zotero Web Library.

    Edit for cross-referencing: I've posted a bug report of the freehand problem, with Debug ID, here: https://forums.zotero.org/discussion/126421/debug-id-d918391774-android-app-freehand-draw-slow-and-wrong-rendering
  • Olib170
    I have the same problem with the stable version 1.0.0-218 on my Onyx Boox Note Air : handwriting notes on the pdf is extremely slow, even when writing slowly, the actually show trace lags one letter behind. On the native Onyx pdf reader the response is immediate, without any delay noticable. This makes handwritten commens on the pdf completely unuseable for me. Which is a pity, because I really like my workflow of synching to-read references and then read and commet and tag them on the tablet. Well done !!!!
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