When saving a CALC file, an arbitrary part of an arbitrary sheet is taken as thumbnail image. This is extremely annoying for templates, which should be easy to identify. As a workaround, we now change the the thumbnail.png image in the zipped ots file after modifying the template. At a minimum it should be deterministic, which area is taken for the thumbnail. But to make the thumbnails useful, there should be an easy way to set a predefined image as thumbnail or to at least an option to keep the current thumbnail picture.
Hi Fritz, Could you please share a sample file for testing?
Created attachment 181827 [details] Spreadsheet with pictures, page 2 used for the thumbnail Here, the sheet (2) with the latest picture added is used. This is working sometimes, but not always.
Created attachment 181828 [details] Spreadsheet with pictures, new sheet added as first sheet Now the new first sheet is used to generate the thumbnail. But it is neither always the case, that the latest edit determines the page used, nor is is clear, which part of a page is used for the thumbnail.
[Automated Action] NeedInfo-To-Unconfirmed
Created attachment 181850 [details] Screenshot of Start Center with thumbnails (In reply to Fritz R. Paul from comment #2) > Created attachment 181827 [details] > Here, the sheet (2) with the latest picture added is used. This is working > sometimes, but not always. For me Slide 1 was used as thumbnail here after I opened the file (did not edit anything nor saved anything) (In reply to Fritz R. Paul from comment #3) > Created attachment 181828 [details] > Now the new first sheet is used to generate the thumbnail. But it is neither > always the case, that the latest edit determines the page used, nor is is > clear, which part of a page is used for the thumbnail. Here LO used slide 3 as the thumbnail. See attached image with the screenshot of my start center. Indeed this seems a bit unstable and unpredictable from the user's perspective.
I could not find any official documentation about thumbnail generation, but it seems that the last save determines the thumbnail. https://ask.libreoffice.org/t/calc-desktop-icon-displays-a-miniature-version-of-one-of-the-sheets-in-the-document/60459/3 Need to look into this a bit further.
I came up with reproducible steps so that Sheet 2 ends up being the thumbnail for no apparent reason: 1) Create a new Calc document with 2 sheets 2) Edit Sheet 1 3) Now edit Sheet 2 4) Save and close the document 5) Go to the start center and notice the thumbnail; It'll use Sheet 1 as the thumbnail 6) Now open the file from the start center 7) Edit Sheet 2 and save; Close the document 8) Go to the start center and notice the thumbnail; It'll use Sheet 2 now as the thumbnail (why??) In the first version of the document Sheet 1 was used after editing and saving Sheet 2. Then in the second attempt I edited Sheet 2 and now Sheet 2 becomes the thumbnail. I do not see a logic in this. I'm setting this to NEW because improvements can be made.