runtime error: index out of range [0] with length 0 about pdfcpu HOT 8 CLOSED

This is the simsun font used，This is a new one, not cropped
ebCert.pdf

This is a new document using Times Roman font，It can be filled correctly, but it does not support Chinese
ebCert.pdf

from pdfcpu.

Did you check if your pdf file is valid as far as pdfcpu is concerned?
pdfcpu val ebCert.pdf

Also I would not add a user font on the fly instead do it separately and ensure it can be loaded prior to using it using the API.

In any case if you can share your file I can take a look and provide a fix.

from pdfcpu.

Hello!
Filling a form using a specific font is still an open issue.
See also #715 and #825

from pdfcpu.

This is fixed with the latest commit!
Your filling with SimSun will work since your input file is already prepared with Textfields expected to be filled with SimSun.
Specifying a fill font when filling remains an open issue.

from pdfcpu.

Just go get the latest commit and it will work.

from pdfcpu.

Just go get the latest commit and it will work.

Thank you for your efforts, but I have another question. When I open the PDF file generated after filling, the Chinese fonts cannot be displayed normally, either not displayed or garbled. When I click on the corresponding form field, the fonts are displayed normally. Is this still because the fonts are not embedded correctly? It may be related to rendering. When I try to click on the form field and do a simple operation, such as pressing the spacebar, then the form field that does not need to be focused can be displayed normally.

from pdfcpu.

Which PDF Viewer are you using.
Try Acrobat Reader.
Please also attach some screen shots.

from pdfcpu.

Please test the following and let me know how that goes.
If this fails, please post the edited ebCert.json so I can reproduce the result:

pdfcpu font install simsun.ttf
pdfcpu form fill ebCert.pdf ebCert.json out.pdf

from pdfcpu.