Use cups-pdf with cups-filters to print doesn't have effect

[hustliyilin]

Describe the bug

When I use the cups-pdf in Linux alone to print, I can see that the printed PDF content is normal. However, when I use cups-pdf with cups-filters，the printed content is empty. I don't know what's causing it and how to locate and fix it. Could you give me some advice ? Thanks a lot.

To Reproduce
Steps to reproduce the behavior:

1. install the cups-filters and cups-pdf
2. configure the cups-pdf and add the cups-filter to the cups-pdf's ppd configure file

lpinfo -m | grep -i pdf
cat /usr/share/cups/model/CUPS-PDF_noopt.ppd | grep filter
lpadmin -p cups-pdf -v cups-pdf:/ -m CUPS-PDF_noopt.ppd -E
lpstat -p -d

3. restart the cups by typing sudo systemctl restart cups
   

4. use the cups-pdf with cups-filters to print the test.txt by typing lp -d cups-pdf ./test.txt
   

5. view the printed file. However, the content of the out file is empty like this:
   

Expected behavior

I hope to correctly configure cups-filter to print the correct content with cups-pdf. In addition, in addition to texttopdf, I have also configured other filters, but all the printed pages are blank，I don't know how to fix it.

System Information:

• OS: fedora 40
• Version: 1.20.0