Bug: Redaction incorrectly hides text outside of redacted area
Redaction hides (but does not remove) text outside of the redacted area in certain cases when:
- A clipping path is set around the content, leaving the outside clipped away
- The clipping path uses the even-odd rule
- The clipping path is set while a non-identity transformation matrix is active
- Before the visible objects are defined the CTM is restored to the identity matrix by concatenating the inverse CTM (rather than restoring the graphics state)
Steps to reproduce:
* Open one of the attached files in Adobe Acrobat Pro DC
* Use the redaction tool to remove the word "Hello"
* A black box where the word "Hello" was, the text is removed.
* The word "Hello" is redacted correctly, but the word "World" disappears. "World" can still be selected and copy&pasted, but it is not visible.
Further investigation shows that the clipping path has been modified such that it no longer encloses the text, which causes it to be clipped off, see pic1.png
Tested with Adobe Acrobat Pro DC version 2018.009.20050 on Windows Server 2008 R2.
Thanks for reporting this issue. The team is looking into this and we will try to fix this soon.
Kasper Brandt commented
Forgot to mention that in minimal2.pdf the word "World" is only partially cut off.