Not sure. I think it isn’t using ocr but is able to rip video subsystem while it auto-scrolls text in active app’s window.
If an app has no protection on text it displays, SnagIt seems to be able to intercept char codes sent to video subsystem and thus render document contents back into editable text.
When SnagIt is unable to render things into text (presumably, when some protection prevents it from intercepting the char codes, I guess), SnagIt is still able to render video memory into an image file that one can convert later by using external ocr.
Here’s an experiment whose amazing results I can’t seem to comprehend.
1. Initial PDF: uses non-system embedded fonts, RC4 128 bit encryption, strong password, any and all options disallowed except opening and viewing.
2. SnagIt auto-scrols initial PDF and then saves captured image as an “image PDF” (purely image file).
3. The “image PDF” is then opened in Acrobat Pro and is recognized by Acrobat’s built-in OCR.
4. The resulting PDF is found to be identical with the initial PDF. It has editable text, the same formatting, same non-system embedded fonts, BUT is no longer password protected. All options (including copy, print, TTS, etc) appear to be allowed.