The reason why it is already (partially) displayed correctly in older Poppler versions (on Ubuntu systems) is due to an early patch for Ubuntu, fixing the display of the selection for the GlyphLessFont used specifically in tesseract.
#Invisible text iphone copy and paste pdf#
In both versions the selection in pdf files created with tesseract is displayed transparently, but not in the example from my question where I use text rendering mode 3. Previously, any selection was not rendered transparently, even in files created by tesseract.įor the examples in my question I used Ubuntu 19.10 with Poppler 0.80.0 and currently I use Ubuntu 20.04 with Poppler 0.86.1. TheĬhange in Poppler he mentioned, with which any selection of text in text rendering mode 3 is displayed transparently, is included in version 20.09.0. Great thanks to Nelson for his enlightening informations in his answer!Īs Nelson explains, uses Evince the Poppler library to display pdf files.
Now you see me\invisible, now you don't\endinvisible. How can I create text like tesseract that is invisible, searchable, selectable and has that special highlighting (transparent, without text appearing (in Evince)), so you can see an image behind it even when the text is selected? Example \documentclass\allowbreak% It seems that the texts in both files are marked as different content types (or something similar), so they are highlighted differently. When selected, the text becomes visible in the highlighting and the highlighting is not transparent as in the file generated by tesseract. When I try to create something like this by hand in latex, for example with the transparent package or text rendering mode 3 (see code below), I get invisible text, but the highlighting appears different (in Evince). In Evince the highlighting for this type of text is transparent. The selected text does not appear (only its highlighting). You only see the image and the highlighting of the text. When you select such text in an OCR generated PDF file it looks (in Evince) like this. You can't see the text, but you can select, search and copy it. When you process an image with an OCR tool like tesseract, you will get a PDF file with that image and the text invisible on top.
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