[tor-bugs] #31209 [Applications/Tor Browser]: View PDF in Tor browser is fuzzy

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#31209: View PDF in Tor browser is fuzzy
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 Reporter:  null                      |          Owner:  tbb-team
     Type:  defect                    |         Status:  new
 Priority:  Medium                    |      Milestone:
Component:  Applications/Tor Browser  |        Version:
 Severity:  Normal                    |     Resolution:
 Keywords:  ff60-esr                  |  Actual Points:
Parent ID:                            |         Points:
 Reviewer:                            |        Sponsor:
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Comment (by gk):

 Replying to [comment:2 pospeselr]:
 > The tldr for why this happens is that RFP spoofs your monitor's DPI and
 as a result things which render to canvas and take the screen DPI into
 account (google docs, js pdf renderers, etc) will have the wrong value and
 so the contents of the canvas element's backing frame buffer will be
 stretched or squished to the page content's logical size.
 >
 > So for example suppose you have a high DPI screen and a page has a
 canvas element with logical dimensions of 100x100 but the web app would
 normally take DPI into account and request the framebuffer be 200x200 to
 match your monitor's physical dimensions. With RFP enabled, the page now
 thinks the physical dimensions are the same as the logical dimensions and
 request a 100x100 framebuffer, whose contents are now stretched to fit the
 200x200 physical dimensions, resulting in blurriness.

 Are we missing a "Is this a privileged context and thus no RFP"-check here
 somewhere?

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/31209#comment:4>
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