[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 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.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/31209#comment:2>
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