[tor-bugs] #14429 [Tor Browser]: Automated rounding of content window dimensions

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#14429: Automated rounding of content window dimensions
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     Reporter:           |      Owner:  arthuredelstein
  arthuredelstein        |     Status:  needs_revision
         Type:  defect   |  Milestone:
     Priority:  normal   |    Version:
    Component:  Tor      |   Keywords:  tbb-fingerprinting-resolution, tbb-
  Browser                |  torbutton
   Resolution:           |  Parent ID:
Actual Points:           |
       Points:           |
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Comment (by arthuredelstein):

 Here's a new patch for improving the quantizing behavior:

 https://github.com/arthuredelstein/torbutton/commits/da4f7262ee4794a9aa2e751256fda56dd920f7f8

 If anyone would like to test this, you can download the torbutton XPI
 here:
 https://people.torproject.org/~arthuredelstein/downloads/torbutton-1.9.1.0.xpi
 Signed by me:
 https://people.torproject.org/~arthuredelstein/downloads/torbutton-1.9.1.0.xpi.asc

 The sha256sum of the XPI is:
 `f2c1a7a3606538ecaa77397d98bc27a42ff331dbd86c917f1762c20c53d39f74`

 To test it, after verifying, open the torbutton XPI in Tor Browser and
 restart. (You'll need to make sure that the
 `extensions.torbutton.resize_windows` pref is set to `true`.)

 The main changes are:
 * Windows are now being quantized to 100x100 because I found that interval
 to be substantially less annoying than 200x100. Question: can we afford
 that 1 bit of extra entropy?
 * Non-maximized windows stay at 100% zoom and "shrink" to the nearest
 multiple of 100x100, so that no margins are visible.
 * Shrinking now only happens after the user actively resizes the window.
 This change in policy gets rid of the problem where pressing "ALT" to show
 the menu bar, or zooming, causing an additional window shrink.
 * Maximized windows don't shrink (because the user intends to fill the
 screen), but the content window is zoomed to minimize the margin at the
 bottom of the window. Margins remain at left and right. I took this
 approach because most pages wrap their text horizontally and scroll
 downwards.
 * The contents of "docked" windows (which fill the screen vertically but
 not horizontally) are zoomed to fill the available height to minimize the
 margin at the bottom of the window (similar to maximized windows).
 * On systems with tiling window managers, the window is never resized, but
 the contents are zoomed to best fit the tile aspect ratio and minimize
 margins.
 * In fullscreen mode, the contents are shaped and zoomed to best fit the
 screen aspect ratio and minimize margins.
 * The background "multiple resizing attempts" on linux have been removed,
 because these caused many problems. Instead, in the (hopefully) unusual
 case where a resize may have failed, the window waits for a mouseover or
 keypress to definitively shrink the margins.
 * Windows "DPI" settings are now accounted for.
 * Window zoom is reset whenever the user browses to a new domain.
 * The "resize new window" code in torbutton.js has been modified slightly
 so that the "content-sizer.js" code doesn't interfere with it.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/14429#comment:64>
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