[Bug 744808] Re: image sprite is packed very asymmetrically and triggers poor rendering performance in firefox3 and missing icons in firefox4

[Robert Collins]

** Description changed:

  Ubuntu 10.10.  Viewing a bug, e.g.
  https://bugs.launchpad.net/ubuntu/+source/anacron/+bug/606491, is very
  slow in Firefox.  It's observable in many ways, e.g. scrolling is
  extremely sluggish, especially when the top of the page is neared.  Even
  having the page redraw on an X Expose event takes seconds, e.g. when
  Firefox is unminimised with the bug tab selected.  The CPU fan audibly
  steps.  The X server continues to process other clients though during
  Firefox's hiatus.
  
  If I adblock just
  https://bugs.launchpad.net/+icing/rev12670/icon-sprites then fast snappy
  speed is restored.  This is a PNG although the HTTP server is specifying
  a text/plain content-type.
  
-     $ HEAD https://bugs.launchpad.net/+icing/rev12670/icon-sprites | grep Content-Type
-     Content-Type: text/plain
-     $ wget -qO- https://bugs.launchpad.net/+icing/rev12670/icon-sprites | file -
-     /dev/stdin: PNG image, 64 x 20553, 8-bit/color RGBA, non-interlaced
+     $ HEAD https://bugs.launchpad.net/+icing/rev12670/icon-sprites | grep Content-Type
+     Content-Type: text/plain
+     $ wget -qO- https://bugs.launchpad.net/+icing/rev12670/icon-sprites | file -
+     /dev/stdin: PNG image, 64 x 20553, 8-bit/color RGBA, non-interlaced
  
  It is of huge vertical size.  A friend reports Webkit also having issues
  with the Bug View page using it, but not Opera.  Perhaps Firefox and
  Webkit hand the huge image onto the X server but Opera cuts out the
  sprites itself and hands many small images on.  I'm using Nvidia
  graphics hardware and did find this comment by an AaronP, an Nvidia
  employee.
  
-     http://www.nvnews.net/vbulletin/showthread.php?t=152295#7
-     Re: launchpad.net bug views excruciatingly slow
+     http://www.nvnews.net/vbulletin/showthread.php?t=152295#7
+     Re: launchpad.net bug views excruciatingly slow
  
-     Thanks for reporting this.  I took a look today, and it appears that
-     Firefox is using an enormous pixmap that exceeds the GPU's maximum
-     rendering dimensions, causing software fallbacks.  While we will
-     attempt to make it as fast as possible, performance would be greatly
-     improved if Firefox would render using surfaces that fit within the
-     maximum renderable dimensions.
+     Thanks for reporting this.  I took a look today, and it appears that
+     Firefox is using an enormous pixmap that exceeds the GPU's maximum
+     rendering dimensions, causing software fallbacks.  While we will
+     attempt to make it as fast as possible, performance would be greatly
+     improved if Firefox would render using surfaces that fit within the
+     maximum renderable dimensions.
  
  A brief look at .../rev12670/icon-sprites didn't show up why it's packed
  so poorly giving such a large height.  The simplest solution may be to
  pack the sprites more tightly resulting in a dense squarish image.  I
  agree with AaronP that perhaps Firefox could cope better but it seems
  poor for Launchpad to dish up such a sprite collection.
  
  As it stands, viewing bugs on Launchpad is very frustrating.  Every
  expose means seconds delay.
+ 
+ See also bug 605567

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https://bugs.launchpad.net/bugs/744808

Title:
  image sprite is packed very asymmetrically and triggers poor rendering
  performance in firefox3 and missing icons in firefox4

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