Degraded performance updating <tspan> due to excessive repaint 
https://bugs.webkit.org/show_bug.cgi?id=43809
Summary Degraded performance updating <tspan> due to excessive repaint
Tony Sung
Reported 2010-08-10 14:40:17 PDT
Open the attached test case, which by default shows 60 lines of text and which the first line of text is updated continuously with a setTimeout(func, 0) call. There're 3 cases, where the DOM structures are all the same but having the first 2, 60, or 200 <tspan> visible. In the test cases all except the first <tspan> is static. Compare the frame rates of the 3 cases with the help of QuartzDebug. The more number of visible <tspan> we have, the slower the frame rate it is, even though we're changing only one of the <tspan> in all 3 cases. Enabling "Flash Screen Updates" in QuartzDebug suggests that the browser is repainting all <tspan> including those which haven't been changed.
Attachments
Primary test case (5.99 KB, application/zip)
2010-08-10 14:42 PDT, Tony Sung 		no flags
Details
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Tony Sung
Comment 1 2010-08-10 14:42:01 PDT
Created attachment 64044 [details] Primary test case
Tim Horton
Comment 2 2011-07-06 11:38:01 PDT
<rdar://problem/8293628>
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