[Webkit-unassigned] [Bug 21458] Improve image comparison algorithm in ImageDiff

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=21458





------- Comment #3 from pol at apple.com  2008-10-08 18:46 PDT -------
Current behavior:
WebKitTools/Scripts/run-webkit-tests --pixel --threshold 0
LayoutTests/fast/repaint
21.45s total testing time
44 test cases (44%) succeeded
56 test cases (56%) had incorrect layout

New behavior (faster):
WebKitTools/Scripts/run-webkit-tests --pixel --alternate-difference --threshold
0 LayoutTests/fast/repaint
18.60s total testing time
44 test cases (44%) succeeded
56 test cases (56%) had incorrect layout

New behavior taking advantage of more flexible tolerance (ignore differences
less than "threshold" percents):
WebKitTools/Scripts/run-webkit-tests --pixel --alternate-difference --threshold
0.1 LayoutTests/fast/repaint
17.16s total testing time
91 test cases (91%) succeeded
9 test cases (9%) had incorrect layout

In the latest usage mode, we managed to avoid almost all "false negatives"
(tests that failed because of font rendering), although we have a few "false
positives" (tests that have differences not due to font rendering but passed
because they were really small):
fast/repaint/box-shadow-dynamic.html (0.04%)
fast/repaint/overflow-scroll-delete-diffs.html (0.10%)
fast/repaint/selection-gap-overflow-scroll-diffs.html (0.04%)
fast/repaint/table-cell-collapsed-border.html (0.01%)

Suggestions needed for:
- better name than "--alternate-difference" for the new option in the script
- better name than "--alternate" for the new option in the tool
- better phrasing for updated usage of the script


-- 
Configure bugmail: https://bugs.webkit.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.