In the attached test case and number 14 on the MathML torture test, the delimiters have too much spacing around them.
Adding bug 99620, since having proper operator spacing will help here. I suspect we will end up doing something similar as Gecko to get accurate ink/logical metrics and do width correction.
It looks like the issue here is very specific to the delimiter. In STIX, the stretchable delimiter is thicker with a very large left and right bearing. For us, this means that when we consider the stretchable delimiter as a possibility for drawing an operator we will always create a large amount of horizontal space for that operator. I think the fix here is to copy Gecko and ignore the stretchable delimiter.
Created attachment 215684 [details] Patch
Created attachment 215688 [details] Adjust the test to use ‖ instead of &DoubleVerticalLine;
Bug 123543 also changes the mo-stretch test so it might makes sense to create Mac baselines when both these patches have landed.
Comment on attachment 215688 [details] Adjust the test to use ‖ instead of &DoubleVerticalLine; Attachment 215688 [details] did not pass mac-wk2-ews (mac-wk2): Output: http://webkit-queues.appspot.com/results/19298017 New failing tests: mathml/presentation/mo-stretch.html
Created attachment 215693 [details] Archive of layout-test-results from webkit-ews-13 for mac-mountainlion-wk2 The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews. Bot: webkit-ews-13 Port: mac-mountainlion-wk2 Platform: Mac OS X 10.8.5
Comment on attachment 215688 [details] Adjust the test to use ‖ instead of &DoubleVerticalLine; Attachment 215688 [details] did not pass mac-ews (mac): Output: http://webkit-queues.appspot.com/results/19358066 New failing tests: mathml/presentation/mo-stretch.html
Created attachment 215711 [details] Archive of layout-test-results from webkit-ews-05 for mac-mountainlion The attached test failures were seen while running run-webkit-tests on the mac-ews. Bot: webkit-ews-05 Port: mac-mountainlion Platform: Mac OS X 10.8.5
Tests fail for Mac because they need a rebaseline.
Martin can you grab the results from the layout-test-results in the attached archives and update your patch again?
Created attachment 215930 [details] Patch with Mac results from archive
Looks like tests are passing now. :)
Comment on attachment 215930 [details] Patch with Mac results from archive r=me
<rdar://problem/15394108>
Committed r158678: <http://trac.webkit.org/changeset/158678>
Re-opened since this is blocked by bug 123820
Created attachment 216503 [details] Uploading patch again to get new Mac results
Comment on attachment 216503 [details] Uploading patch again to get new Mac results Attachment 216503 [details] did not pass mac-wk2-ews (mac-wk2): Output: http://webkit-queues.appspot.com/results/22638963 New failing tests: mathml/presentation/mo-stretch.html
Created attachment 216504 [details] Archive of layout-test-results from webkit-ews-13 for mac-mountainlion-wk2 The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews. Bot: webkit-ews-13 Port: mac-mountainlion-wk2 Platform: Mac OS X 10.8.5
Committed r159007: <http://trac.webkit.org/changeset/159007>