Bug 19296 – Regression: SVG mousedown events not generated when clicking on map polygons

• Component: SVG
• Status: RESOLVED INVALID

[Glenn Brauen]

The above URL contains an interactive SVG map and associated text panels.  If you move the cursor over a map area and left click, the text panel to the right should be updated with information specific to the country clicked.

Problem: All builds later than and including r29955 (Feb 4, 2008) do not generate the mousedown events when the mouse is clicked over these map areas.  The mouseup is seen but not the mousedown.  All build earlier than and including r29946 do generate the mousedown events.

My guess is that changeset 29551 (http://trac.webkit.org/changeset/29951 - broad changes in the use of "The notifyAttributeChange() sledgehammer") is where this issue was introduced.

I have not been able to hand build a simple test case that shows the same problem so I am opening this problem report on the hopes that someone familiar with the above changeset may be able to understand why the mousedown events are no longer generated in the above URL.

This works properly in Firefox 2.

Thanks,
Glenn

[Eric Seidel (no email)]

We would really benefit from a simpler reduction here.

[Glenn Brauen]

(In reply to comment #1)
> We would really benefit from a simpler reduction here.

I have created a testcase and loaded it to a local development machine.  The URL has been updated to point to this case.  The map has been simplified so it only contains a single polygon.  I hope this makes the case easier for you to work with.

Steps: 
1) Load the page (http://devel0.gcrc.carleton.ca/webkit_topicActivationTestcase/topicActivationTestcase.xml.html).  Note the right-hand panel contains text beginning with "Main Topic".

2) Click on the displayed polygon in the left-hand panel.

When working, the text panel should be updated and should now contain text beginning "Subtopic".  Clicking either the polygon or the subtopic hyperlink displayed in the right-hand panel when the main topic is displayed should cause the subtopic to be displayed.  With recent webkit nightlies, the hyperlink works but not clicking on the polygon.  As stated in the original report, we do  not see the mousedown events.

Retested with the latest webkit nightly and the boundary cases:
- r29946: works properly
- r29955: fails
- r35138 (latest): fails

- Firefox 2: works properly.

Sorry for the delay in responding.

Cheers,
Glenn

[Eric Seidel (no email)]

Unfortunately what you've posted is not really "simple".  :( It's a multi-frame HTML document which includes some SVG document and dynamically adds the polygon in question.  I'm not even sure what the polygon is called?

It's hard for us to figure out if this is our code or yours when we have to work through several hundred kilo bytes of code. :(  I'm interested in working on this bug, but I will likely need additional help reducing this to a smaller test case.

[Eric Seidel (no email)]

The SVG is also not self-contained.  It depends on scripts provided by the HTML document.  In order for us to understand what's going on here, the first thing we'd do is to try and make a single stand-alone document which reproduced the problem, and then we'd slowly make that document smaller and smaller until it was only a few lines long.  That's generally how we attack most web mis-renderings.

[Nikolas Zimmermann]

I'm closing this bug, unless Glenn can still provide the testcases.