Bug 17179 – [wx] Use PlatformWheelEvent for handling scroll wheel events

• Status: RESOLVED
• Resolution: FIXED
• Component: WebKit wx

[Kevin Ollivier]

We currently catch and handle scroll wheel events directly, but this doesn't allow the event to go through WebCore. Instead, remove our current handler and fix ScrollView so that it properly handles the PlatformWheelEvent.

[Kevin Ollivier]

Created attachment 18923 [details]
Correctly handle PlatformWheelEvent in wx port

[Darin Adler]

Comment on attachment 18923 [details]
Correctly handle PlatformWheelEvent in wx port

Looks fine, r=me.

+IntSize ScrollView::maximumScroll() const
+{
+    IntSize delta = (IntSize(contentsWidth(), contentsHeight()) - IntSize(visibleWidth(), visibleHeight())) - scrollOffset();
+    delta.clampNegativeToZero();
+    return delta;
+}

Is there a guarantee that this can't overflow?

[Kevin Ollivier]

Created attachment 18951 [details]
Updated patch with ASSERTS added to ensure widths and heights are valid

So long as all the values are positive, there should not be any issues with overflows, but you're right that we don't guarantee anywhere that the values are positive. So I've added asserts to guard against negative x, y, width or height values. I wasn't sure if it was okay to land this without the extra review, so I've gone ahead and replaced the patch.

[Darin Adler]

Comment on attachment 18951 [details]
Updated patch with ASSERTS added to ensure widths and heights are valid

r=me

[Kevin Ollivier]

Landed in r30060. Thanks!