Last week in WebKit:
improved calc() support and FlexBox wrapping

715 changes landed in WebKit’s repository last week, bringing highlights such as improved calc() support and wrapping behavior for the new Flexible Box Layout implementation.

As for Web Inspector, not all percentage signs will attempt to be substituted anymore, the Network Panel will show application/json data again and inactive properties will be checked for vendor prefixes. The button allowing you to toggle the Timeline Panel’s overview mode has been moved and the Inspector has gotten more efficient at inspecting arrays containing large (~a million) elements.

WebKit’s implementation of the CSS calc() function is now able to mix absolute values and percentages for lengths. The Flexible Box Module’s flex-wrap property has been taught about the “wrap” and “reverse-wrap” values, and margins won’t be double counted anymore when baseline alignment is used. Finally, multiple values are now accepted for the unicode-bidi CSS property, as an union with bidi-override and isolate is now valid.

Three changes to the JavaScript Speech API have landed, namely the SpeechRecognition(Alternative, Error, Result, ResultList) and the SpeechGrammar(List) interfaces. Support for SVG’s transform-origin attribute has been implemented, getComputedStyle’s result for the height property no longer takes intrinsic paddings into account and rendering of the <shadow> element is now implemented, defining the insertion point for older shadow sub-trees.

Other changes which occurred last week:

  • Initial code paths have been added in preparation for rendering subtitle cues of the <track> element.
  • CSS Property getters have been sped up by 35% for JavaScriptCore, and setters by about 8%.
  • Fierce performance improvements (up to 10.9 times!) for several properties in v8 bindings.
  • All of JavaScriptCore’s forwarding headers have been removed in favor of accessing WTF directly.
  • The compositor will now also be enabled following animated CSS Filters.
  • A WebGL extension enabling anisotropic filters has been added to WebKit.
  • Support for vw/vh/vmin has been rolled out again due to performance issues.
  • Jessie Berlin now is a WebKit Reviewer, congratulations!