The relayout subtree root concept is intended to handle the case where
a node, when it lays itself out for a second time, changes its opinion
about what dimensions it should be. In such a situation, the parent,
if it based its own opinion about what size _it_ should be on the
child's dimensions, would also need to lay itself out again. Thus,
when this scenario is possible, the child remembers the parent, and
when it would be told to relayout, we actually start the layout with
the parent.
In practice, this chains, and we end up with nodes that point to
ancestors ten or more steps up the tree such that when the inner most
child re-lays-out, the whole app ends up relaying out.
This patch tries to short-circuit this for the case where the
constraints being applied to the child are such that actually, the
child has no choice about its dimensions. In that case, the parent
can't change dimensions when the child re-lays-out.
This makes a huge difference on the stocks demo app. Without this, on
the third rendered frame, there are 72 relayoutSubtreeRoot links, the
deepest chain is 8 deep, and 9 of the chains are only 1 level deep.
With it, there are 63 relayoutSubtreeRoot links, the deepest chain is
only 4 deep, and 38 of the chains are only 1 level deep.
R=eseidel@chromium.org
Review URL: https://codereview.chromium.org/1196553004.
We're now 25% faster as scrolling the infinite list than stocks1.
This CL makes cleans up some code to avoid calling layout on all the rows in
the stocks list. Instead, we only layout a row when it first enters the list.
R=ianh@google.com
Review URL: https://codereview.chromium.org/1195113002.
Some files are moved by this:
Copy framework/node.dart into types/ - preparing for framework/'s decomissioning.
Move app/scheduler.dart into sky/scheduler.dart - "app" doesn't really make sense.
As part of the SkyBinding cleanup, I made the hit-testing less
RenderBox-specific, by having the HitTestEntry.target member be a
HitTestTarget, which is an interface with the handleEvent() function,
which is then implemented by RenderBox. In theory, someone could now
extend hit testing from the RenderBox world into their own tree of
nodes, and take part in all the same dispatch logic automatically.
This involved moving all the hit testing type definitions into a new
sky/hittest.dart file.
Renamed SkyBinding._app to SkyBinding._instance for clarity.
Moved code around in SkyBinding so that related things are together.
Made WidgetSkyBinding use the existing SkyBinding.instance singleton
logic rather than having its own copy.
I also added some stub README.md files that describe dependencies.
R=abarth@chromium.org
Review URL: https://codereview.chromium.org/1187393002.
Make old users of RenderSizedBox use RenderConstrainedBox.
Change the semantics of BoxDecoration.apply* to actually apply the provided constraints to the current constraints, rather than the previous behaviour of merging them neutrally.
R=abarth@chromium.org
Review URL: https://codereview.chromium.org/1189603003.
