We had actually talked about performing caching in the container skins
that required it. This would have put the responsibility for caching
in the "right" place, but would have produced a lot of code
duplication. The current approach is just the centralization of that
logic.
This issue is an edge case that we hadn't considered, but I think it
can be addressed pretty easily by providing a small amount of
additional information to Component.
On Aug 11, 2009, at 12:14 PM, Niclas Hedhman wrote:
Another option is to not centralize caching in the component
inheritance
hierarchy and instead provide external caching strategy concerns
that the
components can engage.... oops, this is not Qi4j... seriously, I
think that
caching responsibility should not be generic... and there are a
couple of
ways to provide it.
Also, if you have components with real quick siye calculation, you
have just
wasted memory ;-)
-- Niclas
On Aug 11, 2009 10:44 PM, "Greg Brown (JIRA)" <[email protected]> wrote:
Cached preferred size values cause layout problems in BoxPane
-------------------------------------------------------------
Key: PIVOT-226
URL: https://issues.apache.org/jira/browse/PIVOT-226
Project: Pivot
Issue Type: Bug
Affects Versions: 1.3
Reporter: Greg Brown
Assignee: Greg Brown
Priority: Minor
Fix For: 1.3
We currently cache the values of the preferred size calculations for
performance reasons. As a result, when a vertical BoxPane is set to
fill the
available space, the widest component doesn't get scaled up (nor do
any
other components that report the same preferred width).
One possible fix is to call invalidate() on the component in
BoxPane#layout() before asking it for its constrained preferred
height. That
ensures that we get the correct value, and it doesn't impose a
significant
performance penalty most of the time.
However, this may not be the "right" place to put this logic. Since
this is
a side effect of caching logic in Component, the logic for
invalidating the
cache probably also belongs in Component. Ideally, containers such as
BoxPane shouldn't need to know that they must call invalidate() in
order to
clear the cache.
A better solution may be to add a method to Skin that will allow
Component
to ask it how to handle cases like this. The exact nature/name of this
method is TBD. Some ideas:
isFixedAspectRatio():boolean
isVariableAspectRatio():boolean
getPreferredAspectRatio():float (if Float.NaN, aspect ratio is not
fixed)
If any of these return true/non-NaN, Component would know that it
shouldn't
use the cached value.
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