>
> Turns out I was wrong and JS LayoutBase is not listening for
> widthChanged/heightChanged/sizeChanged. That was SWF-only code I saw
> earlier. IMO, that's the first thing to change by overriding
> handleChildrenAdded in BoxLayout and other MX Layouts. I don't think Basic
> layouts need to watch children for size changes.
Yeah, I mentioned that earlier. Not only was it swf-only, it was only prior
to 'sawInitCompleted' (or whatever the exact name for that flag is, going
from memory).
For the 'handleChildrenAdded' thing it also needs to cover
'handleChildrenRemoved'. Doing things this way would mean adding the 3
size-related listeners on 'add' child and then removing them on 'remove'
child. But I still think that could be avoidable.
Why? Because the children are already listening to these events for
their own layouts. Their own layouts respond to their size changes. So the
question is : when does the parent need to know about the child's size
change: is it before it does it's own layout, or after (and could that
requirement be different for some 'parent' layouts)? The child's own layout
process can inform the parent in either case via beforeLayout (where the
parent could even signal to the child not to continue its own layout, in
which case presumably the parent will simply 'take over') or afterLayout(),
which could trigger a re-flow downwards from the parent - I definitely did
not do all this with the 'workaround' I already added, but maybe there is
something to this approach? On the other hand, if as you suggest, the
parent layouts are also adding their own listeners to each child, then
assuming the execution order of the size change listeners on the children
will be deterministic in terms of when the parent layout runs its listener
versus when the child's own layout runs its listener, it seems to me that
adding individual listeners to each of the children could be doubling up on
something that is already possible without doing that (just by thinking
about it in a different way : 'the children layouts are already listening
to those events, and it is possible for them to talk to their parent
layouts').
If all the MXRoyale layouts were doing something like the 'measure if
needed' before the layout, then maybe it could actually mimic the 2 passes
of the Flex approach, using beforeLayout() and afterLayout() to advise the
parent layouts... just pondering this, not at all sure yet.
Also UIComponent's setActualSize() should set the noEvent flag on
> setWidthAndHeight.
I assume that could work if the layout flow is always from the root of the
display tree downwards, same as Flex. But if it is signaling up to let
parents know that a child's own layout caused some change that should be
interesting to the parent, I am not so sure how that would work.
The reason I'm suggesting these changes is because I think that's closer to
> what Flex does. I don't think Flex has logic like
> sizeChangedBeforeLayout/sizeChangedDuringLayout logic.
Yeah I get that. But unless we actually do the 'measure from bottom-up'.
'layout from top-down' flow as Flex, I think we might be stuck with some
sort of workarounds that are not the same as Flex in any case because we
are already not 'close' enough to how Flex does things (I really hope I am
wrong, definitely keen to see your solution).
On Sun, Jun 7, 2020 at 7:23 PM Alex Harui <aha...@adobe.com.invalid> wrote:
> Easy thing first: The bubbling of layoutNeeded from Image is a hack and
> should go away someday.
>
> Turns out I was wrong and JS LayoutBase is not listening for
> widthChanged/heightChanged/sizeChanged. That was SWF-only code I saw
> earlier. IMO, that's the first thing to change by overriding
> handleChildrenAdded in BoxLayout and other MX Layouts. I don't think Basic
> layouts need to watch children for size changes.
>
> Also UIComponent's setActualSize() should set the noEvent flag on
> setWidthAndHeight.
>
> The reason I'm suggesting these changes is because I think that's closer
> to what Flex does. I don't think Flex has logic like
> sizeChangedBeforeLayout/sizeChangedDuringLayout logic.
>
> For some reason, ApplicationLayout is not getting the
> handleChildrenAdded. I will work on it more tomorrow.
>
> HTH,
> -Alex
>
> On 6/6/20, 12:16 AM, "Greg Dove" <greg.d...@gmail.com> wrote:
>
> Long day... I stepped away from the keyboard and thought I had finished
> that when I returned.
> But this: ' although I know it's not a ' needs ''one:one mapping for
> features/behavior" on the end (or something like that!)
>
>
> On Sat, Jun 6, 2020 at 7:13 PM Greg Dove <greg.d...@gmail.com> wrote:
>
> >
> > Yeah, that is the sort of thinking that I was trying to make work
> with
> > what is there already (and yes it does seem like maybe something
> else is
> > missing). Apart from simple size changes, it is the change on
> measuredSize
> > after layout has happened in the child that I think some parents
> *might* be
> > interested in when their children are containers with percent
> dimensions
> > ('flexible' children I think is how they are described in some Flex
> code -
> > this sort of makes me think of css Flexbox a bit when I look at what
> the
> > BoxLayout stuff is doing, although I know it's not a ).
> > But I am probably only scratching the surface here, you have the
> > experience with this stuff.
> > In terms of plumbing, one thing I pondered about would be whether
> MXRoyale
> > layouts could form their own tree where they connect/detach directly
> to
> > eachother as part of addChild/removeChild so that it is almost like
> a tree
> > in parallel with the display tree.
> > Maybe that could be a structure where they talk to each other
> directly up
> > and down the tree with measurement and layout order somehow
> optimized. I
> > think it still would not be as efficient as using the 'temporal
> buffer' of
> > the Flex life cycle, with enterFrame or with 'requestAnimationFrame'
> but
> > maybe it could be a little better... not sure, was just a thought
> and I
> > know it seems like a radical change, so maybe that alone rules it
> out.
> >
> > I was going to drop another zip into the github issue. It occurred
> to me
> > that it might be easier for you to test if I just put the changed
> files
> > into the test app fileset as a monkey patch. That way you can mess
> with
> > them locally more easily if you want to make quick changes and
> retest,
> > without recompiling MXRoyale. (I was doing this a bit with
> GridItem/GridRow
> > today in the app I am working on, where I have the monkey patch
> approach
> > and it's quite a bit faster when testing changes).
> >
> > A little aside: one other thing I think I noticed today... I think mx
> > Image has a 'layoutNeeded' dispatch on image load. That makes sense.
> But I
> > think I saw that it is a bubbling event. Is that correct? Would this
> call
> > layoutNeeded all the way up to SystemManager for a deeply nested
> Image (I
> > did not check if it does yet)?
> >
> > Thanks again for looking at this. If I can help by creating more test
> > cases or looking into anything specific in more detail, let me know.
> > Greg
> >
> >
> >
> >
> >
> >
> >
> > On Sat, Jun 6, 2020 at 6:30 PM Alex Harui <aha...@adobe.com.invalid>
> > wrote:
> >
> >> I hope to have time tomorrow.
> >>
> >> Looking quickly at the things you've tried to fix the problem, it
> occurs
> >> to me that the piece that is probably missing in MXRoyale is the
> >> propagation of something like invalidateSize() instead of just
> >> "layoutNeeded". My thinking is that in the general case the child
> can't
> >> really know that because something about the child changed that the
> parent
> >> needs to run a new layout and especially the parent of that parent.
> >>
> >> So some new plumbing may be needed where, when a component changes
> in a
> >> way that its measured or explicit size had changed (as opposed to
> the size
> >> change from the parent laying out the child), that some sort of
> >> layoutMightBeNeeded is sent to the parent which then uses its
> measurement
> >> code and explicit sizes to determine whether its size has changed
> and
> >> propagates a layoutMightBeNeeded to its parent. But if it decides
> its size
> >> has not changed, it would then run layout which should start the
> parents
> >> laying out children.
> >>
> >> We'll see if the test case points in that direction.
> >>
> >> HTH,
> >> -Alex
> >>
> >> On 6/5/20, 3:05 AM, "Greg Dove" <greg.d...@gmail.com> wrote:
> >>
> >> Hi Alex, thanks for the detailed explanation and offer to take a
> >> look, for
> >> now some quick replies inline.... please add questions in the
> github
> >> issue
> >> if you want more details about anything I did so far.
> >> thanks
> >> Greg
> >>
> >> On Fri, Jun 5, 2020 at 6:50 PM Alex Harui
> <aha...@adobe.com.invalid>
> >> wrote:
> >>
> >> > Greg,
> >> >
> >> > I think this thread got forked somehow. If you have a simple
> test
> >> case I
> >> > can try to look at it this weekend.
> >> >
> >> > Thanks. I added issue #849 [1] which should give you
> something to
> >> look at.
> >> I suggest you open the Flex build in a browser and then compare
> >> things to
> >> it in Royale. There are 2 royale builds as well with the same
> code in
> >> the
> >> other 2 zips. One without the modifications to MXRoyale and one
> with.
> >> The
> >> 'one with' zip also has the modified MXRoyale files, so you
> should be
> >> able
> >> to drop them in and overwrite in your local MXRoyale and build
> to
> >> test/review/change what I did. I'm the first to admit that I do
> think
> >> it
> >> doesn't feel right. But so far at least it does make a bunch of
> code
> >> work
> >> in one app with a lot of deeply nested layouts that was not
> working
> >> before.
> >> It certainly does not make everything work. But it helps quite
> a bit.
> >> Certainly appreciate any review/consideration. I am really keen
> to
> >> collaborate on a solution that makes sense for most here.
> >>
> >> I don't doubt that the changes you propose work for you, but
> they
> >> make me
> >> > nervous although I'm not the best at reading code and
> understanding
> >> what it
> >> > does. Here's a brain dump on layout in case it helps.
> >> >
> >> > So far they work better 'for me' I agree. But I think you
> probably
> >> know me
> >> enough by now to know that if I am confident that I have a
> >> contribution
> >> that is objectively good (passes unit tests compared with swf
> is my
> >> normal
> >> benchmark) then I will add it. Part of the reason I started this
> >> discussion
> >> is because I feel a bit the same way here. I am still learning
> this
> >> stuff
> >> and figuring things out, so I am not pushing it because I don't
> want
> >> to
> >> inflict anything that is not an objective improvement on others.
> >>
> >> In terms of describing it, the main thing I think, is that the
> view
> >> checks
> >> when layout happens if there was a size change since last time
> layout
> >> ran,
> >> or if there was a change in size during the current run. Then
> there
> >> is some
> >> somewhat awkward checking to see if the parent might be
> interested in
> >> this
> >> because there is some 'sizedToContent' aspect to it (which
> includes a
> >> percentage variation on that check). If we think it is
> relevant, then
> >> request the parent to layout. Is this likely to do it sometimes
> when
> >> it is
> >> not needed, I suspect so. But so far it has not caused any
> problems
> >> in the
> >> codebase I am working with.
> >>
> >> I'm also working on the Grid related stuff, but you could
> probably
> >> just
> >> ignore that for now and focus only on the BoxLayout stuff.
> >>
> >> In Flex, parents always size their children. The children
> probably
> >> > shouldn't override that size or if they do they have to be
> careful
> >> that it
> >> > doesn't trigger the another layout in the parent in a way
> that you
> >> run
> >> > layout forever (a "layout loop"). In Flex, because of the
> >> LayoutManager
> >> > running on frame events, that generally doesn't freeze the UI
> and I
> >> have
> >> > seen situations where the LayoutManager never goes idle even
> though
> >> the app
> >> > appears to be running fine. There is also the case where the
> first
> >> layout
> >> > pass results in scrollbars which causes children to adjust and
> >> results in
> >> > the removal of scrollbars and that loops forever with the
> scrollbars
> >> > blinking on and off. In Royale, there is a greater chance of
> >> hanging.
> >> >
> >> > Also in Flex, with the LayoutManager, EVERY widget added
> itself to
> >> the
> >> > LayoutManager ensuring validation in a particular order,
> enforcing
> >> the
> >> > "parents size children" rule.
> >> >
> >> > In Royale, I tried to go without a LayoutManager because we
> started
> >> out
> >> > targeting IE8 and I wasn’t sure if there were some things
> that were
> >> > exceptions to requestAnimationFrame (like setting text or
> sizing
> >> images).
> >> > To this day, I'm concerned that it will create an poor
> debugging
> >> experience
> >> > because I think when you hit breakpoints the screen updates.
> All
> >> of those
> >> > things need testing before we try a LayoutManager based on
> >> > requestAnimationFrame. And then, as I think you mentioned,
> we have
> >> to be
> >> > concerned about how much code is going to run if we start
> running
> >> all of
> >> > the validation methods.
> >> >
> >> > On the other hand, I think Royale runs layout too often still
> >> because two
> >> > property changes can trigger two layout passes. I looked at
> >> BoxLayout
> >> > which extends LayoutBase which does already watch for
> >> > widthChanged/heightChanged/sizeChanged so whatever is the root
> >> cause of
> >> > your problem may not be triggering the layout pass you want,
> >> although the
> >> > code paths in LayoutBase.childResizeHandler are there to
> prevent
> >> layout
> >> > loops.
> >> >
> >> > Usually, in Flex, a component didn't change its size in
> response to
> >> user
> >> > interaction or data loading, it changed its measured size and
> called
> >> > invalidateSize on itself and its parent. The LayoutManager
> measured
> >> > children before parents, then layed out parents before
> children.
> >> >
> >> > Yeah, that's the vague notion I had, your explanation has
> helped
> >> cement my
> >> understanding.
> >>
> >>
> >> > In Royale, there is little to no measurement subsystem.
> That's
> >> because we
> >> > rely on the browser to "immediately" measure by setting
> >> > offsetWidth/offsetHeight saving us the impossible task of
> writing
> >> code to
> >> > guess at how the browser measures. For PAYG reasons in Basic,
> >> there is no
> >> > code looking for changes that should trigger a layout other
> than
> >> possibly
> >> > child size changes. Everything else is supposed to use
> >> > LayoutChangeNotifier to wire the one event that signals a
> change to
> >> the
> >> > container/layout that cares.
> >>
> >> In MXRoyale, there are complex components that can't rely on
> >> > offsetWidth/Height since MXRoyale cannot rely on browser
> layout
> >> because of
> >> > things like overriding the meaning of width=100%. MXRoyale
> has
> >> measure()
> >> > methods from Flex, but they don't always get run because
> there is no
> >> > LayoutManager measuring the children before the parents and
> existing
> >> > measure() methods expect the children to have been measured.
> It
> >> might be
> >> > that is the root cause here. That some or all
> invalidateSize()
> >> calls need
> >> > to call measure() and then instead of calling layoutNeeded on
> the
> >> parent,
> >> > call the parent's invalidateSize until somehow we know we've
> gone
> >> far
> >> > enough up the chain to start laying out again.
> >> >
> >> > After the changes I made I do still need to make changes in
> some
> >> specific
> >> areas, but usually this type of thing does the trick:
> >>
> >> var layout:BoxLayout =
> >> containerContents.getBeadByType(BoxLayout) as BoxLayout;
> >> if (layout) {
> >> layout.measure();
> >> }
> >> containerContents.layoutNeeded();
> >>
> >> Note: calling measure() explicitly like that with BoxLayout
> seems to
> >> be
> >> necessary sometimes before an explicit layout request. It might
> only
> >> work
> >> more after the changes I made, not sure whether it makes a
> difference
> >> before or not.
> >>
> >>
> >> > HTH,
> >> > -Alex
> >> >
> >> >
> >> > On 6/4/20, 1:51 PM, "Greg Dove" <greg.d...@gmail.com> wrote:
> >> >
> >> > 'I don’t think we’ve dealt with a lot of children changing
> >> sizes (other
> >> > than Images loading late and a few other things) so it
> may be
> >> time to
> >> > listen to widthChanged/heightChanged/sizeChanged as
> children
> >> get added
> >> > if
> >> > there isn’t already code doing that.'
> >> >
> >> > That would be another way of doing it. There is already
> this
> >> code [1]
> >> > that
> >> > is swf-only but seems to only be relevant before
> >> sawInitComplete.
> >> >
> >> > But if the children run their layouts when their own size
> >> changes, then
> >> > they can notify their parent as well if the size changed
> either
> >> before
> >> > or
> >> > during layout. That's sort of what I was trying to do
> with the
> >> > ContainerView change I mentioned earlier. It checks size
> for
> >> change in
> >> > beforeLayout and again in afterLayout and then requests
> parent
> >> layout
> >> > if it
> >> > thinks the parent needs to do something that could affect
> parent
> >> > layout or
> >> > even re-apply its own rules to the current target. In
> this way
> >> there
> >> > is not
> >> > a need to add listeners to every child. But I expect
> there are
> >> some
> >> > downsides or things I cannot see with what I did so far
> because
> >> I have
> >> > not
> >> > spent a lot of time in this code, as you have. I'll post
> more
> >> details
> >> > in
> >> > the github issue at my EOD.
> >> >
> >> > 1.
> >> >
> >> >
> >>
> https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fapache%2Froyale-asjs%2Fblob%2F9c70b052a6fef3ebe7c6a07ca887af4f7381d46f%2Fframeworks%2Fprojects%2FCore%2Fsrc%2Fmain%2Froyale%2Forg%2Fapache%2Froyale%2Fcore%2FLayoutBase.as%23L131&data=02%7C01%7Caharui%40adobe.com%7C8a6459c6e39047dd9d4608d809e97d92%7Cfa7b1b5a7b34438794aed2c178decee1%7C0%7C0%7C637270245738238954&sdata=DtytJwdH1LB91GBcUzPsMGrDRL2jIHAONtVX%2FojUFXA%3D&reserved=0
> >> >
> >> > On Fri, Jun 5, 2020 at 3:32 AM Alex Harui
> >> <aha...@adobe.com.invalid>
> >> > wrote:
> >> >
> >> > > Serkan, is there a bug tracking your layout issue?
> >> > >
> >> > > There should be a difference between first layout if all
> >> children
> >> > have
> >> > > known sizes and what Greg is describing which is
> responding to
> >> > children
> >> > > changing sizes. I don’t think we’ve dealt with a lot of
> >> children
> >> > changing
> >> > > sizes (other than Images loading late and a few other
> things)
> >> so it
> >> > may be
> >> > > time to listen to
> widthChanged/heightChanged/sizeChanged as
> >> children
> >> > get
> >> > > added if there isn’t already code doing that.
> >> > >
> >> > > There might be other issues with containers having an
> inner
> >> > contentArea
> >> > > that might be getting in the way too.
> >> > >
> >> > > HTH,
> >> > > -Alex
> >> > >
> >> > > From: Yishay Weiss <yishayj...@hotmail.com>
> >> > > Reply-To: "dev@royale.apache.org" <
> dev@royale.apache.org>
> >> > > Date: Thursday, June 4, 2020 at 4:30 AM
> >> > > To: "dev@royale.apache.org" <dev@royale.apache.org>
> >> > > Subject: RE: MXRoyale layout issues -
> questions/discussion
> >> > >
> >> > > Call me lazy but this is a bit difficult to parse. If
> you can
> >> spare
> >> > some
> >> > > time, maybe come up with a GitHub issue that describes a
> >> concrete
> >> > case so
> >> > > we can discuss this.
> >> > >
> >> > > > I think the layouts work downward for this, but
> changes in
> >> the
> >> > children
> >> > > don't seem to trigger the parent layout.
> >> > >
> >> > > Yes, I’ve seen that as well. Alex’s advice when I
> pointed it
> >> out to
> >> > him
> >> > > was to just add a parent.dispatchEvent(new
> >> Event(‘layoutNeeded’)) if
> >> > it
> >> > > solves a concrete bug. It’s true that this could result
> in a
> >> > performance
> >> > > hit. If that’s your issue then I guess we can discuss
> >> emulation of
> >> > the
> >> > > layout manager or some other optimization.
> >> > >
> >> > >
> >> > > From: Greg Dove <greg.d...@gmail.com>
> >> > > Sent: Thursday, June 4, 2020 11:12:08 AM
> >> > > To: Apache Royale Development <dev@royale.apache.org>
> >> > > Subject: MXRoyale layout issues - questions/discussion
> >> > >
> >> > > Hi,
> >> > >
> >> > > Just wondered if anyone else is dealing with layout
> issues in
> >> Flex
> >> > > emulation. I have some layout issues that are slowing my
> >> progress on
> >> > a
> >> > > project, and I'd like to resolve them as quickly as I
> can.
> >> > >
> >> > > In particular, I see issues with BoxLayout-based
> containers
> >> which
> >> > have
> >> > > percentWidth or percentHeight set. These don't get
> determined
> >> as
> >> > having
> >> > > width or height 'SizedToContent' when performing
> layout, but
> >> in many
> >> > > situations they behave in a similar way (they can change
> >> their size
> >> > based
> >> > > on their content in terms of layout rules applied by the
> >> parent
> >> > container).
> >> > > This is because in Flex, percentages are not simply a
> >> percentage of
> >> > their
> >> > > parent, but they follow something perhaps a little
> closer to
> >> flexbox
> >> > layout
> >> > > rules for all the percentWidth or percentHeight siblings
> >> (managed by
> >> > their
> >> > > parent's layout). In other words, they are also related
> to the
> >> > measured
> >> > > size of their content if the parent needs to manage
> them (I'm
> >> not
> >> > sure how
> >> > > best to describe this, but I think that sort of
> captures it).
> >> They
> >> > can
> >> > > expand beyond their percent allocation or contract
> below it
> >> > depending on
> >> > > their measured sizes.
> >> > > I think the layouts work downward for this, but changes
> in the
> >> > children
> >> > > don't seem to trigger the parent layout.
> >> > >
> >> > > An example might be
> >> > > <mx:HBox id='addThingsToMe' width='50%' />
> >> > >
> >> > > If you have the above at the application level (where
> the
> >> > application has
> >> > > vertical layout) and keep adding buttons (for example)
> to the
> >> HBox
> >> > via a UI
> >> > > test button that adds a new Button to that on each
> click,
> >> then it
> >> > should
> >> > > expand horizontally greater than 50% width when the
> volume of
> >> buttons
> >> > > exceeds its nominal 50% width. It is definitely easier
> to see
> >> this
> >> > if you
> >> > > add a border to the container.
> >> > >
> >> > > I have been working on this, and made progress, but the
> >> approach I
> >> > am using
> >> > > feels a bit patchwork, and just wondered whether others
> are
> >> seeing
> >> > anything
> >> > > like this, and/or how it has been addressed
> elsewhere....
> >> > >
> >> > > Here's a summary of some of the things I have been
> trying,
> >> which do
> >> > yield
> >> > > improvements, but don't really solve the problem
> completely:
> >> > >
> >> > > 1. added extra listener for 'childrenRemoved' in
> BoxLayout
> >> strand
> >> > setter.
> >> > >
> >> > > 2. Created a new mx 'ContainerView' class
> >> > > (mx.containers.beads.ContainerView extends
> >> > > org.apache.royale.html.beads.ContainerView)
> >> > > This has the following in it:
> >> > >
> >> > > private var widthBefore:Number = -1
> >> > > private var heightBefore:Number = -1;
> >> > > private var sizeChangedBeforeLayout:Boolean;
> >> > >
> >> > > COMPILE::JS
> >> > > override public function beforeLayout():Boolean
> >> > > {
> >> > > var container:Container = host as Container;
> >> > >
> >> > > sizeChangedBeforeLayout = (widthBefore !=
> container.width ||
> >> > heightBefore
> >> > > != container.height);
> >> > > widthBefore = container.width;
> >> > > heightBefore = container.height;
> >> > > return super.beforeLayout();
> >> > > }
> >> > >
> >> > > COMPILE::JS
> >> > > override public function afterLayout():void
> >> > > {
> >> > > var container:Container = host as Container;
> >> > > //size might change during layout
> >> > > var sizeChangedDuringLayout:Boolean =
> >> !sizeChangedBeforeLayout &&
> >> > > (widthBefore != container.width || heightBefore !=
> >> container.height);
> >> > > if (sizeChangedDuringLayout) {
> >> > > //prepare for next time
> >> > > widthBefore = container.width;
> >> > > heightBefore = container.height;
> >> > > }
> >> > > var requestParentLayout:Boolean =
> sizeChangedBeforeLayout
> >> > > || sizeChangedDuringLayout
> >> > > || (!isNaN(container.percentWidth) &&
> >> container.width <
> >> > > container.measuredWidth) ||
> (!isNaN(container.percentHeight)
> >> &&
> >> > > container.height < container.measuredHeight);
> >> > > if (requestParentLayout && container.parent is
> >> Container) {
> >> > > trace('requesting parent layout of ',(container as
> >> > > Object).ROYALE_CLASS_INFO.names[0].qName );
> >> > > (container.parent as
> Container).layoutNeeded();
> >> > > }
> >> > > }
> >> > >
> >> > > That is pretty much it, and it is being used as a
> replacement
> >> in my
> >> > local
> >> > > MXRoyale css for Container:
> >> > >
> >> > > /*IBeadView:
> >> > >
> >> ClassReference("org.apache.royale.html.beads.ContainerView");*/
> >> > > IBeadView:
> >> ClassReference("mx.containers.beads.ContainerView");
> >> > >
> >> > > I'm not saying this is right, but it does help quite a
> bit
> >> with what
> >> > I am
> >> > > facing.
> >> > >
> >> > > In addition to BoxLayout in general, I have been
> working on
> >> the
> >> > > Grid/GridRow/GridItem layouts which are more specific in
> >> terms of
> >> > layout
> >> > > changes needed, but also can have similar problems.
> >> > >
> >> > >
> >> > > Although I am seeing improvements with what I have done
> so
> >> far, I'm
> >> > not
> >> > > really satisfied with it, and I am keen for
> input/discussion
> >> (or
> >> > > collaboration). I have been pursuing what I would mostly
> >> describe as
> >> > a
> >> > > 'workaround' approach, so would welcome any thoughts on
> how
> >> best to
> >> > tackle
> >> > > this.
> >> > > I think there is something missing because of the way
> Flex
> >> does
> >> > layouts vs.
> >> > > the way Royale does it, but I can't describe it fully
> yet.
> >> Perhaps
> >> > things
> >> > > are only currently envisaged to work with mxml
> declarative
> >> content
> >> > onto
> >> > > display and not so much with dynamic updates. But I
> think
> >> state-based
> >> > > changes could have similar effects for some of these
> things
> >> if they
> >> > happen
> >> > > inside containers that have their own percent
> dimensions.
> >> > >
> >> > >
> >> > > Thanks,
> >> > > Greg
> >> > > From: Greg Dove<mailto:greg.d...@gmail.com>
> >> > > Sent: Thursday, June 4, 2020 11:12 AM
> >> > > To: Apache Royale Development<mailto:
> dev@royale.apache.org>
> >> > > Subject: MXRoyale layout issues - questions/discussion
> >> > >
> >> > > Hi,
> >> > >
> >> > > Just wondered if anyone else is dealing with layout
> issues in
> >> Flex
> >> > > emulation. I have some layout issues that are slowing my
> >> progress on
> >> > a
> >> > > project, and I'd like to resolve them as quickly as I
> can.
> >> > >
> >> > > In particular, I see issues with BoxLayout-based
> containers
> >> which
> >> > have
> >> > > percentWidth or percentHeight set. These don't get
> determined
> >> as
> >> > having
> >> > > width or height 'SizedToContent' when performing
> layout, but
> >> in many
> >> > > situations they behave in a similar way (they can change
> >> their size
> >> > based
> >> > > on their content in terms of layout rules applied by the
> >> parent
> >> > container).
> >> > > This is because in Flex, percentages are not simply a
> >> percentage of
> >> > their
> >> > > parent, but they follow something perhaps a little
> closer to
> >> flexbox
> >> > layout
> >> > > rules for all the percentWidth or percentHeight siblings
> >> (managed by
> >> > their
> >> > > parent's layout). In other words, they are also related
> to the
> >> > measured
> >> > > size of their content if the parent needs to manage
> them (I'm
> >> not
> >> > sure how
> >> > > best to describe this, but I think that sort of
> captures it).
> >> They
> >> > can
> >> > > expand beyond their percent allocation or contract
> below it
> >> > depending on
> >> > > their measured sizes.
> >> > > I think the layouts work downward for this, but changes
> in the
> >> > children
> >> > > don't seem to trigger the parent layout.
> >> > >
> >> > > An example might be
> >> > > <mx:HBox id='addThingsToMe' width='50%' />
> >> > >
> >> > > If you have the above at the application level (where
> the
> >> > application has
> >> > > vertical layout) and keep adding buttons (for example)
> to the
> >> HBox
> >> > via a UI
> >> > > test button that adds a new Button to that on each
> click,
> >> then it
> >> > should
> >> > > expand horizontally greater than 50% width when the
> volume of
> >> buttons
> >> > > exceeds its nominal 50% width. It is definitely easier
> to see
> >> this
> >> > if you
> >> > > add a border to the container.
> >> > >
> >> > > I have been working on this, and made progress, but the
> >> approach I
> >> > am using
> >> > > feels a bit patchwork, and just wondered whether others
> are
> >> seeing
> >> > anything
> >> > > like this, and/or how it has been addressed
> elsewhere....
> >> > >
> >> > > Here's a summary of some of the things I have been
> trying,
> >> which do
> >> > yield
> >> > > improvements, but don't really solve the problem
> completely:
> >> > >
> >> > > 1. added extra listener for 'childrenRemoved' in
> BoxLayout
> >> strand
> >> > setter.
> >> > >
> >> > > 2. Created a new mx 'ContainerView' class
> >> > > (mx.containers.beads.ContainerView extends
> >> > > org.apache.royale.html.beads.ContainerView)
> >> > > This has the following in it:
> >> > >
> >> > > private var widthBefore:Number = -1
> >> > > private var heightBefore:Number = -1;
> >> > > private var sizeChangedBeforeLayout:Boolean;
> >> > >
> >> > > COMPILE::JS
> >> > > override public function beforeLayout():Boolean
> >> > > {
> >> > > var container:Container = host as Container;
> >> > >
> >> > > sizeChangedBeforeLayout = (widthBefore !=
> container.width ||
> >> > heightBefore
> >> > > != container.height);
> >> > > widthBefore = container.width;
> >> > > heightBefore = container.height;
> >> > > return super.beforeLayout();
> >> > > }
> >> > >
> >> > > COMPILE::JS
> >> > > override public function afterLayout():void
> >> > > {
> >> > > var container:Container = host as Container;
> >> > > //size might change during layout
> >> > > var sizeChangedDuringLayout:Boolean =
> >> !sizeChangedBeforeLayout &&
> >> > > (widthBefore != container.width || heightBefore !=
> >> container.height);
> >> > > if (sizeChangedDuringLayout) {
> >> > > //prepare for next time
> >> > > widthBefore = container.width;
> >> > > heightBefore = container.height;
> >> > > }
> >> > > var requestParentLayout:Boolean =
> sizeChangedBeforeLayout
> >> > > || sizeChangedDuringLayout
> >> > > || (!isNaN(container.percentWidth) &&
> >> container.width <
> >> > > container.measuredWidth) ||
> (!isNaN(container.percentHeight)
> >> &&
> >> > > container.height < container.measuredHeight);
> >> > > if (requestParentLayout && container.parent is
> >> Container) {
> >> > > trace('requesting parent layout of ',(container as
> >> > > Object).ROYALE_CLASS_INFO.names[0].qName );
> >> > > (container.parent as
> Container).layoutNeeded();
> >> > > }
> >> > > }
> >> > >
> >> > > That is pretty much it, and it is being used as a
> replacement
> >> in my
> >> > local
> >> > > MXRoyale css for Container:
> >> > >
> >> > > /*IBeadView:
> >> > >
> >> ClassReference("org.apache.royale.html.beads.ContainerView");*/
> >> > > IBeadView:
> >> ClassReference("mx.containers.beads.ContainerView");
> >> > >
> >> > > I'm not saying this is right, but it does help quite a
> bit
> >> with what
> >> > I am
> >> > > facing.
> >> > >
> >> > > In addition to BoxLayout in general, I have been
> working on
> >> the
> >> > > Grid/GridRow/GridItem layouts which are more specific in
> >> terms of
> >> > layout
> >> > > changes needed, but also can have similar problems.
> >> > >
> >> > >
> >> > > Although I am seeing improvements with what I have done
> so
> >> far, I'm
> >> > not
> >> > > really satisfied with it, and I am keen for
> input/discussion
> >> (or
> >> > > collaboration). I have been pursuing what I would mostly
> >> describe as
> >> > a
> >> > > 'workaround' approach, so would welcome any thoughts on
> how
> >> best to
> >> > tackle
> >> > > this.
> >> > > I think there is something missing because of the way
> Flex
> >> does
> >> > layouts vs.
> >> > > the way Royale does it, but I can't describe it fully
> yet.
> >> Perhaps
> >> > things
> >> > > are only currently envisaged to work with mxml
> declarative
> >> content
> >> > onto
> >> > > display and not so much with dynamic updates. But I
> think
> >> state-based
> >> > > changes could have similar effects for some of these
> things
> >> if they
> >> > happen
> >> > > inside containers that have their own percent
> dimensions.
> >> > >
> >> > >
> >> > > Thanks,
> >> > > Greg
> >> > >
> >> > >
> >> >
> >> >
> >> >
> >>
> >>
> >>
>
>
>
