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 <[email protected]> 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" <[email protected]> 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 <[email protected]>
> 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" <[email protected]> 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%7C34080cf90f504c1b7ef508d809380095%7Cfa7b1b5a7b34438794aed2c178decee1%7C0%7C0%7C637269483425406744&sdata=na2D5dkZziw7na8WuNrz%2FRIJzphWgVEVmGX64aPJ1UA%3D&reserved=0
> >
> > On Fri, Jun 5, 2020 at 3:32 AM Alex Harui
> <[email protected]>
> > 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 <[email protected]>
> > > Reply-To: "[email protected]" <[email protected]>
> > > Date: Thursday, June 4, 2020 at 4:30 AM
> > > To: "[email protected]" <[email protected]>
> > > 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 <[email protected]>
> > > Sent: Thursday, June 4, 2020 11:12:08 AM
> > > To: Apache Royale Development <[email protected]>
> > > 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:[email protected]>
> > > Sent: Thursday, June 4, 2020 11:12 AM
> > > To: Apache Royale Development<mailto:[email protected]>
> > > 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
> > >
> > >
> >
> >
> >
>
>
>
