Add support for HtmlWidget.renderMode

[daohoangson]

WidgetFactory breaking changes:

• buildColumnPlaceholder removed trimMarginVertical named param
• buildColumnWidget removed tsh param
• onTapAnchor replaced anchorContext param with scrollTo

[github-actions]

Demo app

Deployed 78b0aa6 to https://example-qcbruklwc-flutter-widget-from-html.vercel.app.

Quick links:

• supported/tags.html
• Hello World
• Hello World (core)
• Wordpress
• --web-renderer canvaskit
• --web-renderer html

[codecov]

Codecov Report

Merging #484 (12721f1) into next (b68fef3) will increase coverage by 0.08%.
The diff coverage is 99.38%.

@@            Coverage Diff             @@
##             next     #484      +/-   ##
==========================================
+ Coverage   97.94%   98.02%   +0.08%     
==========================================
  Files          47       48       +1     
  Lines        3019     3145     +126     
==========================================
+ Hits         2957     3083     +126     
  Misses         62       62              

Impacted Files	Coverage Δ
packages/core/lib/src/internal/core_ops.dart	100.00% <ø> (ø)
packages/enhanced/lib/src/html_widget.dart	100.00% <ø> (ø)
packages/core/lib/src/internal/ops/anchor.dart	98.66% <98.66%> (ø)
packages/core/lib/src/core_helpers.dart	100.00% <100.00%> (ø)
packages/core/lib/src/core_html_widget.dart	100.00% <100.00%> (ø)
packages/core/lib/src/core_widget_factory.dart	99.58% <100.00%> (+0.01%)	⬆️
packages/core/lib/src/data/build_bits.dart	100.00% <100.00%> (ø)
packages/core/lib/src/internal/builder.dart	100.00% <100.00%> (ø)
packages/core/lib/src/internal/ops/column.dart	100.00% <100.00%> (+3.57%)	⬆️
packages/core/lib/src/internal/ops/tag_ruby.dart	95.74% <100.00%> (+0.18%)	⬆️
... and 1 more

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[daohoangson]

Check out this screen recording (demo_app, Android, release mode): https://youtu.be/5U10W0VJHOA

• Ignoring the parsing phases: shown in video with the circle indicator
• Column takes 1s (skipped ~60 frames) to render / layout.
• ListView takes 30ms (skipped 2 frames) to do that
• SliverList takes 17ms (skipped a frame)
• After the first frames, scrolling is stable at 60fps in all modes (thanks to the RepaintBoundary)

[DFelten]

Looks really good :) The demo app with the huge html feels great. Thanks for this feature!

[daohoangson]

@DFelten yeah, the huge html is quite slow. There's probably some optimizations to make but it will still take some time in the end.

[DFelten]

@daohoangson I think the duration of 50 milliseconds looks better than 100. At least it feels better in my tests.

One idea here would be to make the value overwritable from the outside. This way, everyone can adjust the value according to their own taste.

[daohoangson]

In my testings, lowering the duration prevented it from working... That's why I kept it at 100ms. I'll do some more tests. Exposing the duration is possible but not ideal though, I want to avoid having a constructor with too many params.

[DFelten]

For me it also works at 30, but if I set the value too low, I also get an error. For example, a value of 10 will stop too early. The list of new indexes is built too late or the lists are still identical. But maybe it depends on how strong the device is and how slow it is when building the widgets.

Couldn't the value rather be overwritten via the core Widget Factory? Then we don't need a larger constructor here either.

[DFelten]

I have just tested a little more. You are right, with a value of 50 it does not work with all articles. But even with 100 there are problems if the article is too long or there are too many images.

But fortunately this happens only on the simulator. On the phone it's working with a duration of 50 and 100.

[daohoangson]

The latest commit changed the way scrolling is done so it's much faster and more reliable. Please try it if you have a chance @DFelten. I think this PR is almost ready now, it maybe merged into next pretty soon.

[DFelten]

The speed is so much better :) Thanks for the latest update, so this can definitely be merged.

[daohoangson]

v0.7.0-dev.2021061301 has been released with this feature. Please try upgrading and let me know if it works for you @DFelten