Added support for rendering as RichText Widgets

[jeffmikels]

The original HTML Parser rendered widgets awkwardly. I have implemented a parser that converts the HTML into a list of Rich Text Widgets with appropriate TextSpans.

[Sub6Resources]

Thank you for the extensive pull request! I'll review this as soon as I am have some time (because this is somewhat of a major change it may take some time).

[jeffmikels]

Thank you for the extensive pull request! I'll review this as soon as I am have some time (because this is somewhat of a major change it may take some time).

To be clear on the changes:

• I have renamed the HtmlParser to HtmlOldParser, but it remains the default parser and currently supports more tags
• The new parser is called HtmlRichTextParser, and can be selected by setting the useRichText flag when creating the Html widget.
• The new parser doesn't support as many tags as the old one, but it renders them more predictably.
• The new parser does NOT support the specification of a customRender function.
• The supported HTML tags are easily seen in the code.

[wwwdata]

I now also noticed the problem when having links inside the HTML #40 , that they are getting rendered on a new line with the old parser. However I would need to still have the ability to use custom renderings. I would be willing to look into how to implement this feature.

@Sub6Resources can you review this and merge?

I will start using this as a base now and see how far I can get implementing the ability to use the custom renderer again. Thank you so much for solving this issue @jeffmikels

[hui00]

with some data and useRichText: true

NoSuchMethodError: The getter 'isEmpty' was called on null. Reveiver: null Tried calling: isEmpty

[jeffmikels]

with some data and useRichText: true

NoSuchMethodError: The getter 'isEmpty' was called on null. Reveiver: null Tried calling: isEmpty

My latest commit fixes this.

[skipness]

I am trying to make nested blockquote like this:
<blockquote><blockquote>2</blockquote>1</blockquote><br /><h1>heading</h1>
works. I get the following result:

Seems the new parser doesn't support nested blockquote tag with non block tag inside?

[jeffmikels]

I am trying to make nested blockquote like this:
<blockquote><blockquote>2</blockquote>1</blockquote><br /><h1>heading</h1>
works. I get the following result:

Seems the new parser doesn't support nested blockquote tag with non block tag inside?

What behavior are you expecting?

[skipness]

I am trying to make nested blockquote like this:
<blockquote><blockquote>2</blockquote>1</blockquote><br /><h1>heading</h1>
works. I get the following result:

Seems the new parser doesn't support nested blockquote tag with non block tag inside?

What behavior are you expecting?

like this

[jeffmikels]

@skipness

I have tweaked the code to treat plain text nodes inside blockquote, ol, and ul elements as if they had been block elements. This will properly indent them. However, there is a limitation to how this rendering is done, and you might not be pleased with the results as they are different from what you expect.

My renderer creates a series of "BlockText" widgets in a column. BlockText Widgets cannot contain other BlockText widgets, so the way the renderer works is that when blockquote, ol, or ul elements are encountered, a flag is set telling the renderer that subsequent block widgets should be indented and might need a left side border.

As a result, this renderer is only capable of handling a small subset of html correctly. For example, block elements inside other block elements will not behave as expected.

To more effectively handle nested block elements, I will need to modify my BlockText widgets to handle multiple children. That has not been done yet.

[Sub6Resources]

Thank you for your patience and for your work on this pull request. I feel good about merging this. Once this is merged and I've updated the CHANGELOG and README, I'll release version 0.9.0.

[Sub6Resources]

These changes have been published as version 0.9.0. Thank you @jeffmikels for your work on this.

[skipness]

@Sub6Resources @jeffmikels thank you very much!

[mesuutt]

@jeffmikels how can we use customRender with useRichText? Why new parser not support customRender?

[jeffmikels]

I didn't understand the implementation of customRender, so I didn't implement it. The new parser has a RichText customRenderer built in.

[mesuutt]

I want to add different style to some of html elements, I achieved it with customRender but old parser not generate correct widget tree and has some issues. How am I achieve what described in #53?

[wwwdata]

@mesuutt it's not implemented yet. We need some custom rendering as well so I already played around but what I currently have is not really a good solution. I can look into it in the next days and open a PR when I have something.

If you need it right now you could also just fork it and add your rendering in the new code for now until there is an extension mechanism

[Sub6Resources]

@mesuutt I've opened a new issue so we can track the progress of this feature here: #64