Markdown image hyperlink

[amis92]

Images as hyperlinks

Main topic is support for images in hyperlinks. Currently there is a limitation in HyperlinkButton that no InlineUIContainer can be added as content.

There already are some issues that touched up this issue:

• Images are not fitting (...)
  (added ImageStretch, stated Hyperlink doesn't support InlineUIContainers)
• v1.4 broke what works in v1.3.1
  (discussion that local refs are not supported and also Hyperlink no-image limitation)
• commit fixing above where we observe the limitation on image links
• statement "we already support images and links (...)"

Solution suggestion

It's quite common to have an image linking to something, be it a badge in readme or a miniature with link to full-res version. We could only support at least that scenario (so the only content of hyperlink is an image) or go the extra mile and expand support for mixed content.

The solution would be a kind of a workaround, as when we'd discover a non-text content in Hyperlink we'd fallback to using InlineUIContainer instead of HyperlinkTextBlock, and make any non-text element respond to click as-if-uri-activated, and text would be just parsed into HyperlinkButtons inside.

[nmetulev]

I agree that image in hyperlink is commonly used. ping @deltakosh to get his thoughts on complexity of this.

[deltakosh]

The problem is that I don't know how to support it right now. MarkdownTextBlock uses RichTextBox. And so far we are using an Hyperlink control which cannot support embedded images.

I guess we can remove the hyperlink and manually create a link with a standard container.
I'll check more asap

[deltakosh]

Actually it more complex than expected.
Hyperlinks are created here:
https://github.com/Microsoft/UWPCommunityToolkit/blob/dev/Microsoft.Toolkit.Uwp.UI.Controls/MarkdownTextBlock/Display/XamlRenderer.cs#L853

The link is then used to hook the Click handler and link.inlines is used as a container. This is where the problem is: hyperlink can only contains text and not images.

I tried to use a Span instead of a link but there is no more Click event. I did not do an extensive review but this seems to be a blocker.

[nmetulev]

I'll take this out of 1.5 as it sounds like we won't be able to fix it by then. Let me know if that is not the case.

[deltakosh]

This is correct. We need to find a smarter way to do it

[avknaidu]

@nmetulev @deltakosh Any ideas on how this can be implemented?

[nmetulev]

Haven't really looked at implementing this so what I suggest might not work. The first thing I would try is to see if there is a way to replace the hyperlink button with another container that does support inline content and hook into a tapped event (or handle pointer events manually)