Image scaling during MediaWiki to Markdown conversion

[peterjc]

Reported by @vincentdavis on issue #1

Some images are scaled, e.g. in http://biopython.org/wiki/Phylo or its MediaWiki equivalent https://github.com/peterjc/peterjc.github.io/blob/master/wiki/Phylo.mediawiki

[[File:phylo-draw-apaf1.png|256px|thumb|right|Rooted phylogram, via Phylo.draw]]

which becomes after conversion to GFM markdown with pandoc https://github.com/peterjc/peterjc.github.io/blob/master/wiki/Phylo.md

![Rooted phylogram, via Phylo.draw](phylo-draw-apaf1.png "fig:Rooted phylogram, via Phylo.draw")

On the actual wiki the image URL is:
http://biopython.org/w/images/thumb/0/04/Phylo-draw-apaf1.png/256px-Phylo-draw-apaf1.png

If you what to see the full size image
http://biopython.org/w/images/0/04/Phylo-draw-apaf1.png

@vincentdavis found a document that suggests code like this can be used for scaling images.

[[ http://url.to/image.png | height = 100px ]]

[peterjc]

As of #1 and #11, we now have the "original" unscaled images within the output.

This bug is now simply how to convert the MediaWiki image markup into (GitHub Flavoured) Markdown while preserving the image scaling information.

This is likely a pandoc configuration question...

[peterjc]

Wow, according to http://stackoverflow.com/questions/24383700/resize-image-in-the-wiki-of-github-using-markdown GFM no longer supports the height or width syntax mentioned above.

[peterjc]

Looks like we'll have to switch to minimal HTML snippets for images, see for example http://stackoverflow.com/questions/22485796/markdown-smaller-images-sizes-not-supported-by-github

<img src="url" alt="alt text" width="whatever" height="whatever">

This might work better with <div> wrapper images as then whole unit is HTML...

[peterjc]

According to recent commit jgm/pandoc@244cd56 pandoc 1.16 will add basic support for image sizes.

This appears to understand the height/width attributes when parsing mediawiki input: jgm/pandoc@244cd56#diff-f003790849ba78911adb2e3836757776L577

It remains to be seen it would be rendered when we request GFM output... jgm/pandoc#2554

[peterjc]

This ought to work with the pandoc fix (see issue linked to above), just need to find/make a test case to confirm this!