html: add width option

[HackbrettXXX]

Currently, there is no easy way to specify the desired width of the html in the PDF. The width can only be specified indirectly over html2canvas' scale option (similar to #2917). It would be very convenient, if we could simply supply a width (in PDF units) to the html method. This option should basically function like the width of a browser window (which means, it should not scale the content).

[hmajid2301]

I can pick this up!

[HackbrettXXX]

@hmajid2301 that would be really great!

One thought: the default value should be the width of the current page.

[hmajid2301]

Sorry I'm afraid I won't be able to pick this up any more.

Thanks

[helpsdev]

Hi there, I'm a first-time contributor, any chance I can work on this?