Construct SVG output files by putting together the recognition results for each page

[kba]

By @jze in #68

[zuphilip]

Here is an example of the output (converted into a png file for easier handling).

I think it is more interesting to continue hocrjs for visualizing the hocr output. Thus, I would suggest to not take this PR in the repo. @kba What do you think about this?

[kba]

SVG is a nice format, portable, can be displayed in the browser and could also be scripted. I considered it for hocrjs but decided against it because hOCR is already HTML and easier to manipulate. If you want to share/compare a visual representation of the hOCR output, it seems like a good option. Github supports diffing SVGs, so you could use that to see what affects positioning etc.

[zuphilip]

Okay, I see that there is some more value into this script. However, I am not sure we should have another top-level command ocropus-svg for that...

If you want to share/compare a visual representation of the hOCR output, it seems like a good option.

Wouldn't we need then something like a hocr2svg tool? Which I guess is possible by rewriting the lines here and could be saved in the hocr-tools...

We could also think about integrating these svg lines into ocropus-visualize-results. These could actually be some replacement for the nowadays obsolete csegs parts in this script.