Low PNG resolution, add DPI switch

[acorreya]

PNG output for imagine/mermaid has low resolution for screen and unimaginable for print. Please set a switch for controlling/increasing the DPI for PNG images to 150 dpi, 300 dpi etc. Thanks for the great work!

[hertogp]

Hi @acorreya,
The png is actually created by the mmcd utility, not by imagine itself. However, if mmcd includes a switch to set the dpi you can include that in the options for your code block:

```{.mermaid im_opt="-w 600 -H 1200"}
...
```

but my version of mmcd doesn't seem to do much with those extra params. See #3.

Development seems to have been moved to a new repo, mermaid, maybe you could re-raise the question there?

[pbsds]

Seems like there now is a -s switch, defaulting to 1, which sets the scale.
I use im_opt="-s 3".

[hertogp]

thanks for the tip!