LaTeX math mode support

[dakusui]

It will be very useful if we can use LaTeX's math mode inside ditaa's ascii art.
That is, if we have a following ascii art,

$Box_1$                    $Box^2$
+---------------------+    +------+   /---------\
|$\sum_{i=0}^{n}x^i$  |    |$cBLU$|   |         |
|                     +--->|cRED  +-=-+cGRE$C_k$|
|{io}                 |    |cXYZ  |   |{o}      |
+----------+----------+    +---+--+   \---------/
           |                   |
           |                   :
           |                   V
           |           +-----------------+
           +---------->|$A_i$ hello $B^i$|
                       +-----------------+

$Q_u^i$, $C_k$, $B_r^{own}$, $F_{ox}$ jumps

over a lazy $d\cdot\frac{o}{g}$.


$\forall x \in X, \quad \exists y \leq \epsilon$


$\sin A \cos B =$

    $ \frac{1}{2}\left[ \sin(A-B)+\sin(A+B) \right]$


$\frac{d}{dx}\left( \int_{0}^{x} f(u)\,du\right)=f(x).$


 $v \sim \mathcal{N} (m,\sigma^2)$

I would see it rendered like this.

I have already implemented this feature in my forked repository and am going to open a pull request soon. Please kindly consider merging it when it's opened.

[stathissideris]

This is amazing, I would gladly merge it when it's ready!

[stathissideris]

Do you think it would work with SVG output as well?

[dakusui]

It's a great point. It will need to be a limitation for the time being.
My enhancement relies on jlatexmath for LaTeX math rendering and it does not support .svg output apparently.
There seems to be other libraries that can output .svg but not in Java (or JVM based languages), which means we'll need to figure out how to integrate such libraries in ditaa's 'uber' jar.

I would suggest supporting this feature for only .png in this pull request rather than making the change too big.

[dakusui]

I have opened a pull request for this feature to have a discussion about its detail. Please have a look at it and leave your thoughts.

[paulvi]

I wonder if it is possible to make this as addon or option? (if not merging directly because of some limitations)

[paulvi]

https://github.com/dakusui/ditaa/tree/issue-39-latex-math-support

[dakusui]

@paulvi , what do you mean by "option"? My current plan is to make it a feature enabled by the "--latex-math" option otherwise defaulting to original behavior.

Making it an addon would be quite a bit challenging, actually.

Actually, I came to think that it might be better to go back to original code base and re-work this pull request since unless otherwise it's difficult to review the enhancement.
And if you want to try this feature, you can simply clone the repo and build it using leiningen (lein uberjar). The artifact should work fine. (If not, please just let me know. I will fix the bug.)

[paulvi]

OK, so if thi Latext support is optional that is only enabled when "--latex-math" option is passed, than I would like to see it merged as it is.
As will / should not affect users who are not aware about it

[dakusui]

Hi, after long period of busy days, I could finally find a time to work on this.
I have reworked the feature from the fresh branch and created a pull request #54 .
Please kindly have a review on it.