Possibilities to embed Latex in QML

Question

I'm doing a presentation system in QML (with C++ backend) similar to this one.

I want to be able to include some Latex code to display some math (only minimum Latex capabilities needed, such as sums, fractions, super- and substript and math fonts).

I see the following possibilities to do so:

• Using latex2e:
  1. Compile the Latex code to a DVI document (with latex)
  2. Convert the DVI to SVG (with dvisvgm)
  3. Display this using an Image in QML (which also supports SVG)

• Using MathJax:
  1. Wrap the Latex code in a small HTML file + include the MathJax JS library
  2. Display this using WebKit for QML

• Custom solution (C++):
  1. Write or include an existing minimal Latex math parser
  2. Write a QDeclarativeItem with custom painting

Is there another solution I don't see? I prefer the first solution as the second sounds too heavy and the third too hard.

I see the following problem with the baseline of the math formula: I want to be able to include inline formulas (within a paragraph). Currently, text paragraphs are renderd using a QML Text element. Is there a possibility to include an image in a Text element (using HTML img element maybe) with a specified baseline? Also, how can I determine the baseline of a rendered Latex document?

Note: The time to pre-render Latex code isn't problematic. I'm going to cache already rendered formulas, so it should be no problem to invoke latex + dvisvgm on every single formula contained in the presentation document.

Also note that I use a preprocessor (I don't write the QML code by hand but generate it). So I don't need a QML element for the Latex code but I can just generate a QML code snippet with an Image element (for the first solution). This should simplify embedding the rendered image.

I also don't need to support wrapping a formula when using inline Latex. (Latex does so when writing inline formulas, but I only use small formulas I don't want to be wrapped anyways.)

Answer 1

I think those are three good options, and I can't think of any other way to do it.

It sounds like you have a requirement to have the formulas in-line with some textual paragraphs, so for that reason I think option 2 is a good way to do it.

It isn't difficult to use the WebKit component. I'm not sure what you mean by "too heavy".

Cheers!

Answer 2

Another option is to use a rich text QML component which also supports images (e.g. TextEdit) rather than Image - then you can place them inline with normal text.