Efficient matplotlib use on iOS and Android apps

Community matplotlib-users
1

Hi,

I need to render LaTeX math formulas on mobile apps (iOS/Android), with high
quality, and as efficiently as possible.

I'm considering matplotlib as the best candidate at the moment. Maybe it
might be a bit overkill because I don't need plotting, just math formulas
rendering, but it has a "copycenter" license (very welcome when you target
iOS), and it seems to render LaTeX math with high quality. So I think it
beats other options I found (MathGL: copyleft license; and MathJax: setting
a complete Javascript engine just for rendering math does seem overkill to
me).

However, I still have some doubts before choosing matplotlib:

1) Can I redirect the output of math rendering to OpenGL calls, or convert
it into a 2D triangle mesh for example? (if the drawing commands issued by
matplotlib when rendering math are a relatively small set, I can translate
them to OpenGL myself, but I need to know where should I do that translation
(I've zero idea about matplotlib internals, and I'm a Python newbie -I'm
here because I need math rendering, not because I use Python).

(note that I wish to render through OpenGL because I want to be able to
interactively pan and zoom math very efficiently: the best approach would be
to cache the matplotlib output as a -for example- 2D triangle mesh, and then
just send the triangles to OpenGL, without having to call matplotlib on each
screen redraw, which would kill performance)

2) In order to get matplotlib running as efficient as possible on mobile
devices, would you recommend that I translate matplotlib to C/C++ using any
of the translators available? If affirmative, what translator would you
suggest me to use?

Thanks a lot!!

···

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2

why not use MathJax?

···

On Thu, Jul 9, 2015 at 8:03 AM, asiga <asiganael@…9…> wrote:

Hi,

I need to render LaTeX math formulas on mobile apps (iOS/Android), with high

quality, and as efficiently as possible.

I’m considering matplotlib as the best candidate at the moment. Maybe it

might be a bit overkill because I don’t need plotting, just math formulas

rendering, but it has a “copycenter” license (very welcome when you target

iOS), and it seems to render LaTeX math with high quality. So I think it

beats other options I found (MathGL: copyleft license; and MathJax: setting

a complete Javascript engine just for rendering math does seem overkill to

me).

However, I still have some doubts before choosing matplotlib:

  1. Can I redirect the output of math rendering to OpenGL calls, or convert

it into a 2D triangle mesh for example? (if the drawing commands issued by

matplotlib when rendering math are a relatively small set, I can translate

them to OpenGL myself, but I need to know where should I do that translation

(I’ve zero idea about matplotlib internals, and I’m a Python newbie -I’m

here because I need math rendering, not because I use Python).

(note that I wish to render through OpenGL because I want to be able to

interactively pan and zoom math very efficiently: the best approach would be

to cache the matplotlib output as a -for example- 2D triangle mesh, and then

just send the triangles to OpenGL, without having to call matplotlib on each

screen redraw, which would kill performance)

  1. In order to get matplotlib running as efficient as possible on mobile

devices, would you recommend that I translate matplotlib to C/C++ using any

of the translators available? If affirmative, what translator would you

suggest me to use?

Thanks a lot!!

–

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3

Why do you suggest MathJax? I assume Javascript will be less efficient than
Python. Moreover, I'm not sure I can get the MathJax output as polygonal
primitives that I can send to OpenGL. And, to complicate things, you cannot
use JIT Javascript engines on iOS such as V8, due to sandboxing.

In fact, I'm considering to build myself a minimal LaTeX distro. Maybe that
would be the best option.

···

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4

The way matplotlib does its MathText rendering is 1) incomplete (we don’t support all of MathTex), and 2) has massive overhead (relatively speaking). Matplotlib is intended for producing figures with many disparate components. The amount of code it takes to just generate a simple plot is fairly significant (along with also firing up a python interpreter). Meanwhile, MathJax is much lighter in the sense that all it needs to do is parse a string and render out font characters.

As for matplotlib vs. MathJax, you will likely sending bitmaps to OpenGL (if possible) anyway because that is pretty much what you will need to do with matplotlib as well as MathJax. It is technically possible to obtain the stroke data to send the font lines to OpenGL, but it will not look the same as it would if you let a font renderer generate the bitmap. There are a few reasons why matplotlib does not have an OpenGL backend yet, one of them is because OpenGL does a terrible job in rendering text.

This is not to say that what you are thinking of doing is impossible to do. It may be quite possible, but given that no one (that I am aware of) have managed to get matplotlib running on a mobile OS, you have a huge undertaking ahead of you just to get started. And, once you get there, it is quite likely that the performance won’t be what you need. In addition, you might not like the resulting render. More power to you if you can get it working, and I know many people who are interested in getting that stack working on tablets and such.

On the other hand, there are plenty of documentation on how to build mobile apps that take advantage of javascript-based technologies. Your startup cost is very low here. And given that you will likely going to need to use bitmaps anyway, it might not be all that bad of an option. I have no clue what the performance penalty of firing up a javascript renderer on a mobile OS, but in the face of the unknown, I avoid guessing. Don’t fall victim to premature optimization. I have been very surprised at how fast certain (slow) technologies can be.

A minimalist LaTeX distro is an intriguing idea. I have no clue how much effort it would take to do that, but that may be quite feasible.

Best of luck to you, and I look forward to finding out what you manage to get working.

Cheers!

Ben Root

···

On Fri, Jul 10, 2015 at 4:37 AM, asiga <asiganael@…9…> wrote:

Why do you suggest MathJax? I assume Javascript will be less efficient than

Python. Moreover, I’m not sure I can get the MathJax output as polygonal

primitives that I can send to OpenGL. And, to complicate things, you cannot

use JIT Javascript engines on iOS such as V8, due to sandboxing.

In fact, I’m considering to build myself a minimal LaTeX distro. Maybe that

would be the best option.

–

View this message in context: http://matplotlib.1069221.n5.nabble.com/Efficient-matplotlib-use-on-iOS-and-Android-apps-tp45901p45914.html
Sent from the matplotlib - users mailing list archive at Nabble.com.

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GigeNET’s Cloud Solutions provide you with the tools and support that

you need to offload your IT needs and focus on growing your business.

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https://www.gigenetcloud.com/

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