Equation style display

• Dear all,

I was wondering if there is a way to get the "pretty formatted" version of an equation (from an NSString) to display within a view (similar to the way Graph.app displays it).
The question is open, any means is acceptable (if not too far-fetched).
I know I can get a .png version using a call to a php script, but since MAC OS already ships with softwares capable of doing it, maybe there is a more elegant (and simple) way of implementing this feature.

Any idea ?

With my thanks,
Jean
• Would not NSAttributedString be of use?

-koko

On Jul 2, 2012, at 9:55 AM, Jean Suisse wrote:

> Dear all,
>
> I was wondering if there is a way to get the "pretty formatted" version of an equation (from an NSString) to display within a view (similar to the way Graph.app displays it).
> The question is open, any means is acceptable (if not too far-fetched).
> I know I can get a .png version using a call to a php script, but since MAC OS already ships with softwares capable of doing it, maybe there is a more elegant (and simple) way of implementing this feature.
>
> Any idea ?
>
> With my thanks,
> Jean
>
• Le 2 juil. 2012 à 17:55, Jean Suisse a écrit :

> Dear all,
>
> I was wondering if there is a way to get the "pretty formatted" version of an equation (from an NSString) to display within a view (similar to the way Graph.app displays it).
> The question is open, any means is acceptable (if not too far-fetched).
> I know I can get a .png version using a call to a php script, but since MAC OS already ships with softwares capable of doing it, maybe there is a more elegant (and simple) way of implementing this feature.
>
> Any idea ?
>

Using MathML and a WebView ?

That said, I don't know what version of the WebKit (and so Mac OS) is required to use MathML.

There is some javascript/css library that let you display them properly if MathML is not supported like http://www.mathjax.org

> With my thanks,
> Jean
>

-- Jean-Daniel
Well, I don't know about the Attributed String. The idea is to get the pretty print of thing like

(9/10) * sin( x/(2*t) )

without having to process the string myself.

On 2 juil. 2012, at 18:15, koko wrote:

> Would not NSAttributedString be of use?
>
> -koko
>
> On Jul 2, 2012, at 9:55 AM, Jean Suisse wrote:
>
>> Dear all,
>>
>> I was wondering if there is a way to get the "pretty formatted" version of an equation (from an NSString) to display within a view (similar to the way Graph.app displays it).
>> The question is open, any means is acceptable (if not too far-fetched).
>> I know I can get a .png version using a call to a php script, but since MAC OS already ships with softwares capable of doing it, maybe there is a more elegant (and simple) way of implementing this feature.
>>
>> Any idea ?
>>
>> With my thanks,
>> Jean
>>
>
• Thank you for your reply. I will investigate this possibility.
Does it take much space for the rendering ? I mean, I would like to display it inside a panel (something like a sheet, or an inspector).

The pretty print is just a feature that would allow the user to quickly spot any mistake in an equation.

On 2 juil. 2012, at 18:23, Jean-Daniel Dupas wrote:

>
> Le 2 juil. 2012 à 17:55, Jean Suisse a écrit :
>
>> Dear all,
>>
>> I was wondering if there is a way to get the "pretty formatted" version of an equation (from an NSString) to display within a view (similar to the way Graph.app displays it).
>> The question is open, any means is acceptable (if not too far-fetched).
>> I know I can get a .png version using a call to a php script, but since MAC OS already ships with softwares capable of doing it, maybe there is a more elegant (and simple) way of implementing this feature.
>>
>> Any idea ?
>>
>
> Using MathML and a WebView ?
>
> That said, I don't know what version of the WebKit (and so Mac OS) is required to use MathML.
>
> There is some javascript/css library that let you display them properly if MathML is not supported like http://www.mathjax.org
>
>> With my thanks,
>> Jean
>>
>
> -- Jean-Daniel
>
>
>
>
• On Jul 2, 2012, at 8:55 AM, Jean Suisse wrote:

> I was wondering if there is a way to get the "pretty formatted" version of an equation (from an NSString) to display within a view (similar to the way Graph.app displays it).
> The question is open, any means is acceptable (if not too far-fetched).
> I know I can get a .png version using a call to a php script, but since MAC OS already ships with softwares capable of doing it, maybe there is a more elegant (and simple) way of implementing this feature.

I'm pretty certain there's nothing already installed to do that, unless maybe WebKit has support for MathML?

—Jens
• Well, it seems that all paths leads towards Webkit and MathML… which unfortunately requires some parsing / rewriting, even for simple equations…
Thank you Jens.

Best regards,
Jean

On 2 juil. 2012, at 18:45, Jens Alfke wrote:

>
> On Jul 2, 2012, at 8:55 AM, Jean Suisse wrote:
>
>
> I'm pretty certain there's nothing already installed to do that, unless maybe WebKit has support for MathML?
>
> —Jens
• Hi Jean,

In terms of parsing, I've written a library to help with that:  https://github.com/davedelong/DDMathParser/  You'll probably want to do something like this:

NSString *equation = @"(9/10) * sin( $x/(2*$t) )";  // note that variables need a \$ in front of them, for simplicity
NSError *error = nil;
DDExpression *expression = [DDExpression expressionFromString:equation error:&error];

Assuming parsing succeeds, it should be relatively straight-forward to recurse through the resulting expression object and build up the MathML string you need.

Feel free to contact me off-list if you have specific questions.

Cheers,

Dave

On Jul 2, 2012, at 10:19 AM, Jean Suisse wrote:

> Well, it seems that all paths leads towards Webkit and MathML… which unfortunately requires some parsing / rewriting, even for simple equations…
> Thank you Jens.
>
> Best regards,
> Jean
• Mathematical typesetting is actually incredibly complex, and people like Donald Knuth have dedicated significant portions of their careers to it. There's no simple way to go from a textual representation of a formula to a typeset version, not least of which because there's no universally agreed-upon textual representation or typeset version.

I'd also recommend using a web view to display an equation, along with one of the JavaScript TeX-to-HTML rendering packages. Stack Exchange uses one for their Mathematics Q&A site that seems to work pretty well. However, note that it's not instant.

-- Chris

On Jul 2, 2012, at 8:55 AM, Jean Suisse <jean.lists...> wrote:

> Dear all,
>
> I was wondering if there is a way to get the "pretty formatted" version of an equation (from an NSString) to display within a view (similar to the way Graph.app displays it).
> The question is open, any means is acceptable (if not too far-fetched).
> I know I can get a .png version using a call to a php script, but since MAC OS already ships with softwares capable of doing it, maybe there is a more elegant (and simple) way of implementing this feature.
>
> Any idea ?
>
> With my thanks,
> Jean
• Dave, Chris,

Thank you so much for your reply. I did check the library at https://github.com/davedelong/DDMathParser/. It incredibly nice. I am grateful to Dave for developing & sharing it.
Il will now investigate the parsing + mathML conversion combined with rendering possibility.

Thanks all for helping me to go forward with my project.
Jean

On 2 juil. 2012, at 21:01, Chris Hanson wrote:

> Mathematical typesetting is actually incredibly complex, and people like Donald Knuth have dedicated significant portions of their careers to it. There's no simple way to go from a textual representation of a formula to a typeset version, not least of which because there's no universally agreed-upon textual representation or typeset version.
>
> I'd also recommend using a web view to display an equation, along with one of the JavaScript TeX-to-HTML rendering packages. Stack Exchange uses one for their Mathematics Q&A site that seems to work pretty well. However, note that it's not instant.
>
> -- Chris
>
> On Jul 2, 2012, at 8:55 AM, Jean Suisse <jean.lists...> wrote:
>
>> Dear all,
>>
>> I was wondering if there is a way to get the "pretty formatted" version of an equation (from an NSString) to display within a view (similar to the way Graph.app displays it).
>> The question is open, any means is acceptable (if not too far-fetched).
>> I know I can get a .png version using a call to a php script, but since MAC OS already ships with softwares capable of doing it, maybe there is a more elegant (and simple) way of implementing this feature.
>>
>> Any idea ?
>>
>> With my thanks,
>> Jean
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