# Math expression editing using an on-screen software keyboard or physical keyboard input in a typeset input field in Flutter.

### Related tags

Example Apps dart tex math flutter
##### Overview

math_keyboard is a Flutter package that allows editing math expressions using a typeset input field (so-called "math field") and a custom-made fully integrated math keyboard in Flutter only - no plugins, no web views.

The math_keyboard package provides a widget that behaves like a Flutter TextField with the same full integration, i.e. focus tree support, input decoration support, and both an on-screen software keyboard as well as physical keyboard input support. On top of that, the math field typesetting uses TeX and the package supports converting to math expressions (that e.g. can be used for calculation).

math_keyboard is an open source project with the aim of providing a way to edit math expression providing the best user experience in terms of input and UI as well as allowing accurate evaluation of the mathematical expressions entered by the user. This is used by the simpleclub app, hence, the association. It is also maintained by simpleclub (see the LICENSE file).

## Features & usage

See the package README for features and usage information.

You can also try the demo app or view the package on Pub →

## Implementation

In the following, some high-level information regarding the implementation of the package is described. This is useful in case you are curious or intend to contribute.

For information on implementing math_keyboard into your own app, please see the package README.

### Math expressions

Notice how the math_keyboard package includes a major feature that allows working with the input expressions in a mathematical matter, i.e. by converting them into "math expressions" (this is how we refer to the format in the context of this project).

We achieve this by essentially working with two formats:

• A data format, i.e. math expressions.

This "data format" depends on the math_expressions package. Handling the expressions in this format allows you to e.g. evaluate the expressions.

### TeX typesetting

Both the math field content, i.e. the expressions typed by the user, as well as some symbols on the keyboard itself are typeset using TeX. For TeX typesetting in Flutter, we created our own proof of concept renderer in early 2020, called CaTeX. This project is on-hold for now and in the meantime, we collaborated on the flutter_math package that aims to achieve something similar.
Due to lack of maintenance on that repo, we are currently using our forked version, flutter_math_fork. Note that our ultimate goal is fully integrating the math_keyboard package with the catex package, which would give us maximum control over the rendering of the typeset math.

## Contributing

Our mission with open source repositories like math_keyboard in particular is creating an ecosystem of science and education related packages for Flutter, allowing users on all platforms to use the optimal tools for learning.

This is also why we want to share and collaborate on this software as a way to give back to the community. Any contributions are more than welcome!

### Missing features

You might notice that some features that you would expect from the math_keyboard package are missing or something is not working as expected. In that case, please file an issue.

In general, we can of course never fully solve every use case, however, especially in this case we are aware of a few shortcomings. For example the customization options of the keyboard are currently limited because this has simply not yet been a requirement in our internal usage. In that case, please consider contributing pull requests to this repo in order to allow as many use cases to be covered as possible :) Please refer to the contributing guide for that.

### Repo structure

The math_keyboard repository is divided into multiple packages. These packages are the following:

Package Content
math_keyboard Main package implementation
math_keyboard_demo Demo app

## Num++ inspiration

During the research phase of this project, we came across the Num++ app, which served as an inspiration for the math expression parsing part of the package.
The main difference between that app and this package (apart from one being a calculator app and the other being a generalized usable package) is the fact that Num++ uses a web view and MathQuill for editing the expression while we built the input field and editing ourselves.

## Description

Bumps the version of a dependency, petitparser

## Related issues & PRs

Fix to https://github.com/simpleclub/math_keyboard/issues/35

## Checklist

• [x] I have made myself familiar with the CaTeX contributing guide.
• [x] I added a PR description.
• [x] I linked all related issues and PRs I could find (no links if there are none).
• [x] If this PR changes anything about the main math_keyboard or example package (also README etc.), I created an entry in CHANGELOG.md (## UPCOMING RELEASE if the change on its own is not worth an update).
• [x] All required checks pass.
opened by garv-shah 7

## Description

Adds parentheses for binary operators, when converting a math_expression to a tex ast. Adds special cases for pi and e when converting a math_expression to a tex ast. Removes the leading zero from an unary minus when converting tex into a math_expression.

## Related issues & PRs

https://simpleclub.atlassian.net/browse/SC-4183

## Checklist

Remove If [...] items that do not apply to your PR.

• [x] I have made myself familiar with the CaTeX contributing guide.
• [x] I added a PR description.
• [x] I linked all related issues and PRs I could find (no links if there are none).
• [x] If this PR changes anything about the main math_keyboard or example package (also README etc.), I created an entry in CHANGELOG.md (## UPCOMING RELEASE if the change on its own is not worth an update).
• [x] If this PR includes a notable change in the math_keyboard package, I updated the version according to Dart's semantic versioning.
• [x] If there is new functionality in code, I added tests covering all my additions.
• [x] All required checks pass.
opened by edhom 5

## Bug description

The package seems to be incompatible with Flutter SVG, as the dependency for petitparser is out of date, set to ^4.0.2

### To Reproduce

Steps to reproduce the behaviour:

1. Install math_keyboard
2. Install flutter_svg
3. Try to run app and observe error

## Expected behavior

For both packages to work together

### Error Log

Because math_keyboard >=0.0.1 depends on petitparser ^4.0.2 and xml >=5.4.0 depends on petitparser ^5.0.0, math_keyboard >=0.0.1 is incompatible with xml >=5.4.0.
And because flutter_svg 1.1.1+1 depends on xml ^6.0.1 and no versions of flutter_svg match >1.1.1+1 <2.0.0, math_keyboard >=0.0.1 is incompatible with flutter_svg ^1.1.1+1.
So, because app_name depends on both flutter_svg ^1.1.1+1 and math_keyboard ^0.1.6, version solving failed.
pub get failed (1; So, because app_name depends on both flutter_svg ^1.1.1+1 and math_keyboard ^0.1.6, version solving failed.)

bug
opened by garv-shah 4

## Description

• Use an updated version of flutter_math_fork 0.6.2 that introduces CursorNode and \cursor function
• Replace Cursor implementation via | symbol with \cursor
• Updated empty field offset dx from -4 to -1, since \cursor has smaller horizontal paddings

## Related issues & PRs

https://simpleclub.atlassian.net/browse/SC-4607

## Checklist

• [x] I have made myself familiar with the CaTeX contributing guide.
• [x] I added a PR description.
• [x] I linked all related issues and PRs I could find (no links if there are none).
• [x] If this PR changes anything about the main math_keyboard or example package (also README etc.), I created an entry in CHANGELOG.md (## UPCOMING RELEASE if the change on its own is not worth an update).
• [x] If this PR includes a notable change in the math_keyboard package, I updated the version according to Dart's semantic versioning.
• [x] If there is new functionality in code, I added tests covering all my additions.
• [x] All required checks pass.
opened by millerovv 3

## Description

This updates flutter_math_fork to the latest version.

n/a

## Checklist

• [x] I have made myself familiar with the CaTeX contributing guide.
• [x] I added a PR description.
• [x] I linked all related issues and PRs I could find (no links if there are none).
• [x] If this PR changes anything about the main math_keyboard or example package (also README etc.), I created an entry in CHANGELOG.md (## UPCOMING RELEASE if the change on its own is not worth an update).
• [x] If this PR includes a notable change in the math_keyboard package, I updated the version according to Dart's semantic versioning.
• [x] If there is new functionality in code, I added tests covering all my additions.
• [x] All required checks pass.
opened by edhom 1

## Description

Updates flutter_math_fork to the latest version.

## Checklist

• [x] I have made myself familiar with the CaTeX contributing guide.
• [x] I added a PR description.
• [x] I linked all related issues and PRs I could find (no links if there are none).
• [x] If this PR changes anything about the main math_keyboard or example package (also README etc.), I created an entry in CHANGELOG.md (## UPCOMING RELEASE if the change on its own is not worth an update).
• [x] If this PR includes a notable change in the math_keyboard package, I updated the version according to Dart's semantic versioning.
• [x] If there is new functionality in code, I added tests covering all my additions.
• [x] All required checks pass.
opened by edhom 1

## Description

This PR adds a new icon for the symbols page and a fraction button to the second page of the keyboard

| New icon for symbols | Fraction button | |---|---| |||

## Checklist

Remove If [...] items that do not apply to your PR.

• [x] I have made myself familiar with the CaTeX contributing guide.
• [x] I added a PR description.
• [x] If this PR changes anything about the main math_keyboard or example package (also README etc.), I created an entry in CHANGELOG.md (## UPCOMING RELEASE if the change on its own is not worth an update).
• [x] If this PR includes a notable change in the math_keyboard package, I updated the version according to Dart's semantic versioning.
• [ ] All required checks pass.
opened by tomkuschka 1

## Description

Previously, the comma styling looked like this:

This PR removes the padding and makes it look proper.

## Checklist

Remove If [...] items that do not apply to your PR.

• [x] I have made myself familiar with the CaTeX contributing guide.
• [x] I added a PR description.
• [x] I linked all related issues and PRs I could find (no links if there are none).
• [x] If this PR changes anything about the main math_keyboard or example package (also README etc.), I created an entry in CHANGELOG.md (## UPCOMING RELEASE if the change on its own is not worth an update).
• [x] If this PR includes a notable change in the math_keyboard package, I updated the version according to Dart's semantic versioning.
• [x] If there is new functionality in code, I added tests covering all my additions.
• [x] All required checks pass.
opened by creativecreatorormaybenot 1

## Description

Removes unnecessary nullability check warnings after Flutter 3.0.x upgrade.

## Checklist

Remove If [...] items that do not apply to your PR.

• [x] I added a PR description.
• [x] If this PR changes anything about the main math_keyboard or example package (also README etc.), I created an entry in CHANGELOG.md (## UPCOMING RELEASE if the change on its own is not worth an update).
• [x] If this PR includes a notable change in the math_keyboard package, I updated the version according to Dart's semantic versioning.
• [x] All required checks pass.
opened by millerovv 0

## Description

The TexParser did not consider an implicit times between a closing and an opening parenthesis. Examples for such cases:

• (1-x)(1+x)
• \\frac{1}{2}(25)
• e^{x}(1+x)

## Checklist

Remove If [...] items that do not apply to your PR.

• [x] I have made myself familiar with the CaTeX contributing guide.
• [x] I added a PR description.
• [x] I linked all related issues and PRs I could find (no links if there are none).
• [x] If this PR changes anything about the main math_keyboard or example package (also README etc.), I created an entry in CHANGELOG.md (## UPCOMING RELEASE if the change on its own is not worth an update).
• [x] If this PR includes a notable change in the math_keyboard package, I updated the version according to Dart's semantic versioning.
• [x] If there is new functionality in code, I added tests covering all my additions.
• [x] All required checks pass.
opened by edhom 0

## Description

Update version and add description to changelog

n/a

## Checklist

Remove If [...] items that do not apply to your PR.

• [x] I have made myself familiar with the CaTeX contributing guide.
• [x] I added a PR description.
• [x] I linked all related issues and PRs I could find (no links if there are none).
• [x] If this PR changes anything about the main math_keyboard or example package (also README etc.), I created an entry in CHANGELOG.md (## UPCOMING RELEASE if the change on its own is not worth an update).
• [x] If this PR includes a notable change in the math_keyboard package, I updated the version according to Dart's semantic versioning.
• [x] If there is new functionality in code, I added tests covering all my additions.
• [x] All required checks pass.
opened by edhom 0

## Bug description

When trying to add fractions into the mathtextfield they end up giving a parser error after trying to edit

### To Reproduce

try editing the fraction using the math keyboard.

## Expected behavior

It would be great if you could add fractions into the mathfield by using addLeaf(). Maybe I'm just not looking in the right places for this functionality.

"Parser Error: Expected '}', got 'EOF' makes sense since I'm deleting the bracket, but how do I make the fraction editable in the mathtextfield?

bug
opened by AlgebraicFloat 1
• #### Error when I want to convert a math problem to an expression

Hello and thank you first of all that you have put so much effort into the package and make it available to us.

Actually everything works very well, I only have a single problem. To help you understand the problem, maybe I should briefly describe my situation: I am currently working on a math app and get a LaTeX string result, which I would like to edit with your package. So as soon as a MathField is created, I want to give it a MathFieldEditingController and change the value with mathFieldEditingController.updateValue('...'); with my LaTeX value when initializing the class. This all works very well, if I take the examples from your or the math_expressions package.

But if I want to take the LaTeX string from me and convert it to an expression I always get an error. I tried it with the TeXParser('...').parse();, as well as the Expression expression = parser.parse('...'); method. I also tried several times to transform the string somehow so that the expression can be created, however it did not work.

Of course it could be that I don't understand the method somehow, but can someone help me and tell me how to put the LaTeX string from me into your MathField?

Here you also have a few examples with the values and the exceptions that occurred, so that you understand even better what exactly I mean:

bug
opened by musiolmarco 1
• #### Parentheses with \left and \right

When I was writing, using normal parentheses, if I entered internal fractions, the parenthesis was visibly small and not beautiful.

So I tried to change the normal parenthesis to \left or \right, but each needs the other, and when the user writes the expression starting with opening the parenthesis '\left(' the system fails because it does not find the \right.

So I tried to create a button for myself, in order to create both the \left (and the \right) and let the user type in between. However, I'm not sure how to set it up, I've tried several cases but I don't understand how to do it or if it's possible.

bug
opened by Francesco-FL 1

## Bug description

node.buildTeXString() seems to have a cursorColor property, but it really shouldn't need one. All it does is append something like \textcolor{#000000}{\cursor} to the end of tex string, and it seems to break loading it back into the MathField document

### To Reproduce

Steps to reproduce the behavior: Get a MathFieldEditingController and call .currentNode.buildTexString() and try to load the string back in

## Expected behavior

bug
opened by garv-shah 1

• #### math_keyboard-v0.0.1+2(Mar 17, 2021)

###### simpleclub
Germany's most popular digital learning platform. Personalised learning, powered by the best content. For 1M+ people.
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