This is the repository for the Schulrechner App. You can get the APK directly from the releases or from F-Droid. You can also install the Linux-desktop version from Flathub or just open the web version. Alternatively you can build it yourself by installing Cordova and then running the steps in the Github CI.

If you want to contribute, just fork this repo and create a merge request. Please also create a quick issue with the label "Feature Request" where you describe what you plan to contribute. Maybe someone is already working on that.

For contributing new calculator designs please read the following:

This project supports multiple GUI designs, which can be switched dynamically.

To add a new GUI design:

1. Create your SVG file

   • Design your GUI as an SVG file, ensuring it meets the following requirements:
     • Use proper element labels (via the inkscape:label property) matching the keys found in www/img/gui/Classic_by_Joris Yidong Scholl.svg.
     • Include polygon elements named display_input and display_output.
     • Include elements scroll_x_order and scroll_y_border to define scrolling behavior.
     • For each key element (key_*), include a corresponding label_background_* element for button press animations (these are handled by CSS).
     • Optionally, add locale-specific labels by appending locale codes like label_,de-DE or label,_en-US. Only de-DE and en-US are supported for now.
   • Add SVG metadata specifying author, date, and an open-source license (e.g., CC0, CC-BY, CC-BY-SA) for compatibility with this GPL3 project.

2. Create your JSON file

   • There are some additional settings needed for a working calculator design
   • Please take a look at www/img/gui/Classic_by_Joris Yidong Scholl.json to see what these are

3. Create a pull request to add your SVG file to the repository

   • Place your GUI SVG and JSON in the www/img/gui/ folder in a pull request. They should be named "Design Name_by_Author Name.svg" and ".json"

4. I'll come test it then and we'll fix any possible errors together

https://github.com/CardiJey/schulrechner

Copyright (C) 2025 Joris Yidong Scholl [email protected]

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.

This project uses math.js https://github.com/josdejong/mathjs

Copyright (C) 2013-2025 Jos de Jong [email protected]

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.