Credits & licenses

Open-source licenses

VizLearn's hand-drawn rendering stands on open-source software. These are the libraries we owe attribution to — including the code we ported directly into our own source — with their licenses in full.

Excalidraw

MIT

The hand-drawn look started here — Excalidraw is the best hand-drawn canvas on the web, and reading its renderer is how we learned to draw clean rounded shapes. We don't ship the Excalidraw editor itself, but two geometry helpers in our drawing layer are ported from it.

Ported into src/components/rough/utils.ts: getCornerRadius (adaptive corner radius) and adjustRoughness (size-aware roughness), including their constants.

Project repository

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MIT License

Copyright (c) 2020 Excalidraw

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Rough.js

MIT

The drawing primitive every lesson renders with — the library that gives each shape its hand-drawn wobble. VizLearn builds its whole canvas on top of it.

Project repository

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MIT License

Copyright (c) 2019 Preet Shihn

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

VizLearn depends on much more open-source software than the two libraries highlighted here; the complete dependency tree and its licenses live in the project's package.json. The entries above are the ones whose code we ship or adapt directly in our rendering layer.