On Thursday, 26 January 2023 at 20:59:17 UTC+13 bapt a wrote:
Hi,I'd like to extract all math equations from my lecture notes (and potentially images too, at some stage) and produce a json file suitable for Excalidraw, so that students could reorganise them, sketch notes collaboratively, etc.:(note that this is using a user-contributed extension*; the plain version of Excalidraw does not support Mathjax or Asciimath).From an equation like this in the source document (beamer tex):```\[\begin{aligned}\nabla\cdot\mathbf{D}&= \rho_f\\\nabla\cdot\mathbf{B}&= 0\\\nabla\times\mathbf{E}&= -\frac{\partial\mathbf{B}}{\partial t}\\\nabla\times\mathbf{H}&= \frac{\partial\mathbf{D}}{\partial t} + \mathbf{J}_f\end{aligned}\]```the full json file suitable for import in Excalidraw looks like:```{"type": "excalidraw","version": 2,"elements": [{"type": "text","version": 104,"versionNonce": 669974443,"isDeleted": false,"id": "iL0y7olLhWzLKVTzIffR1","fillStyle": "hachure","strokeWidth": 1,"strokeStyle": "solid","roughness": 1,"opacity": 100,"angle": 0,"x": 418,"y": -186,"strokeColor": "#000000","backgroundColor": "transparent","width": 202,"height": 169,"seed": 1021462275,"groupIds": [],"roundness": null,"boundElements": [],"updated": 1674718443076,"link": null,"locked": false,"subtype": "math","customData": {"useTex": true,"mathOnly": true,"ariaLabel": "\\begin{aligned} \\nabla\\cdot\\mathbf{D}&= \\rho_f\\\\ \\nabla\\cdot\\mathbf{B}&= 0\\\\ \\nabla\\times\\mathbf{E}&= -\\frac{\\partial\\mathbf{B}}{\\partial t}\\\\ \\nabla\\times\\mathbf{H}&= \\frac{\\partial\\mathbf{D}}{\\partial t} + \\mathbf{J}_f \\end{aligned}"},"fontSize": 20,"fontFamily": 2,"text": "\\begin{aligned}\n\\nabla\\cdot\\mathbf{D}&= \\rho_f\\\\\n\\nabla\\cdot\\mathbf{B}&= 0\\\\\n\\nabla\\times\\mathbf{E}&= -\\frac{\\partial\\mathbf{B}}{\\partial t}\\\\\n\\nabla\\times\\mathbf{H}&= \\frac{\\partial\\mathbf{D}}{\\partial t} + \\mathbf{J}_f\n\\end{aligned}","baseline": 91,"textAlign": "left","verticalAlign": "top","containerId": null,"originalText": "\\begin{aligned}\n\\nabla\\cdot\\mathbf{D}&= \\rho_f\\\\\n\\nabla\\cdot\\mathbf{B}&= 0\\\\\n\\nabla\\times\\mathbf{E}&= -\\frac{\\partial\\mathbf{B}}{\\partial t}\\\\\n\\nabla\\times\\mathbf{H}&= \\frac{\\partial\\mathbf{D}}{\\partial t} + \\mathbf{J}_f\n\\end{aligned}"},{"type": "text","version": 111,"versionNonce": 1291434347,"isDeleted": false,"id": "xzGehwC0igI1rh-jYddgb","fillStyle": "hachure","strokeWidth": 1,"strokeStyle": "solid","roughness": 1,"opacity": 100,"angle": 0,"x": 754,"y": 32,"strokeColor": "#000000","backgroundColor": "transparent","width": 194,"height": 24,"seed": 315800227,"groupIds": [],"roundness": null,"boundElements": [],"updated": 1674718439209,"link": null,"locked": false,"subtype": "math","customData": {"useTex": true,"mathOnly": true,"ariaLabel": "\\mathbf{F}= q\\left(\\mathbf{E}+ \\mathbf{v}\\times \\mathbf{B}\\right)"},"fontSize": 20,"fontFamily": 2,"text": "\\mathbf{F}= q\\left(\\mathbf{E}+ \\mathbf{v}\\times \\mathbf{B}\\right)","baseline": 18,"textAlign": "left","verticalAlign": "top","containerId": null,"originalText": "\\mathbf{F}= q\\left(\\mathbf{E}+ \\mathbf{v}\\times \\mathbf{B}\\right)"}],"appState": {"gridSize": null,"viewBackgroundColor": "#ffffff"},"files": {}}```Obviously there isn't a one-to-one mapping between a typical input document and what's possible or even desirable in a whiteboard context, but for the limited scope of producing a bunch of equations automatically, it would be very nice to have a pandoc writer.At the moment I'm using a lua filter someone kindly contributed on this mailing list, to simply extract all maths from an input file,```_ENV = pandoclocal math_elements = List{}return {-- first document pass{Math = function (m)local comment = "math start"math_elements:insert(comment)math_elements:insert(m)end},-- second document pass{Pandoc = function (_) return Pandoc(math_elements:map(Plain)) end},}```I then use a custom script (I wrote it in R since I'm more fluent in it) to produce suitable json (https://github.com/baptiste/minixcali/blob/main/R/elements.R#L227)It works, but I feel this last step should really be implemented as a custom Writer, especially if other people want to try this; unfortunately, my lua skills are currently very limited. Any pointers / starter / suggestions would be much appreciated!Best regards,baptiste*: fantastic work by user DanielJGeiger, https://github.com/excalidraw/excalidraw/pull/6037
