Kings CalcLaTeX

A browser-native Obsidian plugin that turns your vault into an engineering math workstation. Type LaTeX with trigger suffixes, and results or interactive graphs appear inline in your notes — no backend server, no external dependencies. It also extends into Excalidraw: canvas text auto-renders into equation images, and the full LaTeX Suite snippet engine (tabstops, auto-fraction, Greek letters, conceal, bracket coloring) works both in Markdown notes and inside Excalidraw's own "Edit LaTeX" modal.

Features

Inline Evaluation

Type LaTeX inside $...$ and add a trigger suffix:

Symbolic CAS

Differentiation, integration, solving, factoring — all in-browser.

$x^3 + 2x @diff$               → 3x² + 2
$3x^2 + 2 @int$                → x³ + 2x
$x^2 - 4 = 0 @solve$           → x = ±2
$x^2 - 5x + 6 @factor$         → (x-2)(x-3)
$x^3 - 8 @factor$              → (x-2)(x²+2x+4)

Factoring handles sum/difference of cubes and additional trig identities in simplification.

Advanced CAS (Giac WASM)

Optional 19MB WASM engine for limits, Taylor series, partial fractions, expand, step-by-step solutions, and enhanced solving/integration.

$\frac{\sin(x)}{x} @limit$     → 1
$e^x @taylor$                  → 1 + x + x²/2 + x³/6 + ...
$\frac{1}{x^2-1} @partfrac$    → partial fraction decomposition
$(x+1)^3 @expand$              → x³ + 3x² + 3x + 1
$x^2 - 5x + 6 @steps$         → step-by-step solution walkthrough

2D Graphing

Explicit, implicit, parametric, polar curves, inequalities, and multi-equation overlays with interactive pan/zoom. Download any graph as PNG via the toolbar.

$y = \sin(x) @plot2d$
$x^2 + y^2 = 25 @plot2d$
$r = 1 + \cos(\theta) @plot2d$
$y > \sin(x) @plot2d$
$y = a\sin(bx) @plot2d$          ← auto-generates sliders for a, b
$(5,5) @plot2d$                  ← renders as filled dot
$y = \begin{cases} x^2 & x > 0 \\ -x & x \leq 0 \end{cases} @plot2d$
$y = \sin(x) \{0 < x < 2\pi\} @plot2d$

Free variables auto-generate sliders with editable min/max bounds.

3D Graphing

WebGL surfaces, implicit surfaces (marching cubes), parametric curves, vectors, and points with click-to-interact rotation. All three axes use 1:1:1 proportional scaling by default (consistent with Desmos/GeoGebra behavior). Analytical planes fill the full bounding box with no diamond artifacts. Explicit surfaces use height-based coloring (blue-to-red gradient by z-value) for Desmos-style visualization.

$z = x^2 + y^2 @plot3d$
$x^2 + y^2 + z^2 = 9 @plot3d$
$(\cos(t), \sin(t), t/3) @plot3d$
$\langle 1, 2, 3 \rangle @plot3d$
$(1,2,3) @plot3d$                ← renders as sphere

Multivariable Calculus

Partial derivatives, gradients with contour overlays, surface normals, tangent planes.

$x^2 y + y^3 @px$              → 2xy
$x^2 + y^2 @gradient$          → ∇f = (2x, 2y) with contour + arrow plot
$z = x^2 + y^2 @normal$        → n = (2x, 2y, -1)
$x^2 + y^2; (1,1) @tangent$    → tangent plane visualization

Linear Algebra

Matrix multiplication, determinants, transpose, inverse, cross product, dot product.

$\begin{pmatrix}1 & 2\\3 & 4\end{pmatrix}\begin{pmatrix}5 & 6\\7 & 8\end{pmatrix} =$
$\det\begin{pmatrix}1 & 2\\3 & 4\end{pmatrix} =$
$\begin{pmatrix}1 & 0 & 0\end{pmatrix}\times\begin{pmatrix}0 & 1 & 0\end{pmatrix} =$

ODE Phase Portraits

Solve first-order ODEs numerically — direction field + solution curves via RK4.

$y' = x - y @phase$            → direction field + solution curves
$y' = y(1-y) @ode$             → direction field only

Laplace Transforms (Giac WASM)

$t^2 @laplace$                 → 2/s³
$\frac{1}{s^2+1} @ilaplace$   → sin(t)

Per-Expression Colors & Line Styles

$y = \sin(x) #red; y = \cos(x) #blue @plot2d$
$y = x^2 --; y = -x .. @plot2d$    ← dashed and dotted

Vector Fields & Contour Plots

$-y; x @vecfield$              → rotation field
$x^2 + y^2 @contour$           → concentric contour lines
$y = x^2; y = 2x @region$      → shaded region between curves

Unit Conversion

$5\text{ft} \to \text{m} @convert$     → 1.524 m
$100\text{kg} \to \text{lb} @convert$   → 220.462 lb

LaTeX Suite Snippet Engine (Markdown Notes)

The full LaTeX Suite snippet-expansion engine is vendored directly into the editor — no separate plugin required. Inside any $...$/$$...$$ block:

mk           → $ | $                (inline math block, cursor in the middle)
dm           → $$ | $$              (display math block, cursor in the middle)
sr           → ^2                   (superscript squared)
sq           → \sqrt{ }             (square root, cursor inside)
fra          → \frac{ }{ }          (fraction, cursor in numerator)
pmat         → \begin{pmatrix} ... \end{pmatrix}

Tab jumps between tabstops after a snippet expands. Also included: Greek-letter and symbol shortcuts, matrix-environment shortcuts, tabout (Tab exits the current bracket/subscript at the end of an expression), concealed LaTeX commands (rendered as their symbol until the cursor is nearby), color-matched/highlighted bracket pairs, and a hover math-preview tooltip. Every knob (custom snippets, trigger characters, regex snippets, conceal timing, bracket coloring, etc.) is configurable under Settings → LaTeX Suite Features.

Excalidraw OD (On-Demand Math Companion)

Turns Excalidraw canvases into a math-aware surface, entirely through this plugin (no changes to Excalidraw itself). Enable/configure under Settings → Excalidraw OD Features.

• Auto-render on blur: type $x^2 + 1$ or $$...$$ into a canvas text element and click away — it's automatically replaced with a rendered LaTeX equation image (MathJax SVG), the same as pasting/creating a math element directly.
• Same real snippet engine, on canvas too: the identical LaTeX Suite engine used in Markdown notes (see above) also drives Excalidraw's text-editing overlays and its native "Edit LaTeX" equation-editor modal — snippets, tabstops, auto-fraction, matrix shortcuts, conceal, and bracket coloring all work identically in both places.
• Enhanced "Edit LaTeX" modal:
  • Live rendered MathJax preview as you type (Excalidraw's own modal doesn't include one).
  • Inline color picker (\color{...}) and a border/box panel (\bbox[...]{...}) for quickly styling an equation without hand-writing the LaTeX.
  • Configurable cursor start position (end of equation by default, so continuing/appending doesn't require a manual click — or start, if you prefer).
  • Configurable modal window position (bottom/top/center/near cursor).
  • The modal is width-capped to the Excalidraw pane it was opened from (won't overflow into a split-screen neighbor), and long equations pan horizontally to keep the cursor in view instead of clipping off-screen.
  • Quick-open shortcut on a selected equation element (default Ctrl + L, configurable modifier/key).
• Element styling shortcuts: with elements selected, left-hand keyboard shortcuts cycle common style properties without touching the mouse — default Shift + F (line style: solid/dashed/dotted), Shift + D (stroke width), Shift + X (edge roundness), Shift + Q (sloppiness/roughness). A number key (1–4) picks a specific variant directly, and a floating HUD shows the active options. All trigger keys and the modifier are configurable.
• Text underline toggle: adds an underline button directly into Excalidraw's own text-properties panel when a text element is selected.
• Drawing snapshot/restore (Command Palette): Excalidraw regenerates equation images from their stored LaTeX source on every load, rescaling each one back to its current on-canvas size -- a step that has proven fragile in practice and can silently reset manually-resized equations back to their natural size after a reload. Two commands protect against this:
  • "Kings CalcLaTeX — Excalidraw: Snapshot current drawing (element positions/sizes)": captures every element's current x/y/width/height/angle and saves it as a timestamped JSON file next to the drawing (e.g. MyDrawing.snapshot.2026-08-01_14-30-00.json).
  • "Kings CalcLaTeX — Excalidraw: Restore current drawing from a snapshot": lists every snapshot found for the current drawing, and after picking one, restores only the elements whose position/size actually drifted from the snapshot -- anything added or removed since is left untouched.
  • Snapshot before any big resizing session (e.g. building a formula sheet), and again whenever you're happy with the layout -- if a reload ever resets sizes, restoring is one command instead of manually re-resizing everything.

All Triggers

Installation

From Community Plugins (recommended)

1. Open Settings > Community Plugins > Browse
2. Search for "Kings CalcLaTeX"
3. Click Install, then Enable

Manual Installation

1. Download main.js, manifest.json, and styles.css from the latest release
2. Create folder .obsidian/plugins/kings-calclatex/
3. Place the three files inside
4. Reload Obsidian and enable the plugin in Settings

Excalidraw OD features require the Excalidraw community plugin to also be installed and enabled — they're inert without it.

Enabling Giac WASM (optional)

For advanced CAS operations (@limit, @taylor, @partfrac, @expand, @steps, enhanced @solve/@int):

1. Download giacwasm.js (19 MB) from [Giac WASM builds](https://www-fourier.univ-grenoble-alpes.fr/parMDisse/giac/giac_online/giacwasm.js)
2. Place it in .obsidian/plugins/kings-calclatex/giacwasm.js
3. Enable "Giac WASM" in plugin settings
4. Reload Obsidian — look for "Giac WASM initialized" in console

Tech Stack

Settings

Settings are organized into three sections:

1. Markdown Note Features — evaluation/graphing behavior in .md files:

2. Excalidraw OD Features — canvas math companion (see above): modal position/cursor behavior, snippet/preview toggles, the "Edit LaTeX" quick-open shortcut, and the element-styling shortcut keys/modifier/HUD toggle.

3. LaTeX Suite Features — snippet engine behavior (applies to both Markdown notes and Excalidraw): inline/display math triggers, tabstop navigation, auto-fraction, matrix shortcuts, conceal, bracket coloring/highlighting, math-preview tooltip, custom/regex snippets, and related fine-tuning.

There are ~70 individual settings across these sections — open Settings → Kings CalcLaTeX in Obsidian for the full, current list with descriptions; this README covers the highlights.

Development

git clone https://github.com/kingsleyfong/King-s-CalcLatex.git
cd repo-v2
npm install
npm run dev     # Watch mode
npm run build   # Production build

Changelog

See CHANGELOG.md for the full version history.

License

MIT