Grapher

An Obsidian plugin that renders mathematical equations as graphs directly in your notes using a grapher code block.

Repository: https://github.com/jsglazer/grapher-dev

---

Usage

Create a fenced code block with the language set to grapher:

```grapher
eq: f(x) = x^3 - 3x^2 - 4x
axis: #c2c2c2
lines: #1e56d9
linewidth: 2px
render: 60%
```

---

Parameters

Global options

Parameter	Description	Example
title:	Graph title displayed at the top in a white box	title: My Graph
axis:	Color of axes, tick marks, and grid	axis: #c2c2c2
render:	Width of the rendered graph (px or %)	render: 50% or render: 400px
scalex:	X-axis range. Two values = min,max. Single value = symmetric ±n. Omit for auto.	scalex: -10,10 or scalex: 5
scaley:	Y-axis range. Same format as scalex.	scaley: -2,2 or scaley: 3
EqLoc:	Position of equation label on the graph. Options: left, right, above, below. Omit to hide.	EqLoc: left
params:	Named constants available to all equations, comma-separated name=value pairs.	params: n=3, a=2

Constants (params)

Use params: to define named constant values that can be referenced in any equation. This is useful for equations with variable exponents, scaling factors, or any expression that depends on a value you want to change without rewriting the equation.

eq: f(x) = x^{1/n}
params: n=3

Multiple constants are comma-separated:

eq: f(x) = a * x^{1/n}
params: n=3, a=2

Params apply to all equations in the block, so you can share a constant across curves:

```grapher
eq1: f(x) = x^{1/n}
eq2: g(x) = x^{2/n}
params: n=3
axis: #c2c2c2
EqLoc: right
```

When EqLoc: is set, param values are shown in the equation label below the curve list.

Note: Only x is the free variable. Every other letter in an equation must be given a value via params:, otherwise the curve will not render.

---

Per-equation options

Single equation — use eq: with options at the global level:

eq: f(x) = x^2
lines: #1e56d9
linewidth: 2px
intx: true

Multiple equations — use eq1:, eq2:, etc. with per-equation sub-options prefixed by -. eq: is not valid when graphing multiple equations.

eq1: f(x) = x^2
 - lines: #1e56d9
 - linewidth: 2px
 - intx: true
eq2: g(x) = x + 1
 - lines: #d91e1e
 - linewidth: 1px

Parameter	Description	Example
eq:	Equation key for a single equation only.	eq: f(x) = sin(x)
eq1: / eq2: / eq3: ...	Equation keys for multiple equations.	eq1: f(x) = x^2
lines:	Curve color (hex)	lines: #1e56d9
linewidth:	Stroke width in px	linewidth: 2px
intx:	Plot x-intercepts with coordinate labels	intx: true
inty:	Plot y-intercept with coordinate label	inty: true

---

Supported expressions

Grapher uses math.js for evaluation. Supported syntax includes:

• Polynomials: x^3 - 3x^2 + 2x - 1
• Trig functions: sin(x), cos(x), tan(x), asin(x), acos(x), atan(x)
• Exponentials and logs: e^x, exp(x), log(x), log(x, 10)
• Square roots and powers: sqrt(x), x^(1/3)
• Constants: pi, e
• Implicit multiplication: 3x, 2sin(x)

LaTeX input

LaTeX notation is also accepted and converted automatically. Common patterns:

LaTeX	math.js equivalent
\frac{a}{b}	(a)/(b)
\sqrt{x}	sqrt(x)
\sqrt[n]{x}	x^(1/n)
x^{n+1}	x^(n+1)
\sin, \cos, \ln, etc.	sin, cos, ln, etc.
\pi	pi
\left(\ldots\right)	(...)
\left|x\right|	abs(x)
\cdot, \times	*

Example: eq: f(x) = 2 + \frac{1}{x} is valid.

Piecewise-defined functions

Use \begin{cases}...\end{cases} LaTeX notation. Each row is expression & condition, rows separated by \\. The last row's condition is optional (it acts as the default/else branch).

```grapher
eq: f(x) = \begin{cases} x+3 & x < 1 \\ (x-2)^2 & x \ge 1 \end{cases}
```

Open circles ○ are drawn at strict-inequality boundaries (<, >); closed circles ● at inclusive boundaries (\le, \ge, \leq, \geq).

More than two pieces are supported:

```grapher
eq: f(x) = \begin{cases} -x & x < -1 \\ x^2 & -1 \le x < 2 \\ 4 & x \ge 2 \end{cases}
scalex: -5,5
scaley: -2,6
```

Each piece can use any expression valid in a regular eq: field, including LaTeX like \frac, \sqrt, trig functions, and params: constants.

---

Sample — multiple equations

```grapher
title: Quadratic vs Cubic
eq1: f(x) = -2x^2 + 4x - 1
 - lines: #1e56d9
 - linewidth: 2px
 - intx: true
 - inty: true
eq2: g(x) = x^3 - 3x^2 - 4x
 - lines: #d91e1e
 - linewidth: 1px
 - intx: true
axis: #c2c2c2
render: 75%
EqLoc: above
scalex: -5,6
scaley: 5
```