gram-js

Gram JS

A turtle based geometry library for creating parametric line drawings. Used in the Gram Drawing Language.

Test it out in the playground.

Better documentation coming.

Can be imported like:

import { Turtle, drawTurtle, group } from "https://leomcelroy.com/gram-js/exports.js";

Here are available methods on the Turtle class:

• firstPath(): path returns first path
• lastPath(): path returns last path
• getPoint(i: number): [number, number] returns point in Turtle from index i (negative i indexes from end of Turtle)
• addPoint(point, down = true): turtle
• pathMap(func): turtle: applies function to all paths
• pointMap(func): turtle: applies function to all points
• pointFilter(func): turtle: filters points with functions
• extrema(): object: returns extremal points
• copy(): turtle: returns copy of turtle
• point(target: string): [number, number] returns requested point
• store(): turtle stores current position and orientation
• restore(): turtle restores last stored position and orientation
• lastAngle(): number returns angle between last two points
• alignHead(): turtle sets angle to angle between last two points
• fillColor(color: string): turtle
• strokeWidth(thickness): turtle
• strokeColor(color: string): turtle
• floodFill(color: string): turtle
• strokeLinecap(type: string): turtle
• strokeLinejoin(type: string): turtle
• group(): turtle
• flatten(): turtle
• getPathData(merge: boolean = true): string
• forward(distance: number, down: boolean = true): turtle
• goTo(point: [number, number], down: boolean = true): turtle
• vec(vector: [number, number], down: boolean = true): turtle
• turnForward(angle: number, distance: number): turtle
• arc(angle: number, radius: number, down: boolean = true): turtle
• turn(angle: number): turtle
• right(angle: number): turtle
• left(angle: number): turtle
• setAngle(angle: number): turtle
• flatGoTo(point: [number, number], axis: string): turtle
• closePath(): turtle
• translate(toPoint: [number, number], fromPoint: [number, number] = [0, 0]): turtle
• rotate(angle: number: number, point): turtle
• scale(factor: number, point: [number, number]): turtle
• slide(angle: number, distance: number): turtle
• originate(): turtle
• reverse(): turtle
• flip(axis): turtle
• repeat(num: number): turtle
• mirror(): turtle
• fillet(radius: number): turtle
• roundCorners(radius: number, all: boolean = false): turtle
• thicken(thickness: number): turtle
• copyPaste(num: number, transformations: function): turtle
• offset(distance: number, options = {}): turtle
• outline(): turtle
• expand(distanc: number): turtle
• intersect(): turtle intersects turtle with arguements
• difference(): turtle difference turtle with arguements
• union(): turtle union turtle with arguements
• xor(): turtle xor turtle with arguements
• text(word: string): turtle draws text of word
• dogbone(radius: number, all: boolean = false): turtle
• trim(start: number, end: number): turtle
• placeAlong(turtle): turtle
• dashed(number: number): turtle
• bezier(string: string): turtle
• polylines(asArray: boolean = false, prec = 0): turtle
• lSystem(args): turtle
• transform(matrix): turtle

You can reference special points on the Turtle with these methods. “l” stands for left, “c” for center, “r” for right, “t” for top, and “b” for bottom.

lt -- ct -- rt 
 |     |     |        
lc -- cc -- rc   
 |     |     |      
lb -- cb -- rb 

• lt: [number, number]
• lc: [number, number]
• lb: [number, number]
• ct: [number, number]
• cc: [number, number]
• cb: [number, number]
• rt: [number, number]
• rc: [number, number]
• rb: [number, number]

You can also reference:

• start: [number, number] returns first point
• end: [number, number] returns last point
• centroid: [number, number] returns centroid
• width: number returns width
• height: number returns height
• points: list of numbers

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