code.org-grapher

Code.org Grapher

On 10/2/17, in AP Computer Science Principles, I was supposed to draw a black-and-white picture in code.org's b&w image widget. The format is a two-byte header (one byte representing the width and the other the height), and a stream of bits, each one representing a black or white pixel (0 for black, 1 for white).

Example:

0000 0011
0000 0101
101010000010010

becomes

So, What Does This Thing Do?

Basically, it's a library that graphs a function by creating an image compatible with the code.org black-and-white or color image tool. Just pass it a few parameters and it'll spit out a string of binary or hex that you can copy and paste into the widget.

Usage

You can use the grapher either on Web or Node.js, provided there is support for ES6 and CommonJS imports. The reason it is written that way is because I wanted to use ES6 classes and I wanted to use it in the backend. If people really want ES6 imports, you have full license to change that last line to export default Grapher;.

General Use

Just so I don't have to type things twice, here are the instructions applicable to b&w and color graphs:

• Install from npm

• npm i code.org-grapher

• Import the library

• let Grapher = require('code.org-grapher');

• Instantiate a plot

• let parabola = new Grapher(254, 254, Math.pow(x, 2));

• Graph the plot

• parabola.graph().then(pic => console.log(pic));

• (optional) include an options object somewhere. There are two places you can put your options: as the fourth parameter of the Grapher constructor or as the sole parameter of the graph method.

Black-and-white

By default, all plots are drawn in black-and-white. All you have to do is use the class as shown above. However, you do have some options you can use:

let options = {
  y: "center" || "left" || "right",
  x: "center" || "top" || "bottom",
  axes: false || true
}

• options.x: tells the grapher where to put the x axis on the plot. It DOES move the graph's center to that location.
• options.y: same as options.x but it moves the y axis
• options.axes: whether or not to draw the x and y axis

Note: the default for each property is listed first.

Color

Coming Soon

API Reference

Coming Soon