# Shannon Case Project 07 – Curves

``````//Shannon Case
//Section D
//scase@andrew.cmu.edu
//assignment 07-A

var nPoints = 100;
//var valE = 2.718; // This is the value of # 'e'

function setup() {
createCanvas(400, 400);
frameRate(10);
}

function draw() {

// draw the frame
fill((mouseY/height)*100,(mouseY/height)*200,(mouseY/height)*255);
rect(0, 0, width-1, height-1);

// draw the curve
push();
translate(width / 2, height / 2);
drawEllipseEvoluteCurve();

pop();

}

function drawEllipseEvoluteCurve() {
// Ellipse Evolute
// http://mathworld.wolfram.com/EllipseEvolute.html

var x;
var y;

var a = constrain((mouseX / width), 0.1, 0.5);
var b = constrain((mouseY / height), 0.1, 0.5);

fill((mouseX/width)*255,(mouseX/width)*100,(mouseX/width)*255);
strokeWeight(5);
stroke((mouseX/width)*200,(mouseX/width)*55,(mouseX/width)*255);
beginShape();
for(var i = 0; i < nPoints; i++) {
var t = map(i, 0, nPoints, 0, TWO_PI);

x = ((Math.pow(a+(mouseX/45), 2) - Math.pow(b, 2)) / a * (Math.pow(cos(t), 3)));
y = ((Math.pow(b+(mouseY/48), 2) - Math.pow(a, 2)) / b * (Math.pow(sin(t), 3)));
vertex(x, y);

}
endShape(CLOSE);

}

``````

For this project I really struggled with choosing a curve that worked. I chose a bunch that weren’t really able to move well with both the x and y values, but eventually decided on the Ellipse Evolute because it was more easily able to stretch and shrink with my mouseX and mouseY. I chose to have the background color evolve with the mouseY values and the color of the shape change with the mouseX values.