curve.js-e

${{
	Curve = function (x1, y1, x2, y2, r, elasticity, theta1, theta2, mid, overshoot, dirSwitch, colours, drawingOptions) {
		this.x1 = x1;
		this.y1 = y1;
		this.x2 = x2;
		this.y2 = y2;
		this.r = r;
		this.elasticity = elasticity;
		this.theta1 = theta1;
		this.theta2 = theta2;
		this.mid = mid;
		this.overshoot = overshoot;
		this.dirSwitch = dirSwitch;
		this.colours = colours;
		this.drawingOptions = drawingOptions;

		elasticity = elasticity * 0.94;
		var xDistance = x2 - x1;
		var yDistance = y2 - y1;
		this.theta3 = Math.atan2(yDistance, xDistance);
		this.fullLength = Math.sqrt(xDistance * xDistance + yDistance * yDistance);
		this.length1 = mid * this.fullLength;
		var length2 = this.fullLength - this.length1;

		var radiansPerUnit = Math.PI / root.lookup("semicircleAngle").value();
		this.delta1 = elasticity * this.length1;
		this.delta2 = elasticity * length2;
		var fullTurn = 2 * Math.PI;

		if (theta1 === undefined) {
			this.deltaX1 = 0;
			this.deltaY1 = 0;
		} else {
			var theta1Normalized = (theta1 * radiansPerUnit) % fullTurn;
			if (theta1Normalized < 0) {
				theta1Normalized = theta1Normalized + fullTurn;
			}
			var tanTheta1 = Math.abs(Math.tan(theta1Normalized));

			if (theta1Normalized > fullTurn/4 && theta1Normalized <= fullTurn * 3/4) {
				this.deltaX1 = -overshoot;
			} else {
				this.deltaX1 = Math.abs(this.length1 - this.delta1);
			}

			this.deltaY1 = Math.abs(this.deltaX1) * tanTheta1;
			if (theta1Normalized > fullTurn/2) {
				this.deltaY1 = -this.deltaY1;
			} else if (this.deltaY1 > r) {
				this.deltaY1 = r;
				this.deltaX1 = r / tanTheta1;
			}
		}

		if (theta2 === undefined) {
			this.deltaX2 = 0;
			this.deltaY2 = 0;
		} else {
			var theta2Normalized = (theta2 * radiansPerUnit) % fullTurn;
			if (theta2Normalized < 0) {
				theta2Normalized = theta2Normalized + fullTurn;
			}
			var tanTheta2 = Math.abs(Math.tan(theta2Normalized));

			if (theta2Normalized > fullTurn/4 && theta2Normalized <= fullTurn * 3/4) {
				this.deltaX2 = -overshoot;
			} else {
				this.deltaX2 = Math.abs(length2 - this.delta2);
			}

			this.deltaY2 = Math.abs(this.deltaX2) * tanTheta2;
			if (theta2Normalized > fullTurn/2) {
				this.deltaY2 = -this.deltaY2;
			} else if (this.deltaY2 > r) {
				this.deltaY2 = r;
				this.deltaX2 = r / tanTheta2;
			}
		}

		if (dirSwitch) {
			this.radius = -r;
			this.deltaY1 = -this.deltaY1;
			this.deltaY2 = -this.deltaY2;
		} else {
			this.radius = r;
		}
	}

}}$;

/**
 * Create a Curve
 * 
 * @param x1
 * @param y1
 * @param x2
 * @param y2
 * @param radius
 * @param curviness
 * @param [start_angle
 * @param [end_angle
 * @param [skew Between 0 and 1
 * @param [overshoot]]]]
 * @param [is_flipped]
 * @param [colour(s)]
 * @param [drawing_options]
 * 
 * #canvas #curve #drawingOptions
 */

func Curve {
	${{
		var x1 = arguments[0];
		var y1 = arguments[1];
		var x2 = arguments[2];
		var y2 = arguments[3];
		var r = arguments[4];
		var elasticity = arguments[5];

		var direction, theta1, theta2, mid = 0.5, overshoot = 150, direction, colours, drawingOptions;
		var lastArg = arguments[arguments.length - 1];
		var processUpTo;
		if (lastArg !== undefined && (lastArg instanceof Object) && !Array.isArray(lastArg)) {
			drawingOptions = lastArg;
			processUpTo = arguments.length - 2;
			lastArg = arguments[processUpTo];
		} else {
			processUpTo = arguments.length - 1;
		}
		if (typeof(lastArg) == "string") {
			colours = [lastArg];
			processUpTo--;
		} else if (Array.isArray(lastArg)) {
			colours = lastArg;
			processUpTo--;
		} else {
			colours = ["black"];
		}
		lastArg = arguments[processUpTo];
		if (typeof(lastArg) == "boolean") {
			direction = lastArg;
			processUpTo--;
		}
		if (processUpTo > 5) {
			theta1 = arguments[6];
			if (processUpTo > 6) {
				theta2 = arguments[7];
				if (processUpTo > 7) {
					mid = arguments[8];
					if (processUpTo > 8) {
						overshoot = arguments[9];
					}
				}
			} else {
				theta2 = theta1;
			}
		}
		return new Curve(x1, y1, x2, y2, r, elasticity, theta1, theta2, mid, overshoot, direction, colours, drawingOptions);
	}}$;
}
semicircleAngle ~> [Curve];

${{
	Curve.prototype.draw = function (context, scale) {
		if (this.colours.length == 1) {
			context.strokeStyle = this.colours[0];
		} else {
			var gradient = context.createLinearGradient(0, 0, this.fullLength, 0);
			for (var i = 0; i < this.colours.length; i++) {
				gradient.addColorStop(i / (this.colours.length - 1), this.colours[i]);
			}
			context.strokeStyle = gradient;
		}

		context.translate(this.x1, this.y1);
		context.rotate(this.theta3);
		context.beginPath();
		context.moveTo(0, 0);
		context.bezierCurveTo(this.deltaX1, this.deltaY1, this.length1 - this.delta1, this.radius, this.length1, this.radius);
		context.bezierCurveTo(this.length1 + this.delta2, this.radius, this.fullLength - this.deltaX2, this.deltaY2, this.fullLength, 0);
		context.stroke();

		if (this.drawingOptions !== undefined && this.drawingOptions.arrowhead instanceof Arrowhead) {
			var gradient1, gradient2, t, x1, y1;
			if (this.deltaX1 == 0 && this.deltaY1 == 0) {
				t = 0.01;
				x1 = 3 * (1 - t) * t * t * (this.length1 - this.delta1) + t * t * t * this.length1;
				y1 = 3 * (1 - t) * t * t * this.radius + t * t * t * this.radius;
				gradient1 = y1 / x1;
			} else {
				gradient1 = this.deltaY1 / this.deltaX1;
			}
			if (this.deltaX2 == 0 && this.deltaY2 == 0) {
				t = 0.99;
				x1 = (1 - t) * (1 - t) * (1 - t) * this.length1 +
					3 * (1 - t) * (1 - t) * t * (this.length1 + this.delta2) +
					3 * (1 - t) * t * t * this.fullLength +
					t * t * t * this.fullLength;
				y1 = (1 - t) * (1 - t) * (1 - t) * this.radius + 3 * (1 - t) * (1 - t) * t * this.radius;
				gradient2 = -y1 / (this.fullLength - x1);
			} else {
				gradient2 = -this.deltaY2 / this.deltaX2;
			}
			this.drawingOptions.arrowhead.draw(context, scale, 0, 0, gradient1, false, this.fullLength, 0, gradient2, false);
		}
	};

	Curve.prototype.toString = function () {
		return "Curve(" + Eden.edenCodeForValues(this.x1, this.y1, this.x2, this.y2, this.r, this.elasticity, this.theta1, this.theta2, this.mid, this.overshoot, this.dirSwitch, this.colours, this.drawingOptions) + ")";
	}
	
	Curve.prototype.getEdenCode = Curve.prototype.toString;
}}$;