Merge branch 'pr/523' into typescript

Tone/signal/Scale.test.ts

@@ -0,0 +1,58 @@
+import { expect } from "chai";
+import { BasicTests } from "test/helper/Basic";
+import { connectFrom, connectTo } from "test/helper/Connect";
+import { ConstantOutput } from "test/helper/ConstantOutput";
+import { Scale } from "./Scale";
+import { Signal } from "./Signal";
+
+describe("Scale", () => {
+
+	BasicTests(Scale);
+
+	context("Scaling", () => {
+
+		it("handles input and output connections", () => {
+			const scale = new Scale({ outputMin: 0, outputMax: 100 });
+			connectFrom().connect(scale);
+			scale.connect(connectTo());
+			scale.dispose();
+		});
+
+		it("can set the min and max values", () => {
+			const scale = new Scale({ outputMin: 0, outputMax: 100 });
+			scale.min = -0.01;
+			expect(scale.min).to.be.closeTo(-0.01, 0.001);
+			scale.max = 1000;
+			expect(scale.max).to.be.closeTo(1000, 0.001);
+			scale.dispose();
+		});
+
+		it("scales to the min when the input is 0", () => {
+			return ConstantOutput(() => {
+				const signal = new Signal(0);
+				const scale = new Scale({ outputMin: -10, outputMax: 8 });
+				signal.connect(scale);
+				scale.toDestination();
+			}, -10);
+		});
+
+		it("scales to the max when the input is 1", () => {
+			return ConstantOutput(() => {
+				const signal = new Signal(1);
+				const scale = new Scale({ outputMin: -10, outputMax: 0 });
+				scale.max = 8;
+				signal.connect(scale);
+				scale.toDestination();
+			}, 8);
+		});
+
+		it("scales an input of 0.5 to 15 (10, 20)", () => {
+			return ConstantOutput(() => {
+				const signal = new Signal(0.5);
+				const scale = new Scale({ outputMin: 10, outputMax: 20 });
+				signal.connect(scale);
+				scale.toDestination();
+			}, 15);
+		});
+	});
+});

Tone/signal/Scale.ts

@@ -0,0 +1,101 @@
+import { ToneAudioNodeOptions } from "Tone/core/context/ToneAudioNode";
+import { optionsFromArguments } from "Tone/core/util/Defaults";
+import { Add } from "./Add";
+import { Multiply } from "./Multiply";
+import { Signal } from "./Signal";
+import { SignalOperator } from "./SignalOperator";
+
+export interface ScaleOptions extends ToneAudioNodeOptions {
+	outputMin: number;
+	outputMax: number;
+}
+
+/**
+ *  @class  Performs a linear scaling on an input signal.
+ *          Scales a NormalRange input to between
+ *          outputMin and outputMax.
+ *
+ *  @constructor
+ *  @extends {SignalOperator}
+ *  @param outputMin The output value when the input is 0.
+ *  @param outputMax The output value when the input is 1.
+ *  @example
+ * var scale = new Scale(50, 100);
+ * var signal = new Signal(0.5).connect(scale);
+ * //the output of scale equals 75
+ */
+export class Scale extends SignalOperator<ScaleOptions> {
+
+	readonly name: string = "Scale";
+
+	input = new Multiply({
+		context: this.context,
+		value: 1,
+	});
+
+	output = new Add({
+		context: this.context,
+		value: 0,
+	});
+
+	private _outputMin!: number;
+
+	private _outputMax!: number;
+
+	constructor(options?: Partial<ScaleOptions>);
+	// tslint:disable-next-line: unified-signatures
+	constructor(value?: number);
+	constructor() {
+		super(Object.assign(optionsFromArguments(Scale.getDefaults(), arguments, ["outputMin", "outputMax"])));
+
+		const options = optionsFromArguments(Scale.getDefaults(), arguments, ["outputMin", "outputMax"]);
+		this._outputMin = options.outputMin;
+		this._outputMax = options.outputMax;
+
+		this.input.connect(this.output);
+		this._setRange();
+	}
+
+	static getDefaults(): ScaleOptions {
+		return Object.assign(Signal.getDefaults(), {
+			outputMax: 1,
+			outputMin: 0,
+		});
+	}
+
+	get min(): number {
+		return this._outputMin;
+	}
+
+	set min(min) {
+		this._outputMin = min;
+		this._setRange();
+	}
+
+	get max(): number {
+		return this._outputMax;
+	}
+
+	set max(max) {
+		this._outputMax = max;
+		this._setRange();
+	}
+
+	/**
+	 *  set the values
+	 */
+	private _setRange(): void {
+		this.output.value = this._outputMin;
+		this.input.value = this._outputMax - this._outputMin;
+	}
+
+	/**
+	 *  Clean up.
+	 */
+	dispose(): this {
+		super.dispose();
+		this.input.dispose();
+		this.output.dispose();
+		return this;
+	}
+}