1 files changed, 75 insertions, 0 deletions
diff --git a/packages/webapi/src/lib/ImageData.ts b/packages/webapi/src/lib/ImageData.ts
new file mode 100644
index 000000000..776213880
--- /dev/null
+++ b/packages/webapi/src/lib/ImageData.ts
@@ -0,0 +1,75 @@
+import * as _ from './utils'
+
+export class ImageData {
+	constructor(width: number, height: number);
+	constructor(width: number, height: number, settings: ImageDataSettings);
+	constructor(data: Uint8ClampedArray, width: number);
+	constructor(data: Uint8ClampedArray, width: number, height: number);
+	constructor(data: Uint8ClampedArray, width: number, height: number, settings: ImageDataSettings);
+
+	constructor(arg0: number | Uint8ClampedArray, arg1: number, ...args: [] | [number] | [ImageDataSettings] | [number, ImageDataSettings]) {
+		if (arguments.length < 2) throw new TypeError(`Failed to construct 'ImageData': 2 arguments required.`)
+
+		/** Whether Uint8ClampedArray data is provided. */
+		const hasData = _.__object_isPrototypeOf(Uint8ClampedArray.prototype, arg0)
+
+		/** Image data, either provided or calculated. */
+		const d = hasData ? arg0 as Uint8ClampedArray : new Uint8ClampedArray(asNumber(arg0, 'width') * asNumber(arg1, 'height') * 4)
+
+		/** Image width. */
+		const w = asNumber(hasData ? arg1 : arg0, 'width')
+
+		/** Image height. */
+		const h = d.length / w / 4
+
+		/** Image color space. */
+		const c = String(Object(hasData ? args[1] : args[0]).colorSpace || 'srgb') as PredefinedColorSpace
+
+		// throw if a provided height does not match the calculated height
+		if (args.length && asNumber(args[0], 'height') !== h) throw new DOMException('height is not equal to (4 * width * height)', 'IndexSizeError')
+
+		// throw if a provided colorspace does not match a known colorspace
+		if (c !== 'srgb' && c !== 'rec2020' && c !== 'display-p3') throw new TypeError('colorSpace is not known value')
+
+		Object.defineProperty(this, 'data', { configurable: true, enumerable: true, value: d })
+
+		_.INTERNALS.set(this, { width: w, height: h, colorSpace: c } as ImageDataInternals)
+	}
+
+	get data(): Uint8ClampedArray {
+		_.internalsOf<ImageDataInternals>(this, 'ImageData', 'data')
+
+		return (Object.getOwnPropertyDescriptor(this, 'data') as { value: Uint8ClampedArray }).value
+	}
+
+	get width(): ImageDataInternals['width'] {
+		return _.internalsOf<ImageDataInternals>(this, 'ImageData', 'width').width
+	}
+
+	get height(): ImageDataInternals['height'] {
+		return _.internalsOf<ImageDataInternals>(this, 'ImageData', 'height').height
+	}
+}
+
+_.allowStringTag(ImageData)
+
+/** Returns a coerced number, optionally throwing if the number is zero-ish. */
+const asNumber = (value: any, axis: string): number => {
+	value = Number(value) || 0
+
+	if (value === 0) throw new TypeError(`The source ${axis} is zero or not a number.`)
+
+	return value
+}
+
+interface ImageDataInternals {
+	colorSpace: PredefinedColorSpace
+	height: number
+	width: number
+}
+
+interface ImageDataSettings {
+	colorSpace?: PredefinedColorSpace
+}
+
+type PredefinedColorSpace = 'srgb' | 'rec2020' | 'display-p3'