Start integrating quantizer in the main data flow

src/codecs/imagequant/quantizer.ts

@@ -1,7 +1,18 @@
 import QuantizerWorker from './Quantizer.worker';
 
 export const name = 'Image Quanitzer';
-export async function quantize(data: ImageData): Promise<ImageData> {
+export async function quantize(data: ImageData, opts: QuantizeOptions): Promise<ImageData> {
   const quantizer = await new QuantizerWorker();
-  return quantizer.quantize(data);
+  return quantizer.quantize(data, opts);
 }
+
+export interface QuantizeOptions {
+  maxNumColors: number;
+  dither: number;
+}
+
+// These come from struct WebPConfig in encode.h.
+export const defaultOptions: QuantizeOptions = {
+  maxNumColors: 256,
+  dither: 1.0,
+};