Option to send photos as high quality

ts/util/canvasToBlob.ts

@@ -0,0 +1,29 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { IMAGE_JPEG } from '../types/MIME';
+
+/**
+ * Similar to [the built-in `toBlob` method][0], but returns a Promise.
+ *
+ * [0]: https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement/toBlob
+ */
+export async function canvasToBlob(
+  canvas: HTMLCanvasElement,
+  mimeType = IMAGE_JPEG,
+  quality?: number
+): Promise<Blob> {
+  return new Promise((resolve, reject) =>
+    canvas.toBlob(
+      result => {
+        if (result) {
+          resolve(result);
+        } else {
+          reject(new Error("Couldn't convert the canvas to a Blob"));
+        }
+      },
+      mimeType,
+      quality
+    )
+  );
+}