Adding oxi shared code

src/features/encoders/oxipng/shared/meta.ts

@@ -0,0 +1,23 @@
+/**
+ * Copyright 2020 Google Inc. All Rights Reserved.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+export interface EncodeOptions {
+  level: number;
+}
+
+export const label = 'OxiPNG';
+export const mimeType = 'image/png';
+export const extension = 'png';
+
+export const defaultOptions: EncodeOptions = {
+  level: 2,
+};