Add QrCodeGenerator for QrCode encoding

Bug: 118794858
Test: RunSettingsRoboTests
Change-Id: I1e27c7b7bf97c1b683be7d200e1f3bbdc763c4c1

src/com/android/settings/wifi/qrcode/QrCodeGenerator.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * 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
+ */
+
+package com.android.settings.wifi.qrcode;
+
+import android.graphics.Bitmap;
+import android.graphics.Color;
+
+import com.google.zxing.BarcodeFormat;
+import com.google.zxing.MultiFormatWriter;
+import com.google.zxing.WriterException;
+import com.google.zxing.common.BitMatrix;
+
+public final class QrCodeGenerator {
+    /**
+     * Generates a barcode image with {@code contents}.
+     *
+     * @param contents The contents to encode in the barcode
+     * @param size     The preferred image size in pixels
+     * @return Barcode bitmap
+     */
+    public static Bitmap encodeQrCode(String contents, int size)
+            throws WriterException, IllegalArgumentException {
+        final BitMatrix qrBits = new MultiFormatWriter().encode(contents, BarcodeFormat.QR_CODE,
+                size, size);
+        final Bitmap bitmap = Bitmap.createBitmap(size, size, Bitmap.Config.RGB_565);
+        for (int x = 0; x < size; x++) {
+            for (int y = 0; y < size; y++) {
+                bitmap.setPixel(x, y, qrBits.get(x, y) ? Color.BLACK : Color.WHITE);
+            }
+        }
+        return bitmap;
+    }
+}