Improve QrCodeGenerator.encodeQrCode performance

/*

 * Copyright (C) 2022 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.settingslib.qrcode;

import android.graphics.Bitmap;

import android.graphics.Color;

import com.google.zxing.BarcodeFormat;

import com.google.zxing.EncodeHintType;

import com.google.zxing.MultiFormatWriter;

import com.google.zxing.WriterException;

import com.google.zxing.common.BitMatrix;

import java.nio.charset.CharsetEncoder;

import java.nio.charset.StandardCharsets;

import java.util.HashMap;

import java.util.Map;

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 Map<EncodeHintType, Object> hints = new HashMap<>();

        if (!isIso88591(contents)) {

            hints.put(EncodeHintType.CHARACTER_SET, StandardCharsets.UTF_8.name());

        }

        final BitMatrix qrBits = new MultiFormatWriter().encode(contents, BarcodeFormat.QR_CODE,

                size, size, hints);

        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;

    }

    private static boolean isIso88591(String contents) {

        CharsetEncoder encoder = StandardCharsets.ISO_8859_1.newEncoder();

        return encoder.canEncode(contents);

    }

}

/*

 * Copyright (C) 2023 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.settingslib.qrcode

import android.annotation.ColorInt

import android.graphics.Bitmap

import android.graphics.Color

import com.google.zxing.BarcodeFormat

import com.google.zxing.EncodeHintType

import com.google.zxing.MultiFormatWriter

import com.google.zxing.WriterException

import java.nio.charset.StandardCharsets

import java.util.EnumMap

object QrCodeGenerator {

    /**

     * Generates a barcode image with [contents].

     *

     * @param contents The contents to encode in the barcode

     * @param size     The preferred image size in pixels

     * @param invert   Whether to invert the black/white pixels (e.g. for dark mode)

     * @return Barcode bitmap

     */

    @JvmStatic

    @Throws(WriterException::class, java.lang.IllegalArgumentException::class)

    fun encodeQrCode(contents: String, size: Int, invert: Boolean): Bitmap =

        encodeQrCode(contents, size, DEFAULT_MARGIN, invert)

    private const val DEFAULT_MARGIN = -1

    /**

     * Generates a barcode image with [contents].

     *

     * @param contents The contents to encode in the barcode

     * @param size     The preferred image size in pixels

     * @param margin   The margin around the actual barcode

     * @param invert   Whether to invert the black/white pixels (e.g. for dark mode)

     * @return Barcode bitmap

     */

    @JvmOverloads

    @JvmStatic

    @Throws(WriterException::class, IllegalArgumentException::class)

    fun encodeQrCode(

        contents: String,

        size: Int,

        margin: Int = DEFAULT_MARGIN,

        invert: Boolean = false,

    ): Bitmap {

        val hints = EnumMap<EncodeHintType, Any>(EncodeHintType::class.java)

        if (!isIso88591(contents)) {

            hints[EncodeHintType.CHARACTER_SET] = StandardCharsets.UTF_8.name()

        }

        if (margin != DEFAULT_MARGIN) {

            hints[EncodeHintType.MARGIN] = margin

        }

        val qrBits = MultiFormatWriter().encode(contents, BarcodeFormat.QR_CODE, size, size, hints)

        @ColorInt val setColor = if (invert) Color.WHITE else Color.BLACK

        @ColorInt val unsetColor = if (invert) Color.BLACK else Color.WHITE

        @ColorInt val pixels = IntArray(size * size)

        for (x in 0 until size) {

            for (y in 0 until size) {

                pixels[x * size + y] = if (qrBits[x, y]) setColor else unsetColor

            }

        }

        return Bitmap.createBitmap(size, size, Bitmap.Config.RGB_565).apply {

            setPixels(pixels, 0, size, 0, 0, size, size)

        }

    }

    private fun isIso88591(contents: String): Boolean =

        StandardCharsets.ISO_8859_1.newEncoder().canEncode(contents)

}