From a1ba421bb4b7aa5cd455e670e3983f809dd17112 Mon Sep 17 00:00:00 2001 From: Daniel Gredler Date: Tue, 11 Nov 2025 03:59:52 +0100 Subject: Add GrayscaleLuminanceSource (#2013) --- .../com/google/zxing/GrayscaleLuminanceSource.java | 144 +++++++++++++++++++++ .../java/com/google/zxing/RGBLuminanceSource.java | 126 +----------------- 2 files changed, 150 insertions(+), 120 deletions(-) create mode 100644 core/src/main/java/com/google/zxing/GrayscaleLuminanceSource.java (limited to 'core/src/main/java/com') diff --git a/core/src/main/java/com/google/zxing/GrayscaleLuminanceSource.java b/core/src/main/java/com/google/zxing/GrayscaleLuminanceSource.java new file mode 100644 index 000000000..7941bad81 --- /dev/null +++ b/core/src/main/java/com/google/zxing/GrayscaleLuminanceSource.java @@ -0,0 +1,144 @@ +/* + * Copyright 2009 ZXing authors + * + * 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.google.zxing; + +/** + * This class is used to help decode images from files which arrive as a grayscale + * pixel array. + * + * @author dswitkin@google.com (Daniel Switkin) + * @author Betaminos + */ +public class GrayscaleLuminanceSource extends LuminanceSource { + + private final byte[] luminances; + private final int dataWidth; + private final int dataHeight; + private final int left; + private final int top; + + public GrayscaleLuminanceSource(int width, int height, byte[] pixels) { + super(width, height); + luminances = pixels; + dataWidth = width; + dataHeight = height; + left = 0; + top = 0; + } + + private GrayscaleLuminanceSource(byte[] pixels, + int dataWidth, + int dataHeight, + int left, + int top, + int width, + int height) { + super(width, height); + if (left + width > dataWidth || top + height > dataHeight) { + throw new IllegalArgumentException("Crop rectangle does not fit within image data."); + } + this.luminances = pixels; + this.dataWidth = dataWidth; + this.dataHeight = dataHeight; + this.left = left; + this.top = top; + } + + @Override + public byte[] getRow(int y, byte[] row) { + if (y < 0 || y >= getHeight()) { + throw new IllegalArgumentException("Requested row is outside the image: " + y); + } + int width = getWidth(); + if (row == null || row.length < width) { + row = new byte[width]; + } + int offset = (y + top) * dataWidth + left; + System.arraycopy(luminances, offset, row, 0, width); + return row; + } + + @Override + public byte[] getMatrix() { + int width = getWidth(); + int height = getHeight(); + + // If the caller asks for the entire underlying image, save the copy and give them the + // original data. The docs specifically warn that result.length must be ignored. + if (width == dataWidth && height == dataHeight) { + return luminances; + } + + int area = width * height; + byte[] matrix = new byte[area]; + int inputOffset = top * dataWidth + left; + + // If the width matches the full width of the underlying data, perform a single copy. + if (width == dataWidth) { + System.arraycopy(luminances, inputOffset, matrix, 0, area); + return matrix; + } + + // Otherwise copy one cropped row at a time. + for (int y = 0; y < height; y++) { + int outputOffset = y * width; + System.arraycopy(luminances, inputOffset, matrix, outputOffset, width); + inputOffset += dataWidth; + } + return matrix; + } + + @Override + public boolean isCropSupported() { + return true; + } + + @Override + public LuminanceSource crop(int left, int top, int width, int height) { + return new GrayscaleLuminanceSource(luminances, + dataWidth, + dataHeight, + this.left + left, + this.top + top, + width, + height); + } + + @Override + public boolean isRotateSupported() { + return true; + } + + @Override + public LuminanceSource rotateCounterClockwise() { + byte[] rotated = new byte[luminances.length]; + for (int y = 0; y < dataHeight; y++) { + for (int x = 0; x < dataWidth; x++) { + int i = (y * dataWidth) + x; + int x2 = y; + int y2 = dataWidth - 1 - x; + int j = (y2 * dataHeight) + x2; + rotated[j] = luminances[i]; + } + } + int newWidth = getHeight(); + int newHeight = getWidth(); + int newLeft = top; + int newTop = dataWidth - (left + getWidth()); + return new GrayscaleLuminanceSource(rotated, dataHeight, dataWidth, newLeft, newTop, newWidth, newHeight); + } +} diff --git a/core/src/main/java/com/google/zxing/RGBLuminanceSource.java b/core/src/main/java/com/google/zxing/RGBLuminanceSource.java index 25ba4975e..5e04e2e1a 100644 --- a/core/src/main/java/com/google/zxing/RGBLuminanceSource.java +++ b/core/src/main/java/com/google/zxing/RGBLuminanceSource.java @@ -23,31 +23,18 @@ package com.google.zxing; * @author dswitkin@google.com (Daniel Switkin) * @author Betaminos */ -public final class RGBLuminanceSource extends LuminanceSource { - - private final byte[] luminances; - private final int dataWidth; - private final int dataHeight; - private final int left; - private final int top; +public final class RGBLuminanceSource extends GrayscaleLuminanceSource { public RGBLuminanceSource(int width, int height, int[] pixels) { - super(width, height); - - dataWidth = width; - dataHeight = height; - left = 0; - top = 0; + super(width, height, toGrayscale(width, height, pixels)); + } - // In order to measure pure decoding speed, we convert the entire image to a greyscale array - // up front, which is the same as the Y channel of the YUVLuminanceSource in the real app. - // - // Total number of pixels suffices, can ignore shape + private static byte[] toGrayscale(int width, int height, int[] pixels) { int size = width * height; if (pixels == null || pixels.length < size) { throw new IllegalArgumentException("Pixel array length is less than width * height"); } - luminances = new byte[size]; + byte[] luminances = new byte[size]; for (int offset = 0; offset < size; offset++) { int pixel = pixels[offset]; int r = (pixel >> 16) & 0xff; // red @@ -56,107 +43,6 @@ public final class RGBLuminanceSource extends LuminanceSource { // Calculate green-favouring average cheaply luminances[offset] = (byte) ((r + g2 + b) / 4); } - } - - private RGBLuminanceSource(byte[] pixels, - int dataWidth, - int dataHeight, - int left, - int top, - int width, - int height) { - super(width, height); - if (left + width > dataWidth || top + height > dataHeight) { - throw new IllegalArgumentException("Crop rectangle does not fit within image data."); - } - this.luminances = pixels; - this.dataWidth = dataWidth; - this.dataHeight = dataHeight; - this.left = left; - this.top = top; - } - - @Override - public byte[] getRow(int y, byte[] row) { - if (y < 0 || y >= getHeight()) { - throw new IllegalArgumentException("Requested row is outside the image: " + y); - } - int width = getWidth(); - if (row == null || row.length < width) { - row = new byte[width]; - } - int offset = (y + top) * dataWidth + left; - System.arraycopy(luminances, offset, row, 0, width); - return row; - } - - @Override - public byte[] getMatrix() { - int width = getWidth(); - int height = getHeight(); - - // If the caller asks for the entire underlying image, save the copy and give them the - // original data. The docs specifically warn that result.length must be ignored. - if (width == dataWidth && height == dataHeight) { - return luminances; - } - - int area = width * height; - byte[] matrix = new byte[area]; - int inputOffset = top * dataWidth + left; - - // If the width matches the full width of the underlying data, perform a single copy. - if (width == dataWidth) { - System.arraycopy(luminances, inputOffset, matrix, 0, area); - return matrix; - } - - // Otherwise copy one cropped row at a time. - for (int y = 0; y < height; y++) { - int outputOffset = y * width; - System.arraycopy(luminances, inputOffset, matrix, outputOffset, width); - inputOffset += dataWidth; - } - return matrix; - } - - @Override - public boolean isCropSupported() { - return true; - } - - @Override - public LuminanceSource crop(int left, int top, int width, int height) { - return new RGBLuminanceSource(luminances, - dataWidth, - dataHeight, - this.left + left, - this.top + top, - width, - height); - } - - @Override - public boolean isRotateSupported() { - return true; - } - - @Override - public LuminanceSource rotateCounterClockwise() { - byte[] rotated = new byte[luminances.length]; - for (int y = 0; y < dataHeight; y++) { - for (int x = 0; x < dataWidth; x++) { - int i = (y * dataWidth) + x; - int x2 = y; - int y2 = dataWidth - 1 - x; - int j = (y2 * dataHeight) + x2; - rotated[j] = luminances[i]; - } - } - int newWidth = getHeight(); - int newHeight = getWidth(); - int newLeft = top; - int newTop = dataWidth - (left + getWidth()); - return new RGBLuminanceSource(rotated, dataHeight, dataWidth, newLeft, newTop, newWidth, newHeight); + return luminances; } } -- cgit v1.2.3