aistudio-wpf-diagram/zxing.core/zxing.core/BinaryBitmap.cs

/*
* 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.
*/

using System;
using ZXing.Common;

namespace ZXing
{
    /// <summary>
    /// This class is the core bitmap class used by ZXing to represent 1 bit data. Reader objects
    /// accept a BinaryBitmap and attempt to decode it.
    /// </summary>
    /// <author>dswitkin@google.com (Daniel Switkin)</author>
    public sealed class BinaryBitmap
    {
        private readonly Binarizer binarizer;
        private BitMatrix matrix;

        /// <summary>
        /// 
        /// </summary>
        /// <param name="binarizer"></param>
        public BinaryBitmap(Binarizer binarizer)
        {
            if (binarizer == null)
            {
                throw new ArgumentException("Binarizer must be non-null.");
            }
            this.binarizer = binarizer;
        }

        internal BinaryBitmap(BitMatrix matrix)
        {
            if (matrix == null)
            {
                throw new ArgumentException("matrix must be non-null.");
            }
            this.matrix = matrix;
        }

        /// <returns>
        /// The width of the bitmap.
        /// </returns>
        public int Width
        {
            get
            {
                return binarizer.Width;
            }
        }
        
        /// <returns>
        /// The height of the bitmap.
        /// </returns>
        public int Height
        {
            get
            {
                return binarizer.Height;
            }
        }

        /// <summary>
        /// Converts one row of luminance data to 1 bit data. May actually do the conversion, or return
        /// cached data. Callers should assume this method is expensive and call it as seldom as possible.
        /// This method is intended for decoding 1D barcodes and may choose to apply sharpening.
        /// </summary>
        /// <param name="y">The row to fetch, which must be in [0, bitmap height).</param>
        /// <param name="row">An optional preallocated array. If null or too small, it will be ignored.
        /// If used, the Binarizer will call BitArray.clear(). Always use the returned object.
        /// </param>
        /// <returns> The array of bits for this row (true means black).</returns>
        public BitArray getBlackRow(int y, BitArray row)
        {
            return binarizer.getBlackRow(y, row);
        }

        /// <summary>
        /// Converts a 2D array of luminance data to 1 bit. As above, assume this method is expensive
        /// and do not call it repeatedly. This method is intended for decoding 2D barcodes and may or
        /// may not apply sharpening. Therefore, a row from this matrix may not be identical to one
        /// fetched using getBlackRow(), so don't mix and match between them.
        /// </summary>
        /// <returns> The 2D array of bits for the image (true means black).</returns>
        public BitMatrix BlackMatrix
        {
            get
            {
                // The matrix is created on demand the first time it is requested, then cached. There are two
                // reasons for this:
                // 1. This work will never be done if the caller only installs 1D Reader objects, or if a
                //    1D Reader finds a barcode before the 2D Readers run.
                // 2. This work will only be done once even if the caller installs multiple 2D Readers.
                return matrix ?? (matrix = binarizer.BlackMatrix);
            }
        }

        /// <returns>
        /// Whether this bitmap can be cropped.
        /// </returns>
        public bool CropSupported
        {
            get
            {
                return binarizer.LuminanceSource.CropSupported;
            }
        }

        /// <summary>
        /// Returns a new object with cropped image data. Implementations may keep a reference to the
        /// original data rather than a copy. Only callable if isCropSupported() is true.
        /// </summary>
        /// <param name="left">The left coordinate, which must be in [0, Width)</param>
        /// <param name="top">The top coordinate, which must be in [0, Height)</param>
        /// <param name="width">The width of the rectangle to crop.</param>
        /// <param name="height">The height of the rectangle to crop.</param>
        /// <returns> A cropped version of this object.</returns>
        public BinaryBitmap crop(int left, int top, int width, int height)
        {
            var newSource = binarizer.LuminanceSource.crop(left, top, width, height);
            return new BinaryBitmap(binarizer.createBinarizer(newSource));
        }

        /// <returns>
        /// Whether this bitmap supports counter-clockwise rotation.
        /// </returns>
        public bool RotateSupported
        {
            get
            {
                return binarizer.LuminanceSource.RotateSupported;
            }
        }

        /// <summary>
        /// Returns a new object with rotated image data by 90 degrees counterclockwise.
        /// Only callable if <see cref="RotateSupported"/> is true.
        /// </summary>
        /// <returns>A rotated version of this object.</returns>
        public BinaryBitmap rotateCounterClockwise()
        {
            var newSource = binarizer.LuminanceSource.rotateCounterClockwise();
            return new BinaryBitmap(binarizer.createBinarizer(newSource));
        }

        /// <summary>
        /// Returns a new object with rotated image data by 45 degrees counterclockwise.
        /// Only callable if <see cref="RotateSupported"/> is true.
        /// </summary>
        /// <returns>A rotated version of this object.</returns>
        public BinaryBitmap rotateCounterClockwise45()
        {
            LuminanceSource newSource = binarizer.LuminanceSource.rotateCounterClockwise45();
            return new BinaryBitmap(binarizer.createBinarizer(newSource));
        }

        /// <summary>
        /// Returns a <see cref="System.String"/> that represents this instance.
        /// </summary>
        /// <returns>
        /// A <see cref="System.String"/> that represents this instance.
        /// </returns>
        public override string ToString()
        {
            var blackMatrix = BlackMatrix;
            return blackMatrix != null ? blackMatrix.ToString() : String.Empty;
        }
    }
}