/*
* 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 hierarchy provides a set of methods to convert luminance data to 1 bit data.
    /// It allows the algorithm to vary polymorphically, for example allowing a very expensive
    /// thresholding technique for servers and a fast one for mobile. It also permits the implementation
    /// to vary, e.g. a JNI version for Android and a Java fallback version for other platforms.
    /// 
    /// <author>dswitkin@google.com (Daniel Switkin)</author>
    /// </summary>
    public abstract class Binarizer
    {
        private readonly LuminanceSource source;

        /// <summary>
        /// Initializes a new instance of the <see cref="Binarizer"/> class.
        /// </summary>
        /// <param name="source">The source.</param>
        protected internal Binarizer(LuminanceSource source)
        {
            if (source == null)
            {
                throw new ArgumentException("Source must be non-null.");
            }
            this.source = source;
        }

        /// <summary>
        /// Gets the luminance source object.
        /// </summary>
        virtual public LuminanceSource LuminanceSource
        {
            get
            {
                return source;
            }
        }

        /// <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.
        /// For callers which only examine one row of pixels at a time, the same BitArray should be reused
        /// and passed in with each call for performance. However it is legal to keep more than one row
        /// at a time if needed.
        /// </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 abstract BitArray getBlackRow(int y, BitArray row);

        /// <summary> Converts a 2D array of luminance data to 1 bit data. 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 abstract BitMatrix BlackMatrix { get; }

        /// <summary> Creates a new object with the same type as this Binarizer implementation, but with pristine
        /// state. This is needed because Binarizer implementations may be stateful, e.g. keeping a cache
        /// of 1 bit data. See Effective Java for why we can't use Java's clone() method.
        /// </summary>
        /// <param name="source">The LuminanceSource this Binarizer will operate on.</param>
        /// <returns> A new concrete Binarizer implementation object.</returns>
        public abstract Binarizer createBinarizer(LuminanceSource source);

        /// <summary>
        /// Gets the width of the luminance source object.
        /// </summary>
        public int Width
        {
            get { return source.Width; }
        }

        /// <summary>
        /// Gets the height of the luminance source object.
        /// </summary>
        public int Height
        {
            get { return source.Height; }
        }
    }
}