mirror of https://github.com/SixLabors/ImageSharp
James South
12 years ago
9 changed files with 357 additions and 29 deletions
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// --------------------------------------------------------------------------------------------------------------------
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// <copyright file="BinaryThreshold.cs" company="James South">
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// Copyright (c) James South.
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// Licensed under the Apache License, Version 2.0.
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// </copyright>
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// <summary>
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// Performs binary threshold filtering against a given greyscale image.
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// </summary>
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// --------------------------------------------------------------------------------------------------------------------
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namespace ImageProcessor.Imaging.Binarization |
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{ |
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using System.Drawing; |
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/// <summary>
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/// Performs binary threshold filtering against a given greyscale image.
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/// </summary>
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public class BinaryThreshold |
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{ |
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/// <summary>
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/// The threshold value.
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/// </summary>
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private byte threshold = 128; |
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/// <summary>
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/// Initializes a new instance of the <see cref="BinaryThreshold"/> class.
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/// </summary>
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/// <param name="threshold">
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/// The threshold.
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/// </param>
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public BinaryThreshold(byte threshold) |
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{ |
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this.threshold = threshold; |
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} |
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/// <summary>
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/// Gets or sets the threshold.
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/// </summary>
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public byte Threshold |
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{ |
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get |
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{ |
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return this.threshold; |
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} |
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set |
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{ |
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this.threshold = value; |
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} |
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} |
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/// <summary>
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/// Processes the given bitmap to apply the threshold.
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/// </summary>
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/// <param name="source">The image to process.</param>
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/// <returns>A processed bitmap.</returns>
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public Bitmap ProcessFilter(Bitmap source) |
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{ |
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int width = source.Width; |
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int height = source.Height; |
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using (FastBitmap fastBitmap = new FastBitmap(source)) |
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{ |
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for (int x = 0; x < width; x++) |
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{ |
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for (int y = 0; y < height; y++) |
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{ |
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Color color = fastBitmap.GetPixel(x, y); |
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fastBitmap.SetPixel(x, y, color.B >= this.threshold ? Color.White : Color.Black); |
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} |
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} |
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} |
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return source; |
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} |
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} |
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} |
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// --------------------------------------------------------------------------------------------------------------------
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// <copyright file="PixelData.cs" company="James South">
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// Copyright (c) James South.
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// Licensed under the Apache License, Version 2.0.
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// </copyright>
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// <summary>
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// Contains the component parts that make up a single pixel.
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// </summary>
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// --------------------------------------------------------------------------------------------------------------------
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namespace ImageProcessor.Imaging |
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{ |
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/// <summary>
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/// Contains the component parts that make up a single pixel.
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/// </summary>
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public struct PixelData |
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{ |
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/// <summary>
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/// The blue component.
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/// </summary>
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public byte B; |
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/// <summary>
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/// The green component.
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/// </summary>
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public byte G; |
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/// <summary>
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/// The red component.
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/// </summary>
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public byte R; |
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/// <summary>
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/// The alpha component.
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/// </summary>
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public byte A; |
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} |
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} |
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// --------------------------------------------------------------------------------------------------------------------
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// <copyright file="AutoCrop.cs" company="James South">
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// Copyright (c) James South.
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// Licensed under the Apache License, Version 2.0.
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// </copyright>
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// --------------------------------------------------------------------------------------------------------------------
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namespace ImageProcessor.Processors |
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{ |
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using System; |
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using System.Collections.Generic; |
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using System.Drawing; |
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using System.Drawing.Imaging; |
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using ImageProcessor.Common.Exceptions; |
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using ImageProcessor.Imaging; |
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using ImageProcessor.Imaging.Binarization; |
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using ImageProcessor.Imaging.EdgeDetection; |
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/// <summary>
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/// The auto crop.
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/// </summary>
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public class AutoCrop : IGraphicsProcessor |
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{ |
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/// <summary>
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/// Initializes a new instance of the <see cref="AutoCrop"/> class.
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/// </summary>
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public AutoCrop() |
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{ |
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this.Settings = new Dictionary<string, string>(); |
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} |
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/// <summary>
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/// Gets or sets the dynamic parameter.
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/// </summary>
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public dynamic DynamicParameter { get; set; } |
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/// <summary>
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/// Gets or sets any additional settings required by the processor.
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/// </summary>
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public Dictionary<string, string> Settings { get; set; } |
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/// <summary>
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/// Processes the image.
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/// </summary>
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/// <param name="factory">
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/// The current instance of the <see cref="T:ImageProcessor.ImageFactory"/> class containing
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/// the image to process.
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/// </param>
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/// <returns>
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/// The processed image from the current instance of the <see cref="T:ImageProcessor.ImageFactory"/> class.
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/// </returns>
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public Image ProcessImage(ImageFactory factory) |
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{ |
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Bitmap newImage = null; |
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Bitmap grey = null; |
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Image image = factory.Image; |
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byte threshold = this.DynamicParameter; |
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try |
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{ |
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grey = new ConvolutionFilter(new SobelEdgeFilter(), true).ProcessFilter((Bitmap)image); |
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grey = new BinaryThreshold(threshold).ProcessFilter(grey);//.Clone(new Rectangle(0, 0, grey.Width, grey.Height), PixelFormat.Format8bppIndexed);
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// lock source bitmap data
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//BitmapData data = grey.LockBits(new Rectangle(0, 0, grey.Width, grey.Height), ImageLockMode.ReadOnly, grey.PixelFormat);
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//Rectangle rectangle = this.FindBoxExactgreyscale(data, 0);
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//grey.UnlockBits(data);
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Rectangle rectangle = FindBox(grey, 0); |
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newImage = new Bitmap(rectangle.Width, rectangle.Height, PixelFormat.Format32bppPArgb); |
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using (Graphics graphics = Graphics.FromImage(newImage)) |
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{ |
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// An unwanted border appears when using InterpolationMode.HighQualityBicubic to resize the image
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// as the algorithm appears to be pulling averaging detail from surrounding pixels beyond the edge
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// of the image. Using the ImageAttributes class to specify that the pixels beyond are simply mirror
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// images of the pixels within solves this problem.
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using (ImageAttributes wrapMode = new ImageAttributes()) |
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{ |
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graphics.DrawImage( |
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image, |
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new Rectangle(0, 0, rectangle.Width, rectangle.Height), |
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rectangle.X, |
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rectangle.Y, |
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rectangle.Width, |
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rectangle.Height, |
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GraphicsUnit.Pixel, |
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wrapMode); |
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} |
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} |
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// Reassign the image.
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//grey.Dispose();
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image.Dispose(); |
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image = newImage; |
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} |
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catch (Exception ex) |
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{ |
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if (grey != null) |
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{ |
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grey.Dispose(); |
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} |
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if (newImage != null) |
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{ |
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newImage.Dispose(); |
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} |
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throw new ImageProcessingException("Error processing image with " + this.GetType().Name, ex); |
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} |
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return image; |
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} |
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/// <summary>
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/// Returns a bounding box that only excludes the specified color.
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/// Only works on 8-bit images.
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/// </summary>
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/// <param name="sourceData"></param>
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/// <param name="colorToRemove">The palette index to remove.</param>
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/// <returns></returns>
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private Rectangle FindBoxExactgreyscale(BitmapData sourceData, byte indexToRemove) |
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{ |
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if (sourceData.PixelFormat != PixelFormat.Format8bppIndexed) throw new ArgumentOutOfRangeException("FindBoxExact only operates on 8-bit greyscale images"); |
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// get source image size
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int width = sourceData.Width; |
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int height = sourceData.Height; |
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int offset = sourceData.Stride - width; |
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int minX = width; |
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int minY = height; |
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int maxX = 0; |
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int maxY = 0; |
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// find rectangle which contains something except color to remove
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unsafe |
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{ |
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byte* src = (byte*)sourceData.Scan0; |
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for (int y = 0; y < height; y++) |
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{ |
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if (y > 0) src += offset; //Don't adjust for offset until after first row
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for (int x = 0; x < width; x++) |
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{ |
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if (x > 0 || y > 0) src++; //Don't increment until after the first pixel.
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if (*src != indexToRemove) |
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{ |
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if (x < minX) |
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minX = x; |
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if (x > maxX) |
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maxX = x; |
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if (y < minY) |
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minY = y; |
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if (y > maxY) |
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maxY = y; |
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} |
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} |
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} |
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} |
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// check
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if ((minX == width) && (minY == height) && (maxX == 0) && (maxY == 0)) |
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{ |
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minX = minY = 0; |
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} |
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return new Rectangle(minX, minY, maxX - minX + 1, maxY - minY + 1); |
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} |
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private Rectangle FindBox(Bitmap bitmap, byte indexToRemove) |
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{ |
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int width = bitmap.Width; |
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int height = bitmap.Height; |
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int startX = width; |
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int startY = height; |
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int stopX = 0; |
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int stopY = 0; |
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using (FastBitmap fastBitmap = new FastBitmap(bitmap)) |
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{ |
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for (int y = 0; y < height; y++) |
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{ |
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for (int x = 0; x < width; x++) |
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{ |
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if (fastBitmap.GetPixel(x, y).B != indexToRemove) |
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{ |
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if (x < startX) |
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{ |
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startX = x; |
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} |
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if (x > stopX) |
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{ |
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stopX = x; |
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} |
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if (y < startY) |
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{ |
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startY = y; |
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} |
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if (y > stopY) |
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{ |
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stopY = y; |
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} |
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} |
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} |
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} |
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} |
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// check
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if ((startX == width) && (startY == height) && (stopX == 0) && (stopY == 0)) |
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{ |
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startX = startY = 0; |
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} |
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return new Rectangle(startX, startY, stopX - startX + 1, stopY - startY + 1); |
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} |
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} |
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} |
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@ -0,0 +1 @@ |
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71ccd68b75f913237cdd2047d5f5d0b39d9b16ae |
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After Width: | Height: | Size: 166 B |
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