How to cartoonify an image

To convert an image to a cartoon style we will use various image editing methods. Detecting areas with similar colors is done by applying a convolution filter to blur the image with Filter method, selecting outlines, binarize outlines with threshold 30 using BinarizeFixed method, and masking the image with ApplyMask method:

	using Aspose.Imaging;
	using Aspose.Imaging.FileFormats.Png;
	using Aspose.Imaging.ImageFilters.FilterOptions;
	using Aspose.Imaging.ImageOptions;
	using Aspose.Imaging.Masking;
	using Aspose.Imaging.Masking.Options;
	using System;
	using System.Collections.Generic;
	using System.IO;
	using System.Linq;

	string templatesFolder = @"c:\Users\USER\Downloads";

	Cartoonify();

	void Cartoonify()
	{
	FilterImages(image =>
	{
	using (var processedImage = new PngImage(image))
	{
	image.Resize(image.Width * 2, image.Height, ResizeType.LeftTopToLeftTop);
	processedImage.Cartoonify();
	var gr = new Graphics(image);
	gr.DrawImage(processedImage, processedImage.Width, 0);
	gr.DrawLine(new Pen(Color.DarkRed, 3), processedImage.Width, 0, processedImage.Width, image.Height);
	}
	}, "cartoonify");
	}

	string RasterizeVectorImage(string formatExt, string inputFile)
	{
	string outputFile = Path.Combine(templatesFolder, $"rasterized.{formatExt}.png");
	using (var image = Image.Load(inputFile))
	{
	image.Save(outputFile, new PngOptions());
	}

	return outputFile;
	}

	void FilterImages(Action<RasterImage> doFilter, string filterName)
	{
	List<string> rasterFormats = new List<string>() { "jpg", "png", "bmp", "apng", "dicom",
	"jp2", "j2k", "tga", "webp", "tif", "gif", "ico" };
	List<string> vectorFormats = new List<string>() { "svg", "otg", "odg", "eps", "wmf", "emf", "wmz", "emz", "cmx", "cdr" };

	List<string> allFormats = new List<string>(rasterFormats);
	allFormats.AddRange(vectorFormats);

	allFormats.ForEach(
	formatExt =>
	{
	var inputFile = Path.Combine(templatesFolder, $"template.{formatExt}");
	bool isVectorFormat = vectorFormats.IndexOf(formatExt) > -1;

	//Need to rasterize vector formats before background remove
	if (isVectorFormat)
	{
	inputFile = RasterizeVectorImage(formatExt, inputFile);
	}

	var outputFile = Path.Combine(templatesFolder, $"{filterName}_{formatExt}.png");

	Console.WriteLine($"Processing {formatExt}");

	using (var image = (RasterImage)Image.Load(inputFile))
	{
	doFilter(image);

	//If image is multipage save each page to png to demonstrate results
	if (image is IMultipageImage multiPage && multiPage.PageCount > 1)
	{
	for (var pageIndex = 0; pageIndex < multiPage.PageCount; pageIndex++)
	{
	string fileName = $"{filterName}_page{pageIndex}_{formatExt}.png";
	multiPage.Pages[pageIndex].Save(templatesFolder + fileName, new PngOptions());
	File.Delete(templatesFolder + fileName);
	}
	}
	else
	{
	image.Save(outputFile, new PngOptions());
	File.Delete(outputFile);
	}
	}

	//Remove rasterized vector image
	if (isVectorFormat)
	{
	File.Delete(inputFile);
	}
	}
	);
	}

	static class ImageFilterExtensions
	{
	public static void Cartoonify(this RasterImage image)
	{
	using var outlines = image.DetectOutlines(Color.Black);

	image.AdjustBrightness(30);
	image.Filter(image.Bounds, new MedianFilterOptions(7));

	var gr = new Graphics(image);
	gr.DrawImage(outlines, Point.Empty);
	}

	public static RasterImage DetectOutlines(this RasterImage image, Color outlineColor)
	{
	var outlines = new PngImage(image);
	outlines
	.GetDataContext()
	.ApplyConvolutionFilter(ConvolutionFilterOptions.Blur)
	.ApplyConvolutionFilter(ConvolutionFilterOptions.Outline)
	.ApplyData();

	outlines.BinarizeFixed(30);
	ImageMasking.ApplyMask(outlines, outlines, new MaskingOptions() { BackgroundReplacementColor = Color.Transparent });
	outlines.ReplaceColor(Color.FromArgb(255, 255, 255), 0, outlineColor);
	outlines.ApplyConvolutionFilter(ConvolutionFilterOptions.Blur);
	return outlines;
	}

	public static RasterImage ApplyOperationToRasterImage(this RasterImage image, Action<RasterImage> operation)
	{
	if (image is IMultipageImage multipage)
	{
	foreach (var page in multipage.Pages)
	{
	operation.Invoke((RasterImage)page);
	}
	}
	else
	{
	operation.Invoke(image);
	}

	return image;
	}

	public static RasterImage ApplyFilter(this RasterImage image, FilterOptionsBase filterOptions)
	{
	return image.ApplyOperationToRasterImage(img =>
	{
	img.Filter(img.Bounds, filterOptions);
	});
	}

	public static RasterImage ApplyConvolutionFilter(this RasterImage image, ConvolutionFilterOptions filterOptions)
	{
	return image.ApplyOperationToRasterImage(img =>
	{
	var pixelsLoader = new ImagePixelsLoader(img.Bounds);
	img.LoadPartialArgb32Pixels(img.Bounds, pixelsLoader);
	var outBuffer = new PixelBuffer(img.Bounds, new int[img.Width * img.Height]);
	ConvolutionFilter.DoFiltering(pixelsLoader.PixelsBuffer, outBuffer, filterOptions);
	img.SaveArgb32Pixels(outBuffer.Rectangle, outBuffer.Pixels);
	});
	}

	public static IImageDataContext GetDataContext(this RasterImage image)
	{
	IPixelBuffer GetImageBuffer(RasterImage img)
	{
	var pixelsLoader = new ImagePixelsLoader(img.Bounds);
	img.LoadPartialArgb32Pixels(img.Bounds, pixelsLoader);
	return pixelsLoader.PixelsBuffer;
	}

	if (image is IMultipageImage multipage)
	{
	return new MultipageDataContext(
	multipage.Pages.Select(page => new ImageDataContext((RasterImage)page)
	{
	Buffer = GetImageBuffer((RasterImage)page)
	}));
	}

	return new ImageDataContext(image)
	{
	Buffer = GetImageBuffer(image)
	};
	}

	public static IImageDataContext ApplyToDataContext(this IImageDataContext dataContext,
	Func<IPixelBuffer, IPixelBuffer> processor)
	{
	if (dataContext is MultipageDataContext multipage)
	{
	foreach (var context in multipage)
	{
	context.Buffer = processor.Invoke(context.Buffer);
	}
	}

	if (dataContext is ImageDataContext imageDataContext)
	{
	imageDataContext.Buffer = processor.Invoke(imageDataContext.Buffer);
	}

	return dataContext;
	}

	public static IImageDataContext ApplyConvolutionFilter(this IImageDataContext dataContext,
	ConvolutionFilterOptions filterOptions)
	{
	return dataContext.ApplyToDataContext(buffer =>
	{
	var outBuffer = new PixelBuffer(buffer.Rectangle, new int[buffer.Rectangle.Width * buffer.Rectangle.Height]);
	ConvolutionFilter.DoFiltering(buffer, outBuffer, filterOptions);
	return outBuffer;
	});
	}
	}

	class ConvolutionFilter
	{
	public static void DoFiltering(
	IPixelBuffer inputBuffer,
	IPixelBuffer outputBuffer,
	ConvolutionFilterOptions options)
	{
	var factor = options.Factor;
	var bias = options.Bias;
	var kernel = options.Kernel;
	var filterWidth = kernel.GetLength(1);
	var filterCenter = (filterWidth - 1) / 2;

	int x, y;
	int filterX, filterY, filterPx, filterPy, filterYPos, pixel;
	double r, g, b, kernelValue;

	int top = inputBuffer.Rectangle.Top;
	int bottom = inputBuffer.Rectangle.Bottom;
	int left = inputBuffer.Rectangle.Left;
	int right = inputBuffer.Rectangle.Right;

	for (y = top; y < bottom; y++)
	{
	for (x = left; x < right; x++)
	{
	r = 0;
	g = 0;
	b = 0;

	for (filterY = -filterCenter; filterY <= filterCenter; filterY++)
	{
	filterYPos = filterY + filterCenter;
	filterPy = filterY + y;

	if (filterPy >= top && filterPy < bottom)
	{
	for (filterX = -filterCenter; filterX <= filterCenter; filterX++)
	{
	filterPx = filterX + x;
	if (filterPx >= left && filterPx < right)
	{
	kernelValue = kernel[filterYPos, filterX + filterCenter];
	pixel = inputBuffer[filterPx, filterPy];
	r += ((pixel >> 16) & 0xFF) * kernelValue;
	g += ((pixel >> 8) & 0xFF) * kernelValue;
	b += (pixel & 0xFF) * kernelValue;
	}
	}
	}
	}

	r = (factor * r) + bias;
	g = (factor * g) + bias;
	b = (factor * b) + bias;
	r = r > 255 ? 255 : (r < 0 ? 0 : r);
	g = g > 255 ? 255 : (g < 0 ? 0 : g);
	b = b > 255 ? 255 : (b < 0 ? 0 : b);

	outputBuffer[x, y] = ((inputBuffer[x, y] >> 24) << 24) \| ((byte)r << 16) \| ((byte)g << 8) \| (byte)b;
	}
	}
	}
	}

	class ConvolutionFilterOptions
	{
	public double Factor { get; set; } = 1.0;

	public int Bias { get; set; } = 0;

	public double[,] Kernel { get; set; }

	public static ConvolutionFilterOptions Blur
	{
	get
	{
	return new ConvolutionFilterOptions
	{
	Kernel = new double[,] { { 1, 2, 1 }, { 2, 4, 2 }, { 1, 2, 1 } },
	Factor = 0.25 * 0.25
	};
	}
	}

	public static ConvolutionFilterOptions Sharpen
	{
	get
	{
	return new ConvolutionFilterOptions
	{
	Kernel = new double[,] { { 0, -1, 0 }, { -1, 5, -1 }, { 0, -1, 0 } }
	};
	}
	}

	public static ConvolutionFilterOptions Emboss
	{
	get
	{
	return new ConvolutionFilterOptions
	{
	Kernel = new double[,] { { -2, -1, 0 }, { -1, 1, 1 }, { 0, 1, 2 } }
	};
	}
	}

	public static ConvolutionFilterOptions Outline
	{
	get
	{
	return new ConvolutionFilterOptions
	{
	Kernel = new double[,] { { -1, -1, -1 }, { -1, 8, -1 }, { -1, -1, -1 } }
	};
	}
	}

	public static ConvolutionFilterOptions BottomSobel
	{
	get
	{
	return new ConvolutionFilterOptions
	{
	Kernel = new double[,] { { -1, -2, -1 }, { 0, 0, 0 }, { 1, 2, 1 } }
	};
	}
	}

	public static ConvolutionFilterOptions TopSobel
	{
	get
	{
	return new ConvolutionFilterOptions
	{
	Kernel = new double[,] { { 1, 2, 1 }, { 0, 0, 0 }, { -1, -2, -1 } }
	};
	}
	}

	public static ConvolutionFilterOptions LeftSobel
	{
	get
	{
	return new ConvolutionFilterOptions
	{
	Kernel = new double[,] { { 1, 0, -1 }, { 2, 0, -2 }, { 1, 0, -1 } }
	};
	}
	}

	public static ConvolutionFilterOptions RightSobel
	{
	get
	{
	return new ConvolutionFilterOptions
	{
	Kernel = new double[,] { { -1, 0, 1 }, { -2, 0, 2 }, { -1, 0, 1 } }
	};
	}
	}
	}

	interface IImageDataContext
	{
	void ApplyData();
	}

	class ImageDataContext : IImageDataContext
	{
	public ImageDataContext(RasterImage image)
	{
	this.Image = image;
	}

	public RasterImage Image { get; }

	public IPixelBuffer Buffer { get; set; }

	public void ApplyData()
	{
	this.Buffer.SaveToImage(this.Image);
	}
	}

	class MultipageDataContext : List<ImageDataContext>, IImageDataContext
	{
	public MultipageDataContext(IEnumerable<ImageDataContext> enumerable) : base(enumerable)
	{
	}

	public void ApplyData()
	{
	foreach (var context in this)
	{
	context.ApplyData();
	}
	}
	}

	class ImagePixelsLoader : IPartialArgb32PixelLoader
	{
	public ImagePixelsLoader(Aspose.Imaging.Rectangle rectangle)
	{
	this.PixelsBuffer = new CompositePixelBuffer(rectangle);
	}

	public CompositePixelBuffer PixelsBuffer { get; }

	public void Process(Aspose.Imaging.Rectangle pixelsRectangle, int[] pixels, Point start, Point end)
	{
	this.PixelsBuffer.AddPixels(pixelsRectangle, pixels);
	}
	}

	interface IPixelBuffer
	{
	Aspose.Imaging.Rectangle Rectangle { get; }

	int this[int x, int y]
	{
	get;
	set;
	}

	void SaveToImage(RasterImage image);
	}

	class PixelBuffer : IPixelBuffer
	{
	public PixelBuffer(Aspose.Imaging.Rectangle rectangle, int[] pixels)
	{
	this.Rectangle = rectangle;
	this.Pixels = pixels;
	}

	public Aspose.Imaging.Rectangle Rectangle { get; }

	public int[] Pixels { get; }

	public int this[int x, int y]
	{
	get => this.Pixels[this.GetIndex(x, y)];
	set => this.Pixels[this.GetIndex(x, y)] = value;
	}

	public void SaveToImage(RasterImage image)
	{
	image.SaveArgb32Pixels(this.Rectangle, this.Pixels);
	}

	public bool Contains(int x, int y)
	{
	return this.Rectangle.Contains(x, y);
	}

	private int GetIndex(int x, int y)
	{
	x -= this.Rectangle.Left;
	y -= this.Rectangle.Top;
	return x + y * this.Rectangle.Width;
	}
	}

	class CompositePixelBuffer : IPixelBuffer
	{
	private readonly List<PixelBuffer> _buffers = new List<PixelBuffer>();

	public CompositePixelBuffer(Aspose.Imaging.Rectangle rectangle)
	{
	this.Rectangle = rectangle;
	}

	public Aspose.Imaging.Rectangle Rectangle { get; }

	public int this[int x, int y]
	{
	get => this.GetBuffer(x, y)[x, y];
	set => this.GetBuffer(x, y)[x, y] = value;
	}

	public void SaveToImage(RasterImage image)
	{
	foreach (var pixelBuffer in this._buffers)
	{
	pixelBuffer.SaveToImage(image);
	}
	}

	public IEnumerable<PixelBuffer> Buffers => this._buffers;

	public void AddPixels(Aspose.Imaging.Rectangle rectangle, int[] pixels)
	{
	if (this.Rectangle.IntersectsWith(rectangle))
	{
	this._buffers.Add(new PixelBuffer(rectangle, pixels));
	}
	}

	private PixelBuffer GetBuffer(int x, int y)
	{
	return this._buffers.First(b => b.Contains(x, y));
	}
	}

view raw cartoonify-images.cs hosted with ❤ by GitHub