How to filter an image

How to filter an image

         You can select different filter types: `SmallRectangular`, `BigRectangular`, `Sharpen`, `MotionWiener`, `BilateralSmoothing`, `GaussBlur`, `GaussWiener` and `Median` to edit a photo or image. The Rectangle filters create the effect of putting a special glass before a camera through which we can see the picture with different filtered views. To filter a photo with a Rectangle filter just set the rectangle dimensions and then apply them to your image by using Filter method with two options. The first option is a Rectangle object and the second is filter type options. If you want to apply a filter for a vector image, you need to rasterize it before:

using Aspose.Imaging;
using Aspose.Imaging.FileFormats.Bmp;
using Aspose.Imaging.FileFormats.Dicom;
using Aspose.Imaging.FileFormats.Emf;
using Aspose.Imaging.FileFormats.Jpeg;
using Aspose.Imaging.FileFormats.Jpeg2000;
using Aspose.Imaging.FileFormats.Png;
using Aspose.Imaging.FileFormats.Psd;
using Aspose.Imaging.FileFormats.Tiff.Enums;
using Aspose.Imaging.ImageFilters.FilterOptions;
using Aspose.Imaging.ImageOptions;
using Aspose.Imaging.Masking;
using Aspose.Imaging.Masking.Options;
using Aspose.Imaging.Masking.Result;
using Aspose.Imaging.Sources;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

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

MedianFilter();

void SmallRectangularFilter()
{
    FilterImages(image =>
    {
	//https://apireference.aspose.com/imaging/net/aspose.imaging.imagefilters.filteroptions/smallrectangularfilteroptions
        var filterRect = new Aspose.Imaging.Rectangle(image.Width / 6, image.Height / 6, image.Width * 2 / 3, image.Height * 2 / 3);
        image.Filter(filterRect, new SmallRectangularFilterOptions());
    }, "smallrectangular");
}


void BigRectangularFilter()
{
    FilterImages(image =>
    {
	//https://apireference.aspose.com/imaging/net/aspose.imaging.imagefilters.filteroptions/bigrectangularfilteroptions
        var filterRect = new Aspose.Imaging.Rectangle(image.Width / 6, image.Height / 6, image.Width * 2 / 3, image.Height * 2 / 3);
        image.Filter(filterRect, new BigRectangularFilterOptions());
    }, "bigrectangular");
}


void SharpenFilter()
{
    FilterImages(image =>
    {
	//https://apireference.aspose.com/imaging/net/aspose.imaging.imagefilters.filteroptions/sharpenfilteroptions
        var filterRect = new Aspose.Imaging.Rectangle(image.Width / 6, image.Height / 6, image.Width * 2 / 3, image.Height * 2 / 3);
        image.Filter(filterRect, new SharpenFilterOptions());
    }, "sharpen");
}


void MotionWienerFilter()
{
    FilterImages(image =>
    {
	//https://apireference.aspose.com/imaging/net/aspose.imaging.imagefilters.filteroptions/motionwienerfilteroptions
        var filterRect = new Aspose.Imaging.Rectangle(image.Width / 6, image.Height / 6, image.Width * 2 / 3, image.Height * 2 / 3);
        image.Filter(filterRect, new MotionWienerFilterOptions(20, 2, 0));
    }, "motionwiener");
}


void BilateralSmoothingFilter()
{
    FilterImages(image =>
    {
	//https://apireference.aspose.com/imaging/net/aspose.imaging.imagefilters.filteroptions/bilateralsmoothingfilteroptions
        var filterRect = new Aspose.Imaging.Rectangle(image.Width / 6, image.Height / 6, image.Width * 2 / 3, image.Height * 2 / 3);
        image.Filter(filterRect, new BilateralSmoothingFilterOptions());
    }, "bilateralsmoothing");
}


void GaussBlurFilter()
{
    FilterImages(image =>
    {
	//https://apireference.aspose.com/imaging/net/aspose.imaging.imagefilters.filteroptions/gaussianblurfilteroptions
        var filterRect = new Aspose.Imaging.Rectangle(image.Width / 6, image.Height / 6, image.Width * 2 / 3, image.Height * 2 / 3);
        image.Filter(filterRect, new GaussianBlurFilterOptions(5, 4));
    }, "gaussblur");
}


void GaussWienerFilter()
{
    FilterImages(image =>
    {
	//https://apireference.aspose.com/imaging/net/aspose.imaging.imagefilters.filteroptions/gausswienerfilteroptions
        var filterRect = new Aspose.Imaging.Rectangle(image.Width / 6, image.Height / 6, image.Width * 2 / 3, image.Height * 2 / 3);
        image.Filter(filterRect, new GaussWienerFilterOptions(5, 5));
    }, "gausswiener");
}


void MedianFilter()
{
    FilterImages(image =>
    {
	//https://apireference.aspose.com/imaging/net/aspose.imaging.imagefilters.filteroptions/medianfilteroptions
        var filterRect = new Aspose.Imaging.Rectangle(image.Width / 6, image.Height / 6, image.Width * 2 / 3, image.Height * 2 / 3);
        image.Filter(filterRect, new MedianFilterOptions(20));
    }, "median");
}

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);
            }
        }
        );
}

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;
}