Using System.Drawing with ASP.NET Core or ASP.NET Service | Using Aspose.Drawing

readme.md

You can find all the details at: Using System.Drawing with ASP.NET Core or ASP.NET Service

FilterThumbnailResult.cs

/// <summary>
/// The result of filtered thumbnail generation.
/// </summary>
public class FilterThumbnailResult
{
    /// <summary>
    /// Initializes a new instance of the FilterThumbnailResult class.
    /// </summary>
    /// <param name="filterType">The type of filter applied to the thumbnail.</param>
    /// <param name="pngData">The image data in PNG format.</param>
    /// <param name="width">The width of the thumbnail.</param>
    /// <param name="height">The height of the thumbnail.</param>
    public FilterThumbnailResult(FilterType filterType, byte[] pngData, int width, int height)
    {
        this.FilterType = filterType;
        this.PngData = pngData;
        this.Width = width;
        this.Height = height;
    }

    /// <summary>
    /// Gets the type of filter applied to the thumbnail.
    /// </summary>
    public FilterType FilterType { get; }

    /// <summary>
    /// Gets the image data in PNG format.
    /// </summary>
    public byte[] PngData { get; }

    /// <summary>
    /// Gets the width of the thumbnail.
    /// </summary>
    public int Width { get; }

    /// <summary>
    /// Gets the height of the thumbnail.
    /// </summary>
    public int Height { get; }
}

FilterType.cs

/// <summary>
/// Available types of the filters.
/// </summary>
public enum FilterType
{
    /// <summary>
    /// Filter for generation of image saturated with red color.
    /// </summary>
    Red,

    /// <summary>
    /// Filter for generation of image saturated with green color.
    /// </summary>
    Green,

    /// <summary>
    /// Filter for generation of image saturated with blue color.
    /// </summary>
    Blue,

    /// <summary>
    /// Filter for generation of a grayscale image.
    /// </summary>
    Grayscale,

    /// <summary>
    /// Filter for generation of a negative image.
    /// </summary>
    Negative,

    /// <summary>
    /// Filter for generation of a sepia image.
    /// </summary>
    Sepia,
}

GenerateAllThumbnails.cs

/// <summary>
/// Generates a set of thumbnails for all available filters.
/// </summary>
/// <param name="sourceImage">Bytes of the source image.</param>
/// <param name="width">Requested width of the preview images.</param>
/// <param name="height">Requested height of the preview images.</param>
/// <returns>A set of thumbnails.</returns>
public IEnumerable<FilterThumbnailResult> GenerateAllThumbnails(byte[] sourceImage, int width, int height)
{
    using (MemoryStream ms = new MemoryStream(sourceImage))
    using (Bitmap bitmap = new Bitmap(ms))
    {
        ConcurrentBag<FilterThumbnailResult> collection = new ConcurrentBag<FilterThumbnailResult>();

        Parallel.ForEach(Processors, (processor) =>
        {
            using (Bitmap previewBitmap = new Bitmap(width, height, PixelFormat.Format32bppArgb))
            using (Graphics graphics = Graphics.FromImage(previewBitmap))
            {
                graphics.DrawImage(bitmap, 0, 0, width, height);
                collection.Add(processor(previewBitmap));
            }
        });

        return collection;
    }
}

IThumbnailGenerator.cs

using System.Collections.Generic;

/// <summary>
/// The interface for thumbnails images generation.
/// </summary>
public interface IThumbnailGenerator
{
    /// <summary>
    /// Generates a set of thumbnails for all available filters.
    /// </summary>
    /// <param name="sourceImage">Bytes of the source image.</param>
    /// <param name="width">Requested width of the preview images.</param>
    /// <param name="height">Requested height of the preview images.</param>
    /// <returns>A set of thumbnails.</returns>
    IEnumerable<FilterThumbnailResult> GenerateAllThumbnails(byte[] sourceImage, int width, int height);
}

ThumbnailGenerator.cs

/// <summary>
/// IThumbnailGenerator interface implementation using System.Drawing.
/// </summary>
public class ThumbnailGenerator
    : IThumbnailGenerator
{
    /// <summary>
    /// A set of thumbnail processors.
    /// </summary>
    private static readonly FilterThumbnailProcessor[] Processors = new FilterThumbnailProcessor[] 
    {
        ApplyRedFilter,
        ApplyGreenFilter,
        ApplyBlueFilter,
        ApplyGrayFilter,
        ApplyNegativeFilter,
        ApplySepiaFilter,
    };

    /// <summary>
    /// Delegate for thumbnail processing.
    /// </summary>
    /// <param name="thumbnail">Thumbnail of the original image.</param>
    /// <returns>Result of filtered thumbnail generation.</returns>
    private delegate FilterThumbnailResult FilterThumbnailProcessor(Bitmap thumbnail);

    /// <summary>
    /// Generates a set of thumbnails for all available filters.
    /// </summary>
    /// <param name="sourceImage">Bytes of the source image.</param>
    /// <param name="width">Requested width of the preview images.</param>
    /// <param name="height">Requested height of the preview images.</param>
    /// <returns>A set of thumbnails.</returns>
    public IEnumerable<FilterThumbnailResult> GenerateAllThumbnails(byte[] sourceImage, int width, int height)
    {
        using (MemoryStream ms = new MemoryStream(sourceImage))
        using (Bitmap bitmap = new Bitmap(ms))
        {
            foreach (var processor in Processors)
            {
                using (Bitmap previewBitmap = new Bitmap(width, height, PixelFormat.Format32bppArgb))
                using (Graphics graphics = Graphics.FromImage(previewBitmap))
                {
                    graphics.DrawImage(bitmap, 0, 0, width, height);

                    yield return processor(previewBitmap);
                }
            }
        }
    }

    /// <summary>
    /// Applies a red filter to thumbnail.
    /// </summary>
    /// <param name="thumbnail">Thumbnail of the original image.</param>
    /// <returns>Result of filtered thumbnail generation.</returns>
    private static FilterThumbnailResult ApplyRedFilter(Bitmap thumbnail)
    {
    ...
    }

    /// <summary>
    /// Applies a green filter to thumbnail.
    /// </summary>
    /// <param name="thumbnail">Thumbnail of the original image.</param>
    /// <returns>Result of filtered thumbnail generation.</returns>
    private static FilterThumbnailResult ApplyGreenFilter(Bitmap thumbnail)
    {
    ...
    }

    /// <summary>
    /// Applies a blue filter to thumbnail.
    /// </summary>
    /// <param name="thumbnail">Thumbnail of the original image.</param>
    /// <returns>Result of filtered thumbnail generation.</returns>
    private static FilterThumbnailResult ApplyBlueFilter(Bitmap thumbnail)
    {
    ...
    }

    /// <summary>
    /// Applies a gray filter to thumbnail.
    /// </summary>
    /// <param name="thumbnail">Thumbnail of the original image.</param>
    /// <returns>Result of filtered thumbnail generation.</returns>
    private static FilterThumbnailResult ApplyGrayFilter(Bitmap thumbnail)
    {
    ...
    }

    /// <summary>
    /// Applies a negative filter to thumbnail.
    /// </summary>
    /// <param name="thumbnail">Thumbnail of the original image.</param>
    /// <returns>Result of filtered thumbnail generation.</returns>
    private static FilterThumbnailResult ApplyNegativeFilter(Bitmap thumbnail)
    {
    ...
    }

    /// <summary>
    /// Applies a sepia filter to thumbnail.
    /// </summary>
    /// <param name="thumbnail">Thumbnail of the original image.</param>
    /// <returns>Result of filtered thumbnail generation.</returns>
    private static FilterThumbnailResult ApplySepiaFilter(Bitmap thumbnail)
    {
    ...
    }
}