create-custom-jpeg-image-converter-net-standard.md

title	description	type	page_title	slug	position	tags	res_type
Create Custom JpegImageConverter in .Net Standard	Describes how to create a custom implementation of JpegImageConverterBase in .Net Standard.	how-to	Create custom implementation of JpegImageConverterBase in .Net Standard	create-custom-jpeg-image-converter-net-standard	0	image, converter, jpeg, jpegimageconverter, netstandard	kb

Product Version	Product	Author
up to 2023.1.410	RadPdfProcessing	Martin Velikov
2.1.6	ImageSharp

Description

.NET Standard specification does not define APIs for converting images or scaling their quality. That is why, when inserting images in a PDF document different than Jpeg and Jpeg2000 or ImageQuality different than High, you will need to implement the JpegImageConverterBase abstract class. This implementation should be passed to the JpegImageConverter property of the FixedExtensibilityManager.

important With the R2 2023 changes SkiaSharp replaced ImageSharp as the required dependency.

Solution

The following code snippets demonstrate how to create a custom implementation of the JpegImageConverterBase abstract class using the SixLabors.ImageSharp library and set it to the JpegImageConverter property of the FixedExtensibilityManager. We are using the ImageSharp library to convert the images from one of the library's supported formats to Jpeg and to change their quality if it is set. Note that this approach is valid up to version 2023.1.410 of RadPdfProcessing.

[C#] Create a custom implementation inheriting the JpegImageConverterBase abstract class

{{region kb-create-custom-jpeg-image-converter1}}

    public class CustomJpegImageConverter : JpegImageConverterBase
    {
        public override bool TryConvertToJpegImageData(byte[] imageData, ImageQuality imageQuality, out byte[] jpegImageData)
        {
            try
            {
                IImageFormat imageFormat;
                using (SixLabors.ImageSharp.Image image = SixLabors.ImageSharp.Image.Load(imageData, out imageFormat))
                {
                    if (imageFormat.GetType() == typeof(PngFormat))
                    {
                        image.Mutate(x => x.BackgroundColor(Color.White));
                    }

                    JpegEncoder options = new JpegEncoder
                    {
                        Quality = (int)imageQuality,
                    };

                    using (MemoryStream ms = new MemoryStream())
                    {
                        image.SaveAsJpeg(ms, options);

                        jpegImageData = ms.ToArray();
                    }
                    
                }

                return true;
            }
            catch (Exception ex)
            {
                if (ex is UnknownImageFormatException || ex is ImageProcessingException)
                {
                    jpegImageData = null;
                    return false;
                }
                else
                {
                    throw ex;
                }
            }
        }
    }

{{endregion}}

[C#] Set the custom implementation to the JpegImageConverter property of the FixedExtensibilityManager

{{region kb-create-custom-jpeg-image-converter2}}

        JpegImageConverterBase customJpegImageConverter = new CustomJpegImageConverter();
        FixedExtensibilityManager.JpegImageConverter = customJpegImageConverter;

        // RadPdfProcessing version up to 2023.1.410
        PdfFormatProvider provider = new PdfFormatProvider();
        string imageFolderPath = @"..\..\..\images";
        string[] imageFiles = Directory.GetFiles(imageFolderPath);
        RadFixedDocument fixedDocument = new RadFixedDocument();
        RadFixedDocumentEditor documentEditor = new RadFixedDocumentEditor(fixedDocument);
        
        foreach (string imageFilePath in imageFiles)
        {
            FileStream fileStream = new FileStream(imageFilePath, FileMode.Open);
            Telerik.Windows.Documents.Fixed.Model.Resources.ImageSource _imageSource = new Telerik.Windows.Documents.Fixed.Model.Resources.ImageSource(fileStream);
            documentEditor.InsertImageInline(_imageSource);
            documentEditor.InsertLineBreak();
        }
        
        documentEditor.Dispose();      
        string outputFilePath = @"output.pdf";
        File.Delete(outputFilePath);
        using (Stream output = File.OpenWrite(outputFilePath))
        {
            provider.Export(fixedDocument, output);
        }
        
        Process.Start(new ProcessStartInfo() { FileName = outputFilePath, UseShellExecute = true });

{{endregion}}

See Also

• [Cross platform >> Images]({%slug radpdfprocessing-cross-platform-images%})