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XImage.FromFile(.png) fails with 6.0.0-preview-2
http://forum.pdfsharp.com/viewtopic.php?f=2&t=4439		 Page 1 of 1
Author:  Francesca [ Sat May 06, 2023 1:08 am ]
Post subject:  XImage.FromFile(.png) fails with 6.0.0-preview-2
I get an "Unsupported image format" when trying to load and image from a file using PdfSharp.Drawing.XImage in a .NET 7.0 project using PDFSharp 6.0.0-preview-2 and trying to read a .png -- works for .jpg.

Code:
using (XImage image = XImage.FromFile(imageFilepath))

I am able to XFont, XBrushes and XGraphics to add text.

This is supposed to work, right? I read in the docs that .png is already supported.

Are there any tricks?

PS I do have
Code:
GlobalFontSettings.FontResolver = new FailsafeFontResolver();
in my Program.cs

PSS I also tried to load the same image from a stream with the same results.
Code:
MemoryStream ms = new MemoryStream();

using (FileStream fs = new FileStream(imageFilepath, FileMode.Open))
{
    byte[] buffer = new byte[4096];
    int bytesRead;
    while ((bytesRead = fs.Read(buffer, 0, buffer.Length)) > 0)
    {
        ms.Write(buffer, 0, bytesRead);
    }
}

XImage image = XImage.FromStream(ms);
Author:  Francesca [ Sat May 06, 2023 4:34 am ]
Post subject:  Re: XImage.FromFile(.png) fails with 6.0.0-preview-2
I figured it out... Seems that you're only suppoting 8-bit color depth as of now.

From ImageImporterPng.cs:
Code:
namespace PdfSharp.Drawing.Internal
{
    internal class ImageImporterPng : ImageImporterRoot, IImageImporter
    {
...
        private bool TestPngInfoHeader(StreamReaderHelper stream, ImportedImage ii)
        {
            stream.CurrentOffset = 16;
            uint dWord = stream.GetDWord(0, bigEndian: true);
            uint dWord2 = stream.GetDWord(4, bigEndian: true);
            byte @byte = stream.GetByte(8);
            byte byte2 = stream.GetByte(9);
...
            switch (byte2)
            {
                case 0:
                    {
                        DefaultInterpolatedStringHandler defaultInterpolatedStringHandler = new DefaultInterpolatedStringHandler(43, 2);
                        defaultInterpolatedStringHandler.AppendLiteral("Unsupported bit depth ");
                        defaultInterpolatedStringHandler.AppendFormatted(@byte);
                        defaultInterpolatedStringHandler.AppendLiteral(" for PNG color type ");
                        defaultInterpolatedStringHandler.AppendFormatted(byte2);
                        defaultInterpolatedStringHandler.AppendLiteral(".");
                        throw new Exception(defaultInterpolatedStringHandler.ToStringAndClear());
                    }
                case 2:
                    {
                        if (@byte == 8)
                        {
                            ii.Information.ImageFormat = ImageInformation.ImageFormats.RGB24;
                            break;
                        }

                        DefaultInterpolatedStringHandler defaultInterpolatedStringHandler = new DefaultInterpolatedStringHandler(43, 2);
                        defaultInterpolatedStringHandler.AppendLiteral("Unsupported bit depth ");
                        defaultInterpolatedStringHandler.AppendFormatted(@byte);
                        defaultInterpolatedStringHandler.AppendLiteral(" for PNG color type ");
                        defaultInterpolatedStringHandler.AppendFormatted(byte2);
                        defaultInterpolatedStringHandler.AppendLiteral(".");
                        throw new Exception(defaultInterpolatedStringHandler.ToStringAndClear());
                    }
                case 3:
                    {
                        if (@byte == 8)
                        {
                            ii.Information.ImageFormat = ImageInformation.ImageFormats.Palette8;
                            break;
                        }

                        DefaultInterpolatedStringHandler defaultInterpolatedStringHandler = new DefaultInterpolatedStringHandler(43, 2);
                        defaultInterpolatedStringHandler.AppendLiteral("Unsupported bit depth ");
                        defaultInterpolatedStringHandler.AppendFormatted(@byte);
                        defaultInterpolatedStringHandler.AppendLiteral(" for PNG color type ");
                        defaultInterpolatedStringHandler.AppendFormatted(byte2);
                        defaultInterpolatedStringHandler.AppendLiteral(".");
                        throw new Exception(defaultInterpolatedStringHandler.ToStringAndClear());
                    }
                case 6:
                    {
                        if (@byte == 8)
                        {
                            ii.Information.ImageFormat = ImageInformation.ImageFormats.ARGB32;
                            break;
                        }

                        DefaultInterpolatedStringHandler defaultInterpolatedStringHandler = new DefaultInterpolatedStringHandler(43, 2);
                        defaultInterpolatedStringHandler.AppendLiteral("Unsupported bit depth ");
                        defaultInterpolatedStringHandler.AppendFormatted(@byte);
                        defaultInterpolatedStringHandler.AppendLiteral(" for PNG color type ");
                        defaultInterpolatedStringHandler.AppendFormatted(byte2);
                        defaultInterpolatedStringHandler.AppendLiteral(".");
                        throw new Exception(defaultInterpolatedStringHandler.ToStringAndClear());
                    }
                default:
                    {
                        DefaultInterpolatedStringHandler defaultInterpolatedStringHandler = new DefaultInterpolatedStringHandler(28, 1);
                        defaultInterpolatedStringHandler.AppendLiteral("Unsupported PNG color type ");
                        defaultInterpolatedStringHandler.AppendFormatted(byte2);
                        defaultInterpolatedStringHandler.AppendLiteral(".");
                        throw new Exception(defaultInterpolatedStringHandler.ToStringAndClear());
                    }
            }
Author:  TH-Soft [ Mon May 08, 2023 8:33 am ]
Post subject:  Re: XImage.FromFile(.png) fails with 6.0.0-preview-2
The list of supported formats can be seen here:
https://docs.pdfsharp.net/PDFsharp/Over ... ge-formats

My boss said nobody needs PNG files with 16 colours.

Which format does the PNG file have which you could not read?
Author:  Francesca [ Thu May 11, 2023 3:59 pm ]
Post subject:  Re: XImage.FromFile(.png) fails with 6.0.0-preview-2
TH-Soft wrote:
My boss said nobody needs PNG files with 16 colours.

Which format does the PNG file have which you could not read?


Yes, the images that I am adding are with 16-bit colors. The images are created with ImageMagick libraries and they use 16-bit colors by default.

I rewrote my code to use different libraries and to create only 8-bit images and it works now.

My eye can see the difference so the quality is much less for photos but at least it works.

Thank you for your response.
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