Png generated by Magick.Net from Pdf file is black

[junaid-ahmed-92]

I have created a small .net core 3.1 console application to convert pdf to png using Magick.Net (https://www.nuget.org/packages/Magick.NET-Q16-AnyCPU/). I have also installed ghostscript public license. It's doing alright but the output image is totally black and I can't read a single line. If I open the file using Paint then it's fine.
Here is my code:

       public static int ConvertFileToImages(string filePath, string destinationPath)
        {
            int noofPages = 0;
            MagickReadSettings magickReadSettings = new MagickReadSettings();
            magickReadSettings.Density = new Density(300, 300);
            using (MagickImageCollection magickImageCollection = new MagickImageCollection())
            {
                magickImageCollection.Read(filePath, magickReadSettings);
                int page = 1;
                noofPages = magickImageCollection.Count;
                foreach (MagickImage magickImage in magickImageCollection)
                {
                    magickImage.Format = MagickFormat.Png;
                    magickImage.BackgroundColor = MagickColors.White;
                    string imageFilePath = string.Concat(destinationPath, "file-", page, ".png");
                    magickImage.Write(imageFilePath);
                    page++;
                }
            }
            return noofPages;
        }

Am I doing anything wrong?

[adscott1982]

To be clear, you are saying that the file output by this code, when opened in Paint looks fine? So in what viewer does it not look fine?

I literally did the same thing today using the 8 bit library.

Here is my code:

            var settings = new MagickReadSettings();

            // Settings the density to 300 dpi will create an image with a better quality
            settings.Density = new Density(300);

            using (var images = new MagickImageCollection())
            {
                // Add all the pages of the pdf file to the collection
                images.Read(filePath, settings);

                // Create new image that appends all the pages vertically
                using (var vertical = images.AppendVertically())
                {
                    // Save result as a BMP in a memory stream
                    var memoryStream = new MemoryStream();
                    vertical.Write(memoryStream, MagickFormat.Bmp);
                    return memoryStream.ToArray();
                }
            }

[dlemstra]

Can you respond to @adscott1982 their questions @junaid-ahmed-92?

[junaid-ahmed-92]

Sorry for the late reply. So I am facing this issue in WIndows default photo viewer. I can try changing the format but I was wondering why it's happening with png?

[dlemstra]

The Windows photo viewer displays transparent as black.

[junaid-ahmed-92]

Alright, so how can I fix that? Means I don't want transparent image

[dlemstra]

I have not tested this but I think you can specify the background color with magickReadSettings.BackgroundColor.