Find Image Format Using Bitmap Object in C#

Find image format using Bitmap object in C#

If you want to know the format of an image, you can load the file with the Image class, and check its RawFormat property:

using(Image img = Image.FromFile(@"C:\path\to\img.jpg"))
{
    if (img.RawFormat.Equals(System.Drawing.Imaging.ImageFormat.Jpeg))
    {
      // ...
    }
}

How to get the image format of a BitmapImage?

How can I get the format of the BitmapImage?

You can't, because it does not have a fixed format.

You may use any of the classed derived from BitmapEncoder to encode a BitmapSource. The format is then determined by the BitmapEncoder that is actually used, e.g. PNG when you use PngBitmapEncoder.

How can I know what image format I get from a stream?

You may checkout the Image.RawFormat property. So once you load the image from the stream you could test:

if (ImageFormat.Jpeg.Equals(image.RawFormat))
{
    // JPEG
}
else if (ImageFormat.Png.Equals(image.RawFormat))
{
    // PNG
}
else if (ImageFormat.Gif.Equals(image.RawFormat))
{
    // GIF
}
... etc

How to retrieve an Image in Bitmap format from the Media Library

I found out eventually; this is the code that will convert an image residing in Sitecore's Media Library in System.Drawing.Bitmap format:

var item = new Sitecore.Context.Database.GetItem(imageId);
var mediaItem = Sitecore.Data.Items.MediaItem(item);
var image = new System.Drawing.Bitmap(mediaItem.GetMediaStream());

how to get exact part of Bitmap object

You can just get a Rectangle as a parameter and look just at the points inside that rectangle, to make sure that all points in rectangle falls inside the bitmap, you need to do Math.Min(bmp.Height, region.Y + region.Height) and Math.Min(bmp.Width, region.X+Region.Width) instead of just region.Y + region.Height and region.X+Region.Width:

ulong CountPixels(Bitmap bm, Color target_color, Rectangle region)
    {
        // Loop through the pixels.
        ulong matches = 0;
        for (int y = region.Y; y < Math.Min(bmp.Height, region.Y + region.Height); y++)
        {
            for (int x = region.X; x < Math.Min(bmp.Width, region.X+Region.Width); x++)
            {

                if (bm.GetPixel(x, y) == target_color)
                {
                    matches++;
                }
            }
        }
        return matches;
    }

Determine the format of an image file?

see my answer here:

Find image format using Bitmap object in C#

using System.Linq;

//...

//get image
var file_bytes = System.Convert.FromBase64String(@"iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==");
var file_stream = new System.IO.MemoryStream(file_bytes);
var file_image = System.Drawing.Image.FromStream(file_stream);

//get image format
var file_image_format = typeof(System.Drawing.Imaging.ImageFormat).GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Static).ToList().ConvertAll(property => property.GetValue(null, null)).Single(image_format => image_format.Equals(file_image.RawFormat));
System.Diagnostics.Debug.WriteLine(file_image_format, "file_image_format");

//get image codec
var file_image_format_codec = System.Drawing.Imaging.ImageCodecInfo.GetImageDecoders().ToList().Single(image_codec => image_codec.FormatID == file_image.RawFormat.Guid);
System.Diagnostics.Debug.WriteLine(file_image_format_codec.CodecName + ", mime: " + file_image_format_codec.MimeType + ", extension: " + file_image_format_codec.FilenameExtension, "image_codecs", "file_image_format_type");

Can bitmap object be save as PNG or JPEG file format

Bitmap extends Image, therefore you can call: Image.Save (String, ImageFormat). For example:

using System.Drawing
// ...

Bitmap img = new Bitmap("file.jpg");
img.Save("file.png", ImageFormat.Png); // ImageFormat.Jpeg, etc

Omitting the second argument and just calling Image.Save(String) will save the image as its raw format.

How to convert Bitmap to Image

A Bitmap is an Image. It inherits from the Image class.

From MSDN:

[SerializableAttribute]
[ComVisibleAttribute(true)]
public sealed class Bitmap : Image

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