如何使用 iText7 从 C# 中的 MemoryStream 创建 Image 对象？

Question

I am working with iText7 in ASP.NET-MVC v5.2. I am very inexperienced with iText and C# am still trying to figure out how the classes in this library work.

Say I have a MemoryStream which contains an image...

MemoryStream imgStream = new MemoryStream(imgLocation);

How can I create an Image object using imgStream ? I am looking for something along the lines of

Image img = new Image(imgStream);

Thanks for the help :)

EDIT : I am trying to create an Image from iText not System.Drawing.Image

Answer 1

To create an iText 7 Image object from a bitmap image, you first have to create an ImageData instance which you then can feed into one of the corresponding Image constructors

public Image(ImageData img);
public Image(ImageData img, float left, float bottom);
public Image(ImageData img, float left, float bottom, float width);

You usually create an ImageData instance using the corresponding ImageDataFactory static methods:

public static ImageData Create(byte[] bytes);
public static ImageData Create(String filename);
public static ImageData Create(Uri url);

As you see, there is no method for a stream. But as your stream is a MemoryStream , you can easily retrieve a byte[] of the image. Thus,

byte[] imageBytes = imgStream.ToArray();
ImageData rawImage = ImageDataFactory.Create(imageBytes);
Image image = new Image(rawImage);

Answer 2

Convert the MemoryStream to a byte[] and use the GetInstance method

public static byte[] GetByteArray(Stream input)
{
    byte[] buffer = new byte[16*1024];
    using (MemoryStream ms = new MemoryStream())
    {
        int read;
        while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
        {
            ms.Write(buffer, 0, read);
        }
        return ms.ToArray();
    }
}

and then use the byte array like this

var Image = Image.GetInstance(GetByteArray(imgStream));