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c#asp.netsystem.drawing

Graphics object to image file


I would like to crop and resize my image. Here is my code:

Image image = Image.FromFile(AppDomain.CurrentDomain.BaseDirectory + "Cropper/tests/castle.jpg");

// Crop and resize the image.
Rectangle destination = new Rectangle(0, 0, 200, 120);
Graphics graphic = Graphics.FromImage(image);
graphic.DrawImage(image, destination, int.Parse(X1.Value), int.Parse(Y1.Value), int.Parse(Width.Value), int.Parse(Height.Value), GraphicsUnit.Pixel);

Now I assume that my resulting cropped/resized image is stored in the graphics object. The question is - how do I save it to a file?


Solution

  • The Graphics object that you get from Graphics.FromImage is a drawing surface for the image. So you can simply save the image object when you are done.

    string fileName = AppDomain.CurrentDomain.BaseDirectory + "Cropper/tests/castle.jpg");
    using (Image image = Image.FromFile(fileName)
    {
        using (Graphics graphic = Graphics.FromImage(image))
        {
            // Crop and resize the image.
            Rectangle destination = new Rectangle(0, 0, 200, 120);
            graphic.DrawImage(image, destination, int.Parse(X1.Value), int.Parse(Y1.Value), int.Parse(Width.Value), int.Parse(Height.Value), GraphicsUnit.Pixel);
        }
        image.Save(fileName);
    }
    

    Beware though that doing this repeatedly on a jpg image may not be a good thing; the image is re-encoded each time and since jpg uses a destructive compression method you will lose some image quality each time. I wouldn't worry about that if this is a once-per-image operation though.