CODEWITHSUNDEEP
c#image
Jeeva J
Jeeva J

Reputation: 3251

Cropping image or scale down using c#

I want to crop the image on the fly in c#.

I have referred some links and implement like following.

Reference:

But I am getting the low quality image. I have seen website they are uploading the image in their server and scale down the website without losing quality

How have they done? Why can't we do in c#?

CODE

 public static Image ScaleImage(Image image, int width, int height)
        {
            if (image.Height < height && image.Width < width) return image;
            using (image)
            {
                double xRatio = (double)image.Width / width;
                double yRatio = (double)image.Height / height;
                double ratio = Math.Max(xRatio, yRatio);
                int nnx = (int)Math.Floor(image.Width / xRatio);
                int nny = (int)Math.Floor(image.Height / yRatio);
                Bitmap resizedImage = new Bitmap(nnx, nny, PixelFormat.Format64bppArgb);
                using (Graphics graphics = Graphics.FromImage(resizedImage))
                {
                    graphics.Clear(Color.Transparent);

                    // This is said to give best quality when resizing images
                    graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
                    graphics.SmoothingMode = SmoothingMode.HighQuality;
                    graphics.CompositingQuality = CompositingQuality.HighQuality;
                    graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;

                    graphics.DrawImage(image,
                       new Rectangle(0, 0, nnx, nny),
                       new Rectangle(0, 0, image.Width, image.Height),
                       GraphicsUnit.Pixel);
                }
                return resizedImage;
            }
        }

Upvotes: 0

Views: 1137

Answers (3)

Rahul Nanwani
Rahul Nanwani

Reputation: 1277

ImageMagick is a viable solution definitely and so is GraphicsMagick or libvips (Though I am not sure if libvips has C# specific bindings but it is a lot faster than IM or GM ).

You may also want to try ImageKit or other similar fully featured third-party image optimisation and delivery solutions to do all this resizing for you.

Upvotes: 0

kleisauke
kleisauke

Reputation: 555

You could try net-vips, the C# binding for libvips. It's a lazy, streaming, demand-driven image processing library, so it can do operations like this without needing to load the whole image.

For example, it comes with a handy image thumbnailer:

Image image = Image.Thumbnail("image.jpg", 300, 300);
image.WriteToFile("my-thumbnail.jpg");

Upvotes: 1

user4783404
user4783404

Reputation:

You could use imagemagic for that. It has its own dll to work with VS. It olso have great forum where you can find all kinds of examples. I made a program with it that does that. it took me about half an hour ( not really a big application, it is only used for a commercial company to make a lot of cropped resized pictues (about 4 terrabyte of pictures lol)). here you can find some examples.

https://www.imagemagick.org/script/index.php

Upvotes: 0

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