C# – generating jpg thumbnails in dotnet

cimage

i am using this code to take a jpg image and save it as a thumbnail but it seems very slow ..

        Image thumbNail = image.GetThumbnailImage(width, height, null, new IntPtr());

is there any faster way to generate a large amount of thumbnails from a directory of images?

Best Answer

Try Draw Image - Re Edited

    public Image ResizeImage(Image openImage, int NewWidth, int NewHeight) {
        var openBitmap = new Bitmap(openImage);
        var newBitmap = new Bitmap(NewWidth, NewHeight);
        using (Graphics g = Graphics.FromImage(openBitmap))
        {
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g.PixelOffsetMode = PixelOffsetMode.HighQuality;
            g.DrawImage(newBitmap, new Rectangle(0, 0, NewWidth, NewHeight));
        }
        openBitmap.Dispose(); //Clear The Old Large Bitmap From Memory

        return (Image)newBitmap;
    }

Typical 3-4mb Image Takes Between 4-8ms

Related Solutions

C++ – ny C++ lib to read thumbnails from thumb.db in Windows Folder

You might find this useful:

ThumbsDBLib in C++

http://www.windameister.org/blog/index.php/thumbslib-in-cpp

Android – Strange OutOfMemory issue while loading an image to a Bitmap object

To fix the OutOfMemory error, you should do something like this:

BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 8;
Bitmap preview_bitmap = BitmapFactory.decodeStream(is, null, options);

This inSampleSize option reduces memory consumption.

Here's a complete method. First it reads image size without decoding the content itself. Then it finds the best inSampleSize value, it should be a power of 2, and finally the image is decoded.

// Decodes image and scales it to reduce memory consumption
private Bitmap decodeFile(File f) {
    try {
        // Decode image size
        BitmapFactory.Options o = new BitmapFactory.Options();
        o.inJustDecodeBounds = true;
        BitmapFactory.decodeStream(new FileInputStream(f), null, o);

        // The new size we want to scale to
        final int REQUIRED_SIZE=70;

        // Find the correct scale value. It should be the power of 2.
        int scale = 1;
        while(o.outWidth / scale / 2 >= REQUIRED_SIZE && 
              o.outHeight / scale / 2 >= REQUIRED_SIZE) {
            scale *= 2;
        }

        // Decode with inSampleSize
        BitmapFactory.Options o2 = new BitmapFactory.Options();
        o2.inSampleSize = scale;
        return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
    } catch (FileNotFoundException e) {}
    return null;
}

Best Answer

Related Solutions

C++ – ny C++ lib to read thumbnails from thumb.db in Windows Folder

Android – Strange OutOfMemory issue while loading an image to a Bitmap object

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