Apply Effects

Advanced imaging effects are helpful in a lot of scenarios such as low-color depth environment, image transmission, medical imaging, remote-sensing, acoustic imagery and forensic surveillance imagery.

DsImaging library offers great flexibility while working with these advanced effects which includes dithering, thresholding, gray scaling, Gaussian blur, and various RGB effects. DsImaging provides the ApplyEffect method in the GcBitmap class which takes the instance of class representing the effect as a parameter. These effects and the corresponding classes are described in detail in the table below. Please note that the ApplyEffect method applies a graphic effect to an image or a portion in-place, which means it stores the result back in the existing Bitmap object instead of storing it in a new instance.

To apply a graphic effect, say dithering, on an image:

1. Initialize the GcBitmap class.

2. Invoke Get method of the DitheringEffect class to define the dithering effect that specifies the method to be used for dithering.

3. Apply dithering effect to an image using the ApplyEffect method which accepts the defined dithering effect as its parameter.

   var imagePath = Path.Combine("Resources", "Images",
                   "color-vegetables-small.jpg");
   
   //Initialize GcBitmap           
   GcBitmap origBmp = new GcBitmap(imagePath,
                      new Rectangle(50, 50, 1024, 1024));
   
   //Apply Dithering effect FloydSteinberg
   origBmp.ApplyEffect(DitheringEffect.Get(DitheringMethod.FloydSteinberg),
                       new Rectangle(0, 0, 1024, 1024));
   
   //Save Dithering effect image
   origBmp.SaveAsJpeg("Dithering.jpg");

Similarly, you can apply any other effect on images as mentioned in the table above.

DsImaging library also provides IsBlackAndWhite and IsGrayscale methods in the GcBitmap class to check whether the image is already black and white or grayscale. Both methods work very quickly, as GcBitmap makes it easy to convert a colorful image to a grayscale or bi-level black and white image. These methods also skip unnecessary conversions if the original image is already grayscale or black and white. However, if the image is colorful, these methods just check a few pixels and return the result immediately.

The IsBlackAndWhite method checks whether all the pixels of the image are either opaque black (0xFF000000) or opaque white (0xFFFFFFFF). Transparent and semi-transparent pixels are neither black nor white.

The IsGrayscale method checks whether all pixels of the image are shades of gray, i.e., their alpha channel is set to 0xFF (fully opaque) and their red, green, and blue channels have the same value.

Refer to the following example code in order to check whether the image is already black and white or grayscale:

// Initialize GcBitmap and load the image.
using var bmp = new GcBitmap("qrcode.png");

// Check if black and white is applied.
if (bmp.IsBlackAndWhite())
{
    Console.WriteLine("The image is black and white.");
}

// Check if grayscale is applied.
if (bmp.IsGrayscale())
{
    Console.WriteLine("The image is grayscale.");
}

For more information about implementation of different effects using DsImaging, see DsImaging sample browser.