Hello World in CSharp

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This example requires Emgu CV 1.5.0.0

Hello World - Version 1

We will start by the Hello World sample, written in C#

using Emgu.CV;
using Emgu.CV.CvEnum;
using Emgu.CV.Structure;
using System.Drawing;
 
...
 
//The name of the window
String win1 = "Test Window";
 
//Create the window using the specific name
CvInvoke.cvNamedWindow(win1);
 
//Create an image of 400x200 of Blue color
using (Image<Bgr, Byte> img = new Image<Bgr, byte>(400, 200, new Bgr(255, 0, 0))) 
{
   //Create the font
   MCvFont f = new MCvFont(CvEnum.FONT.CV_FONT_HERSHEY_COMPLEX, 1.0, 1.0);
   //Draw "Hello, world." on the image using the specific font
   img.Draw("Hello, world", ref f, new Point(10, 80), new Bgr(0, 255, 0));
 
   //Show the image
   CvInvoke.cvShowImage(win1, img.Ptr);
   //Wait for the key pressing event
   CvInvoke.cvWaitKey(0);
   //Destory the window
   CvInvoke.cvDestroyWindow(win1); 
}

The above code will create an image of 400x200 with blue background color and the text "Hello, world" in green on the foreground. The image will be displayed a window named "Test Window".

HelloWorldExample.GIF

Hello World - Version 2

Showing image using cvNamedWindow is good, but Emgu CV has an event better tool for the same purpose, that is, the ImageViewer class under Emgu.CV.UI namespace.

using Emgu.CV;
using Emgu.CV.CvEnum;
using Emgu.CV.Structure;
using Emgu.CV.UI;
using System.Drawing;
 
...
 
//Create an image of 400x200 of Blue color
using (Image<Bgr, Byte> img = new Image<Bgr, byte>(400, 200, new Bgr(255, 0, 0))) 
{
   //Create the font
   MCvFont f = new MCvFont(CvEnum.FONT.CV_FONT_HERSHEY_COMPLEX, 1.0, 1.0);
 
   //Draw "Hello, world." on the image using the specific font
   img.Draw("Hello, world", ref f, new Point(10, 80), new Bgr(0, 255, 0)); 
 
   //Show the image using ImageViewer from Emgu.CV.UI
   ImageViewer.Show(img, "Test Window");
}
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