Getting Started with CVB.Net

Programming Questions .Net API
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2

Loading and Saving Images (Console)

Let’s start very simple: we want a Console app that takes two arguments:

  1. Image input path
  2. Image output path

The app loads the image given as the first argument and saves to the path in the second argument:

  1. Add namespace (we need the Stemmer.Cvb.dll for this):

    using Stemmer.Cvb;

  2. Load the input image via Image.FromFile factory method:

    var image = Image.FromFile(args[0]);

    (we assume that the user provided the input in args[0])

  3. Save the image:

    image.Save(args[1]);

    (we assume that the user provided the output in args[1])

:cvb: determines the file format based on the file’s extension (.bmp, .jpg, .png,…).

The full app with (simple) error handling. 
using Stemmer.Cvb;
using System;
using System.IO;

namespace CvbPlayground
{
  class Program
  {
    static void Main(string[] args)
    {
      if (args.Length != 2)
      {
        PrintHelp();
        return;
      }

      try
      {
        using (var inputImage = Image.FromFile(args[0]))
        {
          inputImage.Save(args[1]);

          Console.WriteLine("Convert");
          Console.WriteLine(" " + Path.GetFullPath(args[0]));
          Console.WriteLine("->");
          Console.WriteLine(" " + Path.GetFullPath(args[1]));
        }
      }
      catch (IOException ex)
      {
        Console.WriteLine(ex);
      }
    }

    private static void PrintHelp()
    {
      Console.WriteLine("Usage: " + AppName + " <input> <output>");
      Console.WriteLine();
      Console.WriteLine("<input>  Path to input file to convert.");
      Console.WriteLine("<output> Path to output file to convert.");
    }

    private static string AppName
    {
      get
      {
        return Path.GetFileNameWithoutExtension(typeof(Program).Assembly.Location);
      }
    }
  }
}

If you read so far :clap:, you get a little bonus: perhaps you have seen the using (var inputImage… block. :cvb: Images are IDisposable types. That means that you can free their resources (memory in this case) immediatly via image.Dispose(). A using block does that always when the program exits its scope. Even if exceptions occur. So we use the image only as long as we actually need it.

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