C# - How to draw image with Gamma or Threshold effect

var rectDest = new Rectangle( 0, 0, this.m_bitmap_source.Width, this.m_bitmap_source.Height );

using ( var graphics = Graphics.FromImage( this.m_bitmap_dest ) )
 using ( var attr = new ImageAttributes() )
 {
   attr.SetGamma( 0.2f );
   
   graphics.DrawImage( this.m_bitmap_source, rectDest, 
                       0, 0, this.m_bitmap_source.Width, this.m_bitmap_source.Height, 
                       GraphicsUnit.Pixel, attr );
 }

You can use Threshold effect too (replace row with Gamma):

attr.SetThreshold( 0.4f );

C# - How to initialize List items in new statement

One possibility:

image.Normalize( new List() { new Rectangle( 100, 100, 300, 100 ) }  );

Another possibility with setting accessible properties by name:

image.Normalize( new List()
{ 
  new Rectangle() { X=100, Y=100, Width=300, Height=100 }, 
  new Rectangle() { X=200, Y=250, Width=200, Height=50 }
}  
);

C# - How to check installed .NET SDK

With this command tool dotnet.exe you can list for example installed .NET SDK.

Tip: If you want make .NET 5 app, create .NET CORE x project and then you can change it into .NET 5 (Feb 2021).