Add Transparency to bitmap

MarketData/MarketDataLib/CNNProcessing/ImageHelper.cs

@@ -414,9 +414,26 @@ namespace MarketData.CNNProcessing
       /// <param name="color"></param>
       public void Fill(SKColor color)
       {
+        Validate();
         SKRectI rect = new SKRectI(0, 0, Width, Height); // x, y, width, height
         bitmap.Erase(color, rect);
       }
+      
+      /// <summary>
+      /// Make the bitmap transparent
+      /// </summary>
+      public void Transparent(SKColor color)
+      {
+        Validate();
+        int pixelCount = Width * Height;
+        SKColor[] colors = new SKColor[pixelCount];
+        SKColor transparent = new SKColor(color.Red, color.Green, color.Blue, 0);
+        for (int index = 0; index < pixelCount; index++)
+        {
+          colors[index] = transparent;
+        }
+        bitmap.Pixels = colors;
+      }      
 
 			/// <summary>
 			/// DrawPoint - With translation