Base: add drawrectangle, getshorthash

Base/GraphicsEx.vb

@@ -2,10 +2,20 @@
 
 Public Class GraphicsEx
 
-    Public Shared Function GetBrightness(c As Color) As Single
+    ''' <summary>
-        Return (c.R * 0.299F + c.G * 0.587F + c.B * 0.114F) / 256.0F
+    ''' Returns the brightness of a color as a number between 0 and 1
+    ''' </summary>
+    ''' <param name="pColor">The color to check</param>
+    ''' <returns>Low values for dark colors, high values for bright colors.</returns>
+    Public Shared Function GetBrightness(pColor As Color) As Single
+        Return (pColor.R * 0.299F + pColor.G * 0.587F + pColor.B * 0.114F) / 256.0F
     End Function
 
+    ''' <summary>
+    ''' Returns a foreground/text color of either black or white, depending on the brightness of `pOtherColor`
+    ''' </summary>
+    ''' <param name="pOtherColor">The Background color whose brightness is determined</param>
+    ''' <returns>A text color which is either white or black</returns>
     Public Shared Function GetContrastedColor(pOtherColor As Color) As Color
         If GetBrightness(pOtherColor) < 0.55 Then
             Return Color.White
@@ -13,4 +23,21 @@ Public Class GraphicsEx
             Return Color.Black
         End If
     End Function
+
+    Public Sub DrawRectangle(Bounds As Rectangle)
+        Dim oContext As IntPtr
+        oContext = NativeMethods.GetDC(IntPtr.Zero)
+
+        Try
+            Dim g As Graphics
+            g = Graphics.FromHdc(oContext)
+            Try
+                g.DrawRectangle(Pens.Red, Bounds)
+            Finally
+                g.Dispose()
+            End Try
+        Finally
+            NativeMethods.ReleaseDC(IntPtr.Zero, oContext)
+        End Try
+    End Sub
 End Class

Base/StringEx.vb

@@ -107,6 +107,10 @@ Public Class StringEx
         Return GetChecksum(pStringToCheck)
     End Function
 
+    Public Shared Function GetShortHash(pStringToCheck As String) As String
+        Return GetChecksum(pStringToCheck).Substring(0, 32)
+    End Function
+
     Friend Class InvalidChars
         Public Shared Filenames As String = Regex.Escape(New String(IO.Path.GetInvalidFileNameChars()))
         Public Shared Paths As String = Regex.Escape(New String(IO.Path.GetInvalidPathChars()))