Bin Packing

   You may have started to wonder how I managed to generate those nifty little graphs at the bottom of the last four pages.  Well, I'm going to tell you.  I created a UserControl that completely separates the algorithm logic, and the painting logic.  The painting logic is the same no matter what algorithm was used to generate the Bins.

   The code really is self explanatory and comes with comments.  This demonstrates the proper way to display process intensive visual data.  Notice that actual drawing is done only when needed.  When a Paint event is fired, the control is merely refreshing itself with a cached Bitmap.  This cuts way down on processing time and is really the correct way of doing things.

   Private Sub UpdateGraph()
      InitDrawingSurface()
      DrawBins(DrawDemarcations())

      pbDrawingSurface.Refresh()
   End Sub

   Private Sub InitDrawingSurface()
      If Me.Width = 0 Or Me.Height = 0 Then Exit Sub

      bmpGraph = New Bitmap(Me.Width, Me.Height)
      g = Graphics.FromImage(bmpGraph)
      g.Clear(Me.BackColor)

      pbDrawingSurface.Size = bmpGraph.Size
   End Sub

   'Returns how wide the text was on the left hand side of the graph as well as draws teh Demarcations
   Private Function DrawDemarcations() As Integer
      Dim TextHeight As Integer = CType(g.MeasureString(Me.BinHeight.ToString, DrawingFont).Height, _
		Integer)

      '100% of BinHeight
      g.DrawString(Me.BinHeight.ToString, DrawingFont, DrawingTextBrush, BORDER, BORDER - 8)
      '75% of BinHeight
      g.DrawString((Me.BinHeight * 0.75).ToString, DrawingFont, DrawingTextBrush, BORDER, _
		CType((Me.Height - BORDER * 2) * 0.25, Integer) + BORDER - TextHeight + 6)
      '50% of BinHeight
      g.DrawString((Me.BinHeight * 0.5).ToString, DrawingFont, DrawingTextBrush, BORDER, _ 
		CType((Me.Height - BORDER * 2) * 0.5, Integer) + BORDER - TextHeight + 6)
      '25% of BinHeight
      g.DrawString((Me.BinHeight * 0.25).ToString, DrawingFont, DrawingTextBrush, BORDER, _
		CType((Me.Height - BORDER * 2) * 0.75, Integer) + BORDER - TextHeight + 6)
      '0% of BinHeight
      g.DrawString("0", DrawingFont, DrawingTextBrush, BORDER, Me.Height - BORDER - TextHeight + 5)

      'If there's decimals, Width2 will be longer, else, Width1 will be
      Dim Width1 As Integer = CType(g.MeasureString(Me.BinHeight.ToString, DrawingFont).Width, Integer)
      Dim Width2 As Integer = CType(g.MeasureString((Me.BinHeight * 0.75).ToString, _
		DrawingFont).Width, Integer)

      Return Math.Max(Width1, Width2) + 5 + BORDER
   End Function

   Private Sub DrawBins(ByVal StartX As Integer)
      Dim BinPixelHeight As Integer = Me.Height - BORDER * 2
      Dim X1, X2, Y1, Y2 As Integer
      Dim i As Integer

      Y1 = BORDER
      Y2 = Me.Height - BORDER

      If Bins Is Nothing Then Exit Sub

      'Draws the vertical lines that make up the bins
      For i = 0 To Bins.GetUpperBound(0) + 1
         X1 = StartX + (BIN_WIDTH * i)
         X2 = X1

         g.DrawLine(DrawingPen, X1, Y1, X2, Y2)
      Next



      Dim j As Integer
      Dim BinValue As Integer
      Dim TotalBinHeight, TotalPixelBinHeight As Integer

      For i = 0 To Bins.GetUpperBound(0) + 1
         X1 = StartX + (BIN_WIDTH * i)
         X2 = X1 + BIN_WIDTH

         'Draws the Bins
         If i < Bins.GetUpperBound(0) + 1 Then

            'Draws the gradient
            TotalBinHeight = 0
            For j = 0 To Bins(i).GetUpperBound(0)
               TotalBinHeight += Bins(i)(j)
            Next

            TotalPixelBinHeight = CType(TotalBinHeight / Me.BinHeight * BinPixelHeight, Integer)

            If TotalPixelBinHeight > 0 Then
               'Draws the Bin gradient
               DrawingBinBrush = New LinearGradientBrush(New Rectangle(X1 + 1, Me.Height - _
			BORDER - TotalPixelBinHeight, BIN_WIDTH - 1, TotalPixelBinHeight), _
			Me.BinColor1, Me.BinColor2, LinearGradientMode.ForwardDiagonal)
               DrawingBinBrush.WrapMode = WrapMode.TileFlipXY
               g.FillRectangle(DrawingBinBrush, New Rectangle(X1 + 1, Me.Height - BORDER - _
			TotalPixelBinHeight, BIN_WIDTH - 1, TotalPixelBinHeight))


               Dim LastY As Integer
               For j = 0 To Bins(i).GetUpperBound(0)
                  BinValue += Bins(i)(j)
                  Y1 = CType(BinValue / Me.BinHeight * BinPixelHeight, Integer)
                  Y1 = Me.Height - Y1 - BORDER
                  Y2 = Y1

                  If j = 0 Then LastY = Me.Height - BORDER

                  'Draws the horizontal lines
                  g.DrawLine(DrawingPen, X1, Y1, X2, Y2)

                  'Draws the Element value
                  Dim TextSize As SizeF = g.MeasureString(Bins(i)(j).ToString, DrawingFont)
                  g.DrawString(Bins(i)(j).ToString, DrawingFont, Me.DrawingBinTextBrush, _
			CType(X1 + (BIN_WIDTH / 2) - (TextSize.Width / 2), Integer), _
			CType(Y1 + ((LastY - Y1) / 2) - (TextSize.Height / 2), Integer))
                  LastY = Y1
               Next

               'Draws the Bin Number
               g.DrawString((i + 1).ToString, DrawingFont, DrawingTextBrush, _
			CType(X1 + (BIN_WIDTH / 2) - (g.MeasureString((i + 1).ToString, _
			DrawingFont).Width / 2), Integer), Me.Height - BORDER)

               'Draws the Bin Count
               g.DrawString(TotalBinHeight.ToString, DrawingFont, DrawingBinTextBrush, _
			CType(X1 + (BIN_WIDTH / 2) - (g.MeasureString(TotalBinHeight.ToString, _
			DrawingFont).Width / 2), Integer), 5)

               BinValue = 0
            End If
         End If
      Next

      'Bottom line
      g.DrawLine(DrawingPen, StartX, Me.Height - BORDER, X1, Me.Height - BORDER)
   End Sub

Complete code may be found as a Resource, downloadable at the top of any page.