根据坐标在图片上绘制多边形边框

'''根据坐标的现有图片上绘制多边形 Public Shared Function GetSelectedActionImage(ByVal imgurl As String, ByVal coords As String, ByVal colors As String) As Bitmap Dim bmp As New Bitmap(imgurl, True) Dim g As Graphics = Graphics.FromImage(bmp) Dim pens As New Pen(getColor(colors), 2) Dim arr As Array = Report.GetStrArray(coords, "|") Dim x As Array = Report.GetStrArray(arr.GetValue(0), ",") Dim y As Array = Report.GetStrArray(arr.GetValue(1), ",") Dim pen As New Pen(Color.Red, 2) Dim points As New ArrayList If x.Length = y.Length Then For j As Integer = 0 To x.Length - 1 Dim pf As PointF = New PointF(x(j), y(j)) points.Add(pf) Next End If Dim i As Integer For i = 0 To points.Count - 2 g.DrawLine(pen, points(i).X, points(i).Y, points(i + 1).X, points(i + 1).Y) Next g.DrawLine(pen, points(i).X, points(i).Y, points(0).X, points(0).Y) g.Dispose() Return bmp End Function '''缩放图片 Public Shared Function Zoom(ByVal myImage As Bitmap, ByVal nWidth As Integer, ByVal nHeight As Integer) As Bitmap Dim iX As Integer Dim iY As Integer Dim xMax As Integer Dim yMax As Integer If nWidth < myImage.Width Or nHeight < myImage.Height Then If myImage.Width / myImage.Height > nWidth / nHeight Then xMax = nWidth yMax = myImage.Height * nWidth / myImage.Width Else yMax = nHeight xMax = myImage.Width * nHeight / myImage.Height End If Else xMax = myImage.Width yMax = myImage.Height End If Dim tembmp As Bitmap = New Bitmap(myImage, xMax, yMax) Return tembmp End Function