VB.net类库——4给屏幕截图，裁剪

VB.net用screen类来截图，其实不需要调用api

在类库myScreen里写函数

 ''' <summary>
    ''' 获取屏幕图片
    ''' </summary>
    ''' <returns>屏幕图片</returns>
    Public Function GetScreen()
        Dim scr As Screen = Screen.PrimaryScreen
        Dim recSc As Rectangle = scr.Bounds
        Image = New Bitmap(recSc.Width, recSc.Height)
        g = Graphics.FromImage(Image)
        g.CopyFromScreen(New Point(0, 0), New Point(0, 0), New Size(recSc.Width, recSc.Height))
        Return Image
    End Function
    ''' <summary>
    ''' 此函数多用来裁剪获取到的屏幕图片。注意：调用时要先在MouseDown中向GDIscr.p1中传入第一个顶点。
    ''' 再在MouseUp中向GDIscr.p2传入第二个顶点，顶点样式为从左上角划向右下角。
    ''' </summary>
    ''' <param name="bmp">传入截图，也可是其他的图片</param>
    ''' <returns>裁剪后的图片</returns>
    Public Function CutScren(bmp As Bitmap)
        g = Graphics.FromImage(bmp)
        Dim rc As Rectangle = New Rectangle(p1, New Size(p2.X - p1.X, p2.Y - p1.Y))   '起点和长宽
        Image = bmp.Clone(rc, Imaging.PixelFormat.Format32bppArgb)
        Return Image
    End Function

 在类中写：

 Public p1 As Point
    Public p2 As Point

公开这两个变量：在主窗体需要调用

调用：test里新建一个窗体叫Cut

加入一个picturebox：

 FromBorderStyle改为none

 WindowState改为Maximized，

Cut写入代码：

'Imports GDI_Make_NET4_5.myScreen
Public Class Cut
    Public GDIscr As New GDI_Make_NET4_5.myScreen
    Private ispick As Boolean
    Public Sub ShowMe(bmp As Bitmap)
        Pic.Location = New Point(0, 0)
        Pic.Width = bmp.Width
        Pic.Height = bmp.Height
        Pic.Image = bmp
        ispick = True
        Me.Show()
    End Sub

    Private Sub Pic_MouseDown(sender As Object, e As MouseEventArgs) Handles Pic.MouseDown
        If ispick = True Then
            GDIscr.p1 = New Point(e.X, e.Y)
        End If
    End Sub

    Private Sub Pic_MouseUp(sender As Object, e As MouseEventArgs) Handles Pic.MouseUp
        If ispick = True Then
            GDIscr.p2 = New Point(e.X, e.Y)
            Pic.Image = GDIscr.CutScren(Pic.Image)
            Clipboard.SetImage(Pic.Image)
            MsgBox("已复制到剪切板，双击图片退出")
            ispick = False
        End If
    End Sub

    Private Sub Pic_DoubleClick(sender As Object, e As EventArgs) Handles Pic.DoubleClick
        Close()
    End Sub
End Class

主窗体用MouseDown获取第一个点，MouseUp获取第二个点并调用函数，传入myScreen，

ispick的作用是防止二次裁剪出现错误，代码中的msgbox段可以自行修改、或保存图片。

 测试：

点screen则获取当前屏幕的截图

点击cut显示Cut窗体，注意，显示一个窗体。选择第一个点是你想选择区域的左上角，第二个点是你想选择区域的右下角，看懂代码就可以了，如果把点的顺序反过来截图，则显示不出。