使.NET 截图工具兼容多个显示器

Question

此帖子中提供了另一种截图工具解决方案：.NET 等效的截图工具

现在有必要使其适用于选定的屏幕（在多显示器系统上）。

代码已进行相应修改：

Public Class SnippingTool


    Private Shared _Screen As Screen

    Private Shared BitmapSize As Size

    Private Shared Graph As Graphics


    Public Shared Function Snip(ByVal screen As Screen) As Image

        _Screen = screen

        Dim bmp As New Bitmap(screen.Bounds.Width, screen.Bounds.Height, System.Drawing.Imaging.PixelFormat.Format32bppPArgb)

        Dim gr As Graphics = Graphics.FromImage(bmp)

        Graph = gr


        gr.SmoothingMode = Drawing2D.SmoothingMode.None '###

        BitmapSize = bmp.Size


        Using snipper = New SnippingTool(bmp)

            snipper.Location = New Point(screen.Bounds.Left, screen.Bounds.Top)

            If snipper.ShowDialog() = DialogResult.OK Then
                Return snipper.Image
            End If

        End Using

        Return Nothing


    End Function



    Public Sub New(ByVal screenShot As Image)
        InitializeComponent()
        Me.BackgroundImage = screenShot
        Me.ShowInTaskbar = False
        Me.FormBorderStyle = FormBorderStyle.None


        'Me.WindowState = FormWindowState.Maximized

        Me.DoubleBuffered = True
    End Sub
    Public Property Image() As Image
        Get
            Return m_Image
        End Get
        Set(ByVal value As Image)
            m_Image = Value
        End Set
    End Property
    Private m_Image As Image


    Private rcSelect As New Rectangle()
    Private pntStart As Point

    Protected Overrides Sub OnMouseDown(ByVal e As MouseEventArgs)
        ' Start the snip on mouse down
        If e.Button <> MouseButtons.Left Then
            Return
        End If
        pntStart = e.Location
        rcSelect = New Rectangle(e.Location, New Size(0, 0))
        Me.Invalidate()
    End Sub
    Protected Overrides Sub OnMouseMove(ByVal e As MouseEventArgs)
        ' Modify the selection on mouse move
        If e.Button <> MouseButtons.Left Then
            Return
        End If
        Dim x1 As Integer = Math.Min(e.X, pntStart.X)
        Dim y1 As Integer = Math.Min(e.Y, pntStart.Y)
        Dim x2 As Integer = Math.Max(e.X, pntStart.X)
        Dim y2 As Integer = Math.Max(e.Y, pntStart.Y)
        rcSelect = New Rectangle(x1, y1, x2 - x1, y2 - y1)
        Me.Invalidate()
    End Sub


    Protected Overrides Sub OnMouseUp(ByVal e As MouseEventArgs)
        ' Complete the snip on mouse-up
        If rcSelect.Width <= 0 OrElse rcSelect.Height <= 0 Then
            Return
        End If
        Image = New Bitmap(rcSelect.Width, rcSelect.Height)
        Using gr As Graphics = Graphics.FromImage(Image)
            gr.DrawImage(Me.BackgroundImage, New Rectangle(0, 0, Image.Width, Image.Height), rcSelect, GraphicsUnit.Pixel)
        End Using
        DialogResult = DialogResult.OK
    End Sub
    Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
        ' Draw the current selection
        Using br As Brush = New SolidBrush(Color.FromArgb(120, Color.White))
            Dim x1 As Integer = rcSelect.X
            Dim x2 As Integer = rcSelect.X + rcSelect.Width
            Dim y1 As Integer = rcSelect.Y
            Dim y2 As Integer = rcSelect.Y + rcSelect.Height
            e.Graphics.FillRectangle(br, New Rectangle(0, 0, x1, Me.Height))
            e.Graphics.FillRectangle(br, New Rectangle(x2, 0, Me.Width - x2, Me.Height))
            e.Graphics.FillRectangle(br, New Rectangle(x1, 0, x2 - x1, y1))
            e.Graphics.FillRectangle(br, New Rectangle(x1, y2, x2 - x1, Me.Height - y2))
        End Using
        Using pen As New Pen(Color.Red, 3)
            e.Graphics.DrawRectangle(pen, rcSelect)
        End Using
    End Sub
    Protected Overrides Function ProcessCmdKey(ByRef msg As Message, ByVal keyData As Keys) As Boolean
        ' Allow canceling the snip with the Escape key
        If keyData = Keys.Escape Then
            Me.DialogResult = DialogResult.Cancel
        End If
        Return MyBase.ProcessCmdKey(msg, keyData)
    End Function

    Protected Overrides Sub OnLoad(ByVal e As System.EventArgs)
        MyBase.OnLoad(e)
        Me.Size = New Size(_Screen.Bounds.Width, _Screen.Bounds.Height)
        Dim area = _Screen.WorkingArea
        Graph.CopyFromScreen(area.X, area.Y, area.Y, area.Y, BitmapSize)
    End Sub

End Class

但它拒绝按预期工作。无论“截图”功能中的“屏幕”参数如何，截图不会出现在所选屏幕上，而是出现在第一个屏幕上。 如何使其正常工作？

更新：最新的截图版本出现在正确的屏幕上，但空白。

更新X2：上面的代码已更新以反映最新版本，现在可以正常工作。

Answer 1

LoveDotNet，我相信您的源代码有一个小问题，以下行：

Graph.CopyFromScreen(area.X,area.Y,area.Y,area.Y,BitmapSize)

应该是：

Graph.CopyFromScreen(area.X, area.Y, 0, 0, BitmapSize)

另外，对于任何想要使用此代码的人来说，这是一个快速提示，您可以像下面这样调用它：

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim img As Image = SnippingTool.Snip(Screen.AllScreens(0)) 'Set to (1) for secondary monitor'
End Sub

另外，当当您创建 SnippingTool 表单时，请务必将 StartPosition 属性更改为 Manual。

大编辑：

我做了一些工作来同时支持多个显示器，这不需要开发人员选择要使用的显示器（这克隆了“截图工具”）。

基本上，我会遍历所有屏幕来查找最小的 X 和 Y 坐标，以及最大的 Right 和 Bottom< /code>，这让我们可以评估“虚拟监视器”的完整大小：

我已经使用我的配置对其进行了测试，配置为：

Primary 1280x800

Secondary 1280x1024 w/ -224 X offset< /code>

代码：

'SnippingTool 代码：将其放入新表单中（将启动属性设置为手动）'
公共类截图工具


私人共享_屏幕作为屏幕

私有共享 BitmapSize 作为大小

私有共享图作为图形

私有结构 MultiScreenSize
    Dim minX 作为整数
    将 minY 变暗为整数
    Dim maxRight 作为整数
    将 maxBottom 变暗为整数
末端结构


私有共享函数 FindMultiScreenSize() As MultiScreenSize

    Dim minX As Integer = Screen.AllScreens(0).Bounds.X
    Dim minY As Integer = Screen.AllScreens(0).Bounds.Y

    Dim maxRight As Integer = Screen.AllScreens(0).Bounds.Right
    Dim maxBottom As Integer = Screen.AllScreens(0).Bounds.Bottom

    对于每个 aScreen 作为 Screen In Screen.AllScreens
        如果 aScreen.Bounds.X < minX 然后
            minX = aScreen.Bounds.X
        结束如果

        如果 aScreen.Bounds.Y <分钟Y 那么
            minY = aScreen.Bounds.Y
        结束如果

        如果 aScreen.Bounds.Right >最大此时
            maxRight = aScreen.Bounds.Right
        结束如果

        如果 aScreen.Bounds.Bottom >那么最大底部
            maxBottom = aScreen.Bounds.Bottom
        结束如果
    下一个
    将 m_MultiScreenSize 调暗为 MultiScreenSize
    使用 m_MultiScreenSize
        .minX = minX
        .minY = minY
        .maxBottom = 最大底部
        .maxRight = 最大Right
    结束于
    返回m_MultiScreenSize
结束功能
公共共享函数 Snip() As Image
    Dim m_MultiScreenSize As MultiScreenSize = FindMultiScreenSize()

    调暗 bmp 作为新位图(m_MultiScreenSize.maxRight - m_MultiScreenSize.minX, _
                          m_MultiScreenSize.maxBottom - m_MultiScreenSize.minY, _
                          System.Drawing.Imaging.PixelFormat.Format32bppPArgb)
    Dim gr As Graphics = Graphics.FromImage(bmp)

    图=gr


    gr.SmoothingMode = Drawing2D.SmoothingMode.None 
    位图大小 = bmp.Size


    使用snipper = New SnippingTool(bmp)

        snipper.Location = 新点(m_MultiScreenSize.minX, m_MultiScreenSize.minY)

        如果 snipper.ShowDialog() = DialogResult.OK 那么
            返回狙击手.图片
        结束如果

    结束使用

    不返回任何内容


结束功能



公共子新（ByVal screenShot As Image）
    初始化组件()
    Me.BackgroundImage = 屏幕截图
    Me.ShowInTaskbar = False
    Me.FormBorderStyle = FormBorderStyle.None

    Me.DoubleBuffered = True
结束子
公共属性 Image() 作为图像
    得到
        返回m_Image
    结束获取
    设置（ByVal 值作为图像）
        m_Image = 值
    结束组
结束财产
私有 m_Image 作为图像


私有 rcSelect 作为新矩形()
私有 pntStart 作为点

受保护的覆盖 Sub OnMouseDown(ByVal e As MouseEventArgs)
    '按下鼠标开始剪辑'
    如果 e.Button <> MouseButtons.Left 然后
        返回
    结束如果
    pntStart = e.Location
    rcSelect = 新矩形(e.位置, 新大小(0, 0))
    Me.Invalidate()
结束子
受保护的覆盖 Sub OnMouseMove(ByVal e As MouseEventArgs)
    '修改鼠标移动时的选择'
    如果 e.Button <> MouseButtons.Left 然后
        返回
    结束如果
    Dim x1 As Integer = Math.Min(eX, pntStart.X)
    Dim y1 As Integer = Math.Min(eY, pntStart.Y)
    Dim x2 As Integer = Math.Max(eX, pntStart.X)
    Dim y2 As Integer = Math.Max(eY, pntStart.Y)
    rcSelect = 新矩形(x1, y1, x2 - x1, y2 - y1)
    Me.Invalidate()
结束子


受保护的覆盖 Sub OnMouseUp(ByVal e As MouseEventArgs)
    ' 完成鼠标悬停的截图'
    如果 rcSelect.Width <= 0 或者 rcSelect.Height <= 0 则
        返回
    结束如果
    图像 = 新位图(rcSelect.Width, rcSelect.Height)
    使用 gr 作为图形 = Graphics.FromImage(Image)
        gr.DrawImage(Me.BackgroundImage, 新矩形(0, 0, Image.Width, Image.Height), _
                     rcSelect、GraphicsUnit.Pixel)
    结束使用
    对话框结果=对话框结果.确定
结束子
受保护的覆盖 Sub OnPaint(ByVal e As PaintEventArgs)
    '绘制当前选择'
    使用 br 作为画笔 = New SolidBrush(Color.FromArgb(120, Color.White))
        Dim x1 As Integer = rcSelect.X
        Dim x2 As Integer = rcSelect.X + rcSelect.Width
        Dim y1 As Integer = rcSelect.Y
        Dim y2 As Integer = rcSelect.Y + rcSelect.Height
        e.Graphics.FillRectangle(br, 新矩形(0, 0, x1, Me.Height))
        e.Graphics.FillRectangle(br, 新矩形(x2, 0, Me.Width - x2, Me.Height))
        e.Graphics.FillRectangle(br, 新矩形(x1, 0, x2 - x1, y1))
        e.Graphics.FillRectangle(br, 新矩形(x1, y2, x2 - x1, Me.Height - y2))
    结束使用
    使用笔作为新笔（颜色.红色，3）
        e.Graphics.DrawRectangle(pen, rcSelect)
    结束使用
结束子
受保护的覆盖函数 ProcessCmdKey(ByRef msg As Message, ByVal keyData As Keys) As Boolean
    '允许使用 Escape 键取消剪辑'
    如果 keyData = Keys.Escape 那么
        Me.DialogResult = DialogResult.Cancel
    结束如果
    返回 MyBase.ProcessCmdKey(msg, keyData)
结束功能

受保护的覆盖 Sub OnLoad(ByVal e As System.EventArgs)
    MyBase.OnLoad(e)
    Dim m_MultiScreenSize As MultiScreenSize = FindMultiScreenSize()
    Me.Size = 新尺寸(m_MultiScreenSize.maxRight - m_MultiScreenSize.minX, _
                       m_MultiScreenSize.maxBottom - m_MultiScreenSize.minY)

    Graph.CopyFromScreen(m_MultiScreenSize.minX, m_MultiScreenSize.minY, 0, 0, BitmapSize)
结束子
 结束课程

你可以这样称呼它：

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim img As Image = SnippingTool.Snip()
    img.Save("C:\ScreenShot.png")
End Sub

Answer 2

您需要设置 StartPosition在设置 SnippingTool 的位置之前将表单设置为Manual，否则无论如何它都会被放置在主屏幕上。在构造函数或 using 语句中执行此操作，它应该可以解决您的问题。

StartPosition = FormStartPosition.Manual;

Answer 3

我没看到你做错什么。我无法测试这个，现在没有设置。 Bounds 有点棘手，它后面有一堆代码确保表单不能在屏幕外显示。作为替代方案，您可以设置 Location 属性并重写 SnippingTool 中的 OnLoad() 以设置 WindowState 属性。

Answer 4

我已经创建了帮助程序类来捕获控件所在的特定屏幕上的选定区域。它适用于多个屏幕。

这个想法取自多个在线资源，这些资源基本上冻结屏幕并放入 PictureBox .NET 控件中。

这是代码：

public class CaptureScreen : IDisposable
{
    readonly Control control;
    readonly Pen penSelectedAreaScreenShot;

    Form frmPictureBox = null;
    PictureBox pictureBoxScreenShot = null;
    Point selectedScreenShotStartPoint;
    Size selectedScreenShotSize;
    bool isMouseDownSelectedScreenShot = false;

    public event Action<object, Bitmap> SelectedScreenAreaCaptured;

    public event Action<object, Exception> ScreenCaptureFailed;

    public CaptureScreen(Control control)
    {
        if (control == null)
        {
            throw new ArgumentNullException("control");
        }

        this.control = control;

        this.penSelectedAreaScreenShot = new Pen(Color.Red, 1);
        this.penSelectedAreaScreenShot.DashStyle = DashStyle.Dot;
    }

    public void BeginStart()
    {
        #region Setup the Picture Box for ScreenShot

        if (this.frmPictureBox != null)
        {
            this.frmPictureBox.Close();
            this.frmPictureBox.Dispose();
            this.frmPictureBox = null;
        }

        if (this.pictureBoxScreenShot != null)
        {
            this.pictureBoxScreenShot.Dispose();
            this.pictureBoxScreenShot = null;
        }

        this.frmPictureBox = new Form
        {
            BackColor = Color.Black,
            Cursor = Cursors.Cross,
            FormBorderStyle = FormBorderStyle.None,
            StartPosition = FormStartPosition.CenterParent,
            TopLevel = true,
            TopMost = true,
            Top = 0,
            Left = 0,
            WindowState = FormWindowState.Maximized,
            KeyPreview = true
        };

        this.pictureBoxScreenShot = new PictureBox
        {
            Location = new Point(0, 0),
            SizeMode = PictureBoxSizeMode.Zoom
        };
        this.frmPictureBox.Controls.Add(this.pictureBoxScreenShot);

        #endregion

        #region Capture the Screen

        Bitmap screenShotBitmap = null;
        Graphics graphics = null;
        MemoryStream stream = null;
        try
        {
            Screen currentScreen = Screen.FromControl(this.control);

            screenShotBitmap = new Bitmap(currentScreen.Bounds.Width, currentScreen.Bounds.Height);

            graphics = Graphics.FromImage(screenShotBitmap as Image);
            graphics.CopyFromScreen(currentScreen.Bounds.X, currentScreen.Bounds.Y, 0, 0, screenShotBitmap.Size);

            stream = new MemoryStream();
            screenShotBitmap.Save(stream, ImageFormat.Png);

            this.pictureBoxScreenShot.Size = screenShotBitmap.Size;
            this.pictureBoxScreenShot.Image = Image.FromStream(stream);
        }
        catch (Exception ex)
        {
            if (this.ScreenCaptureFailed != null)
            {
                this.ScreenCaptureFailed(this, ex);
            }
        }
        finally
        {
            if (stream != null)
            {
                stream.Close();
                stream.Dispose();
                stream = null;
            }

            if (graphics != null)
            {
                graphics.Dispose();
                graphics = null;
            }

            if (screenShotBitmap != null)
            {
                screenShotBitmap.Dispose();
                screenShotBitmap = null;
            }
        }

        #endregion

        this.frmPictureBox.KeyDown += this.frmPictureBox_KeyDown;

        this.pictureBoxScreenShot.MouseMove += this.pictureBoxScreenShot_MouseMove;
        this.pictureBoxScreenShot.MouseDown += this.pictureBoxScreenShot_MouseDown;
        this.pictureBoxScreenShot.MouseUp += this.pictureBoxScreenShot_MouseUp;

        this.frmPictureBox.Show(this.control);
    }

    public void Exit()
    {
        if (this.frmPictureBox != null)
        {
            this.frmPictureBox.Close();
            this.frmPictureBox.Dispose();
            this.frmPictureBox = null;
        }

        if (this.pictureBoxScreenShot != null)
        {
            this.pictureBoxScreenShot.Dispose();
            this.pictureBoxScreenShot = null;
        }

        this.isMouseDownSelectedScreenShot = false;
    }

    [DebuggerStepThrough]
    void frmPictureBox_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.KeyCode == Keys.Escape)
        {
            this.Exit();
        }
    }

    void pictureBoxScreenShot_MouseMove(object sender, MouseEventArgs e)
    {
        if (this.pictureBoxScreenShot.Image == null)
        {
            this.Exit();
            return;
        }

        if (this.isMouseDownSelectedScreenShot)
        {
            this.pictureBoxScreenShot.Refresh();

            this.selectedScreenShotSize = new Size(
                e.X - this.selectedScreenShotStartPoint.X,
                e.Y - this.selectedScreenShotStartPoint.Y);

            // Draw the selected area rectangle.
            this.pictureBoxScreenShot.CreateGraphics().DrawRectangle(this.penSelectedAreaScreenShot,
                this.selectedScreenShotStartPoint.X, this.selectedScreenShotStartPoint.Y,
                this.selectedScreenShotSize.Width, this.selectedScreenShotSize.Height);
        }
    }

    void pictureBoxScreenShot_MouseDown(object sender, MouseEventArgs e)
    {
        if (!this.isMouseDownSelectedScreenShot)
        {
            if (e.Button == MouseButtons.Left)
            {
                this.selectedScreenShotStartPoint = new Point(e.X, e.Y);
            }

            this.pictureBoxScreenShot.Refresh();

            this.isMouseDownSelectedScreenShot = true;
        }
    }

    void pictureBoxScreenShot_MouseUp(object sender, MouseEventArgs e)
    {
        if (this.pictureBoxScreenShot.Image == null)
        {
            this.Exit();
            return;
        }

        isMouseDownSelectedScreenShot = false;

        this.frmPictureBox.Hide();

        // Check whether there is something get selected.
        if (this.selectedScreenShotSize.Width > 0 && this.selectedScreenShotSize.Height > 0)
        {
            Bitmap selectedAreaBitmap = null;
            Graphics graphics = null;
            Bitmap screenShotBitmap = null;

            try
            {
                selectedAreaBitmap = new Bitmap(this.selectedScreenShotSize.Width, this.selectedScreenShotSize.Height);

                graphics = Graphics.FromImage(selectedAreaBitmap);

                graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
                graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
                graphics.CompositingQuality = CompositingQuality.HighQuality;

                screenShotBitmap = new Bitmap(this.pictureBoxScreenShot.Image, this.pictureBoxScreenShot.Size);
                graphics.DrawImage(screenShotBitmap, 0, 0, new Rectangle(this.selectedScreenShotStartPoint, this.selectedScreenShotSize), GraphicsUnit.Pixel);

                if (this.SelectedScreenAreaCaptured != null)
                {
                    this.SelectedScreenAreaCaptured(this, selectedAreaBitmap);
                }
                else
                {
                    Clipboard.SetImage(selectedAreaBitmap);
                    MessageBox.Show(this.control, "Selected Screen is copied to Clipboard.");
                }
            }
            catch (Exception ex)
            {
                if (this.ScreenCaptureFailed != null)
                {
                    this.ScreenCaptureFailed(this, ex);
                }
            }
            finally
            {
                if (screenShotBitmap != null)
                {
                    screenShotBitmap.Dispose();
                    screenShotBitmap = null;
                }

                if (graphics != null)
                {
                    graphics.Dispose();
                    graphics = null;
                }

                if (selectedAreaBitmap != null)
                {
                    selectedAreaBitmap.Dispose();
                    selectedAreaBitmap = null;
                }
            }
        }

        this.Exit();
    }

    #region IDisposable Member

    public void Dispose()
    {
        try
        {
            this.Exit();
        }
        catch { }
    }

    #endregion

}

您可以像这样使用它：

   CaptureScreen captureScreen = new CaptureScreen(this);

   // If event not implement, then by default it will copied to clipboard.
   //captureScreen.SelectedScreenAreaCaptured += delegate(object am_sender, Bitmap am_selectedAreaBitmap)
   //{
        //string destFilename = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory), String.Format("Capture_{0}.png", DateTime.Now.ToString("yyyyMMddHHmmss")));
        //am_selectedAreaBitmap.Save(destFilename, System.Drawing.Imaging.ImageFormat.Png);                
   //};

   // Implements this to handle the exception that occurs during screen capture.
   //captureScreen.ScreenCaptureFailed += delegate(object am_sender, Exception am_ex)
   //{
        //MessageBox.Show(this, am_ex.Message, "Unable to Capture the Screen", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
   //};

   captureScreen.BeginStart();

Answer 5

解决方案是使用 Screen.WorkingArea 属性而不是 Screen.Bounds。
第二个选项使用 Graphics.CopyFromScreen 会产生不正确的结果。
上面的代码片段已更新为全功能版本。