Graphics.IsVisible 方法

参考

定义

命名空间:: System.Drawing

程序集:: System.Drawing.Common.dll

程序集:: System.Drawing.dll

包:: System.Drawing.Common v8.0.7

包:: System.Drawing.Common v9.0.0-preview.6.24327.6

重要

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指示由一对坐标指定的点是否包含在此 Graphics的可见剪辑区域中。

重载

IsVisible(Single, Single, Single, Single)	指示由一对坐标、宽度和高度指定的矩形是否包含在此 Graphics的可见剪辑区域中。
IsVisible(Int32, Int32, Int32, Int32)	指示由一对坐标、宽度和高度指定的矩形是否包含在此 Graphics的可见剪辑区域中。
IsVisible(Int32, Int32)	指示由一对坐标指定的点是否包含在此 Graphics的可见剪辑区域中。
IsVisible(Single, Single)	指示由一对坐标指定的点是否包含在此 Graphics的可见剪辑区域中。
IsVisible(Rectangle)	指示由 Rectangle 结构指定的矩形是否包含在此 Graphics的可见剪辑区域中。
IsVisible(PointF)	指示指定的 PointF 结构是否包含在此 Graphics的可见剪辑区域中。
IsVisible(Point)	指示指定的 Point 结构是否包含在此 Graphics的可见剪辑区域中。
IsVisible(RectangleF)	指示由 RectangleF 结构指定的矩形是否包含在此 Graphics的可见剪辑区域中。

IsVisible(Single, Single, Single, Single)

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

指示由一对坐标、宽度和高度指定的矩形是否包含在此 Graphics的可见剪辑区域中。

public:
 bool IsVisible(float x, float y, float width, float height);

public bool IsVisible (float x, float y, float width, float height);

member this.IsVisible : single * single * single * single -> bool

Public Function IsVisible (x As Single, y As Single, width As Single, height As Single) As Boolean

参数

x: Single

要测试可见性的矩形左上角的 x 坐标。

y: Single

要测试可见性的矩形左上角的 y 坐标。

width: Single

要测试可见性的矩形的宽度。

height: Single

要测试可见性的矩形的高度。

Boolean

如果 x、y、width和 height 参数定义的矩形包含在此 Graphics的可见剪辑区域中，则 true;否则，false。

示例

下面的代码示例设计用于 Windows 窗体，它需要 PaintEventArgse，这是 Paint 事件处理程序的参数。该代码执行以下操作：

创建矩形剪辑区域，并使用 Replace将其设置为窗体图形对象的剪裁区域。
创建两个矩形的位置和大小，一个在剪辑区域内，一个在外部。
测试每个矩形的可见性，并仅绘制可见的矩形。

结果是一个小红色矩形，该矩形位于剪辑区域中。

public:
   void IsVisible4Float( PaintEventArgs^ e )
   {
      // Set clip region.
      System::Drawing::Region^ clipRegion = gcnew System::Drawing::Region( Rectangle(50,50,100,100) );
      e->Graphics->SetClip( clipRegion, CombineMode::Replace );

      // Set up coordinates of rectangles.
      float x1 = 100.0F;
      float y1 = 100.0F;
      float width1 = 20.0F;
      float height1 = 20.0F;
      float x2 = 200.0F;
      float y2 = 200.0F;
      float width2 = 20.0F;
      float height2 = 20.0F;

      // If rectangle is visible, fill it.
      if ( e->Graphics->IsVisible( x1, y1, width1, height1 ) )
      {
         e->Graphics->FillRectangle( gcnew SolidBrush( Color::Red ), x1, y1, width1, height1 );
      }

      if ( e->Graphics->IsVisible( x2, y2, width2, height2 ) )
      {
         e->Graphics->FillRectangle( gcnew SolidBrush( Color::Blue ), x2, y2, width2, height2 );
      }
   }

private void IsVisible4Float(PaintEventArgs e)
{

    // Set clip region.
    Region clipRegion = new Region(new Rectangle(50, 50, 100, 100));
    e.Graphics.SetClip(clipRegion, CombineMode.Replace);

    // Set up coordinates of rectangles.
    float x1 = 100.0F;
    float y1 = 100.0F;
    float width1 = 20.0F;
    float height1 = 20.0F;
    float x2 = 200.0F;
    float y2 = 200.0F;
    float width2 = 20.0F;
    float height2 = 20.0F;

    // If rectangle is visible, fill it.
    if (e.Graphics.IsVisible(x1, y1, width1, height1))
    {
        e.Graphics.FillRectangle(new SolidBrush(Color.Red), x1, y1, width1, height1);
    }
    if (e.Graphics.IsVisible(x2, y2, width2, height2))
    {
        e.Graphics.FillRectangle(new SolidBrush(Color.Blue), x2, y2, width2, height2);
    }
}

Private Sub IsVisible4Float(ByVal e As PaintEventArgs)

    ' Set clip region.
    Dim clipRegion As New [Region](New Rectangle(50, 50, 100, 100))
    e.Graphics.SetClip(clipRegion, CombineMode.Replace)

    ' Set up coordinates of rectangles.
    Dim x1 As Single = 100.0F
    Dim y1 As Single = 100.0F
    Dim width1 As Single = 20.0F
    Dim height1 As Single = 20.0F
    Dim x2 As Single = 200.0F
    Dim y2 As Single = 200.0F
    Dim width2 As Single = 20.0F
    Dim height2 As Single = 20.0F

    ' If rectangle is visible, fill it.
    If e.Graphics.IsVisible(x1, y1, width1, height1) Then
        e.Graphics.FillRectangle(New SolidBrush(Color.Red), x1, y1, _
        width1, height1)
    End If
    If e.Graphics.IsVisible(x2, y2, width2, height2) Then
        e.Graphics.FillRectangle(New SolidBrush(Color.Blue), x2, y2, _
        width2, height2)
    End If
End Sub

适用于

IsVisible(Int32, Int32, Int32, Int32)

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

指示由一对坐标、宽度和高度指定的矩形是否包含在此 Graphics的可见剪辑区域中。

public:
 bool IsVisible(int x, int y, int width, int height);

public bool IsVisible (int x, int y, int width, int height);

member this.IsVisible : int * int * int * int -> bool

Public Function IsVisible (x As Integer, y As Integer, width As Integer, height As Integer) As Boolean

参数

x: Int32

要测试可见性的矩形左上角的 x 坐标。

y: Int32

要测试可见性的矩形左上角的 y 坐标。

width: Int32

要测试可见性的矩形的宽度。

height: Int32

要测试可见性的矩形的高度。

Boolean

如果 x、y、width和 height 参数定义的矩形包含在此 Graphics的可见剪辑区域中，则 true;否则，false。

示例

下面的代码示例设计用于 Windows 窗体，它需要 PaintEventArgse，这是 Paint 事件处理程序的参数。该代码执行以下操作：

创建矩形剪辑区域，并使用 Replace将其设置为窗体图形对象的剪裁区域。
创建两个矩形的位置和大小，一个在剪辑区域内，一个在外部。
测试每个矩形的可见性，并仅绘制可见的矩形。

结果是一个小红色矩形，该矩形位于剪辑区域中。

public:
   void IsVisible4Int( PaintEventArgs^ e )
   {
      // Set clip region.
      System::Drawing::Region^ clipRegion = gcnew System::Drawing::Region( Rectangle(50,50,100,100) );
      e->Graphics->SetClip( clipRegion, CombineMode::Replace );

      // Set up coordinates of rectangles.
      int x1 = 100;
      int y1 = 100;
      int width1 = 20;
      int height1 = 20;
      int x2 = 200;
      int y2 = 200;
      int width2 = 20;
      int height2 = 20;

      // If rectangle is visible, fill it.
      if ( e->Graphics->IsVisible( x1, y1, width1, height1 ) )
      {
         e->Graphics->FillRectangle( gcnew SolidBrush( Color::Red ), x1, y1, width1, height1 );
      }

      if ( e->Graphics->IsVisible( x2, y2, width2, height2 ) )
      {
         e->Graphics->FillRectangle( gcnew SolidBrush( Color::Blue ), x2, y2, width2, height2 );
      }
   }

private void IsVisible4Int(PaintEventArgs e)
{

    // Set clip region.
    Region clipRegion = new Region(new Rectangle(50, 50, 100, 100));
    e.Graphics.SetClip(clipRegion, CombineMode.Replace);

    // Set up coordinates of rectangles.
    int x1 = 100;
    int y1 = 100;
    int width1 = 20;
    int height1 = 20;
    int x2 = 200;
    int y2 = 200;
    int width2 = 20;
    int height2 = 20;

    // If rectangle is visible, fill it.
    if (e.Graphics.IsVisible(x1, y1, width1, height1))
    {
        e.Graphics.FillRectangle(new SolidBrush(Color.Red), x1, y1, width1, height1);
    }
    if (e.Graphics.IsVisible(x2, y2, width2, height2))
    {
        e.Graphics.FillRectangle(new SolidBrush(Color.Blue), x2, y2, width2, height2);
    }
}

Private Sub IsVisible4Int(ByVal e As PaintEventArgs)

    ' Set clip region.
    Dim clipRegion As New [Region](New Rectangle(50, 50, 100, 100))
    e.Graphics.SetClip(clipRegion, CombineMode.Replace)

    ' Set up coordinates of rectangles.
    Dim x1 As Integer = 100
    Dim y1 As Integer = 100
    Dim width1 As Integer = 20
    Dim height1 As Integer = 20
    Dim x2 As Integer = 200
    Dim y2 As Integer = 200
    Dim width2 As Integer = 20
    Dim height2 As Integer = 20

    ' If rectangle is visible, fill it.
    If e.Graphics.IsVisible(x1, y1, width1, height1) Then
        e.Graphics.FillRectangle(New SolidBrush(Color.Red), x1, y1, _
        width1, height1)
    End If
    If e.Graphics.IsVisible(x2, y2, width2, height2) Then
        e.Graphics.FillRectangle(New SolidBrush(Color.Blue), x2, y2, _
        width2, height2)
    End If
End Sub

适用于

IsVisible(Int32, Int32)

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

指示由一对坐标指定的点是否包含在此 Graphics的可见剪辑区域中。

public:
 bool IsVisible(int x, int y);

public bool IsVisible (int x, int y);

member this.IsVisible : int * int -> bool

Public Function IsVisible (x As Integer, y As Integer) As Boolean

参数

x: Int32

要测试可见性的点的 x 坐标。

y: Int32

要测试可见性的点的 y 坐标。

Boolean

如果 x 和 y 参数定义的点包含在此 Graphics的可见剪辑区域中，则 true;否则，false。

示例

下面的代码示例设计用于 Windows 窗体，它需要 PaintEventArgse，这是 Paint 事件处理程序的参数。该代码执行以下操作：

创建矩形剪辑区域，并使用 Replace将其设置为窗体图形对象的剪裁区域。
创建两个点，一个在剪辑区域内部，一个在外部。
测试每个点的可见性，并仅绘制可见点。

结果是一个位于剪辑区域中的一个小红色圆圈。

public:
   void IsVisibleInt( PaintEventArgs^ e )
   {
      // Set clip region.
      System::Drawing::Region^ clipRegion = gcnew System::Drawing::Region( Rectangle(50,50,100,100) );
      e->Graphics->SetClip( clipRegion, CombineMode::Replace );

      // Set up coordinates of points.
      int x1 = 100;
      int y1 = 100;
      int x2 = 200;
      int y2 = 200;

      // If point is visible, fill ellipse that represents it.
      if ( e->Graphics->IsVisible( x1, y1 ) )
      {
         e->Graphics->FillEllipse( gcnew SolidBrush( Color::Red ), x1, y1, 10, 10 );
      }

      if ( e->Graphics->IsVisible( x2, y2 ) )
      {
         e->Graphics->FillEllipse( gcnew SolidBrush( Color::Blue ), x2, y2, 10, 10 );
      }
   }

private void IsVisibleInt(PaintEventArgs e)
{

    // Set clip region.
    Region clipRegion = new Region(new Rectangle(50, 50, 100, 100));
    e.Graphics.SetClip(clipRegion, CombineMode.Replace);

    // Set up coordinates of points.
    int x1 = 100;
    int y1 = 100;
    int x2 = 200;
    int y2 = 200;

    // If point is visible, fill ellipse that represents it.
    if (e.Graphics.IsVisible(x1, y1))
    {
        e.Graphics.FillEllipse(new SolidBrush(Color.Red), x1, y1, 10, 10);
    }
    if (e.Graphics.IsVisible(x2, y2))
    {
        e.Graphics.FillEllipse(new SolidBrush(Color.Blue), x2, y2, 10, 10);
    }
}

Private Sub IsVisibleInt(ByVal e As PaintEventArgs)

    ' Set clip region.
    Dim clipRegion As New [Region](New Rectangle(50, 50, 100, 100))
    e.Graphics.SetClip(clipRegion, CombineMode.Replace)

    ' Set up coordinates of points.
    Dim x1 As Integer = 100
    Dim y1 As Integer = 100
    Dim x2 As Integer = 200
    Dim y2 As Integer = 200

    ' If point is visible, fill ellipse that represents it.
    If e.Graphics.IsVisible(x1, y1) Then
        e.Graphics.FillEllipse(New SolidBrush(Color.Red), x1, y1, _
        10, 10)
    End If
    If e.Graphics.IsVisible(x2, y2) Then
        e.Graphics.FillEllipse(New SolidBrush(Color.Blue), x2, y2, _
        10, 10)
    End If
End Sub

适用于

IsVisible(Single, Single)

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

指示由一对坐标指定的点是否包含在此 Graphics的可见剪辑区域中。

public:
 bool IsVisible(float x, float y);

public bool IsVisible (float x, float y);

member this.IsVisible : single * single -> bool

Public Function IsVisible (x As Single, y As Single) As Boolean

参数

x: Single

要测试可见性的点的 x 坐标。

y: Single

要测试可见性的点的 y 坐标。

Boolean

如果 x 和 y 参数定义的点包含在此 Graphics的可见剪辑区域中，则 true;否则，false。

示例

下面的代码示例设计用于 Windows 窗体，它需要 PaintEventArgse，这是 Paint 事件处理程序的参数。该代码执行以下操作：

创建矩形剪辑区域，并使用 Replace将其设置为窗体图形对象的剪裁区域。
创建两个点，一个在剪辑区域内部，一个在外部。
测试每个点的可见性，并仅绘制可见点。

结果是一个位于剪辑区域中的一个小红色圆圈。

public:
   void IsVisibleFloat( PaintEventArgs^ e )
   {
      // Set clip region.
      System::Drawing::Region^ clipRegion = gcnew System::Drawing::Region( Rectangle(50,50,100,100) );
      e->Graphics->SetClip( clipRegion, CombineMode::Replace );

      // Set up coordinates of points.
      float x1 = 100.0F;
      float y1 = 100.0F;
      float x2 = 200.0F;
      float y2 = 200.0F;

      // If point is visible, fill ellipse that represents it.
      if ( e->Graphics->IsVisible( x1, y1 ) )
      {
         e->Graphics->FillEllipse( gcnew SolidBrush( Color::Red ), x1, y1, 10.0F, 10.0F );
      }

      if ( e->Graphics->IsVisible( x2, y2 ) )
      {
         e->Graphics->FillEllipse( gcnew SolidBrush( Color::Blue ), x2, y2, 10.0F, 10.0F );
      }
   }

private void IsVisibleFloat(PaintEventArgs e)
{

    // Set clip region.
    Region clipRegion = new Region(new Rectangle(50, 50, 100, 100));
    e.Graphics.SetClip(clipRegion, CombineMode.Replace);

    // Set up coordinates of points.
    float x1 = 100.0F;
    float y1 = 100.0F;
    float x2 = 200.0F;
    float y2 = 200.0F;

    // If point is visible, fill ellipse that represents it.
    if (e.Graphics.IsVisible(x1, y1))
    {
        e.Graphics.FillEllipse(new SolidBrush(Color.Red), x1, y1, 10.0F, 10.0F);
    }
    if (e.Graphics.IsVisible(x2, y2))
    {
        e.Graphics.FillEllipse(new SolidBrush(Color.Blue), x2, y2, 10.0F, 10.0F);
    }
}

Private Sub IsVisibleFloat(ByVal e As PaintEventArgs)

    ' Set clip region.
    Dim clipRegion As New [Region](New Rectangle(50, 50, 100, 100))
    e.Graphics.SetClip(clipRegion, CombineMode.Replace)

    ' Set up coordinates of points.
    Dim x1 As Single = 100.0F
    Dim y1 As Single = 100.0F
    Dim x2 As Single = 200.0F
    Dim y2 As Single = 200.0F

    ' If point is visible, fill ellipse that represents it.
    If e.Graphics.IsVisible(x1, y1) Then
        e.Graphics.FillEllipse(New SolidBrush(Color.Red), x1, y1, _
        10.0F, 10.0F)
    End If
    If e.Graphics.IsVisible(x2, y2) Then
        e.Graphics.FillEllipse(New SolidBrush(Color.Blue), x2, y2, _
        10.0F, 10.0F)
    End If
End Sub

适用于

IsVisible(Rectangle)

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

指示由 Rectangle 结构指定的矩形是否包含在此 Graphics的可见剪辑区域中。

public:
 bool IsVisible(System::Drawing::Rectangle rect);

public bool IsVisible (System.Drawing.Rectangle rect);

member this.IsVisible : System.Drawing.Rectangle -> bool

Public Function IsVisible (rect As Rectangle) As Boolean

参数

rect: Rectangle

Rectangle 结构来测试可见性。

Boolean

如果 rect 参数指定的矩形包含在此 Graphics的可见剪辑区域中，则 true ;否则，false。

示例

下面的代码示例设计用于 Windows 窗体，它需要 PaintEventArgse，这是 Paint 事件处理程序的参数。该代码执行以下操作：

创建矩形剪辑区域，并使用 Replace将其设置为窗体图形对象的剪裁区域。
创建两个矩形的位置和大小，一个在剪辑区域内，一个在外部。
测试每个矩形的可见性，并仅绘制可见的矩形。

结果是一个小红色矩形，该矩形位于剪辑区域中。

public:
   void IsVisibleRectangle( PaintEventArgs^ e )
   {
      // Set clip region.
      System::Drawing::Region^ clipRegion = gcnew System::Drawing::Region( Rectangle(50,50,100,100) );
      e->Graphics->SetClip( clipRegion, CombineMode::Replace );

      // Set up coordinates of rectangles.
      Rectangle rect1 = Rectangle(100,100,20,20);
      Rectangle rect2 = Rectangle(200,200,20,20);

      // If rectangle is visible, fill it.
      if ( e->Graphics->IsVisible( rect1 ) )
      {
         e->Graphics->FillRectangle( gcnew SolidBrush( Color::Red ), rect1 );
      }

      if ( e->Graphics->IsVisible( rect2 ) )
      {
         e->Graphics->FillRectangle( gcnew SolidBrush( Color::Blue ), rect2 );
      }
   }

private void IsVisibleRectangle(PaintEventArgs e)
{

    // Set clip region.
    Region clipRegion = new Region(new Rectangle(50, 50, 100, 100));
    e.Graphics.SetClip(clipRegion, CombineMode.Replace);

    // Set up coordinates of rectangles.
    Rectangle rect1 = new Rectangle(100, 100, 20, 20);
    Rectangle rect2 = new Rectangle(200, 200, 20, 20);

    // If rectangle is visible, fill it.
    if (e.Graphics.IsVisible(rect1))
    {
        e.Graphics.FillRectangle(new SolidBrush(Color.Red), rect1);
    }
    if (e.Graphics.IsVisible(rect2))
    {
        e.Graphics.FillRectangle(new SolidBrush(Color.Blue), rect2);
    }
}

Private Sub IsVisibleRectangle(ByVal e As PaintEventArgs)

    ' Set clip region.
    Dim clipRegion As New [Region](New Rectangle(50, 50, 100, 100))
    e.Graphics.SetClip(clipRegion, CombineMode.Replace)

    ' Set up coordinates of rectangles.
    Dim rect1 As New Rectangle(100, 100, 20, 20)
    Dim rect2 As New Rectangle(200, 200, 20, 20)

    ' If rectangle is visible, fill it.
    If e.Graphics.IsVisible(rect1) Then
        e.Graphics.FillRectangle(New SolidBrush(Color.Red), rect1)
    End If
    If e.Graphics.IsVisible(rect2) Then
        e.Graphics.FillRectangle(New SolidBrush(Color.Blue), rect2)
    End If
End Sub

适用于

IsVisible(PointF)

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

指示指定的 PointF 结构是否包含在此 Graphics的可见剪辑区域中。

public:
 bool IsVisible(System::Drawing::PointF point);

public bool IsVisible (System.Drawing.PointF point);

member this.IsVisible : System.Drawing.PointF -> bool

Public Function IsVisible (point As PointF) As Boolean

参数

point: PointF

PointF 结构来测试可见性。

Boolean

如果 point 参数指定的点包含在此 Graphics的可见剪辑区域中，则 true;否则，false。

示例

下面的代码示例设计用于 Windows 窗体，它需要 PaintEventArgse，这是 Paint 事件处理程序的参数。该代码执行以下操作：

创建一个矩形剪辑区域，并使用 Replace将其设置为窗体图形的剪裁区域。
创建两个点，一个在剪辑区域内部，一个在外部。
测试每个点的可见性，并仅绘制可见点。

结果是一个位于剪辑区域中的一个小红色圆圈。

public:
   void IsVisiblePointF( PaintEventArgs^ e )
   {
      // Set clip region.
      System::Drawing::Region^ clipRegion = gcnew System::Drawing::Region( Rectangle(50,50,100,100) );
      e->Graphics->SetClip( clipRegion, CombineMode::Replace );

      // Set up coordinates of points.
      float x1 = 100.0F;
      float y1 = 100.0F;
      float x2 = 200.0F;
      float y2 = 200.0F;
      PointF point1 = PointF(x1,y1);
      PointF point2 = PointF(x2,y2);

      // If point is visible, fill ellipse that represents it.
      if ( e->Graphics->IsVisible( point1 ) )
      {
         e->Graphics->FillEllipse( gcnew SolidBrush( Color::Red ), x1, y1, 10.0F, 10.0F );
      }

      if ( e->Graphics->IsVisible( point2 ) )
      {
         e->Graphics->FillEllipse( gcnew SolidBrush( Color::Blue ), x2, y2, 10.0F, 10.0F );
      }
   }

private void IsVisiblePointF(PaintEventArgs e)
{

    // Set clip region.
    Region clipRegion = new Region(new Rectangle(50, 50, 100, 100));
    e.Graphics.SetClip(clipRegion, CombineMode.Replace);

    // Set up coordinates of points.
    float x1 = 100.0F;
    float y1 = 100.0F;
    float x2 = 200.0F;
    float y2 = 200.0F;
    PointF point1 = new PointF(x1, y1);
    PointF point2 = new PointF(x2, y2);

    // If point is visible, fill ellipse that represents it.
    if (e.Graphics.IsVisible(point1))
    {
        e.Graphics.FillEllipse(new SolidBrush(Color.Red), x1, y1, 10.0F, 10.0F);
    }
    if (e.Graphics.IsVisible(point2))
    {
        e.Graphics.FillEllipse(new SolidBrush(Color.Blue), x2, y2, 10.0F, 10.0F);
    }
}

Private Sub IsVisiblePointF(ByVal e As PaintEventArgs)

    ' Set clip region.
    Dim clipRegion As New [Region](New Rectangle(50, 50, 100, 100))
    e.Graphics.SetClip(clipRegion, CombineMode.Replace)

    ' Set up coordinates of points.
    Dim x1 As Single = 100.0F
    Dim y1 As Single = 100.0F
    Dim x2 As Single = 200.0F
    Dim y2 As Single = 200.0F
    Dim point1 As New PointF(x1, y1)
    Dim point2 As New PointF(x2, y2)

    ' If point is visible, fill ellipse that represents it.
    If e.Graphics.IsVisible(point1) Then
        e.Graphics.FillEllipse(New SolidBrush(Color.Red), x1, y1, _
        10.0F, 10.0F)
    End If
    If e.Graphics.IsVisible(point2) Then
        e.Graphics.FillEllipse(New SolidBrush(Color.Blue), x2, y2, _
        10.0F, 10.0F)
    End If
End Sub

适用于

IsVisible(Point)

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

指示指定的 Point 结构是否包含在此 Graphics的可见剪辑区域中。

public:
 bool IsVisible(System::Drawing::Point point);

public bool IsVisible (System.Drawing.Point point);

member this.IsVisible : System.Drawing.Point -> bool

Public Function IsVisible (point As Point) As Boolean

参数

point: Point

Point 结构来测试可见性。

Boolean

如果 point 参数指定的点包含在此 Graphics的可见剪辑区域中，则 true;否则，false。

示例

下面的代码示例设计用于 Windows 窗体，它需要 PaintEventArgse，这是 Paint 事件处理程序的参数。该代码执行以下操作：

创建矩形剪辑区域，并使用 Replace将其设置为窗体图形对象的剪裁区域。
创建两个点，一个在剪辑区域内部，一个在外部。
测试每个点的可见性，并仅绘制可见点。

结果是一个位于剪辑区域中的一个小红色圆圈。

public:
   void IsVisiblePoint( PaintEventArgs^ e )
   {
      // Set clip region.
      System::Drawing::Region^ clipRegion = gcnew System::Drawing::Region( Rectangle(50,50,100,100) );
      e->Graphics->SetClip( clipRegion, CombineMode::Replace );

      // Set up coordinates of points.
      int x1 = 100;
      int y1 = 100;
      int x2 = 200;
      int y2 = 200;
      Point point1 = Point(x1,y1);
      Point point2 = Point(x2,y2);

      // If point is visible, fill ellipse that represents it.
      if ( e->Graphics->IsVisible( point1 ) )
      {
         e->Graphics->FillEllipse( gcnew SolidBrush( Color::Red ), x1, y1, 10, 10 );
      }

      if ( e->Graphics->IsVisible( point2 ) )
      {
         e->Graphics->FillEllipse( gcnew SolidBrush( Color::Blue ), x2, y2, 10, 10 );
      }
   }

private void IsVisiblePoint(PaintEventArgs e)
{

    // Set clip region.
    Region clipRegion = new Region(new Rectangle(50, 50, 100, 100));
    e.Graphics.SetClip(clipRegion, CombineMode.Replace);

    // Set up coordinates of points.
    int x1 = 100;
    int y1 = 100;
    int x2 = 200;
    int y2 = 200;
    Point point1 = new Point(x1, y1);
    Point point2 = new Point(x2, y2);

    // If point is visible, fill ellipse that represents it.
    if (e.Graphics.IsVisible(point1))
    {
        e.Graphics.FillEllipse(new SolidBrush(Color.Red), x1, y1, 10, 10);
    }
    if (e.Graphics.IsVisible(point2))
    {
        e.Graphics.FillEllipse(new SolidBrush(Color.Blue), x2, y2, 10, 10);
    }
}

Private Sub IsVisiblePoint(ByVal e As PaintEventArgs)

    ' Set clip region.
    Dim clipRegion As New [Region](New Rectangle(50, 50, 100, 100))
    e.Graphics.SetClip(clipRegion, CombineMode.Replace)

    ' Set up coordinates of points.
    Dim x1 As Integer = 100
    Dim y1 As Integer = 100
    Dim x2 As Integer = 200
    Dim y2 As Integer = 200
    Dim point1 As New Point(x1, y1)
    Dim point2 As New Point(x2, y2)

    ' If point is visible, fill ellipse that represents it.
    If e.Graphics.IsVisible(point1) Then
        e.Graphics.FillEllipse(New SolidBrush(Color.Red), x1, y1, _
        10, 10)
    End If
    If e.Graphics.IsVisible(point2) Then
        e.Graphics.FillEllipse(New SolidBrush(Color.Blue), x2, y2, _
        10, 10)
    End If
End Sub

适用于

IsVisible(RectangleF)

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

Source:: Graphics.cs

指示由 RectangleF 结构指定的矩形是否包含在此 Graphics的可见剪辑区域中。

public:
 bool IsVisible(System::Drawing::RectangleF rect);

public bool IsVisible (System.Drawing.RectangleF rect);

member this.IsVisible : System.Drawing.RectangleF -> bool

Public Function IsVisible (rect As RectangleF) As Boolean

参数

rect: RectangleF

RectangleF 结构来测试可见性。

Boolean

如果 rect 参数指定的矩形包含在此 Graphics的可见剪辑区域中，则 true ;否则，false。

示例

下面的代码示例设计用于 Windows 窗体，它需要 PaintEventArgse，这是 Paint 事件处理程序的参数。该代码执行以下操作：

创建矩形剪辑区域，并使用 Replace将其设置为窗体图形对象的剪裁区域。
创建两个矩形，一个在剪辑区域内部，一个在外部。
测试每个矩形的可见性，并仅绘制可见的矩形。

结果是一个小红色矩形，该矩形位于剪辑区域中。

public:
   void IsVisibleRectangleF( PaintEventArgs^ e )
   {
      // Set clip region.
      System::Drawing::Region^ clipRegion = gcnew System::Drawing::Region( Rectangle(50,50,100,100) );
      e->Graphics->SetClip( clipRegion, CombineMode::Replace );

      // Set up coordinates of rectangles.
      RectangleF rect1 = RectangleF(100.0F,100.0F,20.0F,20.0F);
      RectangleF rect2 = RectangleF(200.0F,200.0F,20.0F,20.0F);

      // If rectangle is visible, fill it.
      if ( e->Graphics->IsVisible( rect1 ) )
      {
         e->Graphics->FillRectangle( gcnew SolidBrush( Color::Red ), rect1 );
      }

      if ( e->Graphics->IsVisible( rect2 ) )
      {
         e->Graphics->FillRectangle( gcnew SolidBrush( Color::Blue ), rect2 );
      }
   }

private void IsVisibleRectangleF(PaintEventArgs e)
{

    // Set clip region.
    Region clipRegion = new Region(new Rectangle(50, 50, 100, 100));
    e.Graphics.SetClip(clipRegion, CombineMode.Replace);

    // Set up coordinates of rectangles.
    RectangleF rect1 = new RectangleF(100.0F, 100.0F, 20.0F, 20.0F);
    RectangleF rect2 = new RectangleF(200.0F, 200.0F, 20.0F, 20.0F);

    // If rectangle is visible, fill it.
    if (e.Graphics.IsVisible(rect1))
    {
        e.Graphics.FillRectangle(new SolidBrush(Color.Red), rect1);
    }
    if (e.Graphics.IsVisible(rect2))
    {
        e.Graphics.FillRectangle(new SolidBrush(Color.Blue), rect2);
    }
}

Private Sub IsVisibleRectangleF(ByVal e As PaintEventArgs)

    ' Set clip region.
    Dim clipRegion As New [Region](New Rectangle(50, 50, 100, 100))
    e.Graphics.SetClip(clipRegion, CombineMode.Replace)

    ' Set up coordinates of rectangles.
    Dim rect1 As New RectangleF(100.0F, 100.0F, 20.0F, 20.0F)
    Dim rect2 As New RectangleF(200.0F, 200.0F, 20.0F, 20.0F)

    ' If rectangle is visible, fill it.
    If e.Graphics.IsVisible(rect1) Then
        e.Graphics.FillRectangle(New SolidBrush(Color.Red), rect1)
    End If
    If e.Graphics.IsVisible(rect2) Then
        e.Graphics.FillRectangle(New SolidBrush(Color.Blue), rect2)
    End If
End Sub

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