Graphics.IsVisible Method (Point)

 

Indicates whether the specified Point structure is contained within the visible clip region of this Graphics.

Namespace:   System.Drawing
Assembly:  System.Drawing (in System.Drawing.dll)

public bool IsVisible(
	Point point
)

Parameters

point
Type: System.Drawing.Point

Point structure to test for visibility.

Return Value

Type: System.Boolean

true if the point specified by the point parameter is contained within the visible clip region of this Graphics; otherwise, false.

The following code example is designed for use with Windows Forms, and it requires PaintEventArgse, which is a parameter of the Paint event handler. The code performs the following actions:

  • Creates a rectangular clipping region and sets it as the clipping region for the graphics object of the form using Replace.

  • Creates two points, one inside the clipping region and one outside.

  • Tests each of the points for visibility and draws only the visible one.

The result is one small red circle, which is within the clip region.

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);
    }
}

.NET Framework
Available since 1.1
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