Expand(Envelope,Double,Double,Boolean) Method

Expands or shrinks the envelope.

Syntax

C#
Visual Basic (Declaration)

public Envelope Expand( 
   Envelope envelope,
   double dx,
   double dy,
   bool asRatio
)

Public Overloads Function Expand( _
   ByVal envelope As Envelope, _
   ByVal dx As Double, _
   ByVal dy As Double, _
   ByVal asRatio As Boolean _
) As Envelope

Parameters

envelope: The envelope to expand or shrink.
dx: The scale factor along the x-axis. In other words, the amount to expand or shrink the width of the envelope.
dy: The scale factor along the y-axis. In other words, the amount to expand or shrink the height of the envelope.
asRatio: If asRatio = false, the expansion is additive. If asRatio = true, the expansion is multiplicative.

Return Value

The scaled envelope.

Exceptions

Exception	Description
System.ArgumentNullException	Envelope is null or empty.

Remarks

If asRatio is set to true, dx and dy must be greater than or equal to zero. In this case, if the user wants to increase the envelope width by 10%, then dx = 1.1. On the other hand, if the user wants to decrease the width by 10%, then dx = 0.9.

Example

Envelope env = EnvelopeBuilder.CreateEnvelope(100.0, 100.0, 500.0, 500.0);
// env.HasZ = false

Envelope result = GeometryEngine.Instance.Expand(env, 0.5, 0.5, true);
// result.Center = 300, 300
// result.XMin = 200
// result.YMin = 200
// result.XMax = 400
// result.YMax = 400

result = GeometryEngine.Instance.Expand(env, 100, 200, false);
// result.Center = 300, 300
// result.XMin = 0
// result.YMin = -100
// result.XMax = 600
// result.YMax = 700

try
{
  // expand in 3 dimensions
  result = GeometryEngine.Instance.Expand(env, 0.5, 0.5, 0.5, true);
}
catch (InvalidOperationException e)
{
  // the geometry is not Z-Aware
}

// expand a 3d envelope
MapPoint pt1 = MapPointBuilder.CreateMapPoint(100, 100, 100);
MapPoint pt2 = MapPointBuilder.CreateMapPoint(200, 200, 200);

env = EnvelopeBuilder.CreateEnvelope(pt1, pt2);
// env.HasZ = true
      
result = GeometryEngine.Instance.Expand(env, 0.5, 0.5, 0.5, true);

// result.Center = 150, 150, 150
// result.XMin = 125
// result.YMin = 125
// result.ZMin = 125
// result.XMax = 175
// result.YMax = 175
// result.ZMax = 175

Requirements

Target Platforms: Windows 10, Windows 8.1, Windows 7

Reference

GeometryEngine Class
GeometryEngine Members
Overload List