Expand Method—ArcGIS Pro

Moves the X and Y coordinates of the envelope sides toward or away from each other to scale the size of the envelope.

Syntax

C#
Visual Basic (Declaration)

public Envelope Expand( 
   double sx,
   double sy,
   bool asRatio
)

Public Function Expand( _
   ByVal sx As Double, _
   ByVal sy As Double, _
   ByVal asRatio As Boolean _
) As Envelope

Parameters

sx: Change in x
sy: Change in y
asRatio: If asRatio = true, the expansion is multiplicative. If false, the expansion is additive.

Remarks

If asRatio = false, the expansion is additive. If you want to increase the envelope width by 5 units, then sx = 5. On the other hand, if you want to decrease the envelope width by 5 units, then sx = -5. Similarly, set sy to increase or decrease the envelope height.

If asRatio = true, the expansion is multiplicative. If you want to increase the envelope width by 10%, then sx = 1.1. On the other hand, if you want to decrease the width by 10%, then sx = 0.9. Similarly, set sy to increase or decrease the envelope height. No negative numbers are allowed when asRatio is set to true.

The Envelope remains centered at the same position.

Example

Example: Expand the envelope by 10%

Envelope expanded = myEnvelope.Expand(1.1, 1.1, true);

// Use a builder convenience method or use a builder constructor.

// Builder convenience methods don't need to run on the MCT.
Envelope envelope = EnvelopeBuilder.CreateEnvelope(100.0, 100.0, 500.0, 500.0);

// shrink the envelope by 50%
Envelope result = envelope.Expand(0.5, 0.5, true);

// Builder constructors need to run on the MCT.
ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
{
  using (EnvelopeBuilder eBuilder = new EnvelopeBuilder(100.0, 100.0, 500.0, 500.0))
  {
    // shrink by 50%
    eBuilder.Expand(0.5, 0.5, true);

    result = eBuilder.ToGeometry();
  }
});

// builderEx constructors don't need to run on the MCT.
EnvelopeBuilderEx builderEx = new EnvelopeBuilderEx(100.0, 100.0, 500.0, 500.0);
builderEx.Expand(0.5, 0.5, true);
envelope = builderEx.ToGeometry() as Envelope;

Requirements

Target Platforms: Windows 10, Windows 8.1

Reference

Envelope Class
Envelope Members