RasterRegionXForm Class

Visual Basic
C#
WinRT C#
WinRT JavaScript
C++

public class RasterRegionXForm

'Declaration
 
Public Class RasterRegionXForm

'Usage
 
Dim instance As RasterRegionXForm

public sealed class RasterRegionXForm

function Leadtools.RasterRegionXForm()

public ref class RasterRegionXForm

All region methods accept a null reference (Nothing in Visual Basic). In that case, no transformation occurs. The scalar fields default to 1, the offsets default to 0, and the view perspective defaults to the image view perspective.

Several of the LEADTOOLS methods for creating and working with an image region use coordinates from an external representation of the region, such as a shape drawn in a device context. To compensate for possible differences in view perspective, scaling, and display offsets, these LEADTOOLS methods require that you provide translation information in an RasterRegionXForm object.

In most cases, the external representation of an image region is scaled and positioned relative to the display coordinates of a LEADTOOLS painting method. Therefore, the following table describes the fields to set in the RasterRegionXForm object, based on the parameters of the display methods.

When assigning an external representation to an image, every point (Xa, Ya) in the an external representation is transformed (by RasterRegionXForm) to point (Xc, Yc) in the image region as follows:

             1. Add offsets:
                  Xb = Xa + XForm.XOffset
                  Yb = Ya + XForm.YOffset
            
             2. Multiply by scalars:
                  Xc = (Xb * XForm.XScalarNumerator) / XForm.XScalarDenominator
                  Yc = (Yb * XForm.YScalarNumerator) / XForm.YScalarDenominator
            
             3. Compensate for view perspective (updating Xc and Yc in place):
                  PointToImage(XForm.ViewPerspective, Xc, Yc)

When retrieving an external representation from an image, every point (Xa, Ya) in the image region is transformed (by RasterRegionXForm) to point (Xc, Yc) in the external region as follows:

             1. Compensate for view perspective (updating Xa and Ya in place):
                  PointFromImage(XForm.ViewPerspective, Xa, Ya)
            
             2. Mulitply by scalars:
                  Xb = (Xa * XForm.XScalarNumerator) / XForm.XScalarDenominator
                  Yb = (Ya * XForm.YScalarNumerator) / XForm.YScalarDenominator
            
             3. Add offsets:
                  Xc = Xb + XForm.XOffset
                  Yc = Yb + XForm.YOffset

For more information, refer to Translating Coordinates for a Region..

For an example, refer to RasterRegion.Transform.

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

RasterRegionXForm Members
Leadtools Namespace
Creating an Image Region
Working with the Existing Image Region
Commands and Methods That Transform The Region And the Image