CGpGraphics.TransformPointsmethod

Converts an array of points from one coordinate space to another.

GraphicsmethodCGpGraphics.incdocumented

Syntax

FUNCTION TransformPoints (BYVAL destSpace AS CoordinateSpace, BYVAL srcSpace AS CoordinateSpace, BYVAL pts AS GpPointF PTR, BYVAL count AS LONG) AS GpStatus

FUNCTION TransformPoints (BYVAL destSpace AS CoordinateSpace, BYVAL srcSpace AS CoordinateSpace, BYVAL pts AS GpPoint PTR, BYVAL count AS LONG) AS GpStatus

Parameters

Name		Description
`destSpace`		Element of the CoordinateSpace enumeration that specifies the destination coordinate space.
`srcSpace`		Element of the CoordinateSpace enumeration that specifies the source coordinate space.
`pts`		Pointer to an array that, on input, holds the points to be converted and, on output, holds the converted points.
`count`		Integer that specifies the number of elements in the pts array.

Return value

If the function succeeds, it returns StatusOk, which is an element of the GpStatus enumeration.

If the function fails, it returns one of the other elements of the GpStatus enumeration.

Description

Converts an array of points from one coordinate space to another. The conversion is based on the current world and page transformations of this Graphics object.

Example

' ======================================================================================== ' The following example creates a Graphics object and sets its world transformation to a ' translation 40 units right and 30 units down. Then the code creates an array of points ' and passes the address of that array to the Graphics::TransformPoints method of the same ' Graphics object. The points in the array are transformed by the world transformation of ' the Graphics object. The code calls the Graphics.DrawLine method twice: once to connect ' the two points before the transformation and once to connect the two points after the ' transformation. ' ======================================================================================== SUB Example_TransformPoints (BYVAL hdc AS HDC)

' // Create a graphics object from the window device context DIM graphics AS CGpGraphics = hdc ' // Get the DPI scaling ratio DIM rxRatio AS SINGLE = graphics.GetDpiX / 96 DIM ryRatio AS SINGLE = graphics.GetDpiY / 96 ' // Set the scale transform graphics.ScaleTransform(rxRatio, ryRatio)

DIM bluePen AS CGpPen = ARGB_BLUE

' // Create an array of two Point objects. DIM rgPoints(0 TO 1) AS GpPoint = {(0, 0), (100, 50)}

' // Draw a line that connects the two points. ' // No transformation has been performed yet. graphics.DrawLine(@bluePen, @rgPoints(0), @rgPoints(1))

' // Set the world transformation of the Graphics object. graphics.TranslateTransform(40, 30)

' // Transform the points in the array from world to page coordinates. graphics.TransformPoints(CoordinateSpacePage, CoordinateSpaceWorld, @rgPoints(0), 2)

' // It is the world transformation that takes points from world ' // space to page space. Because the world transformation is a ' // translation 40 to the right and 30 down, the ' // points in the array are now (40, 30) and (140, 80).

' // Draw a line that connects the transformed points. graphics.ResetTransform DIM bluePen2 AS CGpPen = CGpPen(ARGB_BLUE, rxRatio) graphics.DrawLine(@bluePen2, @rgPoints(0), @rgPoints(1))

END SUB ' ========================================================================================

Reference

Include file CGpGraphics.inc
Defined in AfxNova/CGpGraphics.inc:407
Documented in Graphics/GdiPlus Classes/CGpGraphics Classes.md
Topic: CGpGraphics Class