LVectorPolygon::LockObject

#include "ltwrappr.h"

virtual L_INT LVectorPolygon::LockObject(pPolygon)

pointer to a vector object

Gets the object information of the class object.

Parameter	Description
pPolygon	Pointer to a VECTORPOLYGON structure to be updated with the vector object information.

Returns

SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

This function is used to retrieve the object information of the class object.

To use this method, declare a variable of the VECTORPOLYGON type and pass the address to this function. After modifying the vector object settings, call LVectorPolygon::UnlockObject (). LVectorPolygon::LockObject () and LVectorPolygon::UnlockObject () should always be called in pairs.

Before an object has been added to the LVectorBase object, using LVectorBase::AddObject or LVectorLayer::AddObject, LVectorPolygon::UnlockObject () can be used to change ALL properties of an object. However, once the object has been added to the LVectorBase object, some properties cannot be changed using LVectorPolygon::UnlockObject ().However, as long as the number of points does not change, the coordinates of the individual points can always be modified using LVectorPolygon::UnlockObject ().

To change the object information for a class object, call LVectorPolygon::UnlockObject.

LVectorPolygon::LockObject and LVectorPolygon::UnlockObject must be called in pairs.

Note that rotating an object may change the object type. However, not all object types are changed by rotation, and not all rotations result in changing an object type. For example, a rectangle rotated 90 degrees about the z-axis is still a rectangle. A rectangle rotated 45 degrees about the z-axis becomes a polydraw object. The table below indicates object types that may change following rotation and the possible resulting object types.

Original object type	Possible object type following rotation
VECTOR_RECTANGLE	VECTOR_POLYGON
VECTOR_ELLIPSE	VECTOR_POLYDRAW
VECTOR_CIRCLE	VECTOR_POLYDRAW
VECTOR_ARC	VECTOR_POLYDRAW
VECTOR_TEXT	VECTOR_POLYDRAW
VECTOR_PIE	VECTOR_POLYDRAW

If an object type changes, LVectorPolygon::LockObject and LVectorPolygon::UnlockObject will return WRPERR_VECTOR_INVALID_OBJECT_TYPE. Object properties can still be inspected and changed by using LVectorObject::GetObjectAttributes and LVectorObject::SetObjectAttributes.

Required DLLs and Libraries

LVKRN

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Example

This example will add a new green polygon to the Active Layer LVectorBase object Once added, the color will be changed to blue.

L_INT LVectorPolygon__LockObjectExample(HWND hWnd, LVectorBase *pVector) 
{ 
   UNREFERENCED_PARAMETER(hWnd); 
   L_INT          nRet; 
   VECTORPOLYGON  Polygon; 
   //Create Polygon Object 
   VECTORPOINT        Points[5] = 
   { 
      10,  10, 20, 0, 
      20,  10, 20, 0, 
      20,  20, 20, 0, 
      15,  30,  0, 0, 
      10,  20,  0, 0, 
   }; 
   Polygon.nPointCount = 5; 
   Polygon.Point = Points; 
   Polygon.Pen.bExtPen= FALSE; 
   Polygon.Pen.nSize = sizeof( VECTORPEN ); 
   Polygon.Pen.NewPen.LogPen.lopnStyle = PS_SOLID; 
   Polygon.Pen.NewPen.LogPen.lopnWidth.x = 2; 
   Polygon.Pen.NewPen.LogPen.lopnWidth.y = 2; 
   Polygon.Pen.NewPen.LogPen.lopnColor = RGB(0,255,0); 
   LVectorPolygon VectorPolygon(&Polygon); 
   // add to current active layer 
   LVectorLayer VectorLayer; 
   nRet = pVector->GetActiveLayer(&VectorLayer); 
   if (nRet == SUCCESS) 
   { 
      nRet = VectorLayer.AddObject(&VectorPolygon); 
      if(nRet != SUCCESS) 
         return nRet; 
      //Now change color to blue 
      MessageBox(NULL, TEXT("Changing color to blue"), TEXT(""), MB_OK); 
      VECTORPOLYGON PolygonTemp; 
      nRet = VectorPolygon.LockObject(&PolygonTemp); 
      if(nRet != SUCCESS) 
         return nRet; 
      PolygonTemp.Pen.bExtPen = FALSE; 
      PolygonTemp.Pen.NewPen.LogPen.lopnColor = RGB(0,0,255); 
      VectorPolygon.UnlockObject(&PolygonTemp); 
   } 
   else 
   { 
      MessageBox(NULL, TEXT("No Active Layer--Load a vector and run again"), TEXT(""), MB_OK); 
      return nRet; 
   } 
   //LVectorPolygon destructor called when VectorPolygon goes out of scope 
   return SUCCESS; 
}

Help Version 19.0.2017.10.27

LEADTOOLS Vector C++ Class Library Help

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Appendix

Functions:	LVectorPolygon::UnlockObject
Topics:	Working with Vector Objects