LVectorPolygon::LockObject

Summary

Gets the object information of the class object.

Syntax

virtual L_INT LVectorPolygon::LockObject(pPolygon)

Parameters

pVECTORPOLYGON pPolygon

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

Returns

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.

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

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

See Also

Functions

• LVectorPolygon::UnlockObject

Topics

• Working with Vector Objects

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; 
}