1.2

Sends a left button down message to Visual CADD™ effectively selecting a coordinate for a tool, or selecting an entity.

extern "C" void WINAPI VCLButtonDown(long lParam, WORD wParam);

procedure VCLButtonDown(lParam: Longint; wParam: Smallint); stdcall;

Sub LButtonDown(ByVal lParam As Long, ByVal wParam As Integer)

lParam - a packed coordinate pair as used by Windows.
wParam - passed by Windows functions to represent the identifier of the mouse message.

All mouse subroutines as passed by Windows function pass the coordinate values through a lParam structure which contains the x and y coordinates and other pertinent information not used by Visual CADD™. Also included is a wParam which contains any modifiers to the mouse movement such as the state of the shift, ctrl, and alt keys. These may or may not be used by Visual CADD™ to modify the results of the mouse movements depending on the current context in the application. Whenever an external application receives a left button down message in the drawing area, the application should send the VCLButtonDown message to Visual CADD™ in order to invoke the expected response. This makes if behave as if it were in the Visual CADD™ drawing area.

The MFC Class Library in MS Visual C++ references mouse movements and points through a CPoint class structure. The macro MAKELPARAM can be used to convert the given CPoint structure to a LPARAM compatible with the Visual CADD™ API.

VCLButtonDown2, VCRButtondown, VCMButtonDown