Scaling using SetWindowExtEx

[nhungr]

Hello.

I am having problems scaling a Visual Basic Picture control from a C++ DLL. Here is the code that I am using:

In Visual Basic, I call the scaling routine in the C++ DLL using the following code:

Call ScalePicture(Picture1.hWnd, Picture1.hDC)

where:

Declare Sub ScalePicture Lib "C:\ MYDLL.dll" (ByVal inWND As Long, ByVal inDC As Long)

Then, in the C++ DLL, the function is as follows:

void ScalePicture(HWND inWND, HDC inDC)
{
	int xClient, yClient;		[COLOR=green]// variables used for picture dimensioning[/color]
	int xOrigin, yOrigin;		[COLOR=green]// variables used for specifying location of origin[/color]
	int width=100, height=200;	[COLOR=green]// variables used to define the desired logical[/color]
                                    [COLOR=green]//                    dimensions of the picture[/color]
	RECT Picturecoord={0};	[COLOR=green]//picture coordinates[/color]
	SIZE prevsize;

	GetClientRect(inWND, &Screencoord);
    xClient=abs(Screencoord.right-Screencoord.left);
    yClient=abs(Screencoord.bottom-Screencoord.top);

	SetMapMode(inDC,MM_ANISOTROPIC);
	SetWindowExtEx(inDC,width,height,&prevsize);	[COLOR=green]// set screen coordinates[/color]

	SetViewportExtEx(inDC,xClient,-yClient,&prevsize);  [COLOR=green]// set viewport location[/color]

	xOrigin=0;
    yOrigin=0;
	SetViewportOrgEx(inDC,xOrigin,yOrigin,&prevpoint);	[COLOR=green]// set origin[/color]
}

However, when I plot a collection of points in the picture control, it shows that the scale is upside-down and too small (ie. some of the points are drawn off-screen, even though they’re within the width and height specifications used in the SetWindowExtEx function).

Can anyone see why the control is not being scaled properly??? Thank you very much.

Nikolai.