🚀 go-pugleaf

I'm trying to do something very simple.  I want to create a grid in
a window.  I'm using the MM_LOENGLISH map mode because I want the
space between grid lines to be the same no matter what the screen 
resolution.  The following is an excerpt from the code:

   SetMapMode(hDC, MM_LOENGLISH);
   GetClientRect(hDC, &rect);

   POINT PointsArray[2];

   PointsArray[0].x = rect.left;
   PointsArray[0].y = rect.top;
   PointsArray[1].x = rect.right;
   PointsArray[1].y = rect.bottom;

   DPtoLP(hDC, PointsArray, 2);

   const int space = 20;

   for (int x = PointsArray[0].x * space; 
         x < PointsArray[1].x * space; x += space)
   {
      MoveTo(hDC, x, PointsArray[0].y;
      LineTo(hDC, x, PointsArray[1].y;
   }


   for (int y = PointsArray[0].y * space;
         y < PointsArray[1].y * space; y += space)
   {
      MoveTo(hDC, PointsArray[0].x, y);
      LineTo(hDC, PointsArray[1].x, y);
   }


The first loop works fine, and the vertical lines are drawn correctly.
The problem is that DPtoLP is converting rect.bottom to a negative
number!  This obviously causes the second loop to next execute.  When
I look at rect in the debugger, rect.bottom is a positive number.  Why
is it getting translated to a negative?

If I comment out SetMapMode, then the grid is created, but it won't be
the same size on any screen.

Any help would be greatly appreciated.

-- 
_________________________________________________________________________
Andy Deitsch                             email    : deitsch@crd.ge.com  
GE Corporate Research & Development      phone    : (518) 387-7207   
Schenectday, NY 12301                    dial comm: 833-7207