WM_LBUTTONDOWN

using-brushes

case WM_LBUTTONDOWN

Store the mouse coordinates in a POINT structure'

ptlHit=MAKEPOINTS((POINTS FAR *)lParam

Create a rectangular region with dimensions and' 

coordinates that correspond to those of the grid 

window

,hrgnCell=CreateRectRgn(rctGrid.left, rctGrid.top

(rctGrid.right, rctGrid.bottom

Retrieve a window DC for the grid window'

(hdc=GetWindowDC(hwndGrid

Select the region into the DC'

(SelectObject(hdc, hrgnCell

Test for a button click in the grid-window rectangle'

if (PtInRegion(hrgnCell, ptlHit.x, ptlHit.y)) Then