Visual C++ and MFC Programming 2nd Edition

Chapter 7: GDI Accessories and Tools Visual C++ and MFC Fundamentals

is that a polyline does not start where the previous line ended. Each polyline has its own

beginning and its own ending point.

Unlike Polyline(), here, the nCount argument is actually the number of shapes you want

to draw and not the number of points (remember that each polyline "knows" or controls

its beginning and end).

The lpPolyPoints argument is an array or positive integers (unsigned long). Each member

of this array specifies the number of vertices (lines) that its corresponding polyline will

have. For example, imagine you want to draw M, followed by L, followed by Z. The

letter M has 4 lines but you need 5 points to draw it. The letter L has 2 lines and you need

3 points to draw it. The letter Z has 3 lines so 4 points are necessary to draw it. You can

store this combination of lines in an array defined as { 5, 3, 4 }.

Here is an example:

void CExoView::OnDraw(CDC* pDC)

{

CPoint Pt[15];

DWORD lpPts[] = { 4, 4, 7 };

// Left Triangle

Pt[0] = Pt[3] = CPoint(50, 20);

Pt[1] = CPoint(20, 60);

Pt[2] = CPoint(80, 60);

// Second Triangle

Pt[4] = Pt[7] = CPoint(70, 20);

Pt[5] = CPoint(100, 60);

Pt[6] = CPoint(130, 20);

// Hexagon

Pt[8] = Pt[14] = CPoint(145, 20);

Pt[9] = CPoint(130, 40);

Pt[10] = CPoint(145, 60);

Pt[11] = CPoint(165, 60);

Pt[12] = CPoint(180, 40);

Pt[13] = CPoint(165, 20);

pDC->PolyPolyline(Pt, lpPts, 3);

}