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Puzzle 3
Poly Want a Cracker? |
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The windows graphical device interface (GDI) has far more graphics capability than is built into Visual Basic. One of the functions allows you to draw a polygon of as many lines as you wish in a single operation. The Polygon function is defined in the C documentation as follows: |
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BOOL Polygon(
HDC hdc, // handle to device context
CONST POINT *lpPoints, // pointer to polygon's vertices
int nCount // count of polygon's vertices
); |
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The hdc parameter is the device context for the window on which the polygon will be drawn. The lpPoints parameter is a pointer to the first of a series of coordinates describing the points that are to be connected. The nCount parameter is the number of points. |
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Can you fix the following program to display the pattern shown in Figure P3-1? |
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' Poly Example Program
' Copyright © 1998 by Desaware Inc. All Rights Reserved
Option Explicit
Private Type POINTAPI
X As Long
Y As Long
End Type
Private Declare Function Polygon Lib "gdi32" (hdc As Long, _
lpPoint As POINTAPI, nCount As Long) As Long
' Function loads an array of points
Private Sub LoadPointArray(ByVal Width As Long, ByVal Height _
As Long, ByVal Increment As Integer, PointArray() As POINTAPI)
Dim curidx As Integer
ReDim PointArray((Height \ Increment) + 2)
Do |
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