frmpset.frm

Visual Basic 6 大学教程的代码

VERSION 5.00
Begin VB.Form frmPset 
   BackColor       =   &H00FFFFFF&
   Caption         =   "Fig. 9.9: Demonstrating method PSet"
   ClientHeight    =   3195
   ClientLeft      =   2865
   ClientTop       =   1950
   ClientWidth     =   4680
   LinkTopic       =   "Form1"
   ScaleHeight     =   3195
   ScaleWidth      =   4680
End
Attribute VB_Name = "frmPset"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
' Fig. 9.9
' Demonstrating method PSet
Option Explicit

Private Sub Form_Click()
   Call DrawShape
End Sub

Private Sub DrawShape()
   Dim x As Single, y As Single
   Dim totalRadians As Single, r As Single
   Dim a As Single, theta As Single
      
   Call Randomize
   Scale (3, -3)-(-3, 3)         ' Change scale
   totalRadians = 8 * Atn(1)     ' Circle in Radians
    
   a = 3 * Rnd()  ' Offset used in equation
   
   For theta = 0.001 To totalRadians Step 0.01
      r = 2 * a / Sin(2 * theta)
      x = r * Cos(theta)                ' y coordinate
      y = r * Sin(theta)                ' x coordinate
      PSet (x, y)                       ' Turn pixel on
   Next theta
   
End Sub