VB API 之 第九課 映像編程(二)

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用到2個API函數，Polyiine,Polylineto函數原型如下

Declare Function Polyline Lib "gdi32" Alias "Polyline" (ByVal hdc As Long, lpPoint As POINTAPI, ByVal nCount As Long) As Long
Declare Function PolylineTo Lib "gdi32" Alias "PolylineTo" (ByVal hdc As Long, lppt As POINTAPI, ByVal cCount As Long) As Long

功能說明

　　用來繪製線段

參數

hdc： Long   //裝置的控制代碼

lpPoint　　指向一個POINTAPI的結構。

nCount：Long   //lpPoint數組的點數。

樣本：

Option ExplicitPrivate Declare Function Polyline Lib "gdi32" (ByVal hdc As Long, lpPoint As point, ByVal nCount As Long) As LongPrivate Declare Function PolylineTo Lib "gdi32" (ByVal hdc As Long, lppt As point, ByVal cCount As Long) As LongPrivate Type point    x As Long    y As LongEnd Type    Dim Flag1 As BooleanDim Flag2 As BooleanDim Pos(10) As pointDim i As IntegerPrivate Sub Command1_Click()    Flag1 = True    Flag2 = FalseEnd SubPrivate Sub Command2_Click()    Flag1 = False    Flag2 = TrueEnd SubPrivate Sub Command3_Click()    Flag1 = False    Flag2 = FalseEnd SubPrivate Sub Command4_Click()    Me.Picture1.ClsEnd SubPrivate Sub Form_Load()    Flag1 = False    Flag1 = False    ‘禁止繪圖    Me.ScaleMode = 3    Me.Picture1.ScaleMode = 3    ‘設定對象座標的度量單位為像素    i = 0End SubPrivate Sub Picture1_MouseUp(Button As Integer, Shift As Integer, x As Single, y As Single)    If Flag1 Then        Pos(i).x = x        Pos(i).y = y    If (i >= 3) Then        Polyline Me.Picture1.hdc, Pos(0), 4        Me.Picture1.Circle (x, y), 3        i = 0        Exit Sub    End IfEnd If‘利用PolyLine函數繪圖If Flag2 Then    Pos(i).x = x    Pos(i).y = y    If (i >= 3) Then        PolylineTo Me.Picture1.hdc, Pos(0), 3        Me.Picture1.Circle (x, y), 3        i = 0        Exit Sub    End IfEnd If‘利用PolyLineTo函數繪圖If (i <= 3) Then    i = i + 1    Me.Picture1.Circle (x, y), 3End IfEnd Sub

 

VB API 之 第九課 映像編程(二)