Picture控件彩色框绘制及擦除问题
Private Sub Display1_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
If IsSettngRoi(0) = True Then
isMouseDown(0) = True
Display1.MousePointer = 2 'vbCross
Display1.DrawMode = vbXorPen
Display1.Line (Box_X0(0), Box_Y0(0))-(Old_X(0), Old_Y(0)), vbWhite, B
Old_X(0) = X
Old_Y(0) = Y
Box_X0(0) = X
Box_Y0(0) = Y '初始值
End If
End Sub
Private Sub Display1_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
If IsSettngRoi(0) = True Then
If isMouseDown(0) = True Then
'拖动鼠标来定义矩形的另外一个顶点，此时擦除前一个矩形，绘制新的矩形
Display1.Line (Box_X0(0), Box_Y0(0))-(Old_X(0), Old_Y(0)), vbWhite, B
Display1.Line (Box_X0(0), Box_Y0(0))-(X, Y), vbWhite, B
Old_X(0) = X
Old_Y(0) = Y
End If
End If
End Sub
Private Sub Display1_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
If IsSettngRoi(0) = True Then
isMouseDown(0) = False
Display1.MousePointer = vbDefault
Display1.DrawStyle = vbSolid
' Display1.DrawMode = vbCopyPen
Display1.Line (Box_X0(0), Box_Y0(0))-(X, Y), vbBlack, B
Old_X(0) = X
Old_Y(0) = Y '保存矩形的位置
End If
End Sub
这里mouseup中框最终不能够绘制成彩色的，只有黑白的才能擦掉，怎么办呢？
[解决办法]
换成相同的颜色，我将你的你码稍改了一下：
Dim old_X(1) As Single
Dim old_Y(1) As Single
Dim Box_X0(1) As Single
Dim Box_Y0(1) As Single
Dim d As Boolean
Dim myCol As Long
Private Sub Display1_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
d = True
display1.MousePointer = 2 'vbCross
display1.DrawMode = vbXorPen
'display1.Line (Box_X0(0), Box_Y0(0))-(old_X(0), old_Y(0)), mycol, B
old_X(0) = X
old_Y(0) = Y
Box_X0(0) = X
Box_Y0(0) = Y '初始值
End Sub
Private Sub Display1_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
If d = False Then Exit Sub
'拖动鼠标来定义矩形的另外一个顶点，此时擦除前一个矩形，绘制新的矩形
display1.Line (Box_X0(0), Box_Y0(0))-(old_X(0), old_Y(0)), myCol, B
display1.Line (Box_X0(0), Box_Y0(0))-(X, Y), myCol, B
old_X(0) = X
old_Y(0) = Y
End Sub
Private Sub Display1_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
display1.MousePointer = vbDefault
display1.DrawStyle = vbSolid
'display1.DrawMode = vbCopyPen
display1.Line (Box_X0(0), Box_Y0(0))-(X, Y), myCol, B
old_X(0) = X
old_Y(0) = Y '保存矩形的位置
d = False
End Sub
Private Sub Form_Load()
myCol = RGB(0, 255, 255)
End Sub
[解决办法]
这样啊，明白了，那就先定义一个StdPicture对象（模块级），用来保存picturebox的picture，需要擦除的时候，重设picturebox的picture为我们预先保存的StdPicture对象，如果需要保存picturebox上图象的改变，就重新为StdPicture对象赋值
