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图形的色彩控制
1、VB中具有图形功能的常用对象有窗体(Form)、图形框(Picture)和图象框(Image)，其中窗体和图形框即可以装载图片也可以在其中作图，而图象框只能装载图片。
2、自然界中各种颜色都是又红(Red)绿(Green)蓝(Blue)三色光叠加而成。VB中有相应的函数Rgb函数，格式为RGB(R,G,B)，其中R、G和B是0-255之间的整数，如果超过
255，会被当作 255。
3、滚动条是通过滑块在整个滚动条中相对位置的变化和改变Value属性的值，从而控制某些对象的变化。
Private Sub HScroll1_Change()
Picture1.BackColor = RGB(HScroll1.Value, HScroll2.Value,
HScroll3.Value)
End Sub
Private Sub HScroll2_Change()
Picture1.BackColor = RGB(HScroll1.Value, HScroll2.Value,
HScroll3.Value)
End Sub
Private Sub HScroll3_Change()
Picture1.BackColor = RGB(HScroll1.Value, HScroll2.Value,
HScroll3.Value)
End Sub
Draw
Dim x2 As Integer, y2 As Integer, x3 As Integer, y3 As
Integer
x0 = 2000: y0 = 500 '棱锥顶点坐标
x1 = 2500: y1 = 2000 '定义底三角形三顶点坐标
x2 = 500: y2 = 3000
x3 = 3500: y3 = 3000
Cls
DrawStyle = 0: DrawWidth = 2 '实线，线宽为2
Line (x0, y0)-(x2, y2) '画棱锥的一条棱
Line (x2, y2)-(x3, y3)
Line (x3, y3)-(x0, y0)
DrawStyle = 2: DrawWidth = 1 '点线，线宽为1
Line (x0, y0)-(x1, y1)
Line -(x2, y2)
Line (x1, y1)-(x3, y3)
DrawStyle = 3: DrawWidth = 1 '点划线，线宽为1
Line (x0, y0)-(x0, y1 + (y2 - y1) * 2 / 3) '画棱锥的中垂线
End Sub
Private Sub Command2_Click()
Dim x As Integer, y As Integer, r As Integer
x = 1800: y = 1800 '球心坐标
r = 1500 '球半径
Cls
DrawWidth = 2 '线宽为2
Circle (x, y), r '画球外廓圆
DrawWidth = 1 '线宽为1
Circle (x, y), r, , , , 2 '画一长轴在垂直方向的椭圆
FillStyle = 7 '斜网格填充
Circle (x, y), r, , , , 0.4 '画一长轴在水平方向的椭圆
FillStyle = 1 '恢复填充模板为透明
End Sub
Private Sub Command4_Click()
End
End Sub
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