Question

vb中在picture中画三角形

已知平面坐标系中三点的坐标，求三点组成三角形的面积。要求输入点A和B、C的x,y坐标，点击”计算”按钮，计算并输出（在picture中显示）三点组成三角形的面积S，同时在Picture控件中显示这个三角形
这个是我们的作业。。。界面是;6个text分别显示输入的（xa,ya）(xb,yb)(xc,yc)的值，一个picture显示画出的三角形
另外一个picture来显示三角形面积的值 还有一个计算的按钮。。先谢谢了

Answer 1

Private Declare Function LineTo Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long) As Long

Private Sub Command1_Click()
Picture1.Cls
Dim w As Integer, h As Integer, x As Integer, y As Integer
Randomize
w = Picture1.Width
h = Picture1.Height
x = Rnd * (w + 1)
y = Rnd * (h + 1)
Picture1.CurrentX = x
Picture1.CurrentY = y

Picture1.DrawWidth = 5
Picture1.ForeColor = vbRed
Picture1.Print "起点"
Picture1.PSet (x, y)
Picture1.DrawWidth = 1
Picture1.ForeColor = 0

LineTo Picture1.hdc, Rnd * (w + 1) / Screen.TwipsPerPixelX, Rnd * (h + 1) / Screen.TwipsPerPixelY
LineTo Picture1.hdc, Rnd * (w + 1) / Screen.TwipsPerPixelX, Rnd * (h + 1) / Screen.TwipsPerPixelY
LineTo Picture1.hdc, x / Screen.TwipsPerPixelX, y / Screen.TwipsPerPixelY
End Sub

这是随机画三角形 你用坐标来求面积 估计比较难。。