GAMBAS BOOK 3.19.3

The Point class (gb.clipper) describes a point with integer coordinates. This chapter presents the properties and methods of the Point class as well as some examples for using the class.

The Point class has these two properties

Table 25.2.3.1.1 : Properties of the Point class

The two methods for the Point class are described here.

Table 25.2.3.2.1 : Selected methods of the Point class

The Point class can be created. You can use the class like a (static) function:

Dim PointP, PointQ As Point 

PointP = New Point() ' P(0|0)
PointQ = New Point(44,-22)

In the following example, points with random coordinates (from a restricted area) and a random colour are created and drawn on a picture, which is then displayed in a DrawArea:

Public Sub SetPoint(X As Integer, Y As Integer, cColor As Integer)
  Paint.AntiAlias = False
    Paint.FillRect(X, Y, 1, 1, cColor)
  Paint.AntiAlias = True
End
 
Public Sub ScriptPointCloud()
 
  Dim i As Integer
  Dim PointP As Point '-- Class 'Point' in gb.clipper
 
  GenerateNewPicture()
  SetPictureBorder()  
 
  Paint.Begin(hPicture)   
    Paint.Translate(xTranslate, yTranslate)
    Paint.Scale(xScale, yScale) ' +y ▲
    Paint.AntiAlias = False
    DrawCoordinateSystem()      ' +y ▲       
    For i = 1 To 20000
   '-- Points with random coordinates and a random colour
       PointP = New Point(Rnd(10, 550 - 5), Rnd(10, 260))  
       SetPoint(PointP.X, PointP.Y, Color.RGB(Rnd(0, 255), Rnd(0, 255), Rnd(0, 255)))
     Next
     Paint.AntiAlias = True
  Paint.End()     
 
End

If you count exactly, you should get about 20000 points - I have counted all the points:

Figure 25.2.3.3.1: Point cloud

The final example demonstrates how you can determine whether a given point lies within a specific rectangle.

Dim PointP As Point
Dim RectRed As Rect
 
PointP = New Point(260, 150)
RectRed = New Rect(60, 60, 400, 180)
 
Print "P in RectRed? --> "; PointP.InRect(RectRed) '-- Result: TRUE

Figure 25.2.3.3.2: Mutual position of point and rectangle

While only integers are permitted as coordinates for the Point class, you can use real numbers for the coordinates of a point for the PointF class.