How to make the reading for indicating of deflection of the line

Hi All

I have something like this

Code:

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Option Explicit
    Dim Ruch As Boolean
    Dim intDlugosc As Integer

Private Sub Form_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
    intDlugosc = intDlugosc + 1
    Load Line1(intDlugosc)
    Line1(intDlugosc).X1 = X
    Line1(intDlugosc).Y1 = Y
    Ruch = True
End Sub

Private Sub Form_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
    If Ruch Then
        Line1(intDlugosc).X2 = X
        Line1(intDlugosc).Y2 = Y
        Line1(intDlugosc).Visible = True
    End If
End Sub

Private Sub Form_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
    Ruch = False
End Sub

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How to be visible with my code, I can draw a some the straight of the line - for example : in the vertical.
Until I have pressed mouse's button I can this line to incline under any angle (in initial point of line).
Now I want to read the value of this angle - suffice for me only in the range since 0 to 180 degrees, how to make it?

Any suggestions, maybe a some lines of the code, thanks in advance

Try this sample:

Code:

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Private Sub Form_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
Dim a As Single
Dim b As Single
Dim h As Single
Dim sinA As Single
Dim ratio As Single
Dim degreeA As Integer
Dim degreeB As Integer

    Ruch = False
   
    'the following is a typical calculation for right-angled triangles
    'note: approach may vary but results should be the same
   
    a = Abs(Line1.X2 - Line1.X1)
    b = Abs(Line1.Y2 - Line1.Y1)
   
    'if a = 0 then it's a vertical line so there is nothing to calculate - angle is 0 or 90 (however you want it)
    'if b = 0 then it's a horizontal line - angle is 0 or 180 (however you want it)
    If a > 0 And b > 0 Then
        h = Sqr(a ^ 2 + b ^ 2)
        sinA = b / h
       
        'if a=b then angles are 90º,45º,45º and a=b=(sqr(2) / 2) = 0.707106781186548
        ratio = sinA / ((Sqr(2) / 2))
       
        degreeA = 45 * ratio
        degreeB = 90 - degreeA
    End If
   
    MsgBox "Angle a = " & degreeA & Chr(186) & vbNewLine & _
          "Angle b = " & degreeB & Chr(186)

End Sub

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RhinoBull, I'm having problems with your code as lines approach vertical.

I prefer using the ArcTangent function

Code:

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Option Explicit
Const PI As Single = 3.141593 '3.14159265358979
Const PI½ As Single = PI / 2 '1.5707963267949

Public Function ATan2(ByVal DY As Single, ByVal DX As Single) As Single
  If DX <> 0 Then
    ATan2 = Atn(DY / DX) - (Sgn(DX) - 1) * PI½
  Else
    ATan2 = PI½ * Sgn(DY)
  End If
End Function

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calling code being...

Code:

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Dim Radians As Single
With Line1(intDlugosc)
  Radians = ATan2(.Y2 - .Y1, .X2 - .X1)
End With

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...and to convert to degrees...

Code:

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Degrees = Radians / PI * 180
'force degrees to be within 0 to 360
If Degrees < 0 then Degrees = Degrees + 360

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Quote:

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Originally Posted by Milk

I prefer using the ArcTangent function

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You can use anything you want really...

What is the problem that you are/were having?