A little trigonometry help

[torels]

Hi there

I am trying to do a very stupid script... I want the line to do a full circle.

The problem is I actually don't know trigonometry... so I'm trying to put together informations I found, guesses and luck XD

Though I have to say I am starting to understand the x and y part...

Any kind of help would be greatly appreciated

thanks in advance

btw... this skips a quarter of a circle... I think

#include <GDIPlus.au3>
$pi = 3.14159265358979
$degToRad = $pi / 180
$GUI = GUICreate("",600,600)
GUISetState()
_GDIPlus_Startup()
$hGraphics = _GDIPlus_GraphicsCreateFromHWND($GUI)

_GDIPlus_GraphicsFillRect($hGraphics,300,300,2,2)

For $i = 0 to 360
    _GDIPlus_GraphicsClear($hGraphics,0xFFFFFFFF)
    $x = tan($pi/4)
    $y = Tan($i * $degToRad)  ;tangent of 90°
    If Mod($i, 90)=Round(Mod($i, 90),0) And $y>0 Then $x*=(-1)
    If Mod($i, 90)=Round(Mod($i, 90),0) AND $x<0 Then $y*=(-1)
    If Mod($i, 180)=Round(Mod($i, 180), 0) Then 
        $x*=(-1)
        $y=($y+1)*(-1)
    EndIf
    _GDIPlus_GraphicsDrawLine($hGraphics,300,300,300+$x*20,300+$y*20)
    _GDIPlus_GraphicsDrawString($hGraphics, $i&"°"&@CRLF&Round($x,1)&@CRLF&round($y,1),0,0)
    Sleep(50)
Next

while 1
    Switch GUIGetMsg()
        Case -3
            _GDIPlus_Shutdown()
            Exit
    EndSwitch
WEnd

[weaponx]

I made this function awhile back. Input the starting X, Y ,angle (degrees), and length, output is ending X,Y.

Func Angle($x1, $y1, $Ang, $Length)
      Local $Return[2]
      $Return[0] = $x1 + ($Length * Cos($Ang / 180 * 3.14159265358979))
      $Return[1] = $y1 - ($Length * Sin($Ang / 180 * 3.14159265358979))
      Return $Return
  EndFunc;==>Angle

Original post:

#463161

Edited March 4, 2009 by weaponx

[torels]

Thanks weaponx. Nice example

Just to understand... Were I completely wrong assuming I had to use Tan() or is there a way to do this ?

[martin]

Hi there

I am trying to do a very stupid script... I want the line to do a full circle.

The problem is I actually don't know trigonometry... so I'm trying to put together informations I found, guesses and luck XD

Though I have to say I am starting to understand the x and y part...

Any kind of help would be greatly appreciated

thanks in advance

btw... this skips a quarter of a circle... I think

#include <GDIPlus.au3>
$pi = 3.14159265358979
$degToRad = $pi / 180
$GUI = GUICreate("",600,600)
GUISetState()
_GDIPlus_Startup()
$hGraphics = _GDIPlus_GraphicsCreateFromHWND($GUI)

_GDIPlus_GraphicsFillRect($hGraphics,300,300,2,2)

For $i = 0 to 360
    _GDIPlus_GraphicsClear($hGraphics,0xFFFFFFFF)
    $x = tan($pi/4)
    $y = Tan($i * $degToRad)  ;tangent of 90°
    If Mod($i, 90)=Round(Mod($i, 90),0) And $y>0 Then $x*=(-1)
    If Mod($i, 90)=Round(Mod($i, 90),0) AND $x<0 Then $y*=(-1)
    If Mod($i, 180)=Round(Mod($i, 180), 0) Then 
        $x*=(-1)
        $y=($y+1)*(-1)
    EndIf
    _GDIPlus_GraphicsDrawLine($hGraphics,300,300,300+$x*20,300+$y*20)
    _GDIPlus_GraphicsDrawString($hGraphics, $i&"°"&@CRLF&Round($x,1)&@CRLF&round($y,1),0,0)
    Sleep(50)
Next

while 1
    Switch GUIGetMsg()
        Case -3
            _GDIPlus_Shutdown()
            Exit
    EndSwitch
WEnd

You have made it much more difficult than it really is.

#include <GDIPlus.au3>
$pi = 3.14159265358979
$degToRad = $pi / 180
$GUI = GUICreate("",600,600)
GUISetState()
_GDIPlus_Startup()
$hGraphics = _GDIPlus_GraphicsCreateFromHWND($GUI)

_GDIPlus_GraphicsFillRect($hGraphics,300,300,2,2)
$radius = 10
For $i = 0 to 360
    _GDIPlus_GraphicsClear($hGraphics,0xFFFFFFFF)
    $x = $radius*cos($i*$degToRad)
    $y = $Radius*sin($i*$degToRad)
   ;$x = tan($pi/4);this is  1
   ;$y = Tan($i * $degToRad) ;tangent of 90°
   ;If Mod($i, 90)=Round(Mod($i, 90),0) And $y>0 Then $x*=(-1)
  ; If Mod($i, 90)=Round(Mod($i, 90),0) AND $x<0 Then $y*=(-1)
  ; If Mod($i, 180)=Round(Mod($i, 180), 0) Then
    ;;   $x*=(-1)
    ;   $y=($y+1)*(-1)
   ;EndIf
    _GDIPlus_GraphicsDrawLine($hGraphics,300,300,300+$x*20,300+$y*20)
    _GDIPlus_GraphicsDrawString($hGraphics, $i&"°"&@CRLF&Round($x,1)&@CRLF&round($y,1),0,0)
    Sleep(50)
Next

while 1
    Switch GUIGetMsg()
        Case -3
            _GDIPlus_Shutdown()
            Exit
    EndSwitch
WEnd

You don't need to worry about the sign because that is automatically taken care of in the sin and cos functions. EG cos 45 deg is 0.707 approx and cos 135 deg is -0.707

[jvanegmond]

Were I completely wrong assuming I had to use Tan() or is there a way to do this ?

The standard method is using Cos and Sin. But, if you know that Tan = Sin / Cos then you can rewrite it to use Tan and Sin or Tan and Cos. So, not completely off the wrong track.

[torels]

Ok

thanks to everyone for your help