Scripting a graph drawer

[monoceres]

I have been scripting on a script that simple draws a curve in a GUI window, it's pretty sweet, but I have some problems.

First I just draw each pixel with the GUI_GR_PIXEL but that turned out ugly when there was very high difference between the y coordinates. So I used the GUI_GR_LINE instead but I don't get it, it works great when the curve is just a straight line, but when for example using a y = x^2 ekvation there is a line from the top edge of the screen to the curve, my drawing code looks like this:

Global $width=850
Global $height=650
Global $prec=0.015

;some code

Dim $oldx, $oldy
For $x=-($width/2) to $width/2 Step $prec
$y = $x^2 ; Ekvationen som ska ritas
$tcoord = translate($x,$y)
GUICtrlSetGraphic($graph,$GUI_GR_LINE,$oldx,$oldy)
GUICtrlSetGraphic($graph,$GUI_GR_LINE,$tcoord[0],$tcoord[1])
$oldx = $tcoord[0]
$oldy = $tcoord[1]
;~ GUICtrlSetGraphic($graph,$GUI_GR_PIXEL,$tcoord[0],$tcoord[1])
Next
GUICtrlSetGraphic($graph,$GUI_GR_REFRESH)

; Some code

Func translate ($x, $y)
    Dim $answer[2]
    $answer[0] = $width/2-$x*-1
    $answer[1] = $height/2-$y
    Return $answer
EndFunc

That was my graphical problem, my next is that I need a function that returns the answer of an expression, for example:

_expression("2^3*sin(0)+5") would return 5

So my question is: Has made a function like, cause I really don't know how I would script it myself.

Thanks in advance!

[Nahuel]

I had the same problem with the graphic thing. Maybe the link in my sig can help (Sin, Cos, Tan drawer).

I changed $GUI_GR_LINE with $GUI_GR_DOT and it looks good. The higher the value of $prec is, the uglier it will look and the faster it will be drawn, of course.

[monoceres]

The problem with drawing each pixel is that it's going to be super ugly if you use for example tan(), and I know there is someway to do the $GUI_GR_LINE thing right, (read in the help file about something named $GUI_GR_CLOSE but I didn't understand it.)

Does anybody know about the function? I could maybe do it but it would be alot of ugly code and ALOT of StringInstr()