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Color wheel: Difference between revisions
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Looks like mirror image of Smart BASIC entry
</pre>
=={{header|M2000 Interpreter}}==
<lang M2000 Interpreter>
Module Check {
\\ we use an internal object for Math functions (here for Atan2)
Declare Math Math
Const tau=2*Pi, Center=2
\\ change console size, and center it ( using ;) to current monitor
Window 12, 800*twipsX,600*twipsY;
\\ actual size maybe less (so can fit text exactly)
Double ' Double height characters
Report Center, "Color wheel"
Normal ' restore to normal
Atan2=Lambda Math (a, b) ->{
Method Math, "Atan2", a, b As ret
=ret
}
\\ brightness=1 for this program
hsb2rgb=Lambda (hue, sat) ->{
If sat == 0 Then {
= 255, 255, 255
} Else {
h=frac(hue+1)*6
f = frac(h)
p = Int((1-sat)*255 + 0.5)
q = Int((1-sat*f)*255 + 0.5)
t = Int((1-sat*(1-f))*255 + 0.5)
Select Case Int(h)
Case 1
= q, 255, p
Case 2
= p, 255, t
Case 3
= p, q, 255
Case 4
= t, p, 255
Case 5
= 255, p, q
Else Case
= 255, t, p
End Select
}
}
Let OffsetX=X.twips/2-128*TwipsX, OffsetY=Y.twips/2-128*TwipsY
\\ a pixel has a size of TwipsX x TwipsY
OffsetX=(OffsetX div TwipsX)*TwipsX
OffsetY=(OffsetY div TwipsY)*TwipsY
\\ We set hsb2rgb, OffsetX, OffsetY as closures to PrintPixel
\\ We send to stack the R G B values using Stack ! array
\\ hsb2rgb() return an array of values
\\ we pop these values using Number
PrintPixel = Lambda hsb2rgb, OffsetX, OffsetY (x,y, theta, sat) -> {
Stack ! hsb2rgb(theta,sat)
PSet Color(number, number, number), x*TwipsX+offsetX, y*TwipsY+offsetY
}
\\ set Atan2, tau as closures to HueCircle
\\ we can rotate/flip the wheel by changing signs in Atan2() and
\\ by changing order of arguments (dx,dy) or (dy,dx). 8 combinations
HueCircle= Lambda Atan2, tau (PrintPixel) -> {
Let c_width=256, c_height=256
Let cx=c_width/2, cy=c_height/2
Let radius=If(cx<=cy->cx, cy), pi2=pi/2
c_width--
c_height--
dy=-cy
For y=0 To c_height {
dy++ : dy2=dy*dy : dx=-cx
For x=0 To c_width {
dx++ : dist=Sqrt(dx^2+dy2)
If dist>radius Then continue
Call PrintPixel(x,y, Atan2(dx, -dy)/tau, dist/radius)
}
}
}
Call HueCircle(PrintPixel)
Scr$="" ' we use this string to load an image
Move 0,0
\\ scale.x, scale.y are twips height and width, of current layer
Copy scale.x, scale.y to Scr$
Clipboard Scr$ ' save window to clipboard
}
Check
</lang>
{{out}}
see [https://4.bp.blogspot.com/-0swVvNDaTjE/XDlPfuGQkBI/AAAAAAAAHno/wU3eyo1BUIEtPjZMyjGXkbN425zHJlc7wCLcBGAs/s1600/colorwheel.png this image]
=={{header|Perl}}==
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