Bitmap/Midpoint circle algorithm: Difference between revisions

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=={{header|Phix}}==

Requires new_image() from [[Bitmap#Phix|Bitmap]], write_ppm() from [[Bitmap/Write_a_PPM_file#Phix|Write_a_PPM_file]].

Requires new_image() from [[Bitmap#Phix|Bitmap]], write_ppm() from [[Bitmap/Write_a_PPM_file#Phix|Write_a_PPM_file]]. <br>

~~Included as demo\rosetta\Bitmap_Circle.exw, results~~ may be verified with demo\rosetta\viewppm.exw

Results may be verified with demo\rosetta\viewppm.exw

<lang Phix>-- demo\rosetta\Bitmap_Circle.exw (runnable version)

<lang Phix>constant red = 0xff2020,

include ppm.e -- red, yellow, new_image(), write_ppm() -- (covers above requirements)

yellow = 0xffdf20

function SetPx(sequence img, atom x, ~~atom~~ y, integer colour)

function SetPx(sequence img, atom x, y, integer colour)

if x>=1 and x<=length(img)

and y>=1 and y<=length(img[x]) then

img[x][y] = colour

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end function

function Circle(sequence img, atom x, ~~atom~~ y, ~~atom~~ r, integer colour)

function Circle(sequence img, atom x, y, r, integer colour)

atom x1 = -r,

y1 = 0,

err = 2-2*r

if r>=0 then

-- Bresenham algorithm

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sequence img = new_image(400,300,yellow)

img = Circle(img, 200, 150, 100, red)

write_ppm("Circle.ppm",img)</lang>

=={{header|PicoLisp}}==