Ellipse Test

[KawaGeo]

I have coded drawEllipse function in Lua. The arguments are the same as fillRect, in addition of an extra argument, number of segments around the ellipse. The code and screenshot are given here.

NOTE: Don't use screen as an object to draw ellipses upon directly. I don't know why. Maybe Shine could explain.

Code: Select all

-- ellipseTest.lua by Geo Massar, 2005  (aka Geo Massar)

PI2 = math.pi * 2

function math.round(num, dp)
  local mult = 10^(dp or 0)
  return math.floor(num  * mult + 0.5) / mult
end

function Image:drawEllipse(x1,y1, x2,y2, segments, color)
  local a = (x2-x1) / 2; local x0 = (x2+x1) / 2
  local b = (y2-y1) / 2; local y0 = (y2+y1) / 2
  x1, y1 = x0, y0 + b
  for i = 1, segments do
    x2 = math.round(x0 + a * math.sin(PI2*i/segments))
    y2 = math.round(y0 + b * math.cos(PI2*i/segments))
    self:drawLine(x1,y1, x2,y2, color)
    x1,y1 = x2,y2
  end
end

green = Color.new(0, 255, 0)

panel = Image.createEmpty(400,200)
for i = 0, 4 do
  panel:drawEllipse(50*i,0, 400-50*i,200, 60, green)
end

screen:blit(40,36, panel)
screen:print(2,262, "Ellipse Test by Geo Massar, 2005 (aka KawaGeo)", green)
screen.flip()

while true do
  screen.waitVblankStart()
end

[chaos]

looks good