CIRCLE

CIRCLE [STEP] x, y, r [, aspect [, color]] [COLOR color] [FILLED]

Draws a circle (or an ellipse if the aspect is specified). The point [x, y] defines the center and r the radius of the circle in pixel. To set the aspect ration use aspect. An aspect ratio of 1 will draw a circle. color defines the line color of the circle. If FILLED is used, the circle will be filled with the color color. If STEP is used x, y are a step in pixel from the actual graphics cursor position.

By default CIRCLE draws with anti-aliasing. For details, see: Fast, Antialiased Circles and Ellipses To turn off anti-aliasing use option predef antialias off

Example 1: Draw a filled white circle

circle 200, 200, 150 COLOR 15 FILLED

Example 2: Draw a ellipse with aspect ration 1:2

circle 200, 200, 150, 0.5

Example 3: Draw a flower

' Aspect ratio is relation between width-height of a circle,
' for example:
' aspect = 1   = Perfect circle;
' aspect = 1.5 = Stretch circle vertically (ellipse);
' aspect = 0.5 = Stretch circle horizontally (ellipse);
' let's draw perfect circles for the flower:
Const ASPECT_RATIO = 1
' define parameters for main circle:
Const CENTER = [150, 150] ' [x, y] define the center point to draw a circle
Const RADIUS = 50         ' radius in pixels (pixel is a single point)
Const TEXT = "Smile!"     ' text to print in the middle of main circle
' define parameters for leafs:
Const LEAF_RADIUS = 30    ' using smaller circles for leafs
' center point for straight leafs (distance from main circle's center):
Const LEAF_CENTER_STRAIGHT   = RADIUS + LEAF_RADIUS
' rotate center point for transverse leafs (distance as above):
Const LEAF_CENTER_TRANSVERSE = LEAF_CENTER_STRAIGHT * Sin(Rad(45))
' Start the program:
Print " Press any key to draw leaf by leaf...";
Pause
Cls
' draw one invisible point to set the 'current position':
Pset CENTER Color 0
' let's use shorter variable names (easier to read):
a = ASPECT_RATIO
r = LEAF_RADIUS
' draw the straight leafs (relative to the 'current position'):
c = LEAF_CENTER_STRAIGHT
Circle Step 0, -c, r, a Color 15 FILLED: Pause ' top
Circle Step 0, +c, r, a Color 14 FILLED: Pause ' down
Circle Step -c, 0, r, a Color 13 FILLED: Pause ' left
Circle Step +c, 0, r, a Color 12 FILLED: Pause ' right
' draw the transverse leafs (relative to the 'current position'):
c = LEAF_CENTER_TRANSVERSE
Circle Step -c, -c, r, a Color 11 FILLED: Pause ' top-left
Circle Step +c, +c, r, a Color  8 FILLED: Pause ' down-right
Circle Step +c, -c, r, a Color 10 FILLED: Pause ' top-right
Circle Step -c, +c, r, a Color  9 FILLED: Pause ' down-left
' draw the main circle:
Circle CENTER, RADIUS, ASPECT_RATIO Color 14
' print text in the middle of main circle:
At CENTER(0) - (Txtw(TEXT) \ 2), CENTER(1) - (Txth(TEXT) \ 2)
Color 15: Print TEXT;

Example 4: Smiley Face

' SmallBASIC 0.12.2 [B+=MGA] 2016-03-16
' Smiley Face
cx = xmax/2
cy = ymax/2
rface = 250
reye = 50
xle = cx - 100
xre = cx + 100
dir = 1
while 1
  cls
  circle cx, cy, rface, 1, 14 filled
  circle xle, cy, reye, 1 - a, 9 filled
  circle xre, cy, reye, 1 - a, 9 filled
  circle cx, cy + 130 - a * 50, 100 + a * 50, .21 + 2 * a, 12 filled
  circle cx, cy + 100 - a * 50, 100 + a * 50, .21 + a, 14 filled
  showpage
  delay 1
  a+= .002 * dir
  if a = .26 then dir = dir * -1
  if a = -.1 then dir = dir *-1
wend

Example 5: Turn off anti-aliasing

option predef antialias off

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