Bitmap/Midpoint circle algorithm: Difference between revisions

=={{header|Python}}==

{{works with|Python|3.1}}

Extending the example given [[Basic_bitmap_storage#Alternative_version|here]]

<lang python>def circle(self, x0, y0, radius, colour=black):

f = 1 - radius

ddf_x = 1

ddf_y = -2 * radius

x = 0

y = radius

self.set(x0, y0 + radius, colour)

self.set(x0, y0 - radius, colour)

self.set(x0 + radius, y0, colour)

self.set(x0 - radius, y0, colour)

while x < y:

if f >= 0:

y -= 1

ddf_y += 2

f += ddf_y

x += 1

ddf_x += 2

f += ddf_x

self.set(x0 + x, y0 + y, colour)

self.set(x0 - x, y0 + y, colour)

self.set(x0 + x, y0 - y, colour)

self.set(x0 - x, y0 - y, colour)

self.set(x0 + y, y0 + x, colour)

self.set(x0 - y, y0 + x, colour)

self.set(x0 + y, y0 - x, colour)

self.set(x0 - y, y0 - x, colour)

Bitmap.circle = circle

bitmap = Bitmap(25,25)

bitmap.circle(x0=12, y0=12, radius=12)

bitmap.chardisplay()

'''

The origin, 0,0; is the lower left, with x increasing to the right,

and Y increasing upwards.

The program above produces the following display :

+-------------------------+

| @@@@@@@ |

| @@ @@ |

| @@ @@ |

| @ @ |

| @ @ |

| @ @ |

| @ @ |

| @ @ |

| @ @ |

|@ @|

|@ @|

|@ @|

|@ @|

|@ @|

|@ @|

|@ @|

| @ @ |

| @ @ |

| @ @ |

| @ @ |

| @ @ |

| @ @ |

| @@ @@ |

| @@ @@ |

| @@@@@@@ |

+-------------------------+

'''

</lang>