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```# IFS fractals
# FB - 201003221
from PIL import Image
import random

# Fractint IFS definition of Fern
mat=[[0.0,0.0,0.0,0.16,0.0,0.0,0.01],
[0.85,0.04,-0.04,0.85,0.0,1.6,0.85],
[0.2,-0.26,0.23,0.22,0.0,1.6,0.07],
[-0.15,0.28,0.26,0.24,0.0,0.44,0.07]]

### Fractint IFS definition of Dragon
##mat = [[0.824074, 0.281482, -0.212346,  0.864198, -1.882290, -0.110607, 0.787473],
##       [0.088272, 0.520988, -0.463889, -0.377778,  0.785360,  8.095795, 0.212527]]

# image size
imgx = 512
imgy = 512 # will be auto-re-adjusted

m = len(mat)
# find the xmin, xmax, ymin, ymax
x = mat[0][4]
y = mat[0][5]
#
xa = x
xb = x
ya = y
yb = y
#
for k in range(imgx * imgy):
p=random.random()
psum = 0.0
for i in range(m):
psum += mat[i][6]
if p <= psum:
break
x0 = x * mat[i][0] + y * mat[i][1] + mat[i][4]
y  = x * mat[i][2] + y * mat[i][3] + mat[i][5]
x = x0
#
if x < xa:
xa = x
if x > xb:
xb = x
if y < ya:
ya = y
if y > yb:
yb = y

# drawing
imgy = round(imgy * (yb - ya) / (xb - xa)) # auto-re-adjust the aspect ratio
image = Image.new("L", (imgx, imgy))

x=0.0
y=0.0
for k in range(imgx * imgy):
p=random.random()
psum = 0.0
for i in range(m):
psum += mat[i][6]
if p <= psum:
break
x0 = x * mat[i][0] + y * mat[i][1] + mat[i][4]
y  = x * mat[i][2] + y * mat[i][3] + mat[i][5]
x = x0
jx = int((x - xa) / (xb - xa) * (imgx - 1))
jy = (imgy - 1) - int((y - ya) / (yb - ya) * (imgy - 1))
image.putpixel((jx, jy), 255)

image.save("IFS_.png", "PNG")
```

#### Diff to Previous Revision

```--- revision 1 2010-03-21 21:59:11
+++ revision 2 2010-03-21 23:04:50
@@ -1,22 +1,21 @@
# IFS fractals
-# FB - 201003217
+# FB - 201003221
from PIL import Image
import random

-### Fractint IFS definition of Fern
-##mat=[[0.0,0.0,0.0,0.16,0.0,0.0,0.01],
-##     [0.85,0.04,-0.04,0.85,0.0,1.6,0.85],
-##     [0.2,-0.26,0.23,0.22,0.0,1.6,0.07],
-##     [-0.15,0.28,0.26,0.24,0.0,0.44,0.07]]
+# Fractint IFS definition of Fern
+mat=[[0.0,0.0,0.0,0.16,0.0,0.0,0.01],
+     [0.85,0.04,-0.04,0.85,0.0,1.6,0.85],
+     [0.2,-0.26,0.23,0.22,0.0,1.6,0.07],
+     [-0.15,0.28,0.26,0.24,0.0,0.44,0.07]]

-# Fractint IFS definition of Dragon
-mat = [[0.824074, 0.281482, -0.212346,  0.864198, -1.882290, -0.110607, 0.787473],
-       [0.088272, 0.520988, -0.463889, -0.377778,  0.785360,  8.095795, 0.212527]]
+### Fractint IFS definition of Dragon
+##mat = [[0.824074, 0.281482, -0.212346,  0.864198, -1.882290, -0.110607, 0.787473],
+##       [0.088272, 0.520988, -0.463889, -0.377778,  0.785360,  8.095795, 0.212527]]

# image size
imgx = 512
-imgy = 512
-image = Image.new("L", (imgx, imgy))
+imgy = 512 # will be auto-re-adjusted

m = len(mat)
# find the xmin, xmax, ymin, ymax
@@ -49,6 +48,9 @@
yb = y

# drawing
+imgy = round(imgy * (yb - ya) / (xb - xa)) # auto-re-adjust the aspect ratio
+image = Image.new("L", (imgx, imgy))
+
x=0.0
y=0.0
for k in range(imgx * imgy):
@@ -65,4 +67,4 @@
jy = (imgy - 1) - int((y - ya) / (yb - ya) * (imgy - 1))
image.putpixel((jx, jy), 255)

-image.save("IFS.png", "PNG")
+image.save("IFS_.png", "PNG")
```