--- fract/mandelzoom.cgi 2001/02/24 21:36:47 1.1
+++ fract/mandelzoom.cgi 2001/06/26 12:43:34 1.10
@@ -1,70 +1,165 @@
#!/usr/bin/python
-import cgi, Image, ImageDraw, sys
-from string import atoi
+import cgi, Image, ImageDraw, sys, math, signal, errno, os
+from string import atoi, atof
+
+def handler(signum, frame):
+ signal.alarm(0)
+ raise os.error, (errno.ETIME, "Timer expired")
+
+signal.alarm(55)
+signal.signal(signal.SIGALRM, handler)
+
+# This is to get backtrace output
+sys.stderr = sys.stdout
+
+# Uncomment this to get the backtrace more readable
+#print "Content-Type: text/plain"
+#print ""
form= cgi.FieldStorage()
# Image size
if form.has_key('width'):
- width=atoi(form['width'].value)
+ width= atoi(form['width'].value)
else:
- width= 570
+ width= 480
if form.has_key('height'):
- height=atoi(form['height'].value)
+ height= atoi(form['height'].value)
else:
- height= 570
+ height= 480
xmax, ymax = width-1, height-1 # Coordinate maximums
+# Complex number in center of image is (cx+cy*j)
+if form.has_key('cx'):
+ cx= atof(form['cx'].value)
+else:
+ cx= 0.0
+
+if form.has_key('cy'):
+ cy= atof(form['cy'].value)
+else:
+ cy= 0.0
+
+# The length of the diagonal line from corner to corner.
+# Used as a measure of image size independent of aspect ratio.
+if form.has_key('diag'):
+ diag= atof(form['diag'].value)
+else:
+ diag= math.sqrt(32) # sqrt(4**2 + 4**2)
+
debug= form.has_key('debug')
-if debug:
- del form['debug']
if form.has_key('iter'):
- maxiter=atoi(form['iter'].value)
- del form['iter']
+ maxiter= atoi(form['iter'].value)
else:
maxiter= 270
-sys.stderr = sys.stdout
-print "Content-Type: text/plain"
-print ""
-
-# If type==html, then output an HTML page, not an image
-if form.has_key('type') and form['type'].value == "html":
- del form['type']
+# If type!=image, then output an HTML page, not an image
+if not (form.has_key('type') and form['type'].value == "image"):
print """Content-Type: text/html
-Mandel Set Zoomer
+Mandelbrot Set Zoomer
-Mandel Set Zoomer
+Mandelbrot Set Zoomer
+ Debug mode: '
+ else:
+ print '>'
+ print ''
+ for var in (("diag", diag), ("cx", cx), ("cy", cy), ("owidth", width),
+ ("oheight", height)):
+ print '' % var
+ print ''
+
+ print """
+After changing any settings, don't forget to change the "Zoom" setting
+to "Pan" if you don't want to zoom when applying them.
"""
+ # Just exit, don't calculate an image.
sys.exit(0)
-c1, c2 = (-2+2j), (2-2j) # Corner coordinates
+# c1 and c2 are the coordinates of two opposite corners.
+# Figure out c1 and c2 from width, height, diag, cx, and cy.
+
+# Diagonal in pixels
+diagp= math.sqrt(width**2 + height**2)
+# Scale between pixels and coordinates
+scale= diagp/diag
+# half the width/height in real numbers; intermediate values
+x= (width/2.0)/scale
+y= (height/2.0)/scale
+
+# The coordinates of two opposite corners
+c1= cx - x + (cy - y) * (0+1j)
+c2= cx + x + (cy + y) * (0+1j)
+
+#print width, height, diag, cx, cy, diagp, scale, x, y, c1, c2
+#sys.exit(0)
# Force c1 to be upper left and c2 to be lower right
c1, c2= complex(min(c1.real, c2.real), max(c1.imag, c2.imag)), \
complex(max(c1.real, c2.real), min(c1.imag, c2.imag))
+# New image object
mandel= Image.new("L", (width, height))
+# shortcut to the "Draw" method on the image object
draw= ImageDraw.Draw(mandel)
def drawrect((x1, y1), (x2, y2)):
@@ -126,6 +221,7 @@
draw.rectangle([x1, y1m, x2, y2m], fill= color)
def constant(x, y):
+ "Return complex number from pixel coordinates x and y."
creal= (float(x)/xmax)*(c2.real - c1.real)+c1.real
cimag= (float(y)/ymax)*(c2.imag - c1.imag)+c1.imag
return complex(creal, cimag)
@@ -170,7 +266,13 @@
else:
yto= yorig # End at x axis
-drawrect((0, yfrom), (xmax, yto))
+try:
+ drawrect((0, yfrom), (xmax, yto))
+except os.error, the_error:
+ if the_error[0] != errno.ETIME:
+ raise os.error, the_error
+
+signal.alarm(0)
print "Content-type: image/png"
print