/[cvs]/fract/mandelzoom.cgi
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revision 1.2 by teddy, Sun Feb 25 05:49:07 2001 UTC revision 1.10 by teddy, Tue Jun 26 12:43:34 2001 UTC
# Line 1  Line 1 
1  #!/usr/bin/python  #!/usr/bin/python
2    
3  import cgi, Image, ImageDraw, sys, math  import cgi, Image, ImageDraw, sys, math, signal, errno, os
4  from string import atoi, atof  from string import atoi, atof
5    
6    def handler(signum, frame):
7        signal.alarm(0)
8        raise os.error, (errno.ETIME, "Timer expired")
9    
10    signal.alarm(55)
11    signal.signal(signal.SIGALRM, handler)
12    
13    # This is to get backtrace output
14  sys.stderr = sys.stdout  sys.stderr = sys.stdout
15    
16    # Uncomment this to get the backtrace more readable
17    #print "Content-Type: text/plain"
18    #print ""
19    
20  form= cgi.FieldStorage()  form= cgi.FieldStorage()
21    
22  # Image size  # Image size
23  if form.has_key('width'):  if form.has_key('width'):
24      width= atoi(form['width'].value)      width= atoi(form['width'].value)
25  else:  else:
26      width= 570      width= 480
27  if form.has_key('height'):  if form.has_key('height'):
28      height= atoi(form['height'].value)      height= atoi(form['height'].value)
29  else:  else:
30      height= 570      height= 480
31    
32  xmax, ymax = width-1, height-1          # Coordinate maximums  xmax, ymax = width-1, height-1          # Coordinate maximums
33    
# Line 23  xmax, ymax = width-1, height-1 Line 35  xmax, ymax = width-1, height-1
35  if form.has_key('cx'):  if form.has_key('cx'):
36      cx= atof(form['cx'].value)      cx= atof(form['cx'].value)
37  else:  else:
38      cx= 0      cx= 0.0
39    
40  if form.has_key('cy'):  if form.has_key('cy'):
41      cy= atof(form['cy'].value)      cy= atof(form['cy'].value)
42  else:  else:
43      cy= 0      cy= 0.0
44    
45    # The length of the diagonal line from corner to corner.
46    # Used as a measure of image size independent of aspect ratio.
47  if form.has_key('diag'):  if form.has_key('diag'):
48      diag= atof(form['diag'].value)      diag= atof(form['diag'].value)
49  else:  else:
50      diag= math.sqrt(8)      diag= math.sqrt(32) # sqrt(4**2 + 4**2)
51    
52  debug= form.has_key('debug')  debug= form.has_key('debug')
53    
# Line 42  if form.has_key('iter'): Line 56  if form.has_key('iter'):
56  else:  else:
57      maxiter= 270      maxiter= 270
58    
 #print "Content-Type: text/plain"  
 #print ""  
   
59  # If type!=image, then output an HTML page, not an image  # If type!=image, then output an HTML page, not an image
60  if not (form.has_key('type') and form['type'].value == "image"):  if not (form.has_key('type') and form['type'].value == "image"):
61      print """Content-Type: text/html      print """Content-Type: text/html
62    
63  <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">  <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
64  <HTML><HEAD>  <HTML><HEAD>
65  <TITLE>Mandel Set Zoomer</TITLE>  <TITLE>Mandelbrot Set Zoomer</TITLE>
66  </HEAD>  </HEAD>
67  <BODY>  <BODY>
68  <H1>Mandel Set Zoomer</H1>  <H1>Mandelbrot Set Zoomer</H1>
69    
70  <FORM ACTION="mandelzoom.cgi" METHOD=GET>  <FORM ACTION="mandelzoom.cgi" METHOD=GET>
71    
# Line 66  if not (form.has_key('type') and form['t Line 77  if not (form.has_key('type') and form['t
77          ds="&debug=on"          ds="&debug=on"
78      else:      else:
79          ds=""          ds=""
80        # If the user has selected a specific point on the image
81        if form.has_key('image.x') and form.has_key('image.y'):
82            # Adjust cx and cy
83            ix= atof(form['image.x'].value) # Intermediate value
84            iy= atof(form['image.y'].value) # Intermediate value
85            owidth= atof(form['owidth'].value)
86            oheight= atof(form['oheight'].value)
87            diagp= math.sqrt(owidth**2 + oheight**2) # Intermediate value
88            scale= diagp/diag               # Intermediate value
89            cx= (ix/scale) + (cx - (owidth / (scale*2)))
90            cy= ((oheight-iy)/scale) + (cy - (oheight / (scale*2)))
91      if form.has_key('zoom'):      if form.has_key('zoom'):
92          zoom=atoi(form['zoom'].value)          zoom=atof(form['zoom'].value)
93          diag=diag/zoom          diag=diag/zoom
94      else:      else:
95          # If no zoom provided, don't actually zoom          # If no zoom provided, don't actually zoom, but keep the
96          zoom= 2          # default of ×2 zoom.
97            zoom= 2.0
98      print 'SRC="mandelzoom.cgi?type=image&width=%s&height=%s&iter=%s%s&diag=%s&cx=%s&cy=%s"' % (str(width), str(height), str(maxiter), ds, str(diag), str(cx), str(cy)),      print 'SRC="mandelzoom.cgi?type=image&width=%s&height=%s&iter=%s%s&diag=%s&cx=%s&cy=%s"' % (str(width), str(height), str(maxiter), ds, str(diag), str(cx), str(cy)),
99      print 'ALIGN=BOTTOM HEIGHT="%s"' % (str(height)),      print 'ALIGN=BOTTOM HEIGHT="%s"' % (str(height)),
100      print 'WIDTH="%s"><P>' % (str(width))      print 'WIDTH="%s"><P>' % (str(width))
101      print 'Zoom: <SELECT NAME="zoom">'      print 'Zoom: <SELECT NAME="zoom">'
102      for zv in [-5, -3, -2, 1, 2, 3, 5]:      for zv in [1.0/5, 1.0/3, 1.0/2, 1.0/1.5, 1.0, 1.5, 2.0, 3.0, 5.0]:
103          print '<OPTION',          print '<OPTION',
104          if zv==zoom:          if str(zv)==str(zoom):
105              print 'SELECTED',              print 'SELECTED',
106          print 'VALUE="%s"' % (str(zv))          print 'VALUE="%s"' % (str(zv))
107          if zv < 0:          if zv == 1:
108              print '>÷%s' % (str(-zv))              print '>Pan'
109            elif zv < 1:
110                print '>Out ÷%s' % (str(1/zv))
111          else:          else:
112              print '>×%s' % (str(zv))              print '>In ×%s' % (str(zv))
113      print '</SELECT>'      print '</SELECT>'
114      print """Width: <INPUT TYPE=TEXT NAME="width" MAXLENGTH="4" SIZE="3"      print """Width: <INPUT TYPE=TEXT NAME="width" MAXLENGTH="4" SIZE="3"
115      VALUE="%s">      VALUE="%s">
# Line 92  if not (form.has_key('type') and form['t Line 117  if not (form.has_key('type') and form['t
117      VALUE="%s">      VALUE="%s">
118      Iterations: <INPUT TYPE=TEXT NAME="iter" MAXLENGTH="4" SIZE="3"      Iterations: <INPUT TYPE=TEXT NAME="iter" MAXLENGTH="4" SIZE="3"
119      VALUE="%s">      VALUE="%s">
120      Debug mode: <INPUT TYPE=CHECKBOX NAME="debug" """ % (str(width), str(height), str(maxiter))      Debug mode: <INPUT TYPE=CHECKBOX NAME="debug" """ % (str(width), str(height), str(maxiter)),
121      if debug:      if debug:
122          print 'CHECKED>'          print 'CHECKED>'
123      else:      else:
124          print '>'          print '>'
125      for key in form.keys():      print '<INPUT TYPE=SUBMIT VALUE="Apply">'
126          if key not in ["zoom", "type", "debug", "image.x", "image.y", "iter", "height", "width"]:      for var in (("diag", diag), ("cx", cx), ("cy", cy), ("owidth", width),
127              print '<INPUT TYPE=HIDDEN NAME="%s" VALUE="%s">' % (key, form[key].value)                  ("oheight", height)):
128            print '<INPUT TYPE=HIDDEN NAME="%s" VALUE="%s">' % var
129      print '<INPUT TYPE=HIDDEN NAME=type VALUE="html">'      print '<INPUT TYPE=HIDDEN NAME=type VALUE="html">'
130    
131      print """</FORM>      print """</FORM><P>
132    After changing any settings, don't forget to change the "Zoom" setting
133    to "Pan" if you don't want to zoom when applying them.
134  </BODY></HTML>"""  </BODY></HTML>"""
135        # Just exit, don't calculate an image.
136      sys.exit(0)      sys.exit(0)
137    
138  c1, c2 = (-2+2j), (2-2j)                # Corner coordinates  # c1 and c2 are the coordinates of two opposite corners.
139    # Figure out c1 and c2 from width, height, diag, cx, and cy.
140    
141    # Diagonal in pixels
142    diagp= math.sqrt(width**2 + height**2)
143    # Scale between pixels and coordinates
144    scale= diagp/diag
145    # half the width/height in real numbers; intermediate values
146    x= (width/2.0)/scale
147    y= (height/2.0)/scale
148    
149    # The coordinates of two opposite corners
150    c1= cx - x + (cy - y) * (0+1j)
151    c2= cx + x + (cy + y) * (0+1j)
152    
153    #print width, height, diag, cx, cy, diagp, scale, x, y, c1, c2
154    #sys.exit(0)
155    
156  # Force c1 to be upper left and c2 to be lower right  # Force c1 to be upper left and c2 to be lower right
157  c1, c2= complex(min(c1.real, c2.real), max(c1.imag, c2.imag)), \  c1, c2= complex(min(c1.real, c2.real), max(c1.imag, c2.imag)), \
158          complex(max(c1.real, c2.real), min(c1.imag, c2.imag))          complex(max(c1.real, c2.real), min(c1.imag, c2.imag))
159    
160    # New image object
161  mandel= Image.new("L", (width, height))  mandel= Image.new("L", (width, height))
162    # shortcut to the "Draw" method on the image object
163  draw= ImageDraw.Draw(mandel)  draw= ImageDraw.Draw(mandel)
164    
165  def drawrect((x1, y1), (x2, y2)):  def drawrect((x1, y1), (x2, y2)):
# Line 174  def drawrect((x1, y1), (x2, y2)): Line 221  def drawrect((x1, y1), (x2, y2)):
221                  draw.rectangle([x1, y1m, x2, y2m], fill= color)                  draw.rectangle([x1, y1m, x2, y2m], fill= color)
222    
223  def constant(x, y):  def constant(x, y):
224        "Return complex number from pixel coordinates x and y."
225      creal= (float(x)/xmax)*(c2.real - c1.real)+c1.real      creal= (float(x)/xmax)*(c2.real - c1.real)+c1.real
226      cimag= (float(y)/ymax)*(c2.imag - c1.imag)+c1.imag      cimag= (float(y)/ymax)*(c2.imag - c1.imag)+c1.imag
227      return complex(creal, cimag)      return complex(creal, cimag)
# Line 218  if c1.imag > 0 and c2.imag < 0: # the x Line 266  if c1.imag > 0 and c2.imag < 0: # the x
266      else:      else:
267          yto= yorig # End at x axis          yto= yorig # End at x axis
268    
269  drawrect((0, yfrom), (xmax, yto))  try:
270        drawrect((0, yfrom), (xmax, yto))
271    except os.error, the_error:
272        if the_error[0] != errno.ETIME:
273            raise os.error, the_error
274    
275    signal.alarm(0)
276    
277  print "Content-type: image/png"  print "Content-type: image/png"
278  print  print
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