/[cvs]/fract/mandelzoom.cgi
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Revision 1.2 - (hide annotations)
Sun Feb 25 05:49:07 2001 UTC (23 years, 2 months ago) by teddy
Branch: MAIN
Changes since 1.1: +67 -19 lines
More code.  `cx' and `cy' doesn't work yet, but that should be about
it before writing the code to figure out `c1' and `c2' from `diag',
`cx' and `cy'.

1 teddy 1.1 #!/usr/bin/python
2    
3 teddy 1.2 import cgi, Image, ImageDraw, sys, math
4     from string import atoi, atof
5    
6     sys.stderr = sys.stdout
7 teddy 1.1
8     form= cgi.FieldStorage()
9    
10     # Image size
11     if form.has_key('width'):
12 teddy 1.2 width= atoi(form['width'].value)
13 teddy 1.1 else:
14     width= 570
15     if form.has_key('height'):
16 teddy 1.2 height= atoi(form['height'].value)
17 teddy 1.1 else:
18     height= 570
19    
20     xmax, ymax = width-1, height-1 # Coordinate maximums
21    
22 teddy 1.2 # Complex number in center of image is (cx+cy*j)
23     if form.has_key('cx'):
24     cx= atof(form['cx'].value)
25     else:
26     cx= 0
27    
28     if form.has_key('cy'):
29     cy= atof(form['cy'].value)
30     else:
31     cy= 0
32    
33     if form.has_key('diag'):
34     diag= atof(form['diag'].value)
35     else:
36     diag= math.sqrt(8)
37    
38 teddy 1.1 debug= form.has_key('debug')
39    
40     if form.has_key('iter'):
41 teddy 1.2 maxiter= atoi(form['iter'].value)
42 teddy 1.1 else:
43     maxiter= 270
44    
45 teddy 1.2 #print "Content-Type: text/plain"
46     #print ""
47 teddy 1.1
48 teddy 1.2 # If type!=image, then output an HTML page, not an image
49     if not (form.has_key('type') and form['type'].value == "image"):
50 teddy 1.1 print """Content-Type: text/html
51    
52     <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
53     <HTML><HEAD>
54     <TITLE>Mandel Set Zoomer</TITLE>
55     </HEAD>
56     <BODY>
57     <H1>Mandel Set Zoomer</H1>
58    
59     <FORM ACTION="mandelzoom.cgi" METHOD=GET>
60    
61 teddy 1.2 <!-- implies TYPE=SUBMIT -->"""
62     print '<INPUT TYPE=IMAGE NAME="image"',
63     print 'WIDTH="%s"' % (str(width)),
64     print 'HEIGHT="%s"' % (str(height)),
65     if debug:
66     ds="&debug=on"
67     else:
68     ds=""
69     if form.has_key('zoom'):
70     zoom=atoi(form['zoom'].value)
71     diag=diag/zoom
72     else:
73     # If no zoom provided, don't actually zoom
74     zoom= 2
75     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)),
76     print 'ALIGN=BOTTOM HEIGHT="%s"' % (str(height)),
77     print 'WIDTH="%s"><P>' % (str(width))
78     print 'Zoom: <SELECT NAME="zoom">'
79     for zv in [-5, -3, -2, 1, 2, 3, 5]:
80     print '<OPTION',
81     if zv==zoom:
82     print 'SELECTED',
83     print 'VALUE="%s"' % (str(zv))
84     if zv < 0:
85     print '>÷%s' % (str(-zv))
86     else:
87     print '>×%s' % (str(zv))
88     print '</SELECT>'
89     print """Width: <INPUT TYPE=TEXT NAME="width" MAXLENGTH="4" SIZE="3"
90     VALUE="%s">
91     Height: <INPUT TYPE=TEXT NAME="height" MAXLENGTH="4" SIZE="3"
92     VALUE="%s">
93 teddy 1.1 Iterations: <INPUT TYPE=TEXT NAME="iter" MAXLENGTH="4" SIZE="3"
94     VALUE="%s">
95 teddy 1.2 Debug mode: <INPUT TYPE=CHECKBOX NAME="debug" """ % (str(width), str(height), str(maxiter))
96     if debug:
97     print 'CHECKED>'
98     else:
99     print '>'
100 teddy 1.1 for key in form.keys():
101 teddy 1.2 if key not in ["zoom", "type", "debug", "image.x", "image.y", "iter", "height", "width"]:
102     print '<INPUT TYPE=HIDDEN NAME="%s" VALUE="%s">' % (key, form[key].value)
103     print '<INPUT TYPE=HIDDEN NAME=type VALUE="html">'
104 teddy 1.1
105     print """</FORM>
106     </BODY></HTML>"""
107     sys.exit(0)
108    
109     c1, c2 = (-2+2j), (2-2j) # Corner coordinates
110    
111     # Force c1 to be upper left and c2 to be lower right
112     c1, c2= complex(min(c1.real, c2.real), max(c1.imag, c2.imag)), \
113     complex(max(c1.real, c2.real), min(c1.imag, c2.imag))
114    
115     mandel= Image.new("L", (width, height))
116     draw= ImageDraw.Draw(mandel)
117    
118     def drawrect((x1, y1), (x2, y2)):
119     "Draw a rectangle defined by the corners (x1, y1) and (x2, y2)."
120     color= plot(x1, y1) # Plot the upper left corner
121     # Should we cut this rectangle and recurse into the pieces?
122     cut= 0
123     ## Plot the edges and at the same time check if they are all the
124     ## same color.
125     # Upper edge (left to right)
126     x, y= x1+1, y1
127     while x<=x2:
128     if color<>plot(x, y):
129     cut= 1
130     x= x+1
131     # Right edge (top to bottom)
132     x, y= x2, y1+1
133     while y<=y2:
134     if color<>plot(x, y):
135     cut= 1
136     y= y+1
137     # Bottom edge (right to left)
138     x, y= x2-1, y2
139     while x>=x1:
140     if color<>plot(x, y):
141     cut= 1
142     x= x-1
143     # Left edge (bottom to top)
144     x, y= x1, y2-1
145     while y>y1:
146     if color<>plot(x, y):
147     cut= 1
148     y= y-1
149     # If our rectangle is too small to have an inside, we have now
150     # plotted every pixel in it.
151     if x2-x1<=1 or y2-y1<=1:
152     return
153     if cut: # If we're cutting the rectangle
154     if x2-x1 > y2-y1: # If it's wider than high
155     # Cut vertically
156     xc= ((x2-x1)/2)+x1
157     drawrect((x1, y1), (xc, y2))
158     drawrect((xc, y1), (x2, y2))
159     else: # if it's higher than wide
160     # Cut horizontally
161     yc= ((y2-y1)/2)+y1
162     drawrect((x1, y1), (x2, yc))
163     drawrect((x1, yc), (x2, y2))
164     else:
165     # If we're not cutting, it was the same color along the edge
166     if not debug:
167     # Fill in the rectangle
168     draw.rectangle([x1, y1, x2, y2], fill= color)
169     if yorig >= 0: # The x axis is visible on image
170     # Fill in the mirror rectangle
171     # Mirror y1 and y2 over yorig, but keep within image
172     y1m= max(0, min(2*yorig-y1, ymax))
173     y2m= max(0, min(2*yorig-y2, ymax))
174     draw.rectangle([x1, y1m, x2, y2m], fill= color)
175    
176     def constant(x, y):
177     creal= (float(x)/xmax)*(c2.real - c1.real)+c1.real
178     cimag= (float(y)/ymax)*(c2.imag - c1.imag)+c1.imag
179     return complex(creal, cimag)
180    
181     def plot(x, y):
182     c= constant(x, y)
183     z= i= 0
184     color= mandel.getpixel((x, y))
185     if color<>0:
186     return color
187     while i<maxiter and abs(z)<2:
188     z= z**2+c
189     i= i+1
190     color= 16*i%256
191     if i>=maxiter or color==0:
192     if debug:
193     color= 255
194     else:
195     color= 1
196     try:
197     mandel.putpixel((x, y), color)
198     if yorig >= 0: # The x axis is visible on image
199     ym= 2*yorig-y # ym is y mirrored over yorig
200     if ym >= 0 and ym <= ymax:
201     # ym is on the image
202     mandel.putpixel((x, ym), color)
203     except IndexError, the_error:
204     print "coord", x, y, xm, ym
205     raise IndexError, the_error
206     return color
207    
208     # Initial default values
209     yfrom= 0
210     yto= ymax
211     yorig= -1 # The pixel coordinate of the x axis; negative means not on image
212    
213     # Check if we should do mirroring
214     if c1.imag > 0 and c2.imag < 0: # the x axis is visible
215     yorig= int((-c1.imag/(c2.imag-c1.imag))*height) # pixel pos. of x axis
216     if c1.imag < abs(c2.imag): # the x axis is closer to top than bottom
217     yfrom= yorig # Begin at x axis
218     else:
219     yto= yorig # End at x axis
220    
221     drawrect((0, yfrom), (xmax, yto))
222    
223     print "Content-type: image/png"
224     print
225     mandel.save(sys.stdout, "PNG")

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