--- fract/mandelzoom.cgi 2001/02/25 22:54:25 1.5 +++ fract/mandelzoom.cgi 2001/06/26 12:43:34 1.10 @@ -1,8 +1,15 @@ #!/usr/bin/python -import cgi, Image, ImageDraw, sys, math +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 @@ -28,13 +35,15 @@ if form.has_key('cx'): cx= atof(form['cx'].value) else: - cx= 0 + cx= 0.0 if form.has_key('cy'): cy= atof(form['cy'].value) else: - cy= 0 + 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: @@ -53,10 +62,10 @@ -Mandel Set Zoomer +Mandelbrot Set Zoomer -

Mandel Set Zoomer

+

Mandelbrot Set Zoomer

@@ -68,12 +77,24 @@ ds="&debug=on" else: ds="" + # If the user has selected a specific point on the image + if form.has_key('image.x') and form.has_key('image.y'): + # Adjust cx and cy + ix= atof(form['image.x'].value) # Intermediate value + iy= atof(form['image.y'].value) # Intermediate value + owidth= atof(form['owidth'].value) + oheight= atof(form['oheight'].value) + diagp= math.sqrt(owidth**2 + oheight**2) # Intermediate value + scale= diagp/diag # Intermediate value + cx= (ix/scale) + (cx - (owidth / (scale*2))) + cy= ((oheight-iy)/scale) + (cy - (oheight / (scale*2))) if form.has_key('zoom'): zoom=atof(form['zoom'].value) diag=diag/zoom else: - # If no zoom provided, don't actually zoom - zoom= 2 + # If no zoom provided, don't actually zoom, but keep the + # default of ×2 zoom. + zoom= 2.0 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 'ALIGN=BOTTOM HEIGHT="%s"' % (str(height)), print 'WIDTH="%s">

' % (str(width)) @@ -86,10 +107,7 @@ if zv == 1: print '>Pan' elif zv < 1: - if int(1/zv) == 1/zv: - print '>Out ÷%s' % (str(int(1/zv))) - else: - print '>Out ÷%s' % (str(1/zv)) + print '>Out ÷%s' % (str(1/zv)) else: print '>In ×%s' % (str(zv)) print '' @@ -105,35 +123,43 @@ else: print '>' print '' - for var in (("diag", diag), ("cx", cx), ("cy", cy)): + for var in (("diag", diag), ("cx", cx), ("cy", cy), ("owidth", width), + ("oheight", height)): print '' % var print '' - 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 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 -c1= cx - x + cy - y * (0+1j) -c2= cx + x + cy + y * (0+1j) +# 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) -#c1, c2 = (-2+2j), (2-2j) # Corner coordinates - # 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)): @@ -195,6 +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) @@ -239,7 +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