#!/usr/bin/env python
"""\
SVGgraph.py - Construct/display SVG scenes, with support for simple graphs.
The following code is a lightweight wrapper around SVG files. The metaphor
is to construct a scene, add objects to it, and then write it to a file
to display it.
This program uses ImageMagick to display the SVG files. ImageMagick also
does a remarkable job of converting SVG files into other formats.
"""
__author__ = "Perry Kundert (perry@kundert.ca)"
__copyright__ = "Copyright 2006, Perry Kundert"
__contributors__ = []
__version__ = "1.0.1 $Rev:$"
__license__ = "GPL"
__history__ = """
"""
import os
import sys
import cgi
import cgitb
import ImageColor
cgitb.enable()
display_prog = 'display' # Command to execute to display images.
class Scene:
def __init__(self,name="svg",height=400,width=400):
self.name = name
self.items = []
self.height = height
self.width = width
return
def add(self,item): self.items.append(item)
def strarray(self):
var = ["\n",
"\n"]
return var
def write_svg(self,filename=None):
if filename:
self.svgname = filename
else:
self.svgname = self.name + ".svg"
file = open(self.svgname,'w')
file.writelines(self.strarray())
file.close()
return
def display(self,prog=display_prog):
os.system("%s %s" % (prog,self.svgname))
return
class Line:
def __init__(self,start,end):
self.start = start #xy tuple
self.end = end #xy tuple
return
def strarray(self):
return [" \n" %\
(self.start[0],self.start[1],self.end[0],self.end[1])]
class Circle:
def __init__(self,center,radius,color,stroke=None):
self.center = center #xy tuple
self.radius = radius #xy tuple
self.color = color #rgb tuple in range(0,256) or None
self.stroke = stroke #rbg tuple in range(0,256) or None
return
def strarray(self):
try: strkcol = colorstr( self.stroke )
except: strkcol = "none"
try: fillcol = colorstr( self.color )
except: fillcol = "none"
return [ " \n" %\
( strkcol, fillcol ) ]
class Rectangle:
def __init__(self,origin,height,width,color,stroke=None):
self.origin = origin
self.height = height
self.width = width
self.color = color
self.stroke = stroke
return
def strarray(self):
try: strkcol = colorstr( self.stroke )
except: strkcol = "none"
try: fillcol = colorstr( self.color )
except: fillcol = "none"
return [" \n" %\
( self.width, strkcol, fillcol ) ]
class Text:
def __init__( self, origin, text, stroke=None, size="24pt" ):
self.origin = origin
self.text = text
self.stroke = stroke
self.size = size
return
def strarray(self):
try: strkcol = colorstr( self.stroke )
except: strkcol = "#000000"
return [" \n" %\
( self.origin[0], self.origin[1], self.size, strkcol ),
" %s\n" % self.text,
" \n"]
class Comment:
def __init__( self, text ):
self.text = text
def strarray( self ):
return [ "\n" % self.text ]
def colorstr( rgb ):
return "#%02x%02x%02x" % ( rgb[0], rgb[1], rgb[2] )
#
# Graph
#
# Add points. Will auto-scale both axes to the given graph size.
#
class Graph:
def __init__( self, origin, height, width, style = "smooth", line = 1 ):
self.origin = origin # upper left corner of graph (in screen coordinates)
self.height = height # total size of graph
self.width = width
self.style = style
self.line = line
self.xmin = (0,0)
self.xmax = (0,0)
self.ymin = (0,0)
self.ymax = (0,0)
self.extents = False
self.points = {} # dictionary keyed on label, of lists of coordinate 2-tuples
self.colors = {} # dictionary keyed on label, colors in hex form #RRGGBB
return
# Add data point(s), and (latest) axes min/max. Can handle either a list of 2-tuples, or a
# single 2-tuple.
def data( self, things, label = '', color = ( 0, 0, 0 )):
if not self.points.has_key( label ):
self.points[label] = []
self.colors[label] = color
list = []
if type( things ) != type( [] ):
list = [ things ]
else:
list = things
for point in list:
if self.extents:
if point[0] <= self.xmin[0]:
self.xmin = point
if point[0] >= self.xmax[0]:
self.xmax = point
if point[1] <= self.ymin[1]:
self.ymin = point
if point[1] >= self.ymax[1]:
self.ymax = point
else:
self.extents = True
self.xmin = point
self.xmax = point
self.ymin = point
self.ymax = point
self.points[label].append( point )
# Returns the calculated axis scales for the graph. These are used to transform the data points
# into screen coordinates relative to the graph's zero point
def scale( self ):
return ( float( self.width ) / ( 1, self.xmax[0] - self.xmin[0] )[self.xmax[0] != self.xmin[0]],
float( self.height ) / ( 1, self.ymax[1] - self.ymin[1] )[self.ymax[1] != self.ymin[1]] )
# Returns the calculated zero point (in screen coordinates), relative to the origin. After each
# data point is scaled, add this value to transform it into screen coordinates relative to the
# origin. Screen y axis is inverted, remember, compared to graph y axis.
def zero( self, scl ):
return ( -int( self.xmin[0] * scl[0] ),
-int( self.ymin[1] * scl[1] ))
# Compute the graph coordinates of a point, relative to (0,0) in the LL corner
def graph( self, pnt, scl, zro ):
return ( pnt[0] * scl[0] + zro[0],
pnt[1] * scl[1] + zro[1] )
# Compute the screen coordinates of a graph point
def screen( self, gra ):
return ( self.origin[0] + 0 + gra[0],
self.origin[1] + self.height - gra[1] )
# Transform a given datum into the scale of the graph, and offset by the graph's zero point.
# Remember, the SVG scene's origin is the upper left, the graph's origin is the lower left...
def transform( self, pnt, scl = None, zro = None ):
if not scl: scl = self.scale()
if not zro: zro = self.zero( scl )
return self.screen( self.graph( pnt, scl, zro ))
# Returns the transformed graph data points in the specified SVG form (line graph, by default)
def strarray( self ):
res = []
scl = self.scale()
zro = self.zero( scl )
segs = self.ymax[1] - self.ymin[1] + 1 # segment count and size, used for "discrete" only
seg = self.height / segs
for label in self.points.keys(): # key is label
if len( self.points[label] ) > 1:
if self.style != "random": # implies "smooth", too
self.points[label].sort() # nothing else necessary! tuples sort ok! ( cmp = lambda a, b: a[0] - b[0] )
lst = self.transform( self.points[label][0], scl, zro )
if self.style != "discrete":
# smooth, step or random
axi = " \n" % ( colorstr( self.colors[label] ), self.line )
res.append( axi )
else:
# discrete
res.append( " \n" % ( self.line ))
for raw in self.points[label]:
gra = self.graph( raw, scl, zro )
pct = gra[1] * 100 / self.height
bot = ( gra[0], gra[1] - self.line - seg * pct / 100 )
top = ( gra[0], bot[1] + self.line + seg )
bot = self.screen( bot )
top = self.screen( top )
res.append( " \n" \
% ( bot[0], bot[1], top[0], top[1], colorstr( self.colors[label] )))
res.append( " \n" )
return res
def test():
scene = Scene('test')
scene.add(Rectangle((100,100),200,200,(0,255,255)))
scene.add(Line((200,200),(200,300)))
scene.add(Line((200,200),(300,200)))
scene.add(Line((200,200),(100,200)))
scene.add(Line((200,200),(200,100)))
scene.add(Circle((200,200),30,(0,0,255)))
scene.add(Circle((200,300),30,(0,255,0)))
scene.add(Circle((300,200),30,(255,0,0)))
scene.add(Circle((100,200),30,(255,255,0)))
scene.add(Circle((200,100),30,(255,0,255)))
scene.add(Text((50,50),"Testing SVG"))
graph = Graph( (100,100), 100, 300 )
graph.data( (100,100) )
graph.data( (150,150) )
graph.data( (200,100) )
graph.data( (250,300) )
scene.add( graph )
scene.write_svg( "/tmp/test.svg" )
scene.display()
return
# Return the named query's value, or the default. If it is a list (query was supplied multiple
# times), return the last one.
def param( form, name, default ):
if form.has_key( name ):
if type( form[name] ) == type( [] ):
return form[name][-1].value
else:
return form[name].value
else:
return default
def content( type ):
print "Content-type: " + type
print "Status: 200 Ok"
print "ETag: " + str(hash(os.environ['QUERY_STRING'] + __version__))
print ""
def error( status = "Status: 400 Bad Request", errors = [] ):
print "Content-type: text/plain"
print status
print ""
print status
print ""
print "Specify one or more graph data sets, with optional color name:"
print " Label=#,#..."
print " Label=color:#,#..."
print " Label=color:# #,# #,..."
print ""
print "Options:"
print " height=# Graph height in pixels. Padded if max/min requested"
print " width=# Graph width in pixels. Padded if legend requested"
print " max=color Maxima dot, with value printed in same color (unless legend=none,... specified)"
print " min=color Minima dot, with value printed in same color (unless legend=none,... specified)"
print " legend=... none, bottom/top, min, max, all: Display selected legends."
print " style=... smooth (the default), step, discrete, random: Graph style."
print " format=... svg (the default), png, jpg, gif, ..."
print ""
if errors:
sys.stdout.writelines( errors )
sys.stdout.writelines( [ k + ": " + os.environ[k] + "\n" for k in os.environ.keys() ] )
sys.exit()
# If called directly, see if we are being invoked as CGI or not.
if __name__ == '__main__':
try:
if not os.environ['REQUEST_METHOD'] in ['GET', 'HEAD']:
error( "Status: 405 Method Not Allowed: %s" % os.environ['REQUEST_METHOD'] )
except:
# Not CGI (no 'REQUEST_METHOD' found). Do a test...
test()
sys.exit()
# It's CGI and an allowed request. Try to process, and return an error on exception
form = cgi.FieldStorage()
# Extract the known CGI query options (or assume defaults)
querys = [ 'style', 'height', 'width', 'line', 'min', 'max', 'legend', 'format' ]
styl = param( form, 'style', 'smooth' )
high = param( form, 'height', '18' )
wide = param( form, 'width', '100' )
line = param( form, 'line', '1' ) # line weight
minc = param( form, 'min', '' )
maxc = param( form, 'max', '' )
lgnd = param( form, 'legend', '' ) # No legend by default
fmat = param( form, 'format', 'svg' )
if styl not in [ 'smooth', 'step', 'discrete', 'random' ]:
error( "Status: 400 Bad Request: Unrecognized style option: %s" % styl )
lgndmn = minc and 1 or 0
lgndmx = maxc and 1 or 0
lgndlb = None
for l in lgnd.split(','):
if l == "none":
lgndmn = 0; lgndmx = 0; lgndlb = None
elif l == "all":
lgndmn = 1; lgndmx = 1; lgndlb = "bottom"
elif l == "bottom" or l == "top":
lgndlb = l
elif l == "min":
lgndmn = 1
elif l == "max":
lgndmx = 1
elif l != '':
error( "Status: 400 Bad Request: Unrecognized legend option: %s" % l )
# Count the maximal number of characters in the largest max/min value (if
# any); determines if extra padding required due to line size and max./minima dots.
lsiz = max( 1, int( line )) # Requested line size, minimum 1
lpad = 0
if minc or maxc:
lpad = max( 2, lsiz ) # Max./minima dots are 2 pixels radius, or line width (if selected)
graph = Graph( ( lpad, lpad ),
int( high ), int( wide ),
styl, lsiz )
# Get the data set(s). They may be tuples or values (deduce x axis). All the remaining
# query options are assumed to be the named (and optionally the colored) data sets, if they
# look like:
#
# name=[color:]#,#,...
# or: name=[color:]# #,# #,...
comment = ""
for key in [ k for k in form.keys() if k not in querys ]:
data = param( form, key, '' )
# Try to pick a color:#,#,... off the front of the data; default to "black". Convert color
# to an RBG 3-tuple (#,#,#)
label = key
color = "black"
try: color,data = data.split(':')
except: pass
strkcol = ImageColor.getrgb( color )
# If we fail while trying to parse the coordinates, or if we CAN parse it, and there are no
# values, it's an error.
list = []
try:
for item in data.split(','):
if item:
coord = item.split()
if len( coord ) == 2:
# A full coordinate pair! Use it. Mixing 1 and 2+ coords not suggested, after any have been deduced...
list.append( ( int( coord[0] ), int( coord[1] )))
elif len( coord ) == 1:
# Not a coordinate pair. Deduce X from last 0, 1 or 2+ coords.
if len( list ) == 0:
list.append( ( 0, int( coord[0] )))
elif len( list ) == 1:
list.append( ( list[-1][0] + 1, int( coord[0] )))
else:
list.append( ( list[-1][0] + ( list[-1][0] - list[-2][0] ), int( coord[0] )))
except:
error( "Status: 400 Bad Request: Unrecognized query: %s=%s" % ( key, param( form, key, '' )))
if not len( list ):
error( "Status: 400 Bad Request: Label %s had no data" % label )
comment += "\nLabel: %s\n color: %s\n data: %s\n coords: %s\n"\
% ( label, color, data, ', '.join( [ "%d %d" % ( x, y ) for x,y in list ] ))
graph.data( list, label, strkcol )
if not graph.colors.keys():
error( "Status: 400 Bad Request: No graph data set(s) supplied" )
# Create the scene. Legend across bottom (if multiple axes), maxima/minima stacked on right.
# Font size in pixels, is minimum of 1/5 100dpi (5 pitch on 100dpi) or 1/2 the height, and 1/6
# inter-line spacing.
flin = min( 100 / 5, ( int( high ) + 2 * lpad ) / 2 ) # Font line
fsiz = flin * 5 / 6 # Font size
fpad = flin - fsiz # Hence, the font inter-line pad
# Determine total padding around graph, based on max./minima legend and/or label legend display
mnum = 0 # Number of max./minima chars
if lgndmn: mnum = max( mnum, len( str( graph.ymin[1] )))
if lgndmx: mnum = max( mnum, len( str( graph.ymax[1] )))
hpad = 0
if mnum:
hpad += int( line ) + fsiz / 2 + mnum * fsiz * 2 / 3 # glyphs ~ 2/3 wide as high? 1/2 glyph spacing at start
vpad = 0
if lgndlb:
vpad += flin
# Graph is padded on all sides by 'lpad', if any max./minima selected
scene = Scene( 'graph',
int( high ) + 2 * lpad + vpad,
int( wide ) + 2 * lpad + hpad )
scene.add( Comment( comment ))
scene.add( graph )
# Draw graph min/max points if desired (one maxima/minima for ALL axes!)
if minc:
scene.add( Circle( graph.transform( graph.ymin ), lpad,
ImageColor.getrgb( minc )))
if lgndmn:
scene.add( Text( (int( wide ) + int( line ) + fsiz / 2, int( high ) - 0 ), str( graph.ymin[1] ),
ImageColor.getrgb( minc and minc or "black" ), str( fsiz ) + "px" ))
if maxc:
scene.add( Circle( graph.transform( graph.ymax ), lpad,
ImageColor.getrgb( maxc )))
if lgndmx:
scene.add( Text( (int( wide ) + int( line ) + fsiz / 2, int( high ) - flin ), str( graph.ymax[1] ),
ImageColor.getrgb( maxc and maxc or "black" ), str( fsiz ) + "px" ))
if lgndlb: # TODO: allow legend at "top"
x = 0
for label in graph.colors.keys():
scene.add( Text( ( x * int( wide )/len( graph.colors.keys()), int( high ) + flin ), label,
graph.colors[label], str( fsiz ) + "px" ))
x += 1
# All OK. Output the (native) SVG content, or 'convert' to some other format!
if fmat == "svg":
content( "image/svg+xml" )
sys.stdout.writelines( scene.strarray())
else:
# Some other graphics format. Convert to it. Assume they
# know what they are talking about.
to,fr,er = os.popen3( "convert svg:- " + fmat + ":-" )
to.writelines( scene.strarray() )
to.close()
pid,exi = os.wait()
if exi:
# Didn't work; non-zero exit code. Probably a bad image format.
errors = er.readlines() + fr.readlines()
error( "Status: 400 Bad Request: Error converting to format 'image/" + fmat, errors )
content( "image/" + fmat )
sys.stdout.write( fr.read() )
fr.close()
er.close()