src/reportlab/graphics/charts/utils.py
 author rgbecker Thu, 27 May 2010 15:51:47 +0000 changeset 3385 e45ca0b2053c parent 3326 ce725978d11c child 3387 52dc490767e9 permissions -rw-r--r--
graphics: start on run time callback support

#history http://www.reportlab.co.uk/cgi-bin/viewcvs.cgi/public/reportlab/trunk/reportlab/graphics/charts/utils.py

__version__=''' \$Id\$ '''
__doc__="Utilities used here and there."
from time import mktime, gmtime, strftime

### Dinu's stuff used in some line plots (likely to vansih).

def mkTimeTuple(timeString):
"Convert a 'dd/mm/yyyy' formatted string to a tuple for use in the time module."

list = [0] * 9
dd, mm, yyyy = map(int, timeString.split('/'))
list[:3] = [yyyy, mm, dd]

return tuple(list)

def str2seconds(timeString):
"Convert a number of seconds since the epoch into a date string."

return mktime(mkTimeTuple(timeString))

def seconds2str(seconds):
"Convert a date string into the number of seconds since the epoch."

return strftime('%Y-%m-%d', gmtime(seconds))

### Aaron's rounding function for making nice values on axes.

from math import log10

def nextRoundNumber(x):
"""Return the first 'nice round number' greater than or equal to x

Used in selecting apropriate tick mark intervals; we say we want
an interval which places ticks at least 10 points apart, work out
what that is in chart space, and ask for the nextRoundNumber().
Tries the series 1,2,5,10,20,50,100.., going up or down as needed.
"""

#guess to nearest order of magnitude
if x in (0, 1):
return x

if x < 0:
return -1.0 * nextRoundNumber(-x)
else:
lg = int(log10(x))

if lg == 0:
if x < 1:
base = 0.1
else:
base = 1.0
elif lg < 0:
base = 10.0 ** (lg - 1)
else:
base = 10.0 ** lg    # e.g. base(153) = 100
# base will always be lower than x

if base >= x:
return base * 1.0
elif (base * 2) >= x:
return base * 2.0
elif (base * 5) >= x:
return base * 5.0
else:
return base * 10.0

### Robin's stuff from rgb_ticks.

from math import log10, floor

_intervals=(.1, .2, .25, .5)
_j_max=len(_intervals)-1

def find_interval(lo,hi,I=5):
'determine tick parameters for range [lo, hi] using I intervals'

if lo >= hi:
if lo==hi:
if lo==0:
lo = -.1
hi =  .1
else:
lo = 0.9*lo
hi = 1.1*hi
else:
raise ValueError, "lo>hi"
x=(hi - lo)/float(I)
b= (x>0 and (x<1 or x>10)) and 10**floor(log10(x)) or 1
b = b
while 1:
a = x/b
if a<=_intervals[-1]: break
b = b*10

j = 0
while a>_intervals[j]: j = j + 1

while 1:
ss = _intervals[j]*b
n = lo/ss
l = int(n)-(n<0)
n = ss*l
x = ss*(l+I)
a = I*ss
if n>0:
if a>=hi:
n = 0.0
x = a
elif hi<0:
a = -a
if lo>a:
n = a
x = 0
if hi<=x and n<=lo: break
j = j + 1
if j>_j_max:
j = 0
b = b*10
return n, x, ss, lo - n + x - hi

def find_good_grid(lower,upper,n=(4,5,6,7,8,9), grid=None):
if grid:
t = divmod(lower,grid)[0] * grid
hi, z = divmod(upper,grid)
if z>1e-8: hi = hi+1
hi = hi*grid
else:
try:
n[0]
except TypeError:
n = xrange(max(1,n-2),max(n+3,2))

w = 1e308
for i in n:
z=find_interval(lower,upper,i)
if z[3]<w:
t, hi, grid = z[:3]
w=z[3]
return t, hi, grid

def ticks(lower, upper, n=(4,5,6,7,8,9), split=1, percent=0, grid=None):
'''
return tick positions and labels for range lower<=x<=upper
n=number of intervals to try (can be a list or sequence)
split=1 return ticks then labels else (tick,label) pairs
'''
t, hi, grid = find_good_grid(lower, upper, n, grid)
power = floor(log10(grid))
if power==0: power = 1
w = grid/10.**power
w = int(w)!=w

if power > 3 or power < -3:
format = '%+'+repr(w+7)+'.0e'
else:
if power >= 0:
digits = int(power)+w
format = '%' + repr(digits)+'.0f'
else:
digits = w-int(power)
format = '%'+repr(digits+2)+'.'+repr(digits)+'f'

if percent: format=format+'%%'
T = []
n = int(float(hi-t)/grid+0.1)+1
if split:
labels = []
for i in xrange(n):
v = t+grid*i
T.append(v)
labels.append(format % v)
return T, labels
else:
for i in xrange(n):
v = t+grid*i
T.append((v, format % v))
return T

def findNones(data):
m = len(data)
if None in data:
b = 0
while b<m and data[b] is None:
b += 1
if b==m: return data
l = m-1
while data[l] is None:
l -= 1
l+=1
if b or l: data = data[b:l]
I = [i for i in xrange(len(data)) if data[i] is None]
for i in I:
data[i] = 0.5*(data[i-1]+data[i+1])
return b, l, data
return 0,m,data

def pairFixNones(pairs):
Y = [x[1] for x in pairs]
b,l,nY = findNones(Y)
m = len(Y)
if b or l<m or nY!=Y:
if b or l<m: pairs = pairs[b:l]
pairs = [(x[0],y) for x,y in zip(pairs,nY)]
return pairs

def maverage(data,n=6):
data = (n-1)*[data[0]]+data
data = [float(sum(data[i-n:i]))/n for i in xrange(n,len(data)+1)]
return data

def pairMaverage(data,n=6):
return [(x[0],s) for x,s in zip(data, maverage([x[1] for x in data],n))]

import weakref
from reportlab.graphics.shapes import transformPoint, inverse
class DrawTimeCollector:
'''
generic mechanism for collecting information about nodes at the time they are about to be drawn
'''
def __init__(self):
self._nodes = weakref.WeakKeyDictionary()
self.clear()

def clear(self):
self._info = []
self._info_append = self._info.append

def record(self,func,node,*args,**kwds):
self._nodes[node] = (func,args,kwds)
node.__dict__['_drawTimeCallback'] = self

def __call__(self,node,canvas,renderer):
func = self._nodes.get(node,None)
if func:
func, args, kwds = func
i = func(node,canvas,renderer, *args, **kwds)
if i is not None: self._info_append(i)

@staticmethod
def rectDrawTimeCallback(node,canvas,renderer,**kwds):
A = getattr(canvas,'ctm',None)
if not A: return
x1 = node.x
y1 = node.y
x2 = x1 + node.width
y2 = y1 + node.height

iA = inverse(A)
x1,y1 = transformPoint(iA,(x1,y1))
x2,y2 = transformPoint(iA,(x2,y2))
D = kwds.copy()
D['rect']=(x1,y1,x2,y2)
return D