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weewx/bin/weeplot/utilities.py
Tom Keffer 9bf85d18e3 Merge branch 'development' into V5
2023-04-03 18:54:56 -07:00

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#
# Copyright (c) 2009-2023 Tom Keffer <tkeffer@gmail.com>
#
# See the file LICENSE.txt for your full rights.
#
"""Various utilities used by the plot package."""
import datetime
import math
import time
from PIL import ImageFont, ImageColor
import weeplot
def scale(data_min, data_max, prescale=(None, None, None), nsteps=10):
"""Calculates an appropriate min, max, and step size for scaling axes on a plot.
The origin (zero) is guaranteed to be on an interval boundary.
Args:
data_min(float): The minimum data value
data_max(float): The maximum data value. Must be greater than or equal to data_min.
prescale(tuple): A 3-way tuple. A non-None min or max value (positions 0 and 1,
respectively) will be fixed to that value. A non-None interval (position 2)
be at least as big as that value. Default = (None, None, None)
nsteps(int): The nominal number of desired steps. Default = 10
Returns:
tuple: A three-way tuple. First value is the lowest scale value, second the highest.
The third value is the step (increment) between them.
Examples:
>>> print("(%.1f, %.1f, %.1f)" % scale(1.1, 12.3, (0, 14, 2)))
(0.0, 14.0, 2.0)
>>> print("(%.1f, %.1f, %.1f)" % scale(1.1, 12.3))
(0.0, 14.0, 2.0)
>>> print("(%.1f, %.1f, %.1f)" % scale(-1.1, 12.3))
(-2.0, 14.0, 2.0)
>>> print("(%.1f, %.1f, %.1f)" % scale(-12.1, -5.3))
(-13.0, -5.0, 1.0)
>>> print("(%.2f, %.2f, %.2f)" % scale(10.0, 10.0))
(10.00, 10.10, 0.01)
>>> print("(%.2f, %.4f, %.4f)" % scale(10.0, 10.001))
(10.00, 10.0010, 0.0001)
>>> print("(%.2f, %.2f, %.2f)" % scale(10.0, 10.0+1e-8))
(10.00, 10.10, 0.01)
>>> print("(%.2f, %.2f, %.2f)" % scale(0.0, 0.05, (None, None, .1), 10))
(0.00, 1.00, 0.10)
>>> print("(%.2f, %.2f, %.2f)" % scale(16.8, 21.5, (None, None, 2), 10))
(16.00, 36.00, 2.00)
>>> print("(%.2f, %.2f, %.2f)" % scale(16.8, 21.5, (None, None, 2), 4))
(16.00, 22.00, 2.00)
>>> print("(%.2f, %.2f, %.2f)" % scale(0.0, 0.21, (None, None, .02)))
(0.00, 0.22, 0.02)
>>> print("(%.2f, %.2f, %.2f)" % scale(100.0, 100.0, (None, 100, None)))
(99.00, 100.00, 0.20)
>>> print("(%.2f, %.2f, %.2f)" % scale(100.0, 100.0, (100, None, None)))
(100.00, 101.00, 0.20)
>>> print("(%.2f, %.2f, %.2f)" % scale(100.0, 100.0, (0, None, None)))
(0.00, 120.00, 20.00)
>>> print("(%.2f, %.2f, %.2f)" % scale(0.0, 0.2, (None, 100, None)))
(0.00, 100.00, 20.00)
"""
# If all the values are hard-wired in, then there's nothing to do:
if None not in prescale:
return prescale
# Unpack
minscale, maxscale, min_interval = prescale
# Make sure data_min and data_max are float values, in case a user passed
# in integers:
data_min = float(data_min)
data_max = float(data_max)
if data_max < data_min:
raise weeplot.ViolatedPrecondition("scale() called with max value less than min value")
# In case minscale and/or maxscale was specified, clip data_min and data_max to make sure they
# stay within bounds
if maxscale is not None:
data_max = min(data_max, maxscale)
if data_max < data_min:
data_min = data_max
if minscale is not None:
data_min = max(data_min, minscale)
if data_max < data_min:
data_max = data_min
# Check the special case where the min and max values are equal.
if _rel_approx_equal(data_min, data_max):
# They are equal. We need to move one or the other to create a range, while
# being careful that the resultant min/max stay within the interval [minscale, maxscale]
# Pick a step out value based on min_interval if the user has supplied one. Otherwise,
# arbitrarily pick 0.1
if min_interval is not None:
step_out = min_interval * nsteps
else:
step_out = 0.01 * round(abs(data_max), 2) if data_max else 0.1
if maxscale is not None:
# maxscale if fixed. Move data_min.
data_min = data_max - step_out
elif minscale is not None:
# minscale if fixed. Move data_max.
data_max = data_min + step_out
else:
# Both can float. Check special case where data_min and data_max are zero
if data_min == 0.0:
data_max = 1.0
else:
# Just arbitrarily move one. Say, data_max.
data_max = data_min + step_out
if minscale is not None and maxscale is not None:
if maxscale < minscale:
raise weeplot.ViolatedPrecondition("scale() called with prescale max less than min")
frange = maxscale - minscale
elif minscale is not None:
frange = data_max - minscale
elif maxscale is not None:
frange = maxscale - data_min
else:
frange = data_max - data_min
steps = frange / float(nsteps)
mag = math.floor(math.log10(steps))
magPow = math.pow(10.0, mag)
magMsd = math.floor(steps / magPow + 0.5)
if magMsd > 5.0:
magMsd = 10.0
elif magMsd > 2.0:
magMsd = 5.0
else: # magMsd > 1.0
magMsd = 2
# This will be the nominal interval size
interval = magMsd * magPow
# Test it against the desired minimum, if any
if min_interval is None or interval >= min_interval:
# Either no min interval was specified, or its safely
# less than the chosen interval.
if minscale is None:
minscale = interval * math.floor(data_min / interval)
if maxscale is None:
maxscale = interval * math.ceil(data_max / interval)
else:
# The request for a minimum interval has kicked in.
# Sometimes this can make for a plot with just one or
# two intervals in it. Adjust the min and max values
# to get a nice plot
interval = float(min_interval)
if minscale is None:
if maxscale is None:
# Both can float. Pick values so the range is near the bottom
# of the scale:
minscale = interval * math.floor(data_min / interval)
maxscale = minscale + interval * nsteps
else:
# Only minscale can float
minscale = maxscale - interval * nsteps
else:
if maxscale is None:
# Only maxscale can float
maxscale = minscale + interval * nsteps
else:
# Both are fixed --- nothing to be done
pass
return minscale, maxscale, interval
def scaletime(tmin_ts, tmax_ts):
"""Picks a time scaling suitable for a time plot.
Args:
tmin_ts(float): The minimum time that must be included.
tmax_ts(float): The maximum time that must be included
Returns:
tuple: A scaling 3-tuple. First element is the start time, second the stop
time, third the increment. All are in seconds (epoch time in the case of the
first two).
Example 1: 24 hours on an hour boundary
>>> from weeutil.weeutil import timestamp_to_string as to_string
>>> time_ts = time.mktime(time.strptime("2013-05-17 08:00", "%Y-%m-%d %H:%M"))
>>> xmin, xmax, xinc = scaletime(time_ts - 24*3600, time_ts)
>>> print(to_string(xmin), to_string(xmax), xinc)
2013-05-16 09:00:00 PDT (1368720000) 2013-05-17 09:00:00 PDT (1368806400) 10800
Example 2: 24 hours on a 3-hour boundary
>>> time_ts = time.mktime(time.strptime("2013-05-17 09:00", "%Y-%m-%d %H:%M"))
>>> xmin, xmax, xinc = scaletime(time_ts - 24*3600, time_ts)
>>> print(to_string(xmin), to_string(xmax), xinc)
2013-05-16 09:00:00 PDT (1368720000) 2013-05-17 09:00:00 PDT (1368806400) 10800
Example 3: 24 hours on a non-hour boundary
>>> time_ts = time.mktime(time.strptime("2013-05-17 09:01", "%Y-%m-%d %H:%M"))
>>> xmin, xmax, xinc = scaletime(time_ts - 24*3600, time_ts)
>>> print(to_string(xmin), to_string(xmax), xinc)
2013-05-16 12:00:00 PDT (1368730800) 2013-05-17 12:00:00 PDT (1368817200) 10800
Example 4: 27 hours
>>> time_ts = time.mktime(time.strptime("2013-05-17 07:45", "%Y-%m-%d %H:%M"))
>>> xmin, xmax, xinc = scaletime(time_ts - 27*3600, time_ts)
>>> print(to_string(xmin), to_string(xmax), xinc)
2013-05-16 06:00:00 PDT (1368709200) 2013-05-17 09:00:00 PDT (1368806400) 10800
Example 5: 3 hours on a 15 minute boundary
>>> time_ts = time.mktime(time.strptime("2013-05-17 07:45", "%Y-%m-%d %H:%M"))
>>> xmin, xmax, xinc = scaletime(time_ts - 3*3600, time_ts)
>>> print(to_string(xmin), to_string(xmax), xinc)
2013-05-17 05:00:00 PDT (1368792000) 2013-05-17 08:00:00 PDT (1368802800) 900
Example 6: 3 hours on a non-15 minute boundary
>>> time_ts = time.mktime(time.strptime("2013-05-17 07:46", "%Y-%m-%d %H:%M"))
>>> xmin, xmax, xinc = scaletime(time_ts - 3*3600, time_ts)
>>> print(to_string(xmin), to_string(xmax), xinc)
2013-05-17 05:00:00 PDT (1368792000) 2013-05-17 08:00:00 PDT (1368802800) 900
Example 7: 12 hours
>>> time_ts = time.mktime(time.strptime("2013-05-17 07:46", "%Y-%m-%d %H:%M"))
>>> xmin, xmax, xinc = scaletime(time_ts - 12*3600, time_ts)
>>> print(to_string(xmin), to_string(xmax), xinc)
2013-05-16 20:00:00 PDT (1368759600) 2013-05-17 08:00:00 PDT (1368802800) 3600
Example 8: 15 hours
>>> time_ts = time.mktime(time.strptime("2013-05-17 07:46", "%Y-%m-%d %H:%M"))
>>> xmin, xmax, xinc = scaletime(time_ts - 15*3600, time_ts)
>>> print(to_string(xmin), to_string(xmax), xinc)
2013-05-16 17:00:00 PDT (1368748800) 2013-05-17 08:00:00 PDT (1368802800) 7200
"""
if tmax_ts <= tmin_ts:
raise weeplot.ViolatedPrecondition("scaletime called with tmax <= tmin")
tdelta = tmax_ts - tmin_ts
tmin_dt = datetime.datetime.fromtimestamp(tmin_ts)
tmax_dt = datetime.datetime.fromtimestamp(tmax_ts)
if tdelta <= 16 * 3600:
if tdelta <= 3 * 3600:
# For time intervals less than 3 hours, use an increment of 15 minutes
interval = 900
elif tdelta <= 12 * 3600:
# For intervals from 3 hours up through 12 hours, use one hour
interval = 3600
else:
# For intervals from 12 through 16 hours, use two hours.
interval = 7200
# Get to the one hour boundary below tmax:
stop_dt = tmax_dt.replace(minute=0, second=0, microsecond=0)
# if tmax happens to be on a one hour boundary we're done. Otherwise, round
# up to the next one hour boundary:
if tmax_dt > stop_dt:
stop_dt += datetime.timedelta(hours=1)
n_hours = int((tdelta + 3599) / 3600)
start_dt = stop_dt - datetime.timedelta(hours=n_hours)
elif tdelta <= 27 * 3600:
# A day plot is wanted. A time increment of 3 hours is appropriate
interval = 3 * 3600
# h is the hour of tmax_dt
h = tmax_dt.timetuple()[3]
# Subtract off enough to get to the lower 3-hour boundary from tmax:
stop_dt = tmax_dt.replace(minute=0, second=0, microsecond=0) \
- datetime.timedelta(hours=h % 3)
# If tmax happens to lie on a 3 hour boundary we don't need to do anything. If not, we need
# to round up to the next 3 hour boundary:
if tmax_dt > stop_dt:
stop_dt += datetime.timedelta(hours=3)
# The stop time is one day earlier
start_dt = stop_dt - datetime.timedelta(days=1)
if tdelta == 27 * 3600:
# A "slightly more than a day plot" is wanted. Start 3 hours earlier:
start_dt -= datetime.timedelta(hours=3)
elif 27 * 3600 < tdelta <= 31 * 24 * 3600:
# The time scale is between a day and a month. A time increment of one day is appropriate
start_dt = tmin_dt.replace(hour=0, minute=0, second=0, microsecond=0)
stop_dt = tmax_dt.replace(hour=0, minute=0, second=0, microsecond=0)
tmax_tt = tmax_dt.timetuple()
if tmax_tt[3] != 0 or tmax_tt[4] != 0:
stop_dt += datetime.timedelta(days=1)
interval = 24 * 3600
elif tdelta <= 2 * 365.25 * 24 * 3600:
# The time scale is between a month and 2 years, inclusive. A time increment of a month
# is appropriate
start_dt = tmin_dt.replace(day=1, hour=0, minute=0, second=0, microsecond=0)
year, mon, day = tmax_dt.timetuple()[0:3]
if day != 1:
mon += 1
if mon == 13:
mon = 1
year += 1
stop_dt = datetime.datetime(year, mon, 1)
# Average month length:
interval = 365.25 / 12 * 24 * 3600
else:
# The time scale is over 2 years. A time increment of six months is appropriate
start_dt = tmin_dt.replace(day=1, hour=0, minute=0, second=0, microsecond=0)
year, mon, day = tmax_dt.timetuple()[0:3]
if day != 1 or mon != 1:
day = 1
mon = 1
year += 1
stop_dt = datetime.datetime(year, mon, 1)
# Average length of six months
interval = 365.25 * 24 * 3600 / 2.0
# Convert to epoch time stamps
start_ts = int(time.mktime(start_dt.timetuple()))
stop_ts = int(time.mktime(stop_dt.timetuple()))
return start_ts, stop_ts, interval
class ScaledDraw(object):
"""Like an ImageDraw object, but lines are scaled. """
def __init__(self, draw, imagebox, scaledbox):
"""Initialize a ScaledDraw object.
Example:
scaledraw = ScaledDraw(draw, ((10, 10), (118, 246)), ((0.0, 0.0), (10.0, 1.0)))
would create a scaled drawing where the upper-left image coordinate (10, 10) would
correspond to the scaled coordinate( 0.0, 1.0). The lower-right image coordinate
would correspond to the scaled coordinate (10.0, 0.0).
draw: an instance of ImageDraw
imagebox: a 2-tuple of the box coordinates on the image ((ulx, uly), (lrx, lry))
scaledbox: a 2-tuple of the box coordinates of the scaled plot ((llx, lly), (urx, ury))
"""
uli = imagebox[0]
lri = imagebox[1]
lls = scaledbox[0]
urs = scaledbox[1]
if urs[1] == lls[1]:
pass
self.xscale = float(lri[0] - uli[0]) / float(urs[0] - lls[0])
self.yscale = -float(lri[1] - uli[1]) / float(urs[1] - lls[1])
self.xoffset = int(lri[0] - urs[0] * self.xscale + 0.5)
self.yoffset = int(uli[1] - urs[1] * self.yscale + 0.5)
self.draw = draw
def line(self, x, y, line_type='solid', marker_type=None, marker_size=8, maxdx=None,
**options):
"""Draw a scaled line on the instance's ImageDraw object.
Args:
x(list[float]): sequence of x coordinates
y(list[float|None]): sequence of y coordinates, some of which are possibly null
(value of None)
line_type(str|None): 'solid' for line that connect the coordinates
None for no line
marker_type(str|None): None or 'none' for no marker.
'cross' for a cross
'circle' for a circle
'box' for a box
'x' for an X
marker_size(int): Size of the marker in pixels
maxdx(float): defines what constitutes a gap in samples. if two data points
are more than maxdx apart they are treated as separate segments.
For a scatter plot, set line_type to None and marker_type to something other than None.
"""
# Break the line up around any nulls or gaps between samples
for xy_seq in xy_seq_line(x, y, maxdx):
# Create a list with the scaled coordinates...
xy_seq_scaled = [(self.xtranslate(xc), self.ytranslate(yc)) for (xc, yc) in xy_seq]
if line_type == 'solid':
# Now pick the appropriate drawing function, depending on the length of the line:
if len(xy_seq) == 1:
self.draw.point(xy_seq_scaled, fill=options['fill'])
else:
self.draw.line(xy_seq_scaled, **options)
if marker_type and marker_type.lower().strip() not in ['none', '']:
self.marker(xy_seq_scaled, marker_type, marker_size=marker_size, **options)
def marker(self, xy_seq, marker_type, marker_size=10, **options):
half_size = marker_size / 2
marker = marker_type.lower()
for x, y in xy_seq:
if marker == 'cross':
self.draw.line([(x - half_size, y), (x + half_size, y)], **options)
self.draw.line([(x, y - half_size), (x, y + half_size)], **options)
elif marker == 'x':
self.draw.line([(x - half_size, y - half_size), (x + half_size, y + half_size)],
**options)
self.draw.line([(x - half_size, y + half_size), (x + half_size, y - half_size)],
**options)
elif marker == 'circle':
self.draw.ellipse([(x - half_size, y - half_size),
(x + half_size, y + half_size)], outline=options['fill'])
elif marker == 'box':
self.draw.line([(x - half_size, y - half_size),
(x + half_size, y - half_size),
(x + half_size, y + half_size),
(x - half_size, y + half_size),
(x - half_size, y - half_size)], **options)
def rectangle(self, box, **options):
"""Draw a scaled rectangle.
box: A pair of 2-way tuples for the lower-left, then upper-right corners of
the box [(llx, lly), (urx, ury)]
options: passed on to draw.rectangle. Usually contains 'fill' (the color)
"""
# Unpack the box
(llsx, llsy), (ursx, ursy) = box
ulix = int(llsx * self.xscale + self.xoffset + 0.5)
uliy = int(ursy * self.yscale + self.yoffset + 0.5)
lrix = int(ursx * self.xscale + self.xoffset + 0.5)
lriy = int(llsy * self.yscale + self.yoffset + 0.5)
box_scaled = ((ulix, uliy), (lrix, lriy))
self.draw.rectangle(box_scaled, **options)
def vector(self, x, vec, vector_rotate, **options):
if vec is None:
return
xstart_scaled = self.xtranslate(x)
ystart_scaled = self.ytranslate(0)
vecinc_scaled = vec * self.yscale
if vector_rotate:
vecinc_scaled *= complex(math.cos(math.radians(vector_rotate)),
math.sin(math.radians(vector_rotate)))
# Subtract off the x increment because the x-axis
# *increases* to the right, unlike y, which increases
# downwards
xend_scaled = xstart_scaled - vecinc_scaled.real
yend_scaled = ystart_scaled + vecinc_scaled.imag
self.draw.line(((xstart_scaled, ystart_scaled), (xend_scaled, yend_scaled)), **options)
def xtranslate(self, x):
return int(x * self.xscale + self.xoffset + 0.5)
def ytranslate(self, y):
return int(y * self.yscale + self.yoffset + 0.5)
def xy_seq_line(x, y, maxdx=None):
"""Generator function that breaks a line up into individual segments around
any nulls held in y or any gaps in x greater than maxdx.
x: iterable sequence of x coordinates. All values must be non-null
y: iterable sequence of y coordinates, possibly with some embedded
nulls (that is, their value==None)
yields: Lists of (x,y) coordinates
Example 1
>>> x=[ 1, 2, 3]
>>> y=[10, 20, 30]
>>> for xy_seq in xy_seq_line(x,y):
... print(xy_seq)
[(1, 10), (2, 20), (3, 30)]
Example 2
>>> x=[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> y=[0, 10, None, 30, None, None, 60, 70, 80, None]
>>> for xy_seq in xy_seq_line(x,y):
... print(xy_seq)
[(0, 0), (1, 10)]
[(3, 30)]
[(6, 60), (7, 70), (8, 80)]
Example 3
>>> x=[ 0 ]
>>> y=[None]
>>> for xy_seq in xy_seq_line(x,y):
... print(xy_seq)
Example 4
>>> x=[ 0, 1, 2]
>>> y=[None, None, None]
>>> for xy_seq in xy_seq_line(x,y):
... print(xy_seq)
Example 5 (using gap)
>>> x=[0, 1, 2, 3, 5.1, 6, 7, 8, 9]
>>> y=[0, 10, 20, 30, 50, 60, 70, 80, 90]
>>> for xy_seq in xy_seq_line(x,y,2):
... print(xy_seq)
[(0, 0), (1, 10), (2, 20), (3, 30)]
[(5.1, 50), (6, 60), (7, 70), (8, 80), (9, 90)]
"""
line = []
last_x = None
for xy in zip(x, y):
dx = xy[0] - last_x if last_x is not None else 0
last_x = xy[0]
# If the y coordinate is None or dx > maxdx, that marks a break
if xy[1] is None or (maxdx is not None and dx > maxdx):
# If the length of the line is non-zero, yield it
if len(line):
yield line
line = [] if xy[1] is None else [xy]
else:
line.append(xy)
if len(line):
yield line
def pickLabelFormat(increment):
"""Pick an appropriate label format for the given increment.
Examples:
>>> print(pickLabelFormat(1))
%.0f
>>> print(pickLabelFormat(20))
%.0f
>>> print(pickLabelFormat(.2))
%.1f
>>> print(pickLabelFormat(.01))
%.2f
"""
i_log = math.log10(increment)
if i_log < 0:
i_log = abs(i_log)
decimal_places = int(i_log)
if i_log != decimal_places:
decimal_places += 1
else:
decimal_places = 0
return u"%%.%df" % decimal_places
def get_font_handle(fontpath_str, *args):
"""Get a handle for a font path, caching the results"""
# Look for the font in the cache
font_key = (fontpath_str, args)
if font_key in get_font_handle.fontCache:
return get_font_handle.fontCache[font_key]
font = None
if fontpath_str is not None:
try:
if fontpath_str.endswith('.ttf'):
# 1. Nice feature of Pillow: if fontpath_str is an absolute path, and it cannot be
# found, then Pillow will search for the font in system resources as well.
# 2. Specifying the basic layout engine is necessary to avoid a segmentation
# fault in Pillow versions earlier than 8.2.
# See https://github.com/python-pillow/Pillow/issues/3066
font = ImageFont.truetype(fontpath_str, # See note 1 above
layout_engine=ImageFont.LAYOUT_BASIC, # See note 2 above
*args)
else:
font = ImageFont.load_path(fontpath_str)
except IOError:
pass
if font is None:
font = ImageFont.load_default()
if font is not None:
get_font_handle.fontCache[font_key] = font
return font
get_font_handle.fontCache = {}
def _rel_approx_equal(x, y, rel=1e-7):
"""Relative test for equality.
Example
>>> _rel_approx_equal(1.23456, 1.23457)
False
>>> _rel_approx_equal(1.2345678, 1.2345679)
True
>>> _rel_approx_equal(0.0, 0.0)
True
>>> _rel_approx_equal(0.0, 0.1)
False
>>> _rel_approx_equal(0.0, 1e-9)
False
>>> _rel_approx_equal(1.0, 1.0+1e-9)
True
>>> _rel_approx_equal(1e8, 1e8+1e-3)
True
"""
return abs(x - y) <= rel * max(abs(x), abs(y))
def tobgr(x):
"""Convert a color to little-endian integer. The PIL wants either
a little-endian integer (0xBBGGRR) or a string (#RRGGBB). weewx expects
little-endian integer. Accept any standard color format that is known
by ImageColor for example #RGB, #RRGGBB, hslHSL as well as standard color
names from X11 and CSS3. See ImageColor for complete set of colors.
"""
if isinstance(x, str):
if x.startswith('0x'):
return int(x, 0)
try:
r, g, b = ImageColor.getrgb(x)
return r + g * 256 + b * 256 * 256
except ValueError:
try:
return int(x)
except ValueError as exc:
raise ValueError("Unknown color specifier: '%s'. "
"Colors must be specified as 0xBBGGRR, #RRGGBB, "
"or standard color names." % x) from exc
return x
if __name__ == "__main__":
import doctest
if not doctest.testmod().failed:
print("PASSED")
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