# Copyright 2019-2020 The Lux Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from lux.vislib.altair.AltairChart import AltairChart
import altair as alt
import lux
import math
alt.data_transformers.disable_max_rows()
from lux.utils.utils import get_agg_title
[docs]class BarChart(AltairChart):
"""
BarChart is a subclass of AltairChart that render as a bar charts.
All rendering properties for bar charts are set here.
See Also
--------
altair-viz.github.io
"""
[docs] def __init__(self, dobj):
super().__init__(dobj)
def __repr__(self):
return f"Bar Chart <{str(self.vis)}>"
[docs] def initialize_chart(self):
self.tooltip = False
x_attr = self.vis.get_attr_by_channel("x")[0]
y_attr = self.vis.get_attr_by_channel("y")[0]
# Deal with overlong string axes labels
x_attr_abv = str(x_attr.attribute)
y_attr_abv = str(y_attr.attribute)
label_len = lux.config.label_len
prefix_len = math.ceil(3.0 * label_len / 5.0)
suffix_len = label_len - prefix_len
if len(x_attr_abv) > label_len:
x_attr_abv = x_attr.attribute[:prefix_len] + "..." + x_attr.attribute[-suffix_len:]
if len(y_attr_abv) > label_len:
y_attr_abv = y_attr.attribute[:prefix_len] + "..." + y_attr.attribute[-suffix_len:]
if isinstance(x_attr.attribute, str):
x_attr.attribute = x_attr.attribute.replace(".", "")
if isinstance(y_attr.attribute, str):
y_attr.attribute = y_attr.attribute.replace(".", "")
# To get datetime to display correctly on bar charts
if x_attr.data_type == "temporal":
x_attr.data_type = "nominal"
self.code += "from pandas import Timestamp\n"
if y_attr.data_type == "temporal":
y_attr.data_type = "nominal"
self.code += "from pandas import Timestamp\n"
if x_attr.data_model == "measure":
agg_title = get_agg_title(x_attr)
measure_attr = x_attr.attribute
y_attr_field = alt.Y(
str(y_attr.attribute),
type=y_attr.data_type,
axis=alt.Axis(labelOverlap=True, title=y_attr_abv),
)
x_attr_field = alt.X(
str(x_attr.attribute),
type=x_attr.data_type,
title=agg_title,
axis=alt.Axis(title=agg_title),
)
y_attr_field_code = f"alt.Y('{y_attr.attribute}', type= '{y_attr.data_type}', axis=alt.Axis(labelOverlap=True, title='{y_attr_abv}'))"
x_attr_field_code = f"alt.X('{x_attr.attribute}', type= '{x_attr.data_type}', title='{agg_title}', axis=alt.Axis(title='{agg_title}'))"
if y_attr.sort == "ascending":
y_attr_field.sort = "-x"
y_attr_field_code = f"alt.Y('{y_attr.attribute}', type= '{y_attr.data_type}', axis=alt.Axis(labelOverlap=True, title='{y_attr_abv}'), sort ='-x')"
else:
agg_title = get_agg_title(y_attr)
measure_attr = y_attr.attribute
x_attr_field = alt.X(
str(x_attr.attribute),
type=x_attr.data_type,
axis=alt.Axis(labelOverlap=True, title=x_attr_abv),
)
x_attr_field_code = f"alt.X('{x_attr.attribute}', type= '{x_attr.data_type}', axis=alt.Axis(labelOverlap=True, title='{x_attr_abv}'))"
y_attr_field = alt.Y(
str(y_attr.attribute),
type=y_attr.data_type,
title=agg_title,
axis=alt.Axis(title=agg_title),
)
y_attr_field_code = f"alt.Y('{y_attr.attribute}', type= '{y_attr.data_type}', title='{agg_title}', axis=alt.Axis(title='{agg_title}'))"
if x_attr.sort == "ascending":
x_attr_field.sort = "-y"
x_attr_field_code = f"alt.X('{x_attr.attribute}', type= '{x_attr.data_type}', axis=alt.Axis(labelOverlap=True, title='{x_attr_abv}'),sort='-y')"
k = lux.config.number_of_bars
self._topkcode = ""
n_bars = len(self.data.iloc[:, 0].unique())
plotting_scale = lux.config.plotting_scale
if n_bars > k: # Truncating to only top k
remaining_bars = n_bars - k
self.data = self.data.nlargest(k, columns=measure_attr)
self.data = AltairChart.sanitize_dataframe(self.data)
self.text = alt.Chart(self.data).mark_text(
x=155 * plotting_scale,
y=142 * plotting_scale,
align="right",
color="#ff8e04",
fontSize=11,
text=f"+ {remaining_bars} more ...",
)
self._topkcode = f"""text = alt.Chart(visData).mark_text(
x={155 * plotting_scale},
y={142 * plotting_scale},
align="right",
color = "#ff8e04",
fontSize = 11,
text=f"+ {remaining_bars} more ..."
)
chart = chart + text\n"""
self.data = AltairChart.sanitize_dataframe(self.data)
chart = alt.Chart(self.data).mark_bar().encode(y=y_attr_field, x=x_attr_field)
# TODO: tooltip messes up the count() bar charts
# Can not do interactive whenever you have default count measure otherwise output strange error (Javascript Error: Cannot read property 'length' of undefined)
# chart = chart.interactive() # If you want to enable Zooming and Panning
self.code += "import altair as alt\n"
# self.code += f"visData = pd.DataFrame({str(self.data.to_dict(orient='records'))})\n"
self.code += f"visData = pd.DataFrame({str(self.data.to_dict())})\n"
self.code += f"""
chart = alt.Chart(visData).mark_bar().encode(
y = {y_attr_field_code},
x = {x_attr_field_code},
)\n"""
return chart
[docs] def add_text(self):
if self._topkcode != "":
self.chart = self.chart + self.text
self.code += self._topkcode
# override encode_color in AltairChart to enforce add_text occurs afterwards
[docs] def encode_color(self):
AltairChart.encode_color(self)
self.add_text()
# Setting tooltip as non-null
self.chart = self.chart.configure_mark(tooltip=alt.TooltipContent("encoding"))
self.code += f"""chart = chart.configure_mark(tooltip=alt.TooltipContent('encoding'))"""