基于下面的代码示例,我想在 CustomJS 函数中提取数据(例如 x 值)以将其保存在 python 列表 rect_data
中。尽管变量 x 与 ColumnDataSource 对象 source
同步,但当我在下面执行代码的图中绘制矩形选择时,python 列表 rect_data
仍然是一个空列表。我做错了什么,我该如何解决这个问题?
提前致谢!
# You must first run "bokeh serve" to view this example
from bokeh.models import CustomJS, ColumnDataSource, BoxSelectTool, Range1d, Rect
from bokeh.plotting import figure, show
from bokeh.client import push_session
from bokeh.io import curdoc
source = ColumnDataSource(data=dict(x=[], y=[], width=[], height=[]))
callback = CustomJS(args=dict(source=source), code="""
var data = source.get('data');
var geometry = cb_data['geometry'];
var width = geometry['x1'] - geometry['x0'];
var height = geometry['y1'] - geometry['y0'];
var x = geometry['x0'] + width/2;
var y = geometry['y0'] + height/2;
data['x'].push(x);
data['y'].push(y);
data['width'].push(width);
data['height'].push(height);
source.trigger('change');
""")
box_select = BoxSelectTool(callback=callback)
p = figure(plot_width=400,
plot_height=400,
tools=[box_select],
title="Select Below",
x_range=Range1d(start=0.0, end=1.0),
y_range=Range1d(start=0.0, end=1.0))
rect = Rect(x='x',
y='y',
width='width',
height='height',
fill_alpha=0.3,
fill_color='#009933')
p.add_glyph(source, rect, selection_glyph=rect, nonselection_glyph=rect)
session = push_session(curdoc())
def update():
global rect_data
global source
rect_data = source.data['x']
print(rect_data)
curdoc().add_periodic_callback(update,10)
session.show()
session.loop_until_closed()
最佳答案
您可以为此目的使用 ToolEvents。请参见下面的示例。
from bokeh.plotting import figure
from bokeh.client import push_session
from bokeh.io import curdoc
from bokeh.models import ColumnDataSource, CustomJS, BoxSelectTool, Range1d, Rect
source = ColumnDataSource(data=dict(x=[], y=[], width=[], height=[]))
callback = CustomJS(args=dict(source=source), code="""
var data = source.get('data');
var geometry = cb_data['geometry'];
var width = geometry['x1'] - geometry['x0'];
var height = geometry['y1'] - geometry['y0'];
var x = geometry['x0'] + width/2;
var y = geometry['y0'] + height/2;
data['x'].push(x);
data['y'].push(y);
data['width'].push(width);
data['height'].push(height);
source.trigger('change');
""")
box_select = BoxSelectTool(callback=callback)
p = figure(plot_width=400,
plot_height=400,
tools=[box_select],
title="Select Below",
x_range=Range1d(start=0.0, end=1.0),
y_range=Range1d(start=0.0, end=1.0))
rect = Rect(x='x',
y='y',
width='width',
height='height',
fill_alpha=0.3,
fill_color='#009933')
p.add_glyph(source, rect, selection_glyph=rect, nonselection_glyph=rect, name="selectionbox")
session = push_session(curdoc())
def toolEventsCallback(attr, old, new):
print("callback", new)
x0 = new[0]['x0']
x1 = new[0]['x1']
print("x0=%f x1=%f" % (x0, x1))
p.tool_events.on_change("geometries", toolEventsCallback)
session.show()
session.loop_until_closed()
至少在 Bokeh 0.11.1 中,没有为 ColumnDataSource 将事件发送回 Python。
关于python - 如何从与 Bokeh 的 CustomJS 函数的局部变量同步的 ColumnDataSource 对象获取数据?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35669642/