Source code for bokeh.command.subcommands.png

'''
To generate a standalone PNG file for a Bokeh application from a single
Python script, pass the script name to ``bokeh png`` on the command
line:

.. code-block:: sh

    bokeh png app_script.py

The generated PNG will be saved in the current working directory with
the name ``app_script.png``.

It is also possible to run the same commmand with jupyter notebooks:

.. code-block:: sh

    bokeh png app_notebook.ipynb

This will generate an PNG file named ``app_notebook.png`` just like
with a python script.

Applications can also be created from directories. The directory should
contain a ``main.py`` (and any other helper modules that are required) as
well as any additional assets (e.g., theme files). Pass the directory name
to ``bokeh png`` to generate the PNG:

.. code-block:: sh

    bokeh png app_dir

It is possible to generate PNG files for multiple applications at once:

.. code-block:: sh

    bokeh png app_script.py app_dir

For all cases, it's required to explicitly add a Bokeh layout to
``bokeh.io.curdoc`` for it to appear in the output.

'''
from __future__ import absolute_import

import io
import sys
import warnings

from ...io.export import get_screenshot_as_png, create_webdriver, terminate_webdriver
from ...models.plots import Plot
from .file_output import FileOutputSubcommand

[docs]class PNG(FileOutputSubcommand): ''' Subcommand to output applications as standalone PNG files. ''' #: name for this subcommand name = "png" #: file extension for output generated by this :class:`~bokeh.command.subcommands.file_output.FileOutputSubcommand` extension = "png" help = "Create standalone PNG files for one or more applications" args = ( FileOutputSubcommand.files_arg("PNG"), ('--height', dict( metavar='HEIGHT', type=int, help="The desired height of the exported layout obj only if it's a Plot instance", default=None, )), ('--width', dict( metavar='WIDTH', type=int, help="The desired width of the exported layout obj only if it's a Plot instance", default=None, )), ) + FileOutputSubcommand.other_args()
[docs] def invoke(self, args): ''' ''' self.driver = create_webdriver() try: super(PNG, self).invoke(args) finally: terminate_webdriver(self.driver)
[docs] def write_file(self, args, filename, doc): ''' ''' contents = self.file_contents(args, doc) if filename == '-': sys.stdout.buffer.write(contents) else: with io.open(filename, "w+b") as f: f.write(contents) self.after_write_file(args, filename, doc)
[docs] def file_contents(self, args, doc): ''' ''' if args.width is not None or args.height is not None: layout = doc.roots if len(layout) != 1 or not isinstance(layout[0], Plot): warnings.warn("Export called with height or width kwargs on a non-single Plot layout. The size values will be ignored.") else: plot = layout[0] plot.plot_height = args.height or plot.plot_height plot.plot_width = args.width or plot.plot_width image = get_screenshot_as_png(doc, driver=self.driver) buf = io.BytesIO() image.save(buf, "png") buf.seek(0) return buf.read()