def _initialize_webdriver(self):
"""Initialize headless chrome browser"""
options = Options()
options.add_argument("window-size={width},{height}".format(
width=self.style.plot_width, height=self.style.plot_height))
options.add_argument("start-maximized")
options.add_argument("disable-infobars")
options.add_argument("disable-gpu")
options.add_argument('no-sandbox') # Required for use in docker.
options.add_argument("--disable-extensions")
options.add_argument('--headless')
options.add_argument('--hide-scrollbars')
driver = webdriver.Chrome(options=options)
return driver
def _figure_to_png(self):
"""Convert figure object to PNG
Bokeh can only save figure objects as html.
To convert to PNG the HTML file is opened in a headless browser.
"""
# Initialize headless browser options
options = Options()
options.add_argument("window-size={width},{height}".format(
width=self.style.plot_width, height=self.style.plot_height))
options.add_argument("start-maximized")
options.add_argument("disable-infobars")
options.add_argument("disable-gpu")
options.add_argument('no-sandbox') # Required for use in docker.
options.add_argument("--disable-extensions")
options.add_argument('--headless')
options.add_argument('--hide-scrollbars')
driver = webdriver.Chrome(options=options)
# Save figure as HTML
html = file_html(self.figure, resources=INLINE, title="")
fp = tempfile.NamedTemporaryFile('w',
prefix='chartify',
suffix='.html',
encoding='utf-8')
fp.write(html)
fp.flush()
# Open html file in the browser.
driver.get("file:///" + fp.name)
driver.execute_script("document.body.style.margin = '0px';")
png = driver.get_screenshot_as_png()
driver.quit()
fp.close()
# Resize image if necessary.
image = Image.open(BytesIO(png))
target_dimensions = (self.style.plot_width, self.style.plot_height)
if image.size != target_dimensions:
image = image.resize(target_dimensions, resample=Image.LANCZOS)
return image