# Example of embedding CEF browser using PyWin32 library.
# Tested with pywin32 version 221 and CEF Python v57.0+.
#
# Usage:
# python pywin32.py
# python pywin32.py --multi-threaded
#
# By passing --multi-threaded arg CEF will run using multi threaded
# message loop which has best performance on Windows. However there
# is one issue with it on exit, see "Known issues" below. See also
# docs/Tutorial.md and the "Message loop" section.
#
# Known issues:
# - Crash on exit with multi threaded message loop (Issue #380)
from cefpython3 import cefpython as cef
import distutils.sysconfig
import math
import os
import platform
import sys
import win32api
import win32con
import win32gui
# Globals
WindowUtils = cef.WindowUtils()
g_multi_threaded = False
def main():
command_line_args()
check_versions()
sys.excepthook = cef.ExceptHook # To shutdown all CEF processes on error
settings = {
"multi_threaded_message_loop": g_multi_threaded,
}
cef.Initialize(settings=settings)
window_proc = {
win32con.WM_CLOSE: close_window,
win32con.WM_DESTROY: exit_app,
win32con.WM_SIZE: WindowUtils.OnSize,
win32con.WM_SETFOCUS: WindowUtils.OnSetFocus,
win32con.WM_ERASEBKGND: WindowUtils.OnEraseBackground
}
window_handle = create_window(title="PyWin32 example",
class_name="pywin32.example",
width=800,
height=600,
window_proc=window_proc,
icon="resources/chromium.ico")
window_info = cef.WindowInfo()
window_info.SetAsChild(window_handle)
if g_multi_threaded:
# When using multi-threaded message loop, CEF's UI thread
# is no more application's main thread. In such case browser
# must be created using cef.PostTask function and CEF message
# loop must not be run explicitilly.
cef.PostTask(cef.TID_UI,
create_browser,
window_info,
{},
"https://www.google.com/")
win32gui.PumpMessages()
else:
create_browser(window_info=window_info,
settings={},
url="https://www.google.com/")
cef.MessageLoop()
cef.Shutdown()
def command_line_args():
global g_multi_threaded
if "--multi-threaded" in sys.argv:
sys.argv.remove("--multi-threaded")
print("[pywin32.py] Message loop mode: CEF multi-threaded"
" (best performance)")
g_multi_threaded = True
else:
print("[pywin32.py] Message loop mode: CEF single-threaded")
if len(sys.argv) > 1:
print("ERROR: Invalid args passed."
" For usage see top comments in pywin32.py.")
sys.exit(1)
def check_versions():
if platform.system() != "Windows":
print("ERROR: This example is for Windows platform only")
sys.exit(1)
print("[pywin32.py] CEF Python {ver}".format(ver=cef.__version__))
print("[pywin32.py] Python {ver} {arch}".format(
ver=platform.python_version(), arch=platform.architecture()[0]))
# PyWin32 version
python_lib = distutils.sysconfig.get_python_lib(plat_specific=1)
with open(os.path.join(python_lib, "pywin32.version.txt")) as fp:
pywin32_version = fp.read().strip()
print("[pywin32.py] pywin32 {ver}".format(ver=pywin32_version))
assert cef.__version__ >= "57.0", "CEF Python v57.0+ required to run this"
def create_browser(window_info, settings, url):
assert(cef.IsThread(cef.TID_UI))
cef.CreateBrowserSync(window_info=window_info,
settings=settings,
url=url)
def create_window(title, class_name, width, height, window_proc, icon):
# Register window class
wndclass = win32gui.WNDCLASS()
wndclass.hInstance = win32api.GetModuleHandle(None)
wndclass.lpszClassName = class_name
wndclass.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
wndclass.hbrBackground = win32con.COLOR_WINDOW
wndclass.hCursor = win32gui.LoadCursor(0, win32con.IDC_ARROW)
wndclass.lpfnWndProc = window_proc
atom_class = win32gui.RegisterClass(wndclass)
assert(atom_class != 0)
# Center window on screen.
screenx = win32api.GetSystemMetrics(win32con.SM_CXSCREEN)
screeny = win32api.GetSystemMetrics(win32con.SM_CYSCREEN)
xpos = int(math.floor((screenx - width) / 2))
ypos = int(math.floor((screeny - height) / 2))
if xpos < 0:
xpos = 0
if ypos < 0:
ypos = 0
# Create window
window_style = (win32con.WS_OVERLAPPEDWINDOW | win32con.WS_CLIPCHILDREN
| win32con.WS_VISIBLE)
window_handle = win32gui.CreateWindow(class_name, title, window_style,
xpos, ypos, width, height,
0, 0, wndclass.hInstance, None)
assert(window_handle != 0)
# Window icon
icon = os.path.abspath(icon)
if not os.path.isfile(icon):
icon = None
if icon:
# Load small and big icon.
# WNDCLASSEX (along with hIconSm) is not supported by pywin32,
# we need to use WM_SETICON message after window creation.
# Ref:
# 1. http://stackoverflow.com/questions/2234988
# 2. http://blog.barthe.ph/2009/07/17/wmseticon/
bigx = win32api.GetSystemMetrics(win32con.SM_CXICON)
bigy = win32api.GetSystemMetrics(win32con.SM_CYICON)
big_icon = win32gui.LoadImage(0, icon, win32con.IMAGE_ICON,
bigx, bigy,
win32con.LR_LOADFROMFILE)
smallx = win32api.GetSystemMetrics(win32con.SM_CXSMICON)
smally = win32api.GetSystemMetrics(win32con.SM_CYSMICON)
small_icon = win32gui.LoadImage(0, icon, win32con.IMAGE_ICON,
smallx, smally,
win32con.LR_LOADFROMFILE)
win32api.SendMessage(window_handle, win32con.WM_SETICON,
win32con.ICON_BIG, big_icon)
win32api.SendMessage(window_handle, win32con.WM_SETICON,
win32con.ICON_SMALL, small_icon)
return window_handle
def close_window(window_handle, message, wparam, lparam):
browser = cef.GetBrowserByWindowHandle(window_handle)
browser.CloseBrowser(True)
# OFF: win32gui.DestroyWindow(window_handle)
return win32gui.DefWindowProc(window_handle, message, wparam, lparam)
def exit_app(*_):
win32gui.PostQuitMessage(0)
return 0
if __name__ == '__main__':
main()