# You have to overwrite this class and provide implementations

# for these methods.

@classmethod

def OnSetFocus(cls, WindowHandle windowHandle, long msg, long wparam,

long lparam):

# Available only on Windows, but have it available on other

# platforms so that PyCharm doesn't warn about unresolved reference.

pass

@classmethod

def OnSize(cls, WindowHandle windowHandle, long msg, long wparam,

long lparam):

# Available only on Windows, but have it available on other

# platforms so that PyCharm doesn't warn about unresolved reference.

pass

@classmethod

def OnEraseBackground(cls, WindowHandle windowHandle, long msg,

long wparam, long lparam):

# Available only on Windows, but have it available on other

# platforms so that PyCharm doesn't warn about unresolved reference.

pass

@classmethod

def GetParentHandle(cls, WindowHandle windowHandle):

Debug("WindowUtils::GetParentHandle() not implemented (returns 0)")

return 0

@classmethod

def IsWindowHandle(cls, WindowHandle windowHandle):

Debug("WindowUtils::IsWindowHandle() not implemented (always True)")

return True

@classmethod

def gtk_plug_new(cls, WindowHandle gdkNativeWindow):

return <WindowHandle>gtk_plug_new(<unsigned long>gdkNativeWindow)

@classmethod

def gtk_widget_show(cls, WindowHandle gtkWidgetPtr):

with nogil:

gtk_widget_show(<GtkWidget*>gtkWidgetPtr)

@classmethod

def InstallX11ErrorHandlers(cls):

with nogil:

"""Initialize GTK so GDK has an open display connection before CEF.

try:

import os as _os, ctypes as _ct

# Must be set before gtk_init() so GDK opens an X11/Xwayland display.

_os.environ.setdefault("GDK_BACKEND", "x11")

_gtk = _ct.CDLL("libgtk-3.so.0")

_gtk.gtk_disable_setlocale()

_gtk.gtk_init(None, None)

except Exception as _e:

"""Auto-apply Linux defaults that every cefpython app needs.

import os as _os

# Force Chrome's Ozone backend to X11. This is the *only* thing keeping

# Chromium off the Wayland display on a Wayland session — cefpython embeds

# via X11 window handles (CefWindowInfo.SetAsChild) and drives X11 window

# geometry directly. GDK_BACKEND=x11 is set separately in

# _linux_gtk_init() before gtk_init().

#

# Root cause (upstream CEF): native windowed embedding into a client

# parent_window is implemented for X11 only — CreateHostWindow() in CEF's

# libcef/browser/native/browser_platform_delegate_native_linux.cc is wrapped

# entirely in `#if BUILDFLAG(SUPPORTS_OZONE_X11)` (creating a CefWindowX11)

# with no Wayland branch, and there is no window_wayland implementation.

# Wayland has no cross-process window embedding (no X11-style window IDs /

# XReparent), so CEF cannot parent the browser into a foreign Wayland

# surface; embedders must run under X11/XWayland. Verified on CEF 147:

# without this switch, a Wayland session selects the Wayland Ozone backend

# and the embedding path crashes.

cmd_switches.setdefault("ozone-platform", "x11")

# Vulkan ICD fallback for systems with no system-installed driver.

#

# On systems with no Vulkan ICD (typical for VMs and minimal containers),

# Chromium's GPU process fails its Vulkan probe and the renderer logs a

# transient

# ContextResult::kTransientFailure: Failed to send

# GpuControl.CreateCommandBuffer

# before falling back to software rendering. Pointing VK_ICD_FILENAMES

# at the SwiftShader manifest bundled with CEF makes the probe succeed

# immediately and silences the line.

#

# Only apply the fallback when no system ICD is present in the standard

# loader search paths — overriding a working Mesa/NVIDIA/AMD ICD with

# SwiftShader would force software rendering for no reason on real GPUs.

# Honors a pre-set VK_ICD_FILENAMES (setdefault) so users can override.

import glob as _glob

_system_icds = (_glob.glob("/usr/share/vulkan/icd.d/*.json") +

_glob.glob("/etc/vulkan/icd.d/*.json") +

_glob.glob("/usr/local/share/vulkan/icd.d/*.json"))

if not _system_icds:

import cefpython3 as _cef3_pkg

_cef3_dir = _os.path.dirname(_cef3_pkg.__file__)

_vk_icd = _os.path.join(_cef3_dir, "vk_swiftshader_icd.json")

if _os.path.exists(_vk_icd):

_os.environ.setdefault("VK_ICD_FILENAMES", _vk_icd)

# NOTE: external_message_pump is intentionally NOT forced here. On Linux

# cef.MessageLoop() runs CefRunMessageLoop() (same as Windows/macOS and

# upstream cefsimple/cefclient), and Chromium's UI loop is GLib-based so

# GTK works without a separate pump. Apps that integrate CEF into their

# own GUI loop via cef.MessageLoopWork() may still opt in explicitly.

# Allow per-browser opt-in to off-screen rendering. Required by examples

# that pass WindowInfo.SetAsOffscreen() (e.g. pysdl2.py) and by JS-created

# popup browsers, which are destroyed immediately when DoClose returns

# False — no delete_event would be dispatched on a windowed popup.

app_settings.setdefault("windowless_rendering_enabled", True)

# Chromium's Linux sandbox. CEF Linux builds default sandbox-ON and refuse

# to start unless a SUID-root chrome-sandbox helper is installed or

# --no-sandbox is passed. A pip wheel cannot install a chown-root helper,

# so cefpython disables the sandbox on Linux, as it always has. Added only

# when the caller has not set the switch explicitly.

if "no-sandbox" not in cmd_switches: