CefWindowDelegate

Header: cef_window_delegate.h
Category: Views Framework

Overview

Browser-process UI toolkit: windows, panels, layouts, buttons, textfields, and their delegates.

CefWindowDelegate

Source File: include/views/cef_window_delegate.h

Process / Thread Context: Browser Process / UI Thread.

Purpose: Client-implemented delegate interface for handling window events

Methods

virtual void OnWindowCreated(CefRefPtr<CefWindow> window)

Parameters:

• window: The window that was just created.

Return Value: void.

Usage Instruction: Good place to build the view hierarchy, add child

Threading Constraint: Browser process UI thread.

virtual void OnWindowClosing(CefRefPtr<CefWindow> window)

Parameters:

• window: The window that is about to close.

Return Value: void.

Usage Instruction: Last chance to perform cleanup while the window is

Threading Constraint: Browser process UI thread.

virtual void OnWindowDestroyed(CefRefPtr<CefWindow> window)

Parameters:

• window: The window being destroyed.

Return Value: void. Release all references; do not call any methods on

Usage Instruction: Tear down references / state associated with the

Threading Constraint: Browser process UI thread.

virtual void OnWindowActivationChanged(CefRefPtr<CefWindow> window, bool active)

Parameters:

• window: The window.
• active: True if now active, false if deactivated.

Return Value: void.

Usage Instruction: Update UI affordances that depend on activation.

Threading Constraint: Browser process UI thread.

virtual void OnWindowBoundsChanged(CefRefPtr<CefWindow> window, const CefRect& new_bounds)

Parameters:

• window: The window.
• new_bounds: New bounds in DIP screen coordinates.

Return Value: void.

Usage Instruction: Persist window geometry or adjust overlays.

Threading Constraint: Browser process UI thread.

virtual void OnWindowFullscreenTransition(CefRefPtr<CefWindow> window, bool is_completed)

Parameters:

• window: The window.
• is_completed: False at start of an async macOS transition; true after

Return Value: void.

Usage Instruction: Update UI when entering/leaving fullscreen. With

Threading Constraint: Browser process UI thread.

virtual CefRefPtr<CefWindow> GetParentWindow(CefRefPtr<CefWindow> window, bool* is_menu, bool* can_activate_menu)

Parameters:

• window: The window being created.
• is_menu: Out-param — set to true if the window will be displayed as a
• can_activate_menu: Out-param — set to false if is_menu is true and

Return Value: The parent window, or NULL for no parent. Parented

Usage Instruction: Create child windows / menus.

Threading Constraint: Browser process UI thread.

virtual bool IsWindowModalDialog(CefRefPtr<CefWindow> window)

Parameters:

• window: The window.

Return Value: True to create the window as a window-modal dialog (only

Usage Instruction: Choose window-modal dialog style. For a

Threading Constraint: Browser process UI thread.

virtual CefRect GetInitialBounds(CefRefPtr<CefWindow> window)

Parameters:

• window: The window being created.

Return Value: Initial bounds in DIP coordinates. If empty, the window

Usage Instruction: Restore saved geometry.

Threading Constraint: Browser process UI thread.

virtual cef_show_state_t GetInitialShowState(CefRefPtr<CefWindow> window)

Parameters:

• window: The window.

Return Value: The initial show state. Default CEF_SHOW_STATE_NORMAL.

Usage Instruction: Start maximized / minimized / fullscreen.

Threading Constraint: Browser process UI thread.

virtual bool IsFrameless(CefRefPtr<CefWindow> window)

Parameters:

• window: The window.

Return Value: True to create the window without a frame or title bar.

Usage Instruction: Frameless / chromeless windows.

Threading Constraint: Browser process UI thread.

virtual bool WithStandardWindowButtons(CefRefPtr<CefWindow> window)

Parameters:

• window: The window.

Return Value: True to create the window with standard window buttons

Usage Instruction: macOS-specific window chrome configuration.

Threading Constraint: Browser process UI thread.

virtual bool GetTitlebarHeight(CefRefPtr<CefWindow> window, float* titlebar_height)

Parameters:

• window: The window.
• titlebar_height: Out-param — set to the desired title bar height.

Return Value: True if the title bar height should be overridden. On

Usage Instruction: Custom title-bar heights.

Threading Constraint: Browser process UI thread.

virtual cef_state_t AcceptsFirstMouse(CefRefPtr<CefWindow> window)

Parameters:

• window: The window.

Return Value: STATE_ENABLED to accept the initial mouse-down event,

Threading Constraint: Browser process UI thread.

virtual bool CanResize(CefRefPtr<CefWindow> window)

Parameters:

• window: The window.

Return Value: True if the window can be resized. Default true.

Usage Instruction: Restrict resizing for fixed-size dialogs.

Threading Constraint: Browser process UI thread.

virtual bool CanMaximize(CefRefPtr<CefWindow> window)

Parameters:

• window: The window.

Return Value: True if maximize is allowed. Default true.

Usage Instruction: Disable the maximize button.

Threading Constraint: Browser process UI thread.

virtual bool CanMinimize(CefRefPtr<CefWindow> window)

Parameters:

• window: The window.

Return Value: True if minimize is allowed. Default true.

Usage Instruction: Disable the minimize button.

Threading Constraint: Browser process UI thread.

virtual bool CanClose(CefRefPtr<CefWindow> window)

Parameters:

• window: The window.

Return Value: True if the window can be closed. Called for

Usage Instruction: Prompt "are you sure?" or wait for ongoing work to

Threading Constraint: Browser process UI thread.

virtual bool OnAccelerator(CefRefPtr<CefWindow> window, int command_id)

Parameters:

• window: The window.
• command_id: The id registered via CefWindow::SetAccelerator.

Return Value: True if the accelerator was handled.

Usage Instruction: Handle keyboard shortcuts.

Threading Constraint: Browser process UI thread.

virtual bool OnKeyEvent(CefRefPtr<CefWindow> window, const CefKeyEvent& event)

Parameters:

• window: The window.
• event: The keyboard event.

Return Value: True if handled; false to allow default handling. Called

Usage Instruction: Last-resort keyboard event handler at the window

Threading Constraint: Browser process UI thread.

virtual void OnThemeColorsChanged(CefRefPtr<CefWindow> window, bool chrome_theme)

Parameters:

• window: The window.
• chrome_theme: True if the notification is for a Chrome theme (vs.

Return Value: void. Theme colors are reset to standard values before

Usage Instruction: React to system dark/light mode changes or Chrome

Threading Constraint: Browser process UI thread.

virtual cef_runtime_style_t GetWindowRuntimeStyle()

Parameters:

• none.

Return Value: The runtime style for this window. Default

Usage Instruction: Choose between Alloy (native CEF) and Chrome styles.

Threading Constraint: Browser process UI thread.

virtual bool GetLinuxWindowProperties(CefRefPtr<CefWindow> window, CefLinuxWindowProperties& properties)

Parameters:

• window: The window.
• properties: Out-param populated with Linux-specific window properties

Return Value: True if properties were provided.

Usage Instruction: Linux-only customization of WM hints.

Threading Constraint: Browser process UI thread.

Usage Example

class MyWindowDelegate : public CefWindowDelegate {
 public:
  void OnWindowCreated(CefRefPtr<CefWindow> window) override {
    // Build the UI here, then show.
    auto panel = CefPanel::CreatePanel(nullptr);
    auto box = panel->SetToBoxLayout(CefBoxLayoutSettings{});
    panel->AddChildView(CefLabelButton::CreateLabelButton(btn_del_, "Save"));
    panel->AddChildView(CefTextfield::CreateTextfield(tf_del_));
    window->AddChildView(panel);
    window->CenterWindow(CefSize(480, 320));
    window->Show();
  }

  bool CanResize(CefRefPtr<CefWindow>) override { return false; }
  bool CanMaximize(CefRefPtr<CefWindow>) override { return false; }
  bool IsFrameless(CefRefPtr<CefWindow>) override { return true; }

  bool OnAccelerator(CefRefPtr<CefWindow>, int cmd) override {
    if (cmd == IDC_SAVE) { SaveDocument(); return true; }
    return false;
  }
};