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/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at */
#ifndef nsIWidget_h__
#define nsIWidget_h__
#include <cmath>
#include <cstdint>
#include "ErrorList.h"
#include "Units.h"
#include "mozilla/AlreadyAddRefed.h"
#include "mozilla/Assertions.h"
#include "mozilla/Attributes.h"
#include "mozilla/EventForwards.h"
#include "mozilla/Maybe.h"
#include "mozilla/RefPtr.h"
#include "mozilla/TimeStamp.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/gfx/Matrix.h"
#include "mozilla/gfx/Rect.h"
#include "mozilla/layers/LayersTypes.h"
#include "mozilla/layers/ScrollableLayerGuid.h"
#include "mozilla/layers/ZoomConstraints.h"
#include "mozilla/image/Resolution.h"
#include "mozilla/widget/IMEData.h"
#include "nsCOMPtr.h"
#include "nsColor.h"
#include "nsDebug.h"
#include "nsID.h"
#include "nsIObserver.h"
#include "nsISupports.h"
#include "nsITheme.h"
#include "nsITimer.h"
#include "nsIWidgetListener.h"
#include "nsRect.h"
#include "nsSize.h"
#include "nsStringFwd.h"
#include "nsTArray.h"
#include "nsTHashMap.h"
#include "nsWidgetInitData.h"
#include "nsXULAppAPI.h"
#ifdef MOZ_IS_GCC
# include "VsyncSource.h"
// forward declarations
class nsIBidiKeyboard;
class nsIRollupListener;
class imgIContainer;
class nsIContent;
class ViewWrapper;
class nsIScreen;
class nsIRunnable;
namespace mozilla {
class NativeEventData;
class WidgetGUIEvent;
class WidgetInputEvent;
class WidgetKeyboardEvent;
struct FontRange;
enum class StyleWindowShadow : uint8_t;
enum class ColorScheme : uint8_t;
namespace ipc {
class Shmem;
#endif // defined(MOZ_WIDGET_ANDROID)
namespace dom {
class BrowserChild;
enum class CallerType : uint32_t;
} // namespace dom
class WindowRenderer;
namespace layers {
class AsyncDragMetrics;
class Compositor;
class CompositorBridgeChild;
struct FrameMetrics;
class LayerManager;
class WebRenderBridgeChild;
} // namespace layers
namespace gfx {
class VsyncSource;
} // namespace gfx
namespace widget {
class TextEventDispatcher;
class TextEventDispatcherListener;
class CompositorWidget;
class CompositorWidgetInitData;
} // namespace widget
namespace wr {
class DisplayListBuilder;
class IpcResourceUpdateQueue;
enum class RenderRoot : uint8_t;
} // namespace wr
} // namespace mozilla
* Callback function that processes events.
* The argument is actually a subtype (subclass) of WidgetEvent which carries
* platform specific information about the event. Platform specific code
* knows how to deal with it.
* The return value determines whether or not the default action should take
* place.
typedef nsEventStatus (*EVENT_CALLBACK)(mozilla::WidgetGUIEvent* aEvent);
// Hide the native window system's real window type so as to avoid
// including native window system types and APIs. This is necessary
// to ensure cross-platform code.
typedef void* nsNativeWidget;
* Flags for the GetNativeData and SetNativeData functions
// The toplevel GtkWidget containing this nsIWidget:
// This is available only with GetNativeData() in parent process. Anybody
// shouldn't access this pointer as a valid pointer since the result may be
// special value like NS_ONLY_ONE_NATIVE_IME_CONTEXT. So, the result is just
// an identifier of distinguishing a text composition is caused by which native
// IME context. Note that the result is only valid in the process. So,
// XP code should use nsIWidget::GetNativeIMEContext() instead of using this.
#ifdef XP_WIN
# define NS_NATIVE_ICOREWINDOW 103 // winrt specific
#if defined(MOZ_WIDGET_GTK)
# define NS_JAVA_SURFACE 100
#define MOZ_WIDGET_MAX_SIZE 16384
// Must be kept in sync with xpcom/rust/xpcom/src/interfaces/
#define NS_IWIDGET_IID \
{ \
0x06396bf6, 0x2dd8, 0x45e5, { \
0xac, 0x45, 0x75, 0x26, 0x53, 0xb1, 0xc9, 0x80 \
} \
* Transparency modes
enum nsTransparencyMode {
eTransparencyOpaque = 0, // Fully opaque
eTransparencyTransparent, // Parts of the window may be transparent
eTransparencyGlass, // Transparent parts of the window have Vista AeroGlass
// effect applied
eTransparencyBorderlessGlass // As above, but without a border around the
// opaque areas when there would otherwise be
// one with eTransparencyGlass
// If you add to the end here, you must update the serialization code in
// WidgetMessageUtils.h
* Cursor types.
enum nsCursor { ///(normal cursor, usually rendered as an arrow)
///(system is busy, usually rendered as a hourglass or watch)
///(Selecting something, usually rendered as an IBeam)
///(can hyper-link, usually rendered as a human hand)
///(north/south/west/east edge sizing)
///(corner sizing)
eCursor_copy, // CSS3
// This one is used for array sizing, and so better be the last
// one in this list...
// ...except for this one.
eCursorInvalid = eCursorCount + 1
enum nsTopLevelWidgetZPlacement { // for PlaceBehind()
eZPlacementBottom = 0, // bottom of the window stack
eZPlacementBelow, // just below another widget
eZPlacementTop // top of the window stack
* Before the OS goes to sleep, this topic is notified.
#define NS_WIDGET_SLEEP_OBSERVER_TOPIC "sleep_notification"
* After the OS wakes up, this topic is notified.
#define NS_WIDGET_WAKE_OBSERVER_TOPIC "wake_notification"
* Before the OS suspends the current process, this topic is notified. Some
* OS will kill processes that are suspended instead of resuming them.
* For that reason this topic may be useful to safely close down resources.
#define NS_WIDGET_SUSPEND_PROCESS_OBSERVER_TOPIC "suspend_process_notification"
* After the current process resumes from being suspended, this topic is
* notified.
#define NS_WIDGET_RESUME_PROCESS_OBSERVER_TOPIC "resume_process_notification"
* When an app(-shell) is activated by the OS, this topic is notified.
* Currently, this only happens on Mac OSX.
namespace mozilla {
namespace widget {
* Size constraints for setting the minimum and maximum size of a widget.
* Values are in device pixels.
struct SizeConstraints {
SizeConstraints(mozilla::LayoutDeviceIntSize aMinSize,
mozilla::LayoutDeviceIntSize aMaxSize,
mozilla::DesktopToLayoutDeviceScale aScale)
: mMinSize(aMinSize), mMaxSize(aMaxSize), mScale(aScale) {
if (mMaxSize.width > MOZ_WIDGET_MAX_SIZE) {
mMaxSize.width = MOZ_WIDGET_MAX_SIZE;
if (mMaxSize.height > MOZ_WIDGET_MAX_SIZE) {
mMaxSize.height = MOZ_WIDGET_MAX_SIZE;
mozilla::LayoutDeviceIntSize mMinSize;
mozilla::LayoutDeviceIntSize mMaxSize;
* The scale used to convert from desktop to device dimensions.
* MOZ_WIDGET_INVALID_SCALE if the value is not known.
* Bug 1701109 is filed to revisit adding of 'mScale' and deal
* with multi-monitor scaling issues in more complete way across
* all widget implementations.
mozilla::DesktopToLayoutDeviceScale mScale;
struct AutoObserverNotifier {
AutoObserverNotifier(nsIObserver* aObserver, const char* aTopic)
: mObserver(aObserver), mTopic(aTopic) {}
void SkipNotification() { mObserver = nullptr; }
uint64_t SaveObserver() {
if (!mObserver) {
return 0;
uint64_t observerId = ++sObserverId;
sSavedObservers.InsertOrUpdate(observerId, mObserver);
return observerId;
~AutoObserverNotifier() {
if (mObserver) {
mObserver->Observe(nullptr, mTopic, nullptr);
static void NotifySavedObserver(const uint64_t& aObserverId,
const char* aTopic) {
nsCOMPtr<nsIObserver> observer = sSavedObservers.Get(aObserverId);
if (!observer) {
MOZ_ASSERT(aObserverId == 0,
"We should always find a saved observer for nonzero IDs");
observer->Observe(nullptr, aTopic, nullptr);
nsCOMPtr<nsIObserver> mObserver;
const char* mTopic;
static uint64_t sObserverId;
static nsTHashMap<uint64_t, nsCOMPtr<nsIObserver>> sSavedObservers;
} // namespace widget
} // namespace mozilla
* The base class for all the widgets. It provides the interface for
* all basic and necessary functionality.
class nsIWidget : public nsISupports {
typedef mozilla::dom::BrowserChild BrowserChild;
typedef mozilla::layers::CompositorBridgeChild CompositorBridgeChild;
typedef mozilla::layers::AsyncDragMetrics AsyncDragMetrics;
typedef mozilla::layers::FrameMetrics FrameMetrics;
typedef mozilla::layers::LayerManager LayerManager;
typedef mozilla::WindowRenderer WindowRenderer;
typedef mozilla::layers::LayersBackend LayersBackend;
typedef mozilla::layers::LayersId LayersId;
typedef mozilla::layers::ScrollableLayerGuid ScrollableLayerGuid;
typedef mozilla::layers::ZoomConstraints ZoomConstraints;
typedef mozilla::widget::IMEEnabled IMEEnabled;
typedef mozilla::widget::IMEMessage IMEMessage;
typedef mozilla::widget::IMENotification IMENotification;
typedef mozilla::widget::IMENotificationRequests IMENotificationRequests;
typedef mozilla::widget::IMEState IMEState;
typedef mozilla::widget::InputContext InputContext;
typedef mozilla::widget::InputContextAction InputContextAction;
typedef mozilla::widget::NativeIMEContext NativeIMEContext;
typedef mozilla::widget::SizeConstraints SizeConstraints;
typedef mozilla::widget::TextEventDispatcher TextEventDispatcher;
typedef mozilla::widget::TextEventDispatcherListener
typedef mozilla::LayoutDeviceIntMargin LayoutDeviceIntMargin;
typedef mozilla::LayoutDeviceIntPoint LayoutDeviceIntPoint;
typedef mozilla::LayoutDeviceIntRect LayoutDeviceIntRect;
typedef mozilla::LayoutDeviceIntRegion LayoutDeviceIntRegion;
typedef mozilla::LayoutDeviceIntSize LayoutDeviceIntSize;
typedef mozilla::ScreenIntPoint ScreenIntPoint;
typedef mozilla::ScreenIntMargin ScreenIntMargin;
typedef mozilla::ScreenIntSize ScreenIntSize;
typedef mozilla::ScreenPoint ScreenPoint;
typedef mozilla::CSSToScreenScale CSSToScreenScale;
typedef mozilla::DesktopIntRect DesktopIntRect;
typedef mozilla::DesktopPoint DesktopPoint;
typedef mozilla::DesktopRect DesktopRect;
typedef mozilla::DesktopSize DesktopSize;
typedef mozilla::CSSPoint CSSPoint;
typedef mozilla::CSSRect CSSRect;
enum class WindowButtonType {
// Used in UpdateThemeGeometries.
struct ThemeGeometry {
// The ThemeGeometryType value for the themed widget, see
// nsITheme::ThemeGeometryTypeForWidget.
nsITheme::ThemeGeometryType mType;
// The device-pixel rect within the window for the themed widget
LayoutDeviceIntRect mRect;
ThemeGeometry(nsITheme::ThemeGeometryType aType,
const LayoutDeviceIntRect& aRect)
: mType(aType), mRect(aRect) {}
: mLastChild(nullptr),
* Create and initialize a widget.
* All the arguments can be null in which case a top level window
* with size 0 is created. The event callback function has to be
* provided only if the caller wants to deal with the events this
* widget receives. The event callback is basically a preprocess
* hook called synchronously. The return value determines whether
* the event goes to the default window procedure or it is hidden
* to the os. The assumption is that if the event handler returns
* false the widget does not see the event. The widget should not
* automatically clear the window to the background color. The
* calling code must handle paint messages and clear the background
* itself.
* In practice at least one of aParent and aNativeParent will be null. If
* both are null the widget isn't parented (e.g. context menus or
* independent top level windows).
* The dimensions given in aRect are specified in the parent's
* device coordinate system.
* This must not be called for parentless widgets such as top-level
* windows, which use the desktop pixel coordinate system; a separate
* method is provided for these.
* @param aParent parent nsIWidget
* @param aNativeParent native parent widget
* @param aRect the widget dimension
* @param aInitData data that is used for widget initialization
[[nodiscard]] virtual nsresult Create(
nsIWidget* aParent, nsNativeWidget aNativeParent,
const LayoutDeviceIntRect& aRect,
nsWidgetInitData* aInitData = nullptr) = 0;
* As above, but with aRect specified in DesktopPixel units (for top-level
* widgets).
* Default implementation just converts aRect to device pixels and calls
* through to device-pixel Create, but platforms may override this if the
* mapping is not straightforward or the native platform needs to use the
* desktop pixel values directly.
[[nodiscard]] virtual nsresult Create(nsIWidget* aParent,
nsNativeWidget aNativeParent,
const DesktopIntRect& aRect,
nsWidgetInitData* aInitData = nullptr) {
LayoutDeviceIntRect devPixRect =
RoundedToInt(aRect * GetDesktopToDeviceScale());
return Create(aParent, aNativeParent, devPixRect, aInitData);
* Allocate, initialize, and return a widget that is a child of
* |this|. The returned widget (if nonnull) has gone through the
* equivalent of CreateInstance(widgetCID) + Create(...).
* |CreateChild()| lets widget backends decide whether to parent
* the new child widget to this, nonnatively parent it, or both.
* This interface exists to support the PuppetWidget backend,
* which is entirely non-native. All other params are the same as
* for |Create()|.
* |aForceUseIWidgetParent| forces |CreateChild()| to only use the
* |nsIWidget*| this, not its native widget (if it exists), when
* calling |Create()|. This is a timid hack around poorly
* understood code, and shouldn't be used in new code.
virtual already_AddRefed<nsIWidget> CreateChild(
const LayoutDeviceIntRect& aRect, nsWidgetInitData* aInitData = nullptr,
bool aForceUseIWidgetParent = false) = 0;
* Attach to a top level widget.
* In cases where a top level chrome widget is being used as a content
* container, attach a secondary listener and update the device
* context. The primary widget listener will continue to be called for
* notifications relating to the top-level window, whereas other
* notifications such as painting and events will instead be called via
* the attached listener. SetAttachedWidgetListener should be used to
* assign the attached listener.
* aUseAttachedEvents if true, events are sent to the attached listener
* instead of the normal listener.
virtual void AttachViewToTopLevel(bool aUseAttachedEvents) = 0;
* Accessor functions to get and set the attached listener. Used by
* nsView in connection with AttachViewToTopLevel above.
virtual void SetAttachedWidgetListener(nsIWidgetListener* aListener) = 0;
virtual nsIWidgetListener* GetAttachedWidgetListener() = 0;
virtual void SetPreviouslyAttachedWidgetListener(
nsIWidgetListener* aListener) = 0;
virtual nsIWidgetListener* GetPreviouslyAttachedWidgetListener() = 0;
* Accessor functions to get and set the listener which handles various
* actions for the widget.
virtual nsIWidgetListener* GetWidgetListener() = 0;
virtual void SetWidgetListener(nsIWidgetListener* alistener) = 0;
* Close and destroy the internal native window.
* This method does not delete the widget.
virtual void Destroy() = 0;
* Destroyed() returns true if Destroy() has been called already.
* Otherwise, false.
bool Destroyed() const { return mOnDestroyCalled; }
* Reparent a widget
* Change the widget's parent. Null parents are allowed.
* @param aNewParent new parent
virtual void SetParent(nsIWidget* aNewParent) = 0;
* Return the parent Widget of this Widget or nullptr if this is a
* top level window
* @return the parent widget or nullptr if it does not have a parent
virtual nsIWidget* GetParent(void) = 0;
* Return the top level Widget of this Widget
* @return the top level widget
virtual nsIWidget* GetTopLevelWidget() = 0;
* Return the top (non-sheet) parent of this Widget if it's a sheet,
* or nullptr if this isn't a sheet (or some other error occurred).
* Sheets are only supported on some platforms (currently only macOS).
* @return the top (non-sheet) parent widget or nullptr
virtual nsIWidget* GetSheetWindowParent(void) = 0;
* Return the physical DPI of the screen containing the window ...
* the number of device pixels per inch.
virtual float GetDPI() = 0;
* Return the scaling factor between device pixels and the platform-
* dependent "desktop pixels" used to manage window positions on a
* potentially multi-screen, mixed-resolution desktop.
virtual mozilla::DesktopToLayoutDeviceScale GetDesktopToDeviceScale() = 0;
* Return the scaling factor between device pixels and the platform-
* dependent "desktop pixels" by looking up the screen by the position
* of the widget.
virtual mozilla::DesktopToLayoutDeviceScale
GetDesktopToDeviceScaleByScreen() = 0;
* Return the default scale factor for the window. This is the
* default number of device pixels per CSS pixel to use. This should
* depend on OS/platform settings such as the Mac's "UI scale factor"
* or Windows' "font DPI". This will take into account Gecko preferences
* overriding the system setting.
mozilla::CSSToLayoutDeviceScale GetDefaultScale();
* Return the first child of this widget. Will return null if
* there are no children.
nsIWidget* GetFirstChild() const { return mFirstChild; }
* Return the last child of this widget. Will return null if
* there are no children.
nsIWidget* GetLastChild() const { return mLastChild; }
* Return the next sibling of this widget
nsIWidget* GetNextSibling() const { return mNextSibling; }
* Set the next sibling of this widget
void SetNextSibling(nsIWidget* aSibling) { mNextSibling = aSibling; }
* Return the previous sibling of this widget
nsIWidget* GetPrevSibling() const { return mPrevSibling; }
* Set the previous sibling of this widget
void SetPrevSibling(nsIWidget* aSibling) { mPrevSibling = aSibling; }
* Show or hide this widget
* @param aState true to show the Widget, false to hide it
virtual void Show(bool aState) = 0;
* Whether or not a widget must be recreated after being hidden to show
* again properly.
virtual bool NeedsRecreateToReshow() { return false; }
* Make the window modal.
virtual void SetModal(bool aModal) = 0;
* Make the non-modal window opened by modal window fake-modal, that will
* call SetFakeModal(false) on destroy on Cocoa.
virtual void SetFakeModal(bool aModal) { SetModal(aModal); }
* Are we app modal. Currently only implemented on Cocoa.
virtual bool IsRunningAppModal() { return false; }
* The maximum number of simultaneous touch contacts supported by the device.
* In the case of devices with multiple digitizers (e.g. multiple touch
* screens), the value will be the maximum of the set of maximum supported
* contacts by each individual digitizer.
virtual uint32_t GetMaxTouchPoints() const = 0;
* Returns whether the window is visible
virtual bool IsVisible() const = 0;
* Perform platform-dependent sanity check on a potential window position.
* This is guaranteed to work only for top-level windows.
* @param aAllowSlop: if true, allow the window to slop offscreen;
* the window should be partially visible. if false,
* force the entire window onscreen (or at least
* the upper-left corner, if it's too large).
* @param aX in: an x position expressed in screen coordinates.
* out: the x position constrained to fit on the screen(s).
* @param aY in: an y position expressed in screen coordinates.
* out: the y position constrained to fit on the screen(s).
virtual void ConstrainPosition(bool aAllowSlop, int32_t* aX, int32_t* aY) = 0;
* For a top-level window widget, the "parent's coordinate system" is the
* "global" display pixel coordinate space, *not* device pixels (which
* may be inconsistent between multiple screens, at least in the Mac OS
* case with mixed hi-dpi and lo-dpi displays). This applies to all the
* following Move and Resize widget APIs.
* The display-/device-pixel distinction becomes important for (at least)
* macOS with Hi-DPI (retina) displays, and Windows when the UI scale factor
* is set to other than 100%.
* The Move and Resize methods take floating-point parameters, rather than
* integer ones. This is important when manipulating top-level widgets,
* where the coordinate system may not be an integral multiple of the
* device-pixel space.
* Move this widget.
* Coordinates refer to the top-left of the widget. For toplevel windows
* with decorations, this is the top-left of the titlebar and frame .
* @param aX the new x position expressed in the parent's coordinate system
* @param aY the new y position expressed in the parent's coordinate system
virtual void Move(double aX, double aY) = 0;
* Reposition this widget so that the client area has the given offset.
* @param aOffset the new offset of the client area expressed as an
* offset from the origin of the client area of the parent
* widget (for root widgets and popup widgets it is in
* screen coordinates)
virtual void MoveClient(const DesktopPoint& aOffset) = 0;
* Resize this widget. Any size constraints set for the window by a
* previous call to SetSizeConstraints will be applied.
* @param aWidth the new width expressed in the parent's coordinate system
* @param aHeight the new height expressed in the parent's coordinate
* system
* @param aRepaint whether the widget should be repainted
virtual void Resize(double aWidth, double aHeight, bool aRepaint) = 0;
* Lock the aspect ratio of a Window
* @param aShouldLock bool
virtual void LockAspectRatio(bool aShouldLock){};
* Move or resize this widget. Any size constraints set for the window by
* a previous call to SetSizeConstraints will be applied.
* @param aX the new x position expressed in the parent's coordinate
* system
* @param aY the new y position expressed in the parent's coordinate
* system
* @param aWidth the new width expressed in the parent's coordinate system
* @param aHeight the new height expressed in the parent's coordinate
* system
* @param aRepaint whether the widget should be repainted if the size
* changes
virtual void Resize(double aX, double aY, double aWidth, double aHeight,
bool aRepaint) = 0;
virtual mozilla::Maybe<bool> IsResizingNativeWidget() {
return mozilla::Nothing();
* Resize the widget so that the inner client area has the given size.
* @param aSize the new size of the client area.
* @param aRepaint whether the widget should be repainted
virtual void ResizeClient(const DesktopSize& aSize, bool aRepaint) = 0;
* Resize and reposition the widget so tht inner client area has the given
* offset and size.
* @param aRect the new offset and size of the client area. The offset is
* expressed as an offset from the origin of the client area
* of the parent widget (for root widgets and popup widgets it
* is in screen coordinates).
* @param aRepaint whether the widget should be repainted
virtual void ResizeClient(const DesktopRect& aRect, bool aRepaint) = 0;
* Sets the widget's z-index.
virtual void SetZIndex(int32_t aZIndex) = 0;
* Gets the widget's z-index.
int32_t GetZIndex() { return mZIndex; }
* Position this widget just behind the given widget. (Used to
* control z-order for top-level widgets. Get/SetZIndex by contrast
* control z-order for child widgets of other widgets.)
* @param aPlacement top, bottom, or below a widget
* (if top or bottom, param aWidget is ignored)
* @param aWidget widget to place this widget behind
* (only if aPlacement is eZPlacementBelow).
* null is equivalent to aPlacement of eZPlacementTop
* @param aActivate true to activate the widget after placing it
virtual void PlaceBehind(nsTopLevelWidgetZPlacement aPlacement,
nsIWidget* aWidget, bool aActivate) = 0;
* Minimize, maximize or normalize the window size.
* Takes a value from nsSizeMode (see nsIWidgetListener.h)
virtual void SetSizeMode(nsSizeMode aMode) = 0;
virtual void GetWorkspaceID(nsAString& workspaceID) = 0;
virtual void MoveToWorkspace(const nsAString& workspaceID) = 0;
* Suppress animations that are applied to a window by OS.
virtual void SuppressAnimation(bool aSuppress) {}
* Return size mode (minimized, maximized, normalized).
* Returns a value from nsSizeMode (see nsIWidgetListener.h)
virtual nsSizeMode SizeMode() = 0;
* Ask whether the window is tiled.
virtual bool IsTiled() const = 0;
* Ask wether the widget is fully occluded
virtual bool IsFullyOccluded() const = 0;
* Enable or disable this Widget
* @param aState true to enable the Widget, false to disable it.
virtual void Enable(bool aState) = 0;
* Ask whether the widget is enabled
virtual bool IsEnabled() const = 0;
* Whether we should request activation of this widget's toplevel window.
enum class Raise {
* Request activation of this window or give focus to this widget.
virtual void SetFocus(Raise, mozilla::dom::CallerType aCallerType) = 0;
* Get this widget's outside dimensions relative to its parent widget. For
* popup widgets the returned rect is in screen coordinates and not
* relative to its parent widget.
* @return the x, y, width and height of this widget.
virtual LayoutDeviceIntRect GetBounds() = 0;
* Get this widget's outside dimensions in device coordinates. This
* includes any title bar on the window.
* @return the x, y, width and height of this widget.
virtual LayoutDeviceIntRect GetScreenBounds() = 0;
* Similar to GetScreenBounds except that this function will always
* get the size when the widget is in the nsSizeMode_Normal size mode
* even if the current size mode is not nsSizeMode_Normal.
* This method will fail if the size mode is not nsSizeMode_Normal and
* the platform doesn't have the ability.
* This method will always succeed if the current size mode is
* nsSizeMode_Normal.
* @param aRect On return it holds the x, y, width and height of
* this widget.
[[nodiscard]] virtual nsresult GetRestoredBounds(
LayoutDeviceIntRect& aRect) = 0;
* Get this widget's client area bounds, if the window has a 3D border
* appearance this returns the area inside the border. The position is the
* position of the client area relative to the client area of the parent
* widget (for root widgets and popup widgets it is in screen coordinates).
* @return the x, y, width and height of the client area of this widget.
virtual LayoutDeviceIntRect GetClientBounds() = 0;
* Sets the non-client area dimensions of the window. Pass -1 to restore
* the system default frame size for that border. Pass zero to remove
* a border, or pass a specific value adjust a border. Units are in
* pixels. (DPI dependent)
* Platform notes:
* Windows: shrinking top non-client height will remove application
* icon and window title text. Glass desktops will refuse to set
* dimensions between zero and size < system default.
virtual nsresult SetNonClientMargins(LayoutDeviceIntMargin& aMargins) = 0;
* Get the client offset from the window origin.
* @return the x and y of the offset.
virtual LayoutDeviceIntPoint GetClientOffset() = 0;
* Equivalent to GetClientBounds but only returns the size.
virtual LayoutDeviceIntSize GetClientSize() {
// Depending on the backend, overloading this method may be useful if
// requesting the client offset is expensive.
return GetClientBounds().Size();
* Set the background color for this widget
* @param aColor the new background color
virtual void SetBackgroundColor(const nscolor& aColor) {}
* If a cursor type is currently cached locally for this widget, clear the
* cached cursor to force an update on the next SetCursor call.
virtual void ClearCachedCursor() = 0;
struct Cursor {
// The system cursor chosen by the page. This is used if there's no custom
// cursor, or if we fail to use the custom cursor in some way (if the image
// fails to load, for example).
nsCursor mDefaultCursor = eCursor_standard;
// May be null, to represent no custom cursor image.
nsCOMPtr<imgIContainer> mContainer;
uint32_t mHotspotX = 0;
uint32_t mHotspotY = 0;
mozilla::ImageResolution mResolution;
bool IsCustom() const { return !!mContainer; }
bool operator==(const Cursor& aOther) const {
return mDefaultCursor == aOther.mDefaultCursor &&
mContainer.get() == aOther.mContainer.get() &&
mHotspotX == aOther.mHotspotX && mHotspotY == aOther.mHotspotY &&
mResolution == aOther.mResolution;
bool operator!=(const Cursor& aOther) const { return !(*this == aOther); }
* Sets the cursor for this widget.
virtual void SetCursor(const Cursor&) = 0;
static nsIntSize CustomCursorSize(const Cursor&);
* Get the window type of this widget.
nsWindowType WindowType() { return mWindowType; }
* Set the transparency mode of the top-level window containing this widget.
* So, e.g., if you call this on the widget for an IFRAME, the top level
* browser window containing the IFRAME actually gets set. Be careful.
* This can fail if the platform doesn't support
* transparency/glass. By default widgets are not
* transparent. This will also fail if the toplevel window is not
* a Mozilla window, e.g., if the widget is in an embedded
* context.
* After transparency/glass has been enabled, the initial alpha channel
* value for all pixels is 1, i.e., opaque.
* If the window is resized then the alpha channel values for
* all pixels are reset to 1.
* Pixel RGB color values are already premultiplied with alpha channel values.
virtual void SetTransparencyMode(nsTransparencyMode aMode) = 0;
* Get the transparency mode of the top-level window that contains this
* widget.
virtual nsTransparencyMode GetTransparencyMode() = 0;
* Set the shadow style of the window.
* Ignored on child widgets and on non-Mac platforms.
virtual void SetWindowShadowStyle(mozilla::StyleWindowShadow aStyle) = 0;
* Set the opacity of the window.
* Values need to be between 0.0f (invisible) and 1.0f (fully opaque).
* Ignored on child widgets and on non-Mac platforms.
virtual void SetWindowOpacity(float aOpacity) {}
* Set the transform of the window. Values are in device pixels,
* the origin is the top left corner of the window.
* Ignored on child widgets and on non-Mac platforms.
virtual void SetWindowTransform(const mozilla::gfx::Matrix& aTransform) {}
* Set the preferred color-scheme for the widget.
* Ignored on non-Mac platforms.
virtual void SetColorScheme(const mozilla::Maybe<mozilla::ColorScheme>&) {}
* Set whether the window should ignore mouse events or not.
* This is only used on popup windows.
virtual void SetWindowMouseTransparent(bool aIsTransparent) {}
* On macOS, this method shows or hides the pill button in the titlebar
* that's used to collapse the toolbar.
* Ignored on child widgets and on non-Mac platforms.
virtual void SetShowsToolbarButton(bool aShow) = 0;
* On macOS, this method determines whether we tell cocoa that the window
* supports native full screen. If we do so, and another window is in
* native full screen, this window will also appear in native full screen.
* We generally only want to do this for primary application windows.
* Ignored on child widgets and on non-Mac platforms.
virtual void SetSupportsNativeFullscreen(bool aSupportsNativeFullscreen) = 0;
enum WindowAnimationType {
* Sets the kind of top-level window animation this widget should have. On
* macOS, this causes a particular kind of animation to be shown when the
* window is first made visible.
* Ignored on child widgets and on non-Mac platforms.
virtual void SetWindowAnimationType(WindowAnimationType aType) = 0;
* Specifies whether the window title should be drawn even if the window
* contents extend into the titlebar. Ignored on windows that don't draw
* in the titlebar. Only implemented on macOS.
virtual void SetDrawsTitle(bool aDrawTitle) {}
* Hide window chrome (borders, buttons) for this widget.
virtual void HideWindowChrome(bool aShouldHide) = 0;
enum FullscreenTransitionStage {
* Prepares for fullscreen transition and returns whether the widget
* supports fullscreen transition. If this method returns false,
* PerformFullscreenTransition() must never be called. Otherwise,
* caller should call that method twice with "before" and "after"
* stages respectively in order. In the latter case, this method may
* return some data via aData pointer. Caller must pass that data to
* PerformFullscreenTransition() if any, and caller is responsible
* for releasing that data.
virtual bool PrepareForFullscreenTransition(nsISupports** aData) = 0;
* Performs fullscreen transition. This method returns immediately,
* and will post aCallback to the main thread when the transition
* finishes.
virtual void PerformFullscreenTransition(FullscreenTransitionStage aStage,
uint16_t aDuration,
nsISupports* aData,
nsIRunnable* aCallback) = 0;
* Perform any actions needed after the fullscreen transition has ended.
virtual void CleanupFullscreenTransition() = 0;
* Return the screen the widget is in, or null if we don't know.
virtual already_AddRefed<nsIScreen> GetWidgetScreen() = 0;
* Put the toplevel window into or out of fullscreen mode.
* If aTargetScreen is given, attempt to go fullscreen on that screen,
* if possible. (If not, it behaves as if aTargetScreen is null.)
* If !aFullScreen, aTargetScreen is ignored.
* aTargetScreen support is currently only implemented on Windows.
* @return NS_OK if the widget is setup properly for fullscreen and
* FullscreenChanged callback has been or will be called. If other
* value is returned, the caller should continue the change itself.
virtual nsresult MakeFullScreen(bool aFullScreen,
nsIScreen* aTargetScreen = nullptr) = 0;
* Same as MakeFullScreen, except that, on systems which natively
* support fullscreen transition, calling this method explicitly
* requests that behavior.
* It is currently only supported on macOS 10.7+.
virtual nsresult MakeFullScreenWithNativeTransition(
bool aFullScreen, nsIScreen* aTargetScreen = nullptr) {
return MakeFullScreen(aFullScreen, aTargetScreen);
* Invalidate a specified rect for a widget so that it will be repainted
* later.
virtual void Invalidate(const LayoutDeviceIntRect& aRect) = 0;
enum LayerManagerPersistence {
* Return the widget's LayerManager. The layer tree for that
* LayerManager is what gets rendered to the widget.
virtual WindowRenderer* GetWindowRenderer() = 0;
* Called before each layer manager transaction to allow any preparation
* for DrawWindowUnderlay/Overlay that needs to be on the main thread.
* Always called on the main thread.
virtual void PrepareWindowEffects() = 0;
* Called on the main thread at the end of WebRender display list building.
virtual void AddWindowOverlayWebRenderCommands(
mozilla::layers::WebRenderBridgeChild* aWrBridge,
mozilla::wr::DisplayListBuilder& aBuilder,
mozilla::wr::IpcResourceUpdateQueue& aResources) {}
* Called when Gecko knows which themed widgets exist in this window.
* The passed array contains an entry for every themed widget of the right
* type (currently only StyleAppearance::Toolbar) within the window, except
* for themed widgets which are transformed or have effects applied to them
* (e.g. CSS opacity or filters).
* This could sometimes be called during display list construction
* outside of painting.
* If called during painting, it will be called before we actually
* paint anything.
virtual void UpdateThemeGeometries(
const nsTArray<ThemeGeometry>& aThemeGeometries) = 0;
* Informs the widget about the region of the window that is opaque.
* @param aOpaqueRegion the region of the window that is opaque.
virtual void UpdateOpaqueRegion(const LayoutDeviceIntRegion& aOpaqueRegion) {}
* Informs the widget about the region of the window that is draggable.
virtual void UpdateWindowDraggingRegion(
const LayoutDeviceIntRegion& aRegion) {}
* Tells the widget whether the given input block results in a swipe.
* Should be called in response to a WidgetWheelEvent that has
* mFlags.mCanTriggerSwipe set on it.
virtual void ReportSwipeStarted(uint64_t aInputBlockId, bool aStartSwipe) {}
* Internal methods
virtual void AddChild(nsIWidget* aChild) = 0;
virtual void RemoveChild(nsIWidget* aChild) = 0;
virtual void* GetNativeData(uint32_t aDataType) = 0;
virtual void SetNativeData(uint32_t aDataType, uintptr_t aVal) = 0;
virtual void FreeNativeData(void* data, uint32_t aDataType) = 0; //~~~
* Set the widget's title.
* Must be called after Create.
* @param aTitle string displayed as the title of the widget
virtual nsresult SetTitle(const nsAString& aTitle) = 0;
* Set the widget's icon.
* Must be called after Create.
* @param aIconSpec string specifying the icon to use; convention is to
* pass a resource: URL from which a platform-dependent
* resource file name will be constructed
virtual void SetIcon(const nsAString& aIconSpec) = 0;
* Return this widget's origin in screen coordinates.
* @return screen coordinates stored in the x,y members
virtual LayoutDeviceIntPoint WidgetToScreenOffset() = 0;
* The same as WidgetToScreenOffset(), except in the case of
* PuppetWidget where this method omits the chrome offset.
virtual LayoutDeviceIntPoint TopLevelWidgetToScreenOffset() {
return WidgetToScreenOffset();
* For a PuppetWidget, returns the transform from the coordinate
* space of the PuppetWidget to the coordinate space of the
* top-level native widget.
* Identity transform in other cases.
virtual mozilla::LayoutDeviceToLayoutDeviceMatrix4x4
WidgetToTopLevelWidgetTransform() {
return mozilla::LayoutDeviceToLayoutDeviceMatrix4x4();
* Given the specified client size, return the corresponding window size,
* which includes the area for the borders and titlebar. This method
* should work even when the window is not yet visible.
virtual LayoutDeviceIntSize ClientToWindowSize(
const LayoutDeviceIntSize& aClientSize) = 0;
* Dispatches an event to the widget
virtual nsresult DispatchEvent(mozilla::WidgetGUIEvent* event,
nsEventStatus& aStatus) = 0;
* Dispatches an event to APZ only.
* No-op in the child process.
virtual void DispatchEventToAPZOnly(mozilla::WidgetInputEvent* aEvent) = 0;
// A structure that groups the statuses from APZ dispatch and content
// dispatch.
struct ContentAndAPZEventStatus {
// Either of these may not be set if the event was not dispatched
// to APZ or to content.
nsEventStatus mApzStatus = nsEventStatus_eIgnore;
nsEventStatus mContentStatus = nsEventStatus_eIgnore;
* Dispatches an event that must be handled by APZ first, when APZ is
* enabled. If invoked in the child process, it is forwarded to the
* parent process synchronously.
virtual ContentAndAPZEventStatus DispatchInputEvent(
mozilla::WidgetInputEvent* aEvent) = 0;
* Confirm an APZ-aware event target. This should be used when APZ will
* not need a layers update to process the event.
virtual void SetConfirmedTargetAPZC(
uint64_t aInputBlockId,
const nsTArray<ScrollableLayerGuid>& aTargets) const = 0;
* Returns true if APZ is in use, false otherwise.
virtual bool AsyncPanZoomEnabled() const = 0;
* Enables the dropping of files to a widget.
virtual void EnableDragDrop(bool aEnable) = 0;
virtual nsresult AsyncEnableDragDrop(bool aEnable) = 0;
* Enables/Disables system mouse capture.
* @param aCapture true enables mouse capture, false disables mouse capture
virtual void CaptureMouse(bool aCapture) = 0;
* Classify the window for the window manager. Mostly for X11.
virtual void SetWindowClass(const nsAString& xulWinType) = 0;
* Enables/Disables system capture of any and all events that would cause a
* popup to be rolled up. aListener should be set to a non-null value for
* any popups that are not managed by the popup manager.
* @param aDoCapture true enables capture, false disables capture
virtual void CaptureRollupEvents(nsIRollupListener* aListener,
bool aDoCapture) = 0;
* Bring this window to the user's attention. This is intended to be a more
* gentle notification than popping the window to the top or putting up an
* alert. See, for example, Win32 FlashWindow or the NotificationManager on
* the Mac. The notification should be suppressed if the window is already
* in the foreground and should be dismissed when the user brings this window
* to the foreground.
* @param aCycleCount Maximum number of times to animate the window per system
* conventions. If set to -1, cycles indefinitely until
* window is brought into the foreground.
[[nodiscard]] virtual nsresult GetAttention(int32_t aCycleCount) = 0;
* Ask whether there user input events pending. All input events are
* included, including those not targeted at this nsIwidget instance.
virtual bool HasPendingInputEvent() = 0;
* If set to true, the window will draw its contents into the titlebar
* instead of below it.
* Ignored on any platform that does not support it. Ignored by widgets that
* do not represent windows.
* May result in a resize event, so should only be called from places where
* reflow and painting is allowed.
* @param aState Whether drawing into the titlebar should be activated.
virtual void SetDrawsInTitlebar(bool aState) = 0;
* Determine whether the widget shows a resize widget. If it does,
* aResizerRect returns the resizer's rect.
* Returns false on any platform that does not support it.
* @param aResizerRect The resizer's rect in device pixels.
* @return Whether a resize widget is shown.
virtual bool ShowsResizeIndicator(LayoutDeviceIntRect* aResizerRect) = 0;
* Begin a window resizing drag, based on the event passed in.
[[nodiscard]] virtual nsresult BeginResizeDrag(
mozilla::WidgetGUIEvent* aEvent, int32_t aHorizontal,
int32_t aVertical) = 0;
// TODO: Make this an enum class with MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS or
// EnumSet class.
enum Modifiers : uint32_t {
NO_MODIFIERS = 0x00000000,
CAPS_LOCK = 0x00000001, // when CapsLock is active
NUM_LOCK = 0x00000002, // when NumLock is active
SHIFT_L = 0x00000100,
SHIFT_R = 0x00000200,
CTRL_L = 0x00000400,
CTRL_R = 0x00000800,
ALT_L = 0x00001000, // includes Option
ALT_R = 0x00002000,
COMMAND_L = 0x00004000,
COMMAND_R = 0x00008000,
HELP = 0x00010000,
ALTGRAPH = 0x00020000, // AltGr key on Windows. This emulates
// AltRight key behavior of keyboard
// layouts which maps AltGr to AltRight
// key.
FUNCTION = 0x00100000,
NUMERIC_KEY_PAD = 0x01000000 // when the key is coming from the keypad
* Utility method intended for testing. Dispatches native key events
* to this widget to simulate the press and release of a key.
* @param aNativeKeyboardLayout a *platform-specific* constant.
* On Mac, this is the resource ID for a 'uchr' or 'kchr' resource.
* On Windows, it is converted to a hex string and passed to
* LoadKeyboardLayout, see
* @param aNativeKeyCode a *platform-specific* keycode.
* On Windows, this is the virtual key code.
* @param aModifiers some combination of the above 'Modifiers' flags;
* not all flags will apply to all platforms. Mac ignores the _R
* modifiers. Windows ignores COMMAND, NUMERIC_KEY_PAD, HELP and
* @param aCharacters characters that the OS would decide to generate
* from the event. On Windows, this is the charCode passed by
* @param aUnmodifiedCharacters characters that the OS would decide
* to generate from the event if modifier keys (other than shift)
* were assumed inactive. Needed on Mac, ignored on Windows.
* @param aObserver the observer that will get notified once the events
* have been dispatched.
* @return NS_ERROR_NOT_AVAILABLE to indicate that the keyboard
* layout is not supported and the event was not fired
virtual nsresult SynthesizeNativeKeyEvent(
int32_t aNativeKeyboardLayout, int32_t aNativeKeyCode,
uint32_t aModifierFlags, const nsAString& aCharacters,
const nsAString& aUnmodifiedCharacters, nsIObserver* aObserver) = 0;
* Utility method intended for testing. Dispatches native mouse events
* may even move the mouse cursor. On Mac the events are guaranteed to
* be sent to the window containing this widget, but on Windows they'll go
* to whatever's topmost on the screen at that position, so for
* cross-platform testing ensure that your window is at the top of the
* z-order.
* @param aPoint screen location of the mouse, in device
* pixels, with origin at the top left
* @param aNativeMessage abstract native message.
* @param aButton Mouse button defined by DOM UI Events.
* @param aModifierFlags Some values of nsIWidget::Modifiers.
* FYI: On Windows, Android and Headless widget on all
* platroms, this hasn't been handled yet.
* @param aObserver the observer that will get notified once the events
* have been dispatched.
enum class NativeMouseMessage : uint32_t {
ButtonDown, // button down
ButtonUp, // button up
Move, // mouse cursor move
EnterWindow, // mouse cursor comes into a window
LeaveWindow, // mouse cursor leaves from a window
virtual nsresult SynthesizeNativeMouseEvent(
LayoutDeviceIntPoint aPoint, NativeMouseMessage aNativeMessage,
mozilla::MouseButton aButton, nsIWidget::Modifiers aModifierFlags,
nsIObserver* aObserver) = 0;
* A shortcut to SynthesizeNativeMouseEvent, abstracting away the native
* message. aPoint is location in device pixels to which the mouse pointer
* moves to.
* @param aObserver the observer that will get notified once the events
* have been dispatched.
virtual nsresult SynthesizeNativeMouseMove(LayoutDeviceIntPoint aPoint,
nsIObserver* aObserver) = 0;
* Utility method intended for testing. Dispatching native mouse scroll
* events may move the mouse cursor.
* @param aPoint Mouse cursor position in screen coordinates.
* In device pixels, the origin at the top left of
* the primary display.
* @param aNativeMessage Platform native message.
* @param aDeltaX The delta value for X direction. If the native
* message doesn't indicate X direction scrolling,
* this may be ignored.
* @param aDeltaY The delta value for Y direction. If the native
* message doesn't indicate Y direction scrolling,
* this may be ignored.
* @param aDeltaZ The delta value for Z direction. If the native
* message doesn't indicate Z direction scrolling,
* this may be ignored.
* @param aModifierFlags Must be values of Modifiers, or zero.
* @param aAdditionalFlags See nsIDOMWidnowUtils' consts and their
* document.
* @param aObserver The observer that will get notified once the
* events have been dispatched.
virtual nsresult SynthesizeNativeMouseScrollEvent(
LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage, double aDeltaX,
double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
uint32_t aAdditionalFlags, nsIObserver* aObserver) = 0;
* TouchPointerState states for SynthesizeNativeTouchPoint. Match
* touch states in nsIDOMWindowUtils.idl.
enum TouchPointerState {
// The pointer is in a hover state above the digitizer
TOUCH_HOVER = (1 << 0),
// The pointer is in contact with the digitizer
TOUCH_CONTACT = (1 << 1),
// The pointer has been removed from the digitizer detection area
TOUCH_REMOVE = (1 << 2),
// The pointer has been canceled. Will cancel any pending os level
// gestures that would triggered as a result of completion of the
// input sequence. This may not cancel moz platform related events
// that might get tirggered by input already delivered.
TOUCH_CANCEL = (1 << 3),
// ALL_BITS used for validity checking during IPC serialization
ALL_BITS = (1 << 4) - 1
* TouchpadGesturePhase states for SynthesizeNativeTouchPadPinch and
* SynthesizeNativeTouchpadPan. Match phase states in nsIDOMWindowUtils.idl.
enum TouchpadGesturePhase {
* Create a new or update an existing touch pointer on the digitizer.
* To trigger os level gestures, individual touch points should
* transition through a complete set of touch states which should be
* sent as individual messages.
* @param aPointerId The touch point id to create or update.
* @param aPointerState one or more of the touch states listed above
* @param aPoint coords of this event
* @param aPressure 0.0 -> 1.0 float val indicating pressure
* @param aOrientation 0 -> 359 degree value indicating the
* orientation of the pointer. Use 90 for normal taps.
* @param aObserver The observer that will get notified once the events
* have been dispatched.
virtual nsresult SynthesizeNativeTouchPoint(uint32_t aPointerId,
TouchPointerState aPointerState,
LayoutDeviceIntPoint aPoint,
double aPointerPressure,
uint32_t aPointerOrientation,
nsIObserver* aObserver) = 0;
* See nsIDOMWindowUtils.sendNativeTouchpadPinch().
virtual nsresult SynthesizeNativeTouchPadPinch(
TouchpadGesturePhase aEventPhase, float aScale,
LayoutDeviceIntPoint aPoint, int32_t aModifierFlags) = 0;
* Helper for simulating a simple tap event with one touch point. When
* aLongTap is true, simulates a native long tap with a duration equal to
* ui.click_hold_context_menus.delay. This pref is compatible with the
* apzc long tap duration. Defaults to 1.5 seconds.
* @param aObserver The observer that will get notified once the events
* have been dispatched.
virtual nsresult SynthesizeNativeTouchTap(LayoutDeviceIntPoint aPoint,
bool aLongTap,
nsIObserver* aObserver);
virtual nsresult SynthesizeNativePenInput(uint32_t aPointerId,