View

Base class for GUI components.

Header#include "nativeui/view.h"
Namespacenamespace nu
Typeclass (RefCounted)

View provides methods to receive and change various style properties.

View is a RefCounted type. Sub-classes of View can only be created on heap, and must be managed with scoped_refptr. Every API that accepets View* will store a reference to the pointer, so it is safe to pass a newly created raw pointer to public APIs.

scoped_refptr<nu::Container> container = new nu::Container;
container->AddChildView(new nu::Label("child"));

Class properties

const char* kClassName

The class name of this view.

Methods

const char* GetClassName() const

Return the class name.

The returned value is guarenteed to be the kClassName property of each view.

Return

const char*

Vector2dF OffsetFromView(const View* view) const

Return offset from view.

Parameters

Return

Vector2dF

Vector2dF OffsetFromWindow() const

Return offset from the window that owns the view.

Return

Vector2dF

RectF GetBounds() const

Return the position and size of the view, relative to its parent.

Return

RectF

void Layout()

Make the view re-recalculate its layout.

void SchedulePaint()

Schedule to repaint the whole view.

void SchedulePaintRect(const RectF& rect)

Schedule to repaint the rect area in view.

Parameters

void SetVisible(bool visible)

Show/Hide the view.

Parameters

bool IsVisible() const

Return whether the view is visible.

Return

bool

void SetEnabled(bool enable)

Set whether the view is enabled.

The enabled state of each view is not affected by its parent, disabling a container-like view does not have any effect.

Parameters

bool IsEnabled() const

Return whether the view is enabled.

Return

bool

void Focus()

Move the keyboard focus to the view.

bool HasFocus() const

Return whether the view has keyboard focus.

Return

bool

void SetFocusable(bool focusable)

Set whether the view can be focused on.

Parameters

bool IsFocusable() const

Return whether the view can be focused on.

Return

bool

void SetCapture()

Set mouse capture to the view.

void ReleaseCapture()

Release mouse capture if the view has mouse capture.

bool HasCapture() const

Return whether the view has mouse capture.

Return

bool

void SetMouseDownCanMoveWindow(bool can)

Set whether dragging mouse would move the window.

For most platforms this method only works for frameless windows, having this feature may also prevent mouse events to happen.

On macOS the Container view has this feature turned on by default. To turn this feature on for the view, the view's parent view must also has this feature turned on.

On Windows the view with this feature will be treated as titlebar, e.g. double-clicking would maximize the window, right-clicking may show the system menu.

Parameters

bool IsMouseDownCanMoveWindow() const

Return whether dragging the view would move the window.

Return

bool

int DoDrag(std::vector<Clipboard::Data> data, int operations)

Like DoDragWithOptions but do not set drag image.

Parameters

Return

int

int DoDragWithOptions(std::vector<Clipboard::Data> data, int operations, const DragOptions& options)

Start a drag session.

The return value is a DragOperation indicating the result of dragging.

This method should only be called in the on_mouse_down event, when user starts to drag the cursor.

This method is blocking that it does not return until the drag session is finished or cancelled. During the call a nested UI message loop will run and other events will still be emitted.

Note that on macOS certain views may have IsMouseDownCanMoveWindow defaulting to true, which will prevent drag session to start. Make sure to call SetMouseDownCanMoveWindow(false) for drag sources.

Parameters

Return

int

void CancelDrag()

Cancel current drag session if the view is being used as drag source.

bool IsDragging() const

Return whether the view is being used as drag source.

Return

bool

void RegisterDraggedTypes(std::set<Clipboard::Data::Type> types)

Make the view a drag destination that accepets types.

Parameters

void SetCursor(scoped_refptr<Cursor> cursor)

Set the cursor to show when hovering the view.

On Linux, setting cursor would force the view to own its own GDK window. For certain views like Label, this may have remove the view's background color.

Parameters

void SetFont(scoped_refptr<Font> font)

Change the font used for drawing text in the view.

This methods only works for Views that display text, like Label or Entry.

Parameters

void SetColor(Color color)

Change the color used for drawing text in the view.

This methods only works for Views that display text, like Label or Entry.

Parameters

void SetBackgroundColor(Color color)

Change the background color of the view.

Parameters

void SetStyle(Args... styles)

Change the styles of the view.

Available style properties can be found at Layout System.

view->SetStyle("flex", 1, "flex-direction", "row");

Parameters

std::string GetComputedLayout() const

Return string representation of the view's layout.

Return

std::string

SizeF GetMinimumSize() const

Return the minimum size needed to show the view.

Return

SizeF

View* GetParent() const

Return parent view.

Return

View*

Window* GetWindow() const

Return the window that the view belongs to.

Return

Window*

NativeView GetNative() const

Return the native type wrapped by the view.

Return

NativeView

Events

bool on_mouse_down(View* self, const MouseEvent& event)

Emitted when pressing mouse buttons.

Parameters

Preventable

Yes.

bool on_mouse_up(View* self, const MouseEvent& event)

Emitted when releasing mouse buttons.

Parameters

Preventable

Yes.

void on_mouse_move(View* self, const MouseEvent& event)

Emitted when user moves mouse in the view.

Parameters

Preventable

No.

void on_mouse_enter(View* self, const MouseEvent& event)

Emitted when mouse enters the view.

Parameters

Preventable

No.

void on_mouse_leave(View* self, const MouseEvent& event)

Emitted when mouse leaves the view.

Parameters

Preventable

No.

bool on_key_down(View* self, const KeyEvent& event)

Emitted when pressing keyboard.

Parameters

Preventable

Yes.

bool on_key_up(View* self, const KeyEvent& event)

Emitted when releasing keyboard.

Parameters

Preventable

Yes.

void on_drag_leave(View* self, DraggingInfo* info)>

Emitted when cursor leaves the view while dragging.

This event will also be emitted before the handle_drop event when user drops the data on the view.

Parameters

Preventable

No.

void on_size_changed(View* self)

Emitted when the view's size has been changed.

Parameters

Preventable

No.

void on_capture_lost(View* self)

Emitted when the mouse capture on view has been released.

Parameters

Preventable

No.

Delegates

int handle_drag_enter(View* self, DraggingInfo* info, const PointF& point)

Called when user drags the cursor over the view for the first time.

A DragOperation should be returned, indicating which dragging operation the destination will perform when cursor is released.

This delegate will not be called if the view has not registered dragged types, or if the dragged data does not belong to the registered type.

On Linux the dragged data is not yet available when this is called, you should usually only read data in the handle_drop delegate.

Parameters

Return

int

int handle_drag_update(View* self, DraggingInfo* info, const PointF& point)

Called when user moves the cursor over the view while dragging.

A DragOperation should be returned, indicating which dragging operation the destination will perform when cursor is released.

If this delegate is not implemented, the return value of previous handle_drag_enter call will be returned.

This delegate is usually used when implementing a custom view with multiple dropping areas, you only need to implement handle_drag_enter for simple tasks.

On Linux the dragged data is not yet available when this is called, you should usually only read data in the handle_drop delegate.

Parameters

Return

int

bool handle_drop(View* self, DraggingInfo* info, const PointF& point)

Called when user releases the dragged data on the view.

Returning true will inform the drag source that the data has been accepted with the drag operation returned by previous handle_drag_enter or handle_drag_update call.

If the drag operation is Move, the drag source may also take actions to "remove" the data on its side.

Returning false will inform the drag source that the drag has been cancelled, and operating system may display some visual effects.

Parameters

Return

bool

Langauge:

C++ | Lua | JavaScript

Version:

v0.10.3

Formats:

JSON

Class properties:

Methods:

Events:

Delegates:

Components: