Class Widget

include/widget/Widget.hpp:21–523

A node in the 2D [scene graph](https://en.wikipedia.org/wiki/Scene_graph). The bounding box of a Widget is a rectangle specified by `box` relative to their parent. The appearance is defined by overriding `draw()`, and the behavior is defined by overriding `step()` and `on*()` event handlers. */

The appearance is defined by overriding `draw()`, and the behavior is defined by overriding `step()` and `on*()` event handlers.
*/
struct Widget : WeakBase {
	/** Position relative to parent and size of widget. */
	math::Rect box = math::Rect(math::Vec(), math::Vec(INFINITY, INFINITY));
	/** Automatically set when Widget is added as a child to another Widget */
	Widget* parent = NULL;
	std::list<Widget*> children;
	/** Disables rendering but allow stepping.
	Use isVisible(), setVisible(), show(), or hide() instead of using this variable directly.
	*/
	bool visible = true;
	/** If set to true, parent will delete Widget in the next step().
	Use requestDelete() instead of using this variable directly.
	*/
	bool requestedDelete = false;

	virtual ~Widget();

	math::Rect getBox();
	/** Calls setPosition() and then setSize(). */
	void setBox(math::Rect box);
	math::Vec getPosition();
	/** Sets position and triggers RepositionEvent if position changed. */
	void setPosition(math::Vec pos);
	math::Vec getSize();
	/** Sets size and triggers ResizeEvent if size changed. */
	void setSize(math::Vec size);
	widget::Widget* getParent();
	bool isVisible();
	/** Sets `visible` and triggers ShowEvent or HideEvent if changed. */
	void setVisible(bool visible);
	/** Makes Widget visible and triggers ShowEvent if changed. */
	void show() {
		setVisible(true);
	}
	/** Makes Widget not visible and triggers HideEvent if changed. */
	void hide() {
		setVisible(false);
	}

	/** Requests this Widget's parent to delete it in the next step(). */
	void requestDelete();

	/** Returns the smallest rectangle containing this widget's children (visible and invisible) in its local coordinates.
	Returns `Rect(Vec(inf, inf), Vec(-inf, -inf))` if there are no children.
	*/
	virtual math::Rect getChildrenBoundingBox();
	virtual math::Rect getVisibleChildrenBoundingBox();
	/** Returns whether `ancestor` is a parent or distant parent of this widget.
	*/
	bool isDescendantOf(Widget* ancestor);
	/**  Returns `v` (given in local coordinates) transformed into the coordinate system of `ancestor`.
	*/
	virtual math::Vec getRelativeOffset(math::Vec v, Widget* ancestor);
	/** Returns `v` transformed into world/root/global/absolute coordinates.
	*/
	math::Vec getAbsoluteOffset(math::Vec v) {
		return getRelativeOffset(v, NULL);
	}