Code/ThirdParty/RmlUi/Source/Core/WidgetScroll.h - dev - redgpu/ezEngine

Code/ThirdParty/RmlUi/Source/Core/WidgetScroll.h
99 строк3 KB
C-Core
Updated RmlUi to 6.2 and added some improvements (#1813)
10 фев 2026, 01:19
10 фев 2026, 01:1958e2d41
#pragma once

#include "../../Include/RmlUi/Core/EventListener.h"

namespace Rml {

class Element;
enum class ScrollBehavior;

/**
    A widget for incorporating scrolling functionality into an element.
 */

class WidgetScroll final : public EventListener {
public:
	enum Orientation { UNKNOWN, VERTICAL, HORIZONTAL };

	WidgetScroll(Element* parent);
	virtual ~WidgetScroll();

	/// Initialises the slider to a given orientation.
	bool Initialise(Orientation orientation);

	/// Updates the key repeats for the increment / decrement arrows.
	void Update();

	/// Sets the position of the bar.
	/// @param[in] bar_position The new position of the bar (0 representing the start of the track, 1 representing the end).
	void SetBarPosition(float bar_position);
	/// Returns the current position of the bar.
	/// @return The current position of the bar (0 representing the start of the track, 1 representing the end).
	float GetBarPosition() const;

	/// Returns the slider's orientation.
	/// @return The orientation of the slider.
	Orientation GetOrientation() const;

	/// Sets the dimensions to the size of the slider.
	/// @param[in] dimensions The dimensions to size.
	void GetDimensions(Vector2f& dimensions) const;

	/// Sets the length of the entire track in scrollable units (usually lines or characters). This affects the
	/// length of the bar element and the speed of scrolling using the mouse-wheel or arrows.
	/// @param[in] track_length The length of the track.
	void SetTrackLength(float track_length);
	/// Sets the length the bar represents in scrollable units (usually lines or characters), relative to the track
	/// length. For example, for a scroll bar, this would represent how big each visible 'page' is compared to the
	/// whole document (which would be set as the track length).
	/// @param[in] bar_length The length of the slider's bar.
	void SetBarLength(float bar_length);

	/// Lays out and resizes the internal elements.
	/// @param[in] containing_block The padded box containing the slider. This is used to resolve relative properties.
	/// @param[in] slider_length The total length, in pixels, of the slider widget.
	void FormatElements(Vector2f containing_block, float slider_length);

private:
	/// Handles events coming through from the slider's components.
	void ProcessEvent(Event& event) override;

	/// Lays out and positions the bar element.
	void FormatBar();

	// Set the offset on 'bar' based on its position.
	void PositionBar();

	void ScrollLineDown();
	void ScrollLineUp();
	void ScrollPageDown();
	void ScrollPageUp();

	// Scrolls the parent element by the given distance.
	void Scroll(float distance, ScrollBehavior behavior);

	Element* parent;

	Orientation orientation;

	// The background track element, across which the bar slides.
	Element* track;
	// The bar element. This is the element that is dragged across the trough.
	Element* bar;
	// The two (optional) buttons for incrementing and decrementing the slider.
	Element* arrows[2];

	// A number from 0 to 1, indicating how far along the track the bar is.
	float bar_position;
	// If the bar is being dragged, this is the pixel offset from the start of the bar to where it was picked up.
	float bar_drag_anchor;

	// Set to the auto-repeat timer if either of the arrow buttons have been pressed, -1 if they haven't.
	float arrow_timers[2];
	double last_update_time;

	float track_length;
	float bar_length;
};

} // namespace Rml