Scrollbar.hpp

//
// TGUI - Texus' Graphical User Interface
// Copyright (C) 2012-2025 Bruno Van de Velde (vdv_b@tgui.eu)
//
// This software is provided 'as-is', without any express or implied warranty.
// In no event will the authors be held liable for any damages arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it freely,
// subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented;
//    you must not claim that you wrote the original software.
//    If you use this software in a product, an acknowledgment
//    in the product documentation would be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such,
//    and must not be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source distribution.
//
 
#ifndef TGUI_SCROLLBAR_HPP
#define TGUI_SCROLLBAR_HPP
 
#include <TGUI/Widget.hpp>
#include <TGUI/Renderers/ScrollbarRenderer.hpp>
#include <TGUI/CopiedSharedPtr.hpp>
 
#if !TGUI_EXPERIMENTAL_USE_STD_MODULE
    #include <chrono>
#endif

 
TGUI_MODULE_EXPORT namespace tgui
{
    class TGUI_API Scrollbar : public Widget
    {
    public:
 
        using Ptr = std::shared_ptr<Scrollbar>; 
        using ConstPtr = std::shared_ptr<const Scrollbar>; 
 
        static constexpr const char StaticWidgetType[] = "Scrollbar"; 

        enum class Policy
        {
            Automatic,  
            Always,     
            Never       
        };

        Scrollbar(const char* typeName = StaticWidgetType, bool initRenderer = true);

        TGUI_NODISCARD static Scrollbar::Ptr create(Orientation orientation = Orientation::Vertical);

        TGUI_NODISCARD static Scrollbar::Ptr copy(const Scrollbar::ConstPtr& scrollbar);

        TGUI_NODISCARD ScrollbarRenderer* getSharedRenderer() override;
        TGUI_NODISCARD const ScrollbarRenderer* getSharedRenderer() const override;

        TGUI_NODISCARD ScrollbarRenderer* getRenderer() override;

        void setSize(const Layout2d& size) override;
        using Widget::setSize;

        void setMaximum(unsigned int maximum);

        TGUI_NODISCARD unsigned int getMaximum() const;

        void setValue(unsigned int value);

        TGUI_NODISCARD unsigned int getValue() const;

        void setViewportSize(unsigned int viewport);

        TGUI_NODISCARD unsigned int getViewportSize() const;

        TGUI_NODISCARD unsigned int getMaxValue() const;

        void setScrollAmount(unsigned int scrollAmount);

        TGUI_NODISCARD unsigned int getScrollAmount() const;
 
#ifndef TGUI_REMOVE_DEPRECATED_CODE
        TGUI_DEPRECATED("Use setPolicy instead") void setAutoHide(bool autoHide);

        TGUI_DEPRECATED("Use getPolicy instead") TGUI_NODISCARD bool getAutoHide() const;
#endif

        void setPolicy(Policy policy);

        TGUI_NODISCARD Scrollbar::Policy getPolicy() const;

        TGUI_NODISCARD bool isShown() const;

        TGUI_DEPRECATED("Use setOrientation instead") void setVerticalScroll(bool vertical);

        TGUI_DEPRECATED("Use getOrientation instead") TGUI_NODISCARD bool getVerticalScroll() const;

        void setOrientation(Orientation orientation);

        TGUI_NODISCARD Orientation getOrientation() const;

        TGUI_NODISCARD float getDefaultWidth() const;

        TGUI_NODISCARD bool canGainFocus() const override;

        TGUI_NODISCARD bool isMouseOnWidget(Vector2f pos) const override;

        bool leftMousePressed(Vector2f pos) override;

        void leftMouseReleased(Vector2f pos) override;

        void mouseMoved(Vector2f pos) override;

        bool scrolled(float delta, Vector2f pos, bool touch) override;

        void leftMouseButtonNoLongerDown() override;

        void draw(BackendRenderTarget& target, RenderStates states) const override;

    protected:

        // Updates the scrollbar after a size change
        void updateSize();

        TGUI_NODISCARD Signal& getSignal(String signalName) override;

        void rendererChanged(const String& property) override;

        TGUI_NODISCARD std::unique_ptr<DataIO::Node> save(SavingRenderersMap& renderers) const override;

        void load(const std::unique_ptr<DataIO::Node>& node, const LoadingRenderersMap& renderers) override;

        // Updates the position of the thumb based on the current value of the slider
        void updateThumbPosition();

        // Makes a copy of the widget
        TGUI_NODISCARD Widget::Ptr clone() const override;

    private:

        // Schedules a callback to regularly change the value of the scrollbar as long as the mouse remains pressed on an arrow
        void callMousePressPeriodically(std::chrono::time_point<std::chrono::steady_clock> clickedTime, bool repeatedCall);

    public:
 
        SignalUInt onValueChange = {"ValueChanged"}; 

    protected:
 
        enum class Part
        {
            None,
            Track,
            Thumb,
            ArrowUp,
            ArrowDown
        };
 
        // Keep track on which part of the scrollbar the mouse is standing
        Part m_mouseHoverOverPart = Part::None;
 
        // When the mouse went down, did it go down on top of the thumb? If so, where?
        bool m_mouseDownOnThumb = false;
        Vector2f m_mouseDownOnThumbPos;
 
        unsigned int m_maximum = 10;
        unsigned int m_value = 0;
 
        // Maximum should be above this value before the scrollbar is needed
        unsigned int m_viewportSize = 1;
 
        Orientation m_orientation = Orientation::Vertical; // Is the scrollbar drawn horizontally or vertically?
        Orientation m_imageOrientation = Orientation::Vertical;  // Does the loaded image lie horizontally or vertically?
        bool m_orientationLocked = false; // TGUI_NEXT: Remove property and make locked the default
 
        // How far should the value change when pressing one of the arrows?
        unsigned int m_scrollAmount = 1;
 
        // Defines when the scrollbar should be visible or hidden
        Scrollbar::Policy m_policy = Scrollbar::Policy::Automatic;
 
        // Did the mouse went down on one of the arrows?
        bool m_mouseDownOnIncreaseArrow = false;
        bool m_mouseDownOnDecreaseArrow = false;
        std::chrono::time_point<std::chrono::steady_clock> m_lastMousePressTime;
 
        bool m_sizeSet = false; // Has setSize been called?
 
        std::chrono::steady_clock::time_point m_lastSuccessfulScrollTime; // Timestamp of the last mouse wheel scroll event
        Vector2f m_lastSuccessfulScrollPos; // Mouse position at the last mouse wheel scroll event
 
        FloatRect m_track;
        FloatRect m_thumb;
        FloatRect m_arrowUp;
        FloatRect m_arrowDown;
 
        Sprite m_spriteTrack;
        Sprite m_spriteTrackHover;
        Sprite m_spriteThumb;
        Sprite m_spriteThumbHover;
        Sprite m_spriteArrowUp;
        Sprite m_spriteArrowUpHover;
        Sprite m_spriteArrowDown;
        Sprite m_spriteArrowDownHover;
 
        // Cached renderer properties
        Color m_thumbColorCached;
        Color m_thumbColorHoverCached;
        Color m_trackColorCached;
        Color m_trackColorHoverCached;
        Color m_arrowColorCached;
        Color m_arrowColorHoverCached;
        Color m_arrowBackgroundColorCached;
        Color m_arrowBackgroundColorHoverCached;

    };

    class TGUI_API ScrollbarChildWidget : public Scrollbar
    {
    public:

        ScrollbarChildWidget(Orientation orientation = Orientation::Vertical); // TGUI_NEXT: No more default option

        TGUI_NODISCARD bool isMouseDownOnThumb() const;

        void draw(BackendRenderTarget& target, RenderStates states) const override;
    };

    class TGUI_API ScrollbarAccessor
    {
    public:

        ScrollbarAccessor(ScrollbarChildWidget& scrollbar,
                          std::function<void()> valueChangedCallback,
                          std::function<void()> policyChangedCallback,
                          std::function<void()> scrollAmountChangedCallback);

        void setValue(unsigned int value);

        TGUI_NODISCARD unsigned int getValue() const;

        void setScrollAmount(unsigned int scrollAmount);

        TGUI_NODISCARD unsigned int getScrollAmount() const;

        void setPolicy(Scrollbar::Policy policy);

        TGUI_NODISCARD Scrollbar::Policy getPolicy() const;

        TGUI_NODISCARD unsigned int getMaximum() const;

        TGUI_NODISCARD unsigned int getViewportSize() const;

        TGUI_NODISCARD unsigned int getMaxValue() const;

        TGUI_NODISCARD bool isShown() const;

        TGUI_NODISCARD float getWidth() const;
 
    private:
        ScrollbarChildWidget* m_scrollbar;
        std::function<void()> m_valueChangedCallback;
        std::function<void()> m_policyChangedCallback;
        std::function<void()> m_scrollAmountChangedCallback;
    };

    class TGUI_API ScrollbarChildInterface
    {
    public:

        ScrollbarChildInterface();

        ScrollbarChildInterface(const ScrollbarChildInterface&);

        ScrollbarChildInterface(ScrollbarChildInterface&&) noexcept;

        virtual ~ScrollbarChildInterface() = default;

        ScrollbarChildInterface& operator=(const ScrollbarChildInterface&);

        ScrollbarChildInterface& operator=(ScrollbarChildInterface&&) noexcept;

        TGUI_NODISCARD ScrollbarAccessor* getScrollbar();

        TGUI_NODISCARD const ScrollbarAccessor* getScrollbar() const;

    protected:

        virtual void scrollbarValueChanged();

        virtual void scrollbarPolicyChanged();

        virtual void scrollbarScrollAmountChanged();

        void saveScrollbarPolicy(std::unique_ptr<DataIO::Node>& node) const;

        void loadScrollbarPolicy(const std::unique_ptr<DataIO::Node>& node);

    protected:
 
        CopiedSharedPtr<ScrollbarChildWidget> m_scrollbar;
        ScrollbarAccessor m_scrollbarAccessor;
    };

    class TGUI_API DualScrollbarChildInterface
    {
    public:

        DualScrollbarChildInterface();

        DualScrollbarChildInterface(const DualScrollbarChildInterface&);

        DualScrollbarChildInterface(DualScrollbarChildInterface&&) noexcept;

        virtual ~DualScrollbarChildInterface() = default;

        DualScrollbarChildInterface& operator=(const DualScrollbarChildInterface&);

        DualScrollbarChildInterface& operator=(DualScrollbarChildInterface&&) noexcept;

        TGUI_NODISCARD ScrollbarAccessor* getVerticalScrollbar();

        TGUI_NODISCARD const ScrollbarAccessor* getVerticalScrollbar() const;

        TGUI_NODISCARD ScrollbarAccessor* getHorizontalScrollbar();

        TGUI_NODISCARD const ScrollbarAccessor* getHorizontalScrollbar() const;

    protected:

        virtual void scrollbarValueChanged(Orientation orientation);

        virtual void scrollbarPolicyChanged(Orientation orientation);

        virtual void scrollbarScrollAmountChanged(Orientation orientation);

        void saveScrollbarPolicies(std::unique_ptr<DataIO::Node>& node) const;

        void loadScrollbarPolicies(const std::unique_ptr<DataIO::Node>& node);

    protected:
 
        CopiedSharedPtr<ScrollbarChildWidget> m_verticalScrollbar;
        CopiedSharedPtr<ScrollbarChildWidget> m_horizontalScrollbar;
        ScrollbarAccessor m_verticalScrollbarAccessor;
        ScrollbarAccessor m_horizontalScrollbarAccessor;
    };

 
}

 
#endif // TGUI_SCROLLBAR_HPP