guiScrollBar.h

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/*
Copyright (C) 2002-2013 Nikolaus Gebhardt
This file is part of the "Irrlicht Engine".
For conditions of distribution and use, see copyright notice in irrlicht.h
 
Modified 2019.05.01 by stujones11, Stuart Jones <stujones111@gmail.com>
 
This is a heavily modified copy of the Irrlicht CGUIScrollBar class
which includes automatic scaling of the thumb slider and hiding of
the arrow buttons where there is insufficient space.
*/
 
#pragma once
 
#include <optional>
#include <IGUIEnvironment.h>
#include <IGUIScrollBar.h>
 
class ISimpleTextureSource;
 
 
using namespace gui;
 
class GUIScrollBar final : public IGUIScrollBar
{
public:
        GUIScrollBar(IGUIEnvironment *environment, IGUIElement *parent, s32 id,
                        core::rect<s32> rectangle, bool horizontal, bool auto_scale,
                        ISimpleTextureSource *tsrc);
 
        enum ArrowVisibility
        {
                HIDE,
                SHOW,
                DEFAULT
        };
 
        virtual void draw() override;
        virtual void updateAbsolutePosition() override;
        virtual bool OnEvent(const SEvent &event) override;
        virtual void OnPostRender(u32 time_ms) override;
 
        s32 getMax() const override { return max_pos; }
        s32 getMin() const override { return min_pos; }
        s32 getLargeStep() const override { return large_step; }
        s32 getSmallStep() const override { return small_step; }
        s32 getPos() const override;
        s32 getTargetPos() const override;
        bool isHorizontal() const { return is_horizontal; }
 
        void setMax(s32 max) override;
        void setMin(s32 min) override;
        void setSmallStep(s32 step) override;
        void setLargeStep(s32 step) override;
        // setPos does not send EGET_SCROLL_BAR_CHANGED events for you.
        void setPos(const s32 pos) override;
        void setPosAndSend(s32 pos);
        // If you want to do an interpolated addition, use
        // setPosInterpolated(getTargetPos() + x).
        // setPosInterpolated takes care of sending EGET_SCROLL_BAR_CHANGED events.
        void setPosInterpolated(s32 pos) override;
        void setPageSize(s32 size) override;
        void setArrowsVisible(ArrowVisibility visible);
 
private:
        void refreshControls();
        s32 getPosFromMousePos(const core::position2di &p) const;
        f32 range() const { return f32(max_pos - min_pos); }
 
        IGUIButton *up_button;
        IGUIButton *down_button;
        ArrowVisibility arrow_visibility = DEFAULT;
        bool is_dragging;
        bool is_horizontal;
        bool is_auto_scaling;
        bool dragged_by_slider;
        bool tray_clicked;
        s32 scroll_pos;
        s32 draw_center;
        s32 thumb_size;
        s32 min_pos;
        s32 max_pos;
        s32 small_step;
        s32 large_step;
        s32 drag_offset;
        s32 page_size;
        s32 border_size;
 
        core::rect<s32> slider_rect;
        video::SColor current_icon_color;
 
        ISimpleTextureSource *m_tsrc;
 
        void setPosRaw(const s32 pos);
        void updatePos();
        std::optional<s32> target_pos;
        u32 last_time_ms = 0;
        u32 last_delta_ms = 17; // assume 60 FPS
        void interpolatePos();
};