axmol/core/ui/UIScrollView.h

/****************************************************************************
Copyright (c) 2013-2016 Chukong Technologies Inc.
Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

https://adxeproject.github.io/

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****************************************************************************/

#ifndef __UISCROLLVIEW_H__
#define __UISCROLLVIEW_H__

#include "ui/UILayout.h"
#include "ui/GUIExport.h"
#include <list>

NS_CC_BEGIN
/**
 * @addtogroup ui
 * @{
 */

class EventFocusListener;

namespace ui
{

class ScrollViewBar;

/**
 * Layout container for a view hierarchy that can be scrolled by the user, allowing it to be larger than the physical
 * display. It holds a inner `Layout` container for storing child items horizontally or vertically.
 */
class CC_GUI_DLL ScrollView : public Layout
{

    DECLARE_CLASS_GUI_INFO

public:
    /**
     * ScrollView scroll direction type.
     */
    enum class Direction
    {
        NONE,
        VERTICAL,
        HORIZONTAL,
        BOTH
    };

    /**
     * Scrollview scroll event type.
     */
    enum class EventType
    {
        SCROLL_TO_TOP,
        SCROLL_TO_BOTTOM,
        SCROLL_TO_LEFT,
        SCROLL_TO_RIGHT,
        SCROLLING,
        BOUNCE_TOP,
        BOUNCE_BOTTOM,
        BOUNCE_LEFT,
        BOUNCE_RIGHT,
        CONTAINER_MOVED,
        SCROLLING_BEGAN,
        SCROLLING_ENDED,
        AUTOSCROLL_ENDED
    };

    /**
     * A callback which would be called when a ScrollView is scrolling.
     */
    typedef std::function<void(Ref*, EventType)> ccScrollViewCallback;

    /**
     * Default constructor
     * @js ctor
     * @lua new
     */
    ScrollView();

    /**
     * Default destructor
     * @js NA
     * @lua NA
     */
    virtual ~ScrollView();

    /**
     * Create an empty ScrollView.
     * @return A ScrollView instance.
     */
    static ScrollView* create();

    /**
     * Changes scroll direction of scrollview.
     *
     * @see `Direction`
     * @param dir Scroll direction enum.
     */
    virtual void setDirection(Direction dir);

    /**
     * Query scroll direction of scrollview.
     *
     * @see `Direction`      Direction::VERTICAL means vertical scroll, Direction::HORIZONTAL means horizontal scroll
     *
     * @return Scrollview scroll direction.
     */
    Direction getDirection() const;

    /**
     * Get inner container of scrollview.
     *
     * Inner container is a child of scrollview.
     *
     * @return Inner container pointer.
     */
    Layout* getInnerContainer() const;

    /**
     * Immediately stops inner container scroll (auto scrolling is not affected).
     */
    virtual void stopScroll();

    /**
     * Immediately stops inner container scroll initiated by any of the "scrollTo*" member functions
     */
    virtual void stopAutoScroll();

    /**
     * Immediately stops inner container scroll if any.
     */
    virtual void stopOverallScroll();

    /**
     * Scroll inner container to bottom boundary of scrollview.
     * @param timeInSec Time in seconds.
     * @param attenuated Whether scroll speed attenuate or not.
     */
    virtual void scrollToBottom(float timeInSec, bool attenuated);

    /**
     * Scroll inner container to top boundary of scrollview.
     * @param timeInSec Time in seconds.
     * @param attenuated Whether scroll speed attenuate or not.
     */
    virtual void scrollToTop(float timeInSec, bool attenuated);

    /**
     * Scroll inner container to left boundary of scrollview.
     * @param timeInSec Time in seconds.
     * @param attenuated Whether scroll speed attenuate or not.
     */
    virtual void scrollToLeft(float timeInSec, bool attenuated);

    /**
     * Scroll inner container to right boundary of scrollview.
     * @param timeInSec Time in seconds.
     * @param attenuated Whether scroll speed attenuate or not.
     */
    virtual void scrollToRight(float timeInSec, bool attenuated);

    /**
     * Scroll inner container to top and left boundary of scrollview.
     * @param timeInSec Time in seconds.
     * @param attenuated Whether scroll speed attenuate or not.
     */
    virtual void scrollToTopLeft(float timeInSec, bool attenuated);

    /**
     * Scroll inner container to top and right boundary of scrollview.
     * @param timeInSec Time in seconds.
     * @param attenuated Whether scroll speed attenuate or not.
     */
    virtual void scrollToTopRight(float timeInSec, bool attenuated);

    /**
     * Scroll inner container to bottom and left boundary of scrollview.
     * @param timeInSec Time in seconds.
     * @param attenuated Whether scroll speed attenuate or not.
     */
    virtual void scrollToBottomLeft(float timeInSec, bool attenuated);

    /**
     * Scroll inner container to bottom and right boundary of scrollview.
     * @param timeInSec Time in seconds
     * @param attenuated Whether scroll speed attenuate or not.
     */
    virtual void scrollToBottomRight(float timeInSec, bool attenuated);

    /**
     * Scroll inner container to vertical percent position of scrollview.
     * @param percent A value between 0 and 100.
     * @param timeInSec Time in seconds.
     * @param attenuated Whether scroll speed attenuate or not.
     */
    virtual void scrollToPercentVertical(float percent, float timeInSec, bool attenuated);

    /**
     * Scroll inner container to horizontal percent position of scrollview.
     * @param percent A value between 0 and 100.
     * @param timeInSec Time in seconds.
     * @param attenuated Whether scroll speed attenuate or not.
     */
    virtual void scrollToPercentHorizontal(float percent, float timeInSec, bool attenuated);

    /**
     * Scroll inner container to both direction percent position of scrollview.
     * @param percent A value between 0 and 100.
     * @param timeInSec Time in seconds.
     * @param attenuated Whether scroll speed attenuate or not.
     */
    virtual void scrollToPercentBothDirection(const Vec2& percent, float timeInSec, bool attenuated);

    /**
     * @return How far the scroll view is scrolled in the vertical axis
     */
    float getScrolledPercentVertical() const;
    /**
     * @return How far the scroll view is scrolled in the horizontal axis
     */
    float getScrolledPercentHorizontal() const;
    /**
     * @return How far the scroll view is scrolled in both axes, combined as a Vec2
     */
    Vec2 getScrolledPercentBothDirection() const;

    /**
     * Move inner container to bottom boundary of scrollview.
     */
    virtual void jumpToBottom();

    /**
     * Move inner container to top boundary of scrollview.
     */
    virtual void jumpToTop();

    /**
     * Move inner container to left boundary of scrollview.
     */
    virtual void jumpToLeft();

    /**
     * Move inner container to right boundary of scrollview.
     */
    virtual void jumpToRight();

    /**
     * Move inner container to top and left boundary of scrollview.
     */
    virtual void jumpToTopLeft();

    /**
     * Move inner container to top and right boundary of scrollview.
     */
    virtual void jumpToTopRight();

    /**
     * Move inner container to bottom and left boundary of scrollview.
     */
    virtual void jumpToBottomLeft();

    /**
     * Move inner container to bottom and right boundary of scrollview.
     */
    virtual void jumpToBottomRight();

    /**
     * Move inner container to vertical percent position of scrollview.
     * @param percent A value between 0 and 100.
     */
    virtual void jumpToPercentVertical(float percent);

    /**
     * Move inner container to horizontal percent position of scrollview.
     * @param percent   A value between 0 and 100.
     */
    virtual void jumpToPercentHorizontal(float percent);

    /**
     * Move inner container to both direction percent position of scrollview.
     * @param percent   A value between 0 and 100.
     */
    virtual void jumpToPercentBothDirection(const Vec2& percent);

    /**
     * Change inner container size of scrollview.
     *
     * Inner container size must be larger than or equal scrollview's size.
     *
     * @param size Inner container size.
     */
    void setInnerContainerSize(const Vec2& size);

    /**
     * Get inner container size of scrollview.
     *
     * Inner container size must be larger than or equal scrollview's size.
     *
     * @return The inner container size.
     */
    const Vec2& getInnerContainerSize() const;

    /**
     * Set inner container position
     *
     * @param pos Inner container position.
     */
    void setInnerContainerPosition(const Vec2& pos);

    /**
     * Get inner container position
     *
     * @return The inner container position.
     */
    const Vec2& getInnerContainerPosition() const;

    /**
     * Add callback function which will be called  when scrollview event triggered.
     * @param callback A callback function with type of `ccScrollViewCallback`.
     */
    virtual void addEventListener(const ccScrollViewCallback& callback);

    // override functions
    virtual void addChild(Node* child) override;
    virtual void addChild(Node* child, int localZOrder) override;
    virtual void addChild(Node* child, int localZOrder, int tag) override;
    virtual void addChild(Node* child, int localZOrder, std::string_view name) override;
    virtual void removeAllChildren() override;
    virtual void removeAllChildrenWithCleanup(bool cleanup) override;
    virtual void removeChild(Node* child, bool cleanup = true) override;
    virtual Vector<Node*>& getChildren() override;
    virtual const Vector<Node*>& getChildren() const override;
    virtual ssize_t getChildrenCount() const override;
    virtual Node* getChildByTag(int tag) const override;
    virtual Node* getChildByName(std::string_view name) const override;
    // touch event callback
    virtual bool onTouchBegan(Touch* touch, Event* unusedEvent) override;
    virtual void onTouchMoved(Touch* touch, Event* unusedEvent) override;
    virtual void onTouchEnded(Touch* touch, Event* unusedEvent) override;
    virtual void onTouchCancelled(Touch* touch, Event* unusedEvent) override;
    virtual void update(float dt) override;

    /**
     * @brief Toggle bounce enabled when scroll to the edge.
     *
     * @param enabled True if enable bounce, false otherwise.
     */
    void setBounceEnabled(bool enabled);

    /**
     * @brief Query bounce state.
     *
     * @return True if bounce is enabled, false otherwise.
     */
    bool isBounceEnabled() const;

    /**
     * @brief Toggle whether enable scroll inertia while scrolling.
     *
     * @param enabled True if enable inertia, false otherwise.
     */
    void setInertiaScrollEnabled(bool enabled);

    /**
     * @brief Query inertia scroll state.
     *
     * @return True if inertia is enabled, false otherwise.
     */
    bool isInertiaScrollEnabled() const;

    /**
     * @brief Toggle scroll bar enabled.
     *
     * @param enabled True if enable scroll bar, false otherwise.
     */
    void setScrollBarEnabled(bool enabled);

    /**
     * @brief Query scroll bar state.
     *
     * @return True if scroll bar is enabled, false otherwise.
     */
    bool isScrollBarEnabled() const;

    /**
     * @brief Set the scroll bar positions from the left-bottom corner (horizontal) and right-top corner (vertical).
     *
     * @param positionFromCorner The position from the left-bottom corner (horizontal) and right-top corner (vertical).
     */
    void setScrollBarPositionFromCorner(const Vec2& positionFromCorner);

    /**
     * @brief Set the vertical scroll bar position from right-top corner.
     *
     * @param positionFromCorner The position from right-top corner
     */
    void setScrollBarPositionFromCornerForVertical(const Vec2& positionFromCorner);

    /**
     * @brief Get the vertical scroll bar's position from right-top corner.
     *
     * @return positionFromCorner
     */
    Vec2 getScrollBarPositionFromCornerForVertical() const;

    /**
     * @brief Set the horizontal scroll bar position from left-bottom corner.
     *
     * @param positionFromCorner The position from left-bottom corner
     */
    void setScrollBarPositionFromCornerForHorizontal(const Vec2& positionFromCorner);

    /**
     * @brief Get the horizontal scroll bar's position from right-top corner.
     *
     * @return positionFromCorner
     */
    Vec2 getScrollBarPositionFromCornerForHorizontal() const;

    /**
     * @brief Set the scroll bar's width
     *
     * @param width The scroll bar's width
     */
    void setScrollBarWidth(float width);

    /**
     * @brief Get the scroll bar's width
     *
     * @return the scroll bar's width
     */
    float getScrollBarWidth() const;

    /**
     * @brief Set the scroll bar's color
     *
     * @param the scroll bar's color
     */
    void setScrollBarColor(const Color3B& color);

    /**
     * @brief Get the scroll bar's color
     *
     * @return the scroll bar's color
     */
    const Color3B& getScrollBarColor() const;

    /**
     * @brief Set the scroll bar's opacity
     *
     * @param the scroll bar's opacity
     */
    void setScrollBarOpacity(uint8_t opacity);

    /**
     * @brief Get the scroll bar's opacity
     *
     * @return the scroll bar's opacity
     */
    uint8_t getScrollBarOpacity() const;

    /**
     * @brief Set scroll bar auto hide state
     *
     * @param scroll bar auto hide state
     */
    void setScrollBarAutoHideEnabled(bool autoHideEnabled);

    /**
     * @brief Query scroll bar auto hide state
     *
     * @return True if scroll bar auto hide is enabled, false otherwise.
     */
    bool isScrollBarAutoHideEnabled() const;

    /**
     * @brief Set scroll bar auto hide time
     *
     * @param scroll bar auto hide time
     */
    void setScrollBarAutoHideTime(float autoHideTime);

    /**
     * @brief Get the scroll bar's auto hide time
     *
     * @return the scroll bar's auto hide time
     */
    float getScrollBarAutoHideTime() const;

    /**
     * @brief Set the touch total time threshold
     *
     * @param the touch total time threshold
     */
    void setTouchTotalTimeThreshold(float touchTotalTimeThreshold);

    /**
     * @brief Get the touch total time threshold
     *
     * @return the touch total time threshold
     */
    float getTouchTotalTimeThreshold() const;

    /**
     * Set layout type for scrollview.
     *
     * @see `Layout::Type`
     * @param type  Layout type enum.
     */
    virtual void setLayoutType(Type type) override;

    /**
     * Get the layout type for scrollview.
     *
     * @see `Layout::Type`
     * @return LayoutType
     */
    virtual Type getLayoutType() const override;

    /**
     * Return the "class name" of widget.
     */
    virtual std::string getDescription() const override;

    /**
     * @lua NA
     */
    virtual void onEnter() override;

    /**
     * @lua NA
     */
    virtual void onExit() override;

    /**
     *  When a widget is in a layout, you could call this method to get the next focused widget within a specified
     *direction. If the widget is not in a layout, it will return itself
     *@param direction the direction to look for the next focused widget in a layout
     *@param current  the current focused widget
     *@return the next focused widget in a layout
     */
    virtual Widget* findNextFocusedWidget(FocusDirection direction, Widget* current) override;

    /**
     * @return Whether the user is currently dragging the ScrollView to scroll it
     */
    bool isScrolling() const { return _scrolling; }
    /**
     * @return Whether the ScrollView is currently scrolling because of a bounceback or inertia slowdown.
     */
    bool isAutoScrolling() const { return _autoScrolling; }

    virtual bool init() override;

protected:
    enum class MoveDirection
    {
        TOP,
        BOTTOM,
        LEFT,
        RIGHT,
    };

    virtual void initRenderer() override;

    virtual void onSizeChanged() override;
    virtual void doLayout() override;

    virtual Widget* createCloneInstance() override;
    virtual void copySpecialProperties(Widget* model) override;
    virtual void copyClonedWidgetChildren(Widget* model) override;

    virtual void initScrollBar();
    virtual void removeScrollBar();

    Vec2 flattenVectorByDirection(const Vec2& vector);

    virtual Vec2 getHowMuchOutOfBoundary(const Vec2& addition = Vec2::ZERO);
    bool isOutOfBoundary(MoveDirection dir);
    bool isOutOfBoundary();

    virtual void moveInnerContainer(const Vec2& deltaMove, bool canStartBounceBack);

    bool calculateCurrAndPrevTouchPoints(Touch* touch, Vec3* currPt, Vec3* prevPt);
    void gatherTouchMove(const Vec2& delta);
    Vec2 calculateTouchMoveVelocity() const;

    virtual void startAttenuatingAutoScroll(const Vec2& deltaMove, const Vec2& initialVelocity);
    void startAutoScroll(const Vec2& deltaMove, float timeInSec, bool attenuated);
    void startAutoScrollToDestination(const Vec2& des, float timeInSec, bool attenuated);
    bool isNecessaryAutoScrollBrake();
    void processAutoScrolling(float deltaTime);

    void startInertiaScroll(const Vec2& touchMoveVelocity);

    bool startBounceBackIfNeeded();

    void jumpToDestination(const Vec2& des);

    virtual void scrollChildren(const Vec2& deltaMove);

    virtual void handlePressLogic(Touch* touch);
    virtual void handleMoveLogic(Touch* touch);
    virtual void handleReleaseLogic(Touch* touch);

    virtual void interceptTouchEvent(Widget::TouchEventType event, Widget* sender, Touch* touch) override;

    void processScrollEvent(MoveDirection dir, bool bounce);
    void processScrollingEvent();
    void processScrollingEndedEvent();
    void dispatchEvent(EventType eventType);

    void updateScrollBar(const Vec2& outOfBoundary);

protected:
    virtual float getAutoScrollStopEpsilon() const;
    bool fltEqualZero(const Vec2& point) const;
    Layout* _innerContainer;

    Direction _direction;

    float _topBoundary;
    float _bottomBoundary;
    float _leftBoundary;
    float _rightBoundary;

    bool _bePressed;

    float _childFocusCancelOffsetInInch;

    // Touch move speed
    std::list<Vec2> _touchMoveDisplacements;
    std::list<float> _touchMoveTimeDeltas;
    long long _touchMovePreviousTimestamp;
    float _touchTotalTimeThreshold;

    bool _scrolling;

    bool _autoScrolling;
    bool _autoScrollAttenuate;
    Vec2 _autoScrollStartPosition;
    Vec2 _autoScrollTargetDelta;
    float _autoScrollTotalTime;
    float _autoScrollAccumulatedTime;
    bool _autoScrollCurrentlyOutOfBoundary;
    bool _autoScrollBraking;
    Vec2 _autoScrollBrakingStartPosition;

    bool _inertiaScrollEnabled;

    bool _bounceEnabled;

    Vec2 _outOfBoundaryAmount;
    bool _outOfBoundaryAmountDirty;

    bool _scrollBarEnabled;
    ScrollViewBar* _verticalScrollBar;
    ScrollViewBar* _horizontalScrollBar;

    Ref* _scrollViewEventListener;
    ccScrollViewCallback _eventCallback;
};

}  // namespace ui
// end of ui group
/// @}
NS_CC_END
#endif /* defined(__CocoGUI__ScrollView__) */