juce_ScrollBar.h

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/*
  ==============================================================================
 
   This file is part of the JUCE library.
   Copyright (c) 2022 - Raw Material Software Limited
 
   JUCE is an open source library subject to commercial or open-source
   licensing.
 
   By using JUCE, you agree to the terms of both the JUCE 7 End-User License
   Agreement and JUCE Privacy Policy.
 
   End User License Agreement: www.juce.com/juce-7-licence
   Privacy Policy: www.juce.com/juce-privacy-policy
 
   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).
 
   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.
 
  ==============================================================================
*/
 
namespace juce
{
 
//==============================================================================
class JUCE_API  ScrollBar  : public Component,
                             public AsyncUpdater,
                             private Timer
{
public:
    //==============================================================================
    ScrollBar (bool isVertical);

    ~ScrollBar() override;
 
    //==============================================================================
    bool isVertical() const noexcept                                { return vertical; }

    void setOrientation (bool shouldBeVertical);

    void setAutoHide (bool shouldHideWhenFullRange);

    bool autoHides() const noexcept;
 
    //==============================================================================
    void setRangeLimits (Range<double> newRangeLimit,
                         NotificationType notification = sendNotificationAsync);

    void setRangeLimits (double minimum, double maximum,
                         NotificationType notification = sendNotificationAsync);

    Range<double> getRangeLimit() const noexcept                    { return totalRange; }

    double getMinimumRangeLimit() const noexcept                    { return totalRange.getStart(); }

    double getMaximumRangeLimit() const noexcept                    { return totalRange.getEnd(); }
 
    //==============================================================================
    bool setCurrentRange (Range<double> newRange,
                          NotificationType notification = sendNotificationAsync);

    void setCurrentRange (double newStart, double newSize,
                          NotificationType notification = sendNotificationAsync);

    void setCurrentRangeStart (double newStart,
                               NotificationType notification = sendNotificationAsync);

    Range<double> getCurrentRange() const noexcept                  { return visibleRange; }

    double getCurrentRangeStart() const noexcept                    { return visibleRange.getStart(); }

    double getCurrentRangeSize() const noexcept                     { return visibleRange.getLength(); }
 
    //==============================================================================
    void setSingleStepSize (double newSingleStepSize) noexcept;

    double getSingleStepSize() const noexcept                       { return singleStepSize; }

    bool moveScrollbarInSteps (int howManySteps,
                               NotificationType notification = sendNotificationAsync);

    bool moveScrollbarInPages (int howManyPages,
                               NotificationType notification = sendNotificationAsync);

    bool scrollToTop (NotificationType notification = sendNotificationAsync);

    bool scrollToBottom (NotificationType notification = sendNotificationAsync);

    void setButtonRepeatSpeed (int initialDelayInMillisecs,
                               int repeatDelayInMillisecs,
                               int minimumDelayInMillisecs = -1);
 
    //==============================================================================
    enum ColourIds
    {
        backgroundColourId          = 0x1000300,    
        thumbColourId               = 0x1000400,    
        trackColourId               = 0x1000401     
    };
 
    //==============================================================================
    class JUCE_API  Listener
    {
    public:
        virtual ~Listener() = default;

        virtual void scrollBarMoved (ScrollBar* scrollBarThatHasMoved,
                                     double newRangeStart) = 0;
    };

    void addListener (Listener* listener);

    void removeListener (Listener* listener);
 
    //==============================================================================
    struct JUCE_API  LookAndFeelMethods
    {
        virtual ~LookAndFeelMethods() = default;
 
        virtual bool areScrollbarButtonsVisible() = 0;

        virtual void drawScrollbarButton (Graphics& g,
                                          ScrollBar& scrollbar,
                                          int width, int height,
                                          int buttonDirection,
                                          bool isScrollbarVertical,
                                          bool isMouseOverButton,
                                          bool isButtonDown) = 0;

        virtual void drawScrollbar (Graphics& g, ScrollBar& scrollbar,
                                    int x, int y, int width, int height,
                                    bool isScrollbarVertical,
                                    int thumbStartPosition,
                                    int thumbSize,
                                    bool isMouseOver,
                                    bool isMouseDown) = 0;

        virtual ImageEffectFilter* getScrollbarEffect() = 0;

        virtual int getMinimumScrollbarThumbSize (ScrollBar&) = 0;

        virtual int getDefaultScrollbarWidth() = 0;

        virtual int getScrollbarButtonSize (ScrollBar&) = 0;
    };
 
    //==============================================================================
    bool keyPressed (const KeyPress&) override;
    void mouseWheelMove (const MouseEvent&, const MouseWheelDetails&) override;
    void lookAndFeelChanged() override;
    void mouseDown (const MouseEvent&) override;
    void mouseDrag (const MouseEvent&) override;
    void mouseUp   (const MouseEvent&) override;
    void paint (Graphics&) override;
    void resized() override;
    void parentHierarchyChanged() override;
    void setVisible (bool) override;
 
private:
    //==============================================================================
    Range<double> totalRange { 0.0, 1.0 }, visibleRange { 0.0, 1.0 };
    double singleStepSize = 0.1, dragStartRange = 0;
    int thumbAreaStart = 0, thumbAreaSize = 0, thumbStart = 0, thumbSize = 0;
    int dragStartMousePos = 0, lastMousePos = 0;
    int initialDelayInMillisecs = 100, repeatDelayInMillisecs = 50, minimumDelayInMillisecs = 10;
    bool vertical, isDraggingThumb = false, autohides = true, userVisibilityFlag = false;
    class ScrollbarButton;
    std::unique_ptr<ScrollbarButton> upButton, downButton;
    ListenerList<Listener> listeners;
 
    std::unique_ptr<AccessibilityHandler> createAccessibilityHandler() override;
    void handleAsyncUpdate() override;
    void updateThumbPosition();
    void timerCallback() override;
    bool getVisibility() const noexcept;
 
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ScrollBar)
};
 
 
} // namespace juce