juce_Viewport.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  Viewport  : public Component,
                            private ComponentListener,
                            private ScrollBar::Listener
{
public:
    //==============================================================================
    explicit Viewport (const String& componentName = String());

    ~Viewport() override;
 
    //==============================================================================
    void setViewedComponent (Component* newViewedComponent,
                             bool deleteComponentWhenNoLongerNeeded = true);

    Component* getViewedComponent() const noexcept                  { return contentComp.get(); }
 
    //==============================================================================
    void setViewPosition (int xPixelsOffset, int yPixelsOffset);

    void setViewPosition (Point<int> newPosition);

    void setViewPositionProportionately (double proportionX, double proportionY);

    bool autoScroll (int mouseX, int mouseY, int distanceFromEdge, int maximumSpeed);

    Point<int> getViewPosition() const noexcept             { return lastVisibleArea.getPosition(); }

    Rectangle<int> getViewArea() const noexcept             { return lastVisibleArea; }

    int getViewPositionX() const noexcept                   { return lastVisibleArea.getX(); }

    int getViewPositionY() const noexcept                   { return lastVisibleArea.getY(); }

    int getViewWidth() const noexcept                       { return lastVisibleArea.getWidth(); }

    int getViewHeight() const noexcept                      { return lastVisibleArea.getHeight(); }

    int getMaximumVisibleWidth() const;

    int getMaximumVisibleHeight() const;
 
    //==============================================================================
    virtual void visibleAreaChanged (const Rectangle<int>& newVisibleArea);

    virtual void viewedComponentChanged (Component* newComponent);
 
    //==============================================================================
    void setScrollBarsShown (bool showVerticalScrollbarIfNeeded,
                             bool showHorizontalScrollbarIfNeeded,
                             bool allowVerticalScrollingWithoutScrollbar = false,
                             bool allowHorizontalScrollingWithoutScrollbar = false);

    void setScrollBarPosition (bool verticalScrollbarOnRight,
                               bool horizontalScrollbarAtBottom);

    bool isVerticalScrollbarOnTheRight() const noexcept         { return vScrollbarRight; }

    bool isHorizontalScrollbarAtBottom() const noexcept         { return hScrollbarBottom; }

    bool isVerticalScrollBarShown() const noexcept              { return showVScrollbar; }

    bool isHorizontalScrollBarShown() const noexcept            { return showHScrollbar; }

    void setScrollBarThickness (int thickness);

    int getScrollBarThickness() const;

    void setSingleStepSizes (int stepX, int stepY);

    ScrollBar& getVerticalScrollBar() noexcept                  { return *verticalScrollBar; }

    ScrollBar& getHorizontalScrollBar() noexcept                { return *horizontalScrollBar; }

    void recreateScrollbars();

    bool canScrollVertically() const noexcept;

    bool canScrollHorizontally() const noexcept;

    [[deprecated ("Use setScrollOnDragMode instead.")]]
    void setScrollOnDragEnabled (bool shouldScrollOnDrag)
    {
        setScrollOnDragMode (shouldScrollOnDrag ? ScrollOnDragMode::all : ScrollOnDragMode::never);
    }

    [[deprecated ("Use getScrollOnDragMode instead.")]]
    bool isScrollOnDragEnabled() const noexcept { return getScrollOnDragMode() == ScrollOnDragMode::all; }
 
    enum class ScrollOnDragMode
    {
        never,          
        nonHover,       
        all             
    };

    void setScrollOnDragMode (ScrollOnDragMode scrollOnDragMode);

    ScrollOnDragMode getScrollOnDragMode() const { return scrollOnDragMode; }

    bool isCurrentlyScrollingOnDrag() const noexcept;
 
    //==============================================================================
    void resized() override;
    void scrollBarMoved (ScrollBar*, double newRangeStart) override;
    void mouseWheelMove (const MouseEvent&, const MouseWheelDetails&) override;
    void mouseDown (const MouseEvent& e) override;
    bool keyPressed (const KeyPress&) override;
    void componentMovedOrResized (Component&, bool wasMoved, bool wasResized) override;
    void lookAndFeelChanged() override;
    bool useMouseWheelMoveIfNeeded (const MouseEvent&, const MouseWheelDetails&);
    static bool respondsToKey (const KeyPress&);
 
protected:
    //==============================================================================
    virtual ScrollBar* createScrollBarComponent (bool isVertical);
 
private:
    //==============================================================================
    class AccessibilityIgnoredComponent : public Component
    {
        std::unique_ptr<AccessibilityHandler> createAccessibilityHandler() override
        {
            return createIgnoredAccessibilityHandler (*this);
        }
    };
 
    std::unique_ptr<ScrollBar> verticalScrollBar, horizontalScrollBar;
    AccessibilityIgnoredComponent contentHolder;
    WeakReference<Component> contentComp;
    Rectangle<int> lastVisibleArea;
    int scrollBarThickness = 0;
    int singleStepX = 16, singleStepY = 16;
    ScrollOnDragMode scrollOnDragMode = ScrollOnDragMode::nonHover;
    bool showHScrollbar = true, showVScrollbar = true, deleteContent = true;
    bool customScrollBarThickness = false;
    bool allowScrollingWithoutScrollbarV = false, allowScrollingWithoutScrollbarH = false;
    bool vScrollbarRight = true, hScrollbarBottom = true;
 
    struct DragToScrollListener;
    std::unique_ptr<DragToScrollListener> dragToScrollListener;
 
    Point<int> viewportPosToCompPos (Point<int>) const;
 
    void updateVisibleArea();
    void deleteOrRemoveContentComp();
 
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Viewport)
};
 
} // namespace juce