JUCE/modules/juce_gui_basics/misc/juce_FocusOutline.h

/*
  ==============================================================================

   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
{

/**
    Adds a focus outline to a component.

    This object creates and manages a component that sits on top of a target
    component. It will track the position of the target component and will be
    brought to the front with the tracked component.

    Use the Component::setHasFocusOutline() method to indicate that a component
    should have a focus outline drawn around it, and when it receives keyboard
    focus one of these objects will be created using the
    LookAndFeel::createFocusOutlineForComponent() method. You can override this
    method in your own LookAndFeel classes to draw a custom outline if required.

    @tags{GUI}
*/
class JUCE_API  FocusOutline  : private ComponentListener
{
public:
    //==============================================================================
    /** Defines the focus outline window properties.

        Pass an instance of one of these to the FocusOutline constructor to control
        the bounds for the outline window and how it is drawn.
    */
    struct JUCE_API  OutlineWindowProperties
    {
        virtual ~OutlineWindowProperties() = default;

        /** Return the bounds for the outline window in screen coordinates. */
        virtual Rectangle<int> getOutlineBounds (Component& focusedComponent) = 0;

        /** This method will be called to draw the focus outline. */
        virtual void drawOutline (Graphics&, int width, int height) = 0;
    };

    //==============================================================================
    /** Creates a FocusOutline.

        Call setOwner to attach it to a component.
    */
    FocusOutline (std::unique_ptr<OutlineWindowProperties> props);

    /** Destructor. */
    ~FocusOutline() override;

    /** Attaches the outline to a component. */
    void setOwner (Component* componentToFollow);

private:
    //==============================================================================
    void componentMovedOrResized (Component&, bool, bool) override;
    void componentBroughtToFront (Component&) override;
    void componentParentHierarchyChanged (Component&) override;
    void componentVisibilityChanged (Component&) override;

    void updateOutlineWindow();
    void updateParent();

    //==============================================================================
    std::unique_ptr<OutlineWindowProperties> properties;

    WeakReference<Component> owner;
    std::unique_ptr<Component> outlineWindow;
    WeakReference<Component> lastParentComp;

    bool reentrant = false;

    //==============================================================================
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (FocusOutline)
};

} // namespace juce