JUCE/modules/juce_gui_basics/misc/juce_FocusOutline.h

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

   This file is part of the JUCE 7 technical preview.
   Copyright (c) 2022 - Raw Material Software Limited

   You may use this code under the terms of the GPL v3
   (see www.gnu.org/licenses).

   For the technical preview this file cannot be licensed commercially.

   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