juce_DragAndDropContainer.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  DragAndDropContainer
{
public:
    //==============================================================================
    DragAndDropContainer();

    virtual ~DragAndDropContainer();
 
    //==============================================================================
    void startDragging (const var& sourceDescription,
                        Component* sourceComponent,
                        const ScaledImage& dragImage = ScaledImage(),
                        bool allowDraggingToOtherJuceWindows = false,
                        const Point<int>* imageOffsetFromMouse = nullptr,
                        const MouseInputSource* inputSourceCausingDrag = nullptr);
 
    [[deprecated ("This overload does not allow the image's scale to be specified. Use the other overload of startDragging instead.")]]
    void startDragging (const var& sourceDescription,
                        Component* sourceComponent,
                        Image dragImage,
                        bool allowDraggingToOtherJuceWindows = false,
                        const Point<int>* imageOffsetFromMouse = nullptr,
                        const MouseInputSource* inputSourceCausingDrag = nullptr)
    {
        startDragging (sourceDescription,
                       sourceComponent,
                       ScaledImage (dragImage),
                       allowDraggingToOtherJuceWindows,
                       imageOffsetFromMouse,
                       inputSourceCausingDrag);
    }

    bool isDragAndDropActive() const;

    int getNumCurrentDrags() const;

    var getCurrentDragDescription() const;

    var getDragDescriptionForIndex (int index) const;

    void setCurrentDragImage (const ScaledImage& newImage);
 
    [[deprecated ("This overload does not allow the image's scale to be specified. Use the other overload of setCurrentDragImage instead.")]]
    void setCurrentDragImage (const Image& newImage) { setCurrentDragImage (ScaledImage (newImage)); }

    void setDragImageForIndex (int index, const ScaledImage& newImage);
 
    [[deprecated ("This overload does not allow the image's scale to be specified. Use the other overload of setDragImageForIndex instead.")]]
    void setDragImageForIndex (int index, const Image& newImage) { setDragImageForIndex (index, ScaledImage (newImage)); }

    static DragAndDropContainer* findParentDragContainerFor (Component* childComponent);
 
 
    //==============================================================================
    static bool performExternalDragDropOfFiles (const StringArray& files, bool canMoveFiles,
                                                Component* sourceComponent = nullptr,
                                                std::function<void()> callback = nullptr);

    static bool performExternalDragDropOfText (const String& text, Component* sourceComponent = nullptr,
                                               std::function<void()> callback = nullptr);
 
protected:
    virtual bool shouldDropFilesWhenDraggedExternally (const DragAndDropTarget::SourceDetails& sourceDetails,
                                                       StringArray& files, bool& canMoveFiles);

    virtual bool shouldDropTextWhenDraggedExternally (const DragAndDropTarget::SourceDetails& sourceDetails,
                                                      String& text);

    virtual void dragOperationStarted (const DragAndDropTarget::SourceDetails&);

    virtual void dragOperationEnded (const DragAndDropTarget::SourceDetails&);
 
private:
    //==============================================================================
    class DragImageComponent;
    OwnedArray<DragImageComponent> dragImageComponents;
 
    const MouseInputSource* getMouseInputSourceForDrag (Component* sourceComponent, const MouseInputSource* inputSourceCausingDrag);
    bool isAlreadyDragging (Component* sourceComponent) const noexcept;
 
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (DragAndDropContainer)
};
 
} // namespace juce