JUCE/modules/juce_gui_basics/mouse/juce_MouseCursor.cpp

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

   This file is part of the JUCE 6 technical preview.
   Copyright (c) 2020 - Raw Material Software Limited

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

   For this technical preview, this file is not subject to commercial licensing.

   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
{

struct CustomMouseCursorInfo
{
    CustomMouseCursorInfo (const Image& im, Point<int> hs, float scale = 1.0f) noexcept
        : image (im), hotspot (hs), scaleFactor (scale)
    {}

    void* create() const;

    Image image;
    const Point<int> hotspot;
    const float scaleFactor;

    JUCE_DECLARE_NON_COPYABLE (CustomMouseCursorInfo)
};

class MouseCursor::SharedCursorHandle
{
public:
    explicit SharedCursorHandle (const MouseCursor::StandardCursorType type)
        : handle (createStandardMouseCursor (type)),
          standardType (type),
          isStandard (true)
    {
    }

    SharedCursorHandle (const Image& image, Point<int> hotSpot, float scaleFactor)
        : info (new CustomMouseCursorInfo (image, hotSpot, scaleFactor)),
          handle (info->create()),
          standardType (MouseCursor::NormalCursor),
          isStandard (false)
    {
        // your hotspot needs to be within the bounds of the image!
        jassert (image.getBounds().contains (hotSpot));
    }

    ~SharedCursorHandle()
    {
        deleteMouseCursor (handle, isStandard);
    }

    static SharedCursorHandle* createStandard (const MouseCursor::StandardCursorType type)
    {
        jassert (isPositiveAndBelow (type, MouseCursor::NumStandardCursorTypes));

        const SpinLock::ScopedLockType sl (lock);
        auto& c = getSharedCursor (type);

        if (c == nullptr)
            c = new SharedCursorHandle (type);
        else
            c->retain();

        return c;
    }

    bool isStandardType (MouseCursor::StandardCursorType type) const noexcept
    {
        return type == standardType && isStandard;
    }

    SharedCursorHandle* retain() noexcept
    {
        ++refCount;
        return this;
    }

    void release()
    {
        if (--refCount == 0)
        {
            if (isStandard)
            {
                const SpinLock::ScopedLockType sl (lock);
                getSharedCursor (standardType) = nullptr;
            }

            delete this;
        }
    }

    void* getHandle() const noexcept                            { return handle; }
    void setHandle (void* newHandle)                            { handle = newHandle; }

    MouseCursor::StandardCursorType getType() const noexcept    { return standardType; }
    CustomMouseCursorInfo* getCustomInfo() const noexcept       { return info.get(); }

private:
    std::unique_ptr<CustomMouseCursorInfo> info;
    void* handle;
    Atomic<int> refCount { 1 };
    const MouseCursor::StandardCursorType standardType;
    const bool isStandard;
    static SpinLock lock;

    static SharedCursorHandle*& getSharedCursor (const MouseCursor::StandardCursorType type)
    {
        static SharedCursorHandle* cursors[MouseCursor::NumStandardCursorTypes] = {};
        return cursors[type];
    }

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (SharedCursorHandle)
};

SpinLock MouseCursor::SharedCursorHandle::lock;

//==============================================================================
MouseCursor::MouseCursor() noexcept
{
}

MouseCursor::MouseCursor (const StandardCursorType type)
    : cursorHandle (type != MouseCursor::NormalCursor ? SharedCursorHandle::createStandard (type) : nullptr)
{
}

MouseCursor::MouseCursor (const Image& image, int hotSpotX, int hotSpotY)
    : MouseCursor (image, hotSpotX, hotSpotY, 1.0f)
{
}

MouseCursor::MouseCursor (const Image& image, int hotSpotX, int hotSpotY, float scaleFactor)
    : cursorHandle (new SharedCursorHandle (image, { hotSpotX, hotSpotY }, scaleFactor))
{
}

MouseCursor::MouseCursor (const MouseCursor& other)
    : cursorHandle (other.cursorHandle == nullptr ? nullptr : other.cursorHandle->retain())
{
}

MouseCursor::~MouseCursor()
{
    if (cursorHandle != nullptr)
        cursorHandle->release();
}

MouseCursor& MouseCursor::operator= (const MouseCursor& other)
{
    if (other.cursorHandle != nullptr)
        other.cursorHandle->retain();

    if (cursorHandle != nullptr)
        cursorHandle->release();

    cursorHandle = other.cursorHandle;
    return *this;
}

MouseCursor::MouseCursor (MouseCursor&& other) noexcept
    : cursorHandle (other.cursorHandle)
{
    other.cursorHandle = nullptr;
}

MouseCursor& MouseCursor::operator= (MouseCursor&& other) noexcept
{
    std::swap (cursorHandle, other.cursorHandle);
    return *this;
}

bool MouseCursor::operator== (const MouseCursor& other) const noexcept
{
    return getHandle() == other.getHandle();
}

bool MouseCursor::operator== (StandardCursorType type) const noexcept
{
    return cursorHandle != nullptr ? cursorHandle->isStandardType (type)
                                   : (type == NormalCursor);
}

bool MouseCursor::operator!= (const MouseCursor& other) const noexcept  { return ! operator== (other); }
bool MouseCursor::operator!= (StandardCursorType type)  const noexcept  { return ! operator== (type); }

void* MouseCursor::getHandle() const noexcept
{
    return cursorHandle != nullptr ? cursorHandle->getHandle() : nullptr;
}

void MouseCursor::showWaitCursor()
{
    Desktop::getInstance().getMainMouseSource().showMouseCursor (MouseCursor::WaitCursor);
}

void MouseCursor::hideWaitCursor()
{
    Desktop::getInstance().getMainMouseSource().revealCursor();
}

} // namespace juce