JUCE/modules/juce_gui_extra/native/juce_mac_NSViewComponent.mm

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

   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
{

class NSViewAttachment  : public ReferenceCountedObject,
                          public ComponentMovementWatcher
{
public:
    NSViewAttachment (NSView* v, Component& comp)
        : ComponentMovementWatcher (&comp),
          view (v), owner (comp),
          currentPeer (nullptr)
    {
        [view retain];
        [view setPostsFrameChangedNotifications: YES];
        updateAlpha();

        if (owner.isShowing())
            componentPeerChanged();
    }

    ~NSViewAttachment() override
    {
        removeFromParent();
        [view release];
    }

    void componentMovedOrResized (Component& comp, bool wasMoved, bool wasResized) override
    {
        ComponentMovementWatcher::componentMovedOrResized (comp, wasMoved, wasResized);

        // The ComponentMovementWatcher version of this method avoids calling
        // us when the top-level comp is resized, but if we're listening to the
        // top-level comp we still want the NSView to track its size.
        if (comp.isOnDesktop() && wasResized)
            componentMovedOrResized (wasMoved, wasResized);
    }

    void componentMovedOrResized (bool /*wasMoved*/, bool /*wasResized*/) override
    {
        if (auto* peer = owner.getTopLevelComponent()->getPeer())
        {
            const auto newArea = peer->getAreaCoveredBy (owner);

            if (convertToRectInt ([view frame]) != newArea)
                [view setFrame: makeNSRect (newArea)];
        }
    }

    void componentPeerChanged() override
    {
        auto* peer = owner.getPeer();

        if (currentPeer != peer)
        {
            currentPeer = peer;

            if (peer != nullptr)
            {
                auto peerView = (NSView*) peer->getNativeHandle();
                [peerView addSubview: view];
                componentMovedOrResized (false, false);
            }
            else
            {
                removeFromParent();
            }
        }

        [view setHidden: ! owner.isShowing()];
    }

    void componentVisibilityChanged() override
    {
        componentPeerChanged();
    }

    void updateAlpha()
    {
        [view setAlphaValue: (CGFloat) owner.getAlpha()];
    }

    NSView* const view;

    using Ptr = ReferenceCountedObjectPtr<NSViewAttachment>;

private:
    Component& owner;
    ComponentPeer* currentPeer;
    NSViewFrameWatcher frameWatcher { view, [this] { owner.childBoundsChanged (nullptr); } };

    void removeFromParent()
    {
        if ([view superview] != nil)
            [view removeFromSuperview]; // Must be careful not to call this unless it's required - e.g. some Apple AU views
                                        // override the call and use it as a sign that they're being deleted, which breaks everything..
    }

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (NSViewAttachment)
};

//==============================================================================
NSViewComponent::NSViewComponent() = default;
NSViewComponent::~NSViewComponent() = default;

void NSViewComponent::setView (void* view)
{
    if (view != getView())
    {
        auto old = attachment;

        attachment = nullptr;

        if (view != nullptr)
            attachment = attachViewToComponent (*this, view);

        old = nullptr;
    }
}

void* NSViewComponent::getView() const
{
    return attachment != nullptr ? static_cast<NSViewAttachment*> (attachment.get())->view
                                 : nullptr;
}

void NSViewComponent::resizeToFitView()
{
    if (attachment != nullptr)
    {
        auto* view = static_cast<NSViewAttachment*> (attachment.get())->view;
        auto r = [view frame];
        setBounds (Rectangle<int> ((int) r.size.width, (int) r.size.height));

        if (auto* peer = getTopLevelComponent()->getPeer())
        {
            const auto position = peer->getAreaCoveredBy (*this).getPosition();
            [view setFrameOrigin: convertToCGPoint (position)];
        }
    }
}

void NSViewComponent::paint (Graphics&) {}

void NSViewComponent::alphaChanged()
{
    if (attachment != nullptr)
        (static_cast<NSViewAttachment*> (attachment.get()))->updateAlpha();
}

ReferenceCountedObject* NSViewComponent::attachViewToComponent (Component& comp, void* view)
{
    return new NSViewAttachment ((NSView*) view, comp);
}

} // namespace juce