JUCE/modules/juce_audio_processors/utilities/juce_NativeScaleFactorNotifier.cpp

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

   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
{

static void removeScaleFactorListenerFromAllPeers (ComponentPeer::ScaleFactorListener& listener)
{
     for (int i = 0; i < ComponentPeer::getNumPeers(); ++i)
         ComponentPeer::getPeer (i)->removeScaleFactorListener (&listener);
}

NativeScaleFactorNotifier::NativeScaleFactorNotifier (Component* comp, std::function<void (float)> onScaleChanged)
    : ComponentMovementWatcher (comp),
      scaleChanged (std::move (onScaleChanged))
{
    componentPeerChanged();
}

NativeScaleFactorNotifier::~NativeScaleFactorNotifier()
{
    removeScaleFactorListenerFromAllPeers (*this);
}

void NativeScaleFactorNotifier::nativeScaleFactorChanged (double newScaleFactor)
{
    NullCheckedInvocation::invoke (scaleChanged, (float) newScaleFactor);
}

void NativeScaleFactorNotifier::componentPeerChanged()
{
    removeScaleFactorListenerFromAllPeers (*this);

    if (auto* x = getComponent())
        peer = x->getPeer();

    if (auto* x = peer)
    {
        x->addScaleFactorListener (this);
        nativeScaleFactorChanged (x->getPlatformScaleFactor());
    }
}

} // namespace juce