JUCE/modules/juce_gui_basics/layout/juce_ComponentMovementWatcher.cpp

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

   This file is part of the JUCE library - "Jules' Utility Class Extensions"
   Copyright 2004-11 by Raw Material Software Ltd.

  ------------------------------------------------------------------------------

   JUCE can be redistributed and/or modified under the terms of the GNU General
   Public License (Version 2), as published by the Free Software Foundation.
   A copy of the license is included in the JUCE distribution, or can be found
   online at www.gnu.org/licenses.

   JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

  ------------------------------------------------------------------------------

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.rawmaterialsoftware.com/juce for more information.

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

ComponentMovementWatcher::ComponentMovementWatcher (Component* const comp)
    : component (comp),
      lastPeerID (0),
      reentrant (false),
      wasShowing (comp->isShowing())
{
    jassert (component != nullptr); // can't use this with a null pointer..

    component->addComponentListener (this);

    registerWithParentComps();
}

ComponentMovementWatcher::~ComponentMovementWatcher()
{
    if (component != nullptr)
        component->removeComponentListener (this);

    unregister();
}

//==============================================================================
void ComponentMovementWatcher::componentParentHierarchyChanged (Component&)
{
    if (component != nullptr && ! reentrant)
    {
        const ScopedValueSetter<bool> setter (reentrant, true);

        ComponentPeer* const peer = component->getPeer();
        const uint32 peerID = peer != nullptr ? peer->getUniqueID() : 0;

        if (peerID != lastPeerID)
        {
            componentPeerChanged();

            if (component == nullptr)
                return;

            lastPeerID = peerID;
        }

        unregister();
        registerWithParentComps();

        componentMovedOrResized (*component, true, true);

        if (component != nullptr)
            componentVisibilityChanged (*component);
    }
}

void ComponentMovementWatcher::componentMovedOrResized (Component&, bool wasMoved, bool wasResized)
{
    if (component != nullptr)
    {
        if (wasMoved)
        {
            const Point<int> pos (component->getTopLevelComponent()->getLocalPoint (component, Point<int>()));

            wasMoved = lastBounds.getPosition() != pos;
            lastBounds.setPosition (pos);
        }

        wasResized = (lastBounds.getWidth() != component->getWidth() || lastBounds.getHeight() != component->getHeight());
        lastBounds.setSize (component->getWidth(), component->getHeight());

        if (wasMoved || wasResized)
            componentMovedOrResized (wasMoved, wasResized);
    }
}

void ComponentMovementWatcher::componentBeingDeleted (Component& comp)
{
    registeredParentComps.removeFirstMatchingValue (&comp);

    if (component == &comp)
        unregister();
}

void ComponentMovementWatcher::componentVisibilityChanged (Component&)
{
    if (component != nullptr)
    {
        const bool isShowingNow = component->isShowing();

        if (wasShowing != isShowingNow)
        {
            wasShowing = isShowingNow;
            componentVisibilityChanged();
        }
    }
}

void ComponentMovementWatcher::registerWithParentComps()
{
    for (Component* p = component->getParentComponent(); p != nullptr; p = p->getParentComponent())
    {
        p->addComponentListener (this);
        registeredParentComps.add (p);
    }
}

void ComponentMovementWatcher::unregister()
{
    for (int i = registeredParentComps.size(); --i >= 0;)
        registeredParentComps.getUnchecked(i)->removeComponentListener (this);

    registeredParentComps.clear();
}