Qt-Advanced-Docking-System/AdvancedDockingSystem/src/ads/drop_overlay.cpp

#include "drop_overlay.h"

#include <QDebug>
#include <QPointer>
#include <QPaintEvent>
#include <QResizeEvent>
#include <QMoveEvent>
#include <QPainter>
#include <QGridLayout>
#include <QCursor>
#include <QtGui/QIcon>
#include <QtWidgets/QLabel>

ADS_NAMESPACE_BEGIN

// Helper /////////////////////////////////////////////////////////////

static QWidget* createDropWidget(const QString& img)
{
	auto label = new QLabel();
	label->setObjectName("DropAreaLabel");
	label->setPixmap(QPixmap(img));
	return label;
}

///////////////////////////////////////////////////////////////////////

DropOverlay::DropOverlay(QWidget *parent) :
	QFrame(parent),
	_splitAreas(NULL)
{
	setAttribute(Qt::WA_TransparentForMouseEvents);
	setWindowFlags(windowFlags() | Qt::Tool);
	setWindowFlags(windowFlags() | Qt::FramelessWindowHint);
	setWindowOpacity(0.2);

	auto l = new QBoxLayout(QBoxLayout::TopToBottom);
	l->setContentsMargins(0, 0, 0, 0);
	l->setSpacing(0);
	setLayout(l);

	_splitAreas = new DropSplitAreas(parent);
	_splitAreas->move(pos());
	_splitAreas->resize(size());
	_splitAreas->setVisible(true);
}

DropOverlay::~DropOverlay()
{
	if (_splitAreas)
	{
		delete _splitAreas;
		_splitAreas = NULL;
	}
}

DropArea DropOverlay::cursorLocation() const
{
	auto loc = InvalidDropArea;
	if (_splitAreas)
	{
		loc = _splitAreas->cursorLocation();
	}
	return loc;
}

void DropOverlay::paintEvent(QPaintEvent*)
{
	QPainter p(this);

	// Draw rect over the entire size + border.
	auto r = rect();
	r.setWidth(r.width() - 1);
	r.setHeight(r.height() - 1);

	p.fillRect(r, QBrush(QColor(0, 100, 255), Qt::Dense4Pattern));
	p.setBrush(QBrush(QColor(0, 100, 255)));
	p.drawRect(r);
}

void DropOverlay::resizeEvent(QResizeEvent* e)
{
	// Keep it in center of DropOverlay
	if (_splitAreas)
	{
		_splitAreas->resize(e->size());
	}
}

void DropOverlay::moveEvent(QMoveEvent* e)
{
	// Keep it in center of DropOverlay
	if (_splitAreas)
	{
		_splitAreas->move(e->pos());
	}
}

///////////////////////////////////////////////////////////////////////

DropSplitAreas::DropSplitAreas(QWidget* parent) : AbstractDropAreas(parent)
{
	//setAttribute(Qt::WA_TransparentForMouseEvents);
	setAttribute(Qt::WA_TranslucentBackground);
	setWindowFlags(windowFlags() | Qt::Tool);
	setWindowFlags(windowFlags() | Qt::FramelessWindowHint);

	_top = createDropWidget(":/img/split-top.png");
	_right = createDropWidget(":/img/split-right.png");
	_bottom = createDropWidget(":/img/split-bottom.png");
	_left = createDropWidget(":/img/split-left.png");
	_center = createDropWidget(":/img/dock-center.png");

	QGridLayout* grid = new QGridLayout();
	grid->setContentsMargins(0, 0, 0, 0);
	grid->setSpacing(6);
	grid->addWidget(_top, 0, 1, Qt::AlignHCenter | Qt::AlignBottom);
	grid->addWidget(_right, 1, 2, Qt::AlignLeft | Qt::AlignVCenter);
	grid->addWidget(_bottom, 2, 1, Qt::AlignHCenter | Qt::AlignTop);
	grid->addWidget(_left, 1, 0, Qt::AlignRight | Qt::AlignVCenter);
	grid->addWidget(_center, 1, 1, Qt::AlignCenter);

	QBoxLayout* bl1 = new QBoxLayout(QBoxLayout::TopToBottom);
	bl1->setContentsMargins(0, 0, 0, 0);
	bl1->setSpacing(0);
	setLayout(bl1);

	QBoxLayout* bl2 = new QBoxLayout(QBoxLayout::LeftToRight);
	bl2->setContentsMargins(0, 0, 0, 0);
	bl2->setSpacing(0);

	bl1->addStretch(1);
	bl1->addLayout(bl2);
	bl2->addStretch(1);
	bl2->addLayout(grid, 0);
	bl2->addStretch(1);
	bl1->addStretch(1);
}

DropArea DropSplitAreas::cursorLocation() const
{
	auto loc = InvalidDropArea;
	auto pos = mapFromGlobal(QCursor::pos());
	if (_top->geometry().contains(pos))
	{
		loc = TopDropArea;
	}
	else if (_right->geometry().contains(pos))
	{
		loc = RightDropArea;
	}
	else if (_bottom->geometry().contains(pos))
	{
		loc = BottomDropArea;
	}
	else if (_left->geometry().contains(pos))
	{
		loc = LeftDropArea;
	}
	else if (_center->geometry().contains(pos))
	{
		loc = CenterDropArea;
	}
	return loc;
}

// Globals ////////////////////////////////////////////////////////////

static QPointer<DropOverlay> MyOverlay;
static QPointer<QWidget> MyOverlayParent;
static QRect MyOverlayParentRect;

DropArea showDropOverlay(QWidget* parent)
{
	if (MyOverlay)
	{
		if (MyOverlayParent == parent)
		{
			// Hint: We could update geometry of overlay here.
			return MyOverlay->cursorLocation();
		}
		hideDropOverlay();
	}

	// Create new overlay and move it directly over the "parent" widget.
	MyOverlay = new DropOverlay(parent);
	MyOverlay->resize(parent->size());
	MyOverlay->move(parent->mapToGlobal(parent->rect().topLeft()));
	MyOverlay->show();
	MyOverlayParent = parent;
	return MyOverlay->cursorLocation();
}

void showDropOverlay(QWidget* parent, const QRect& areaRect)
{
	if (MyOverlay)
	{
		if (MyOverlayParent == parent && MyOverlayParentRect == areaRect)
		{
			return;
		}
		hideDropOverlay();
	}

	// Create overlay and move it to the parent's areaRect
	MyOverlay = new DropOverlay(parent);
	MyOverlay->resize(areaRect.size());
	MyOverlay->move(parent->mapToGlobal(QPoint(areaRect.x(), areaRect.y())));
	MyOverlay->show();
	MyOverlayParent = parent;
	MyOverlayParentRect = areaRect;
	return;
}

void hideDropOverlay()
{
	if (MyOverlay)
	{
		MyOverlay->hide();
		delete MyOverlay;
		MyOverlayParent.clear();
		MyOverlayParentRect = QRect();
	}
}

ADS_NAMESPACE_END