Qt-Advanced-Docking-System/src/ResizeHandle.cpp

//============================================================================
/// \file   ResizeHandle.cpp
/// \author Uwe Kindler
/// \date   24.10.2022
/// \brief  Implementation of CResizeHandle class
//============================================================================

//============================================================================
//                                   INCLUDES
//============================================================================
#include "ResizeHandle.h"

#include <QDebug>
#include <QStyle>
#include <QStyleOption>
#include <QMouseEvent>
#include <QRubberBand>
#include <QPointer>

#include "ads_globals.h"

namespace ads
{
/**
 * Private data class of CResizeHandle class (pimpl)
 */
struct ResizeHandlePrivate
{
	CResizeHandle *_this;
	Qt::Edge HandlePosition = Qt::LeftEdge;
	QWidget* Target = nullptr;
	int MouseOffset = 0;
	bool Pressed = false;
	int MinSize = 0;
	int MaxSize = 1;
	QPointer<QRubberBand> RubberBand;
	bool OpaqueResize = false;
	int HandleWidth = 4;

	/**
	 * Private data constructor
	 */
	ResizeHandlePrivate(CResizeHandle *_public);

	/**
	 * Pick position component from pos depending on orientation
	 */
	int pick(const QPoint &pos) const
    {
		return _this->orientation() == Qt::Horizontal ? pos.x() : pos.y();
    }

	/**
	 * Returns true, if orientation is horizontal
	 */
	bool isHorizontal() const
	{
		return _this->orientation() == Qt::Horizontal;
	}

	/**
	 * Set rubberband position
	 */
	void setRubberBand(int Pos);

	/**
	 * Calculates the resize position and geometry
	 */
	void doResizing(QMouseEvent* e, bool ForceResize = false);
};
// struct ResizeHandlePrivate

//============================================================================
ResizeHandlePrivate::ResizeHandlePrivate(CResizeHandle *_public) :
	_this(_public)
{

}


//============================================================================
void ResizeHandlePrivate::setRubberBand(int Pos)
{
	if (!RubberBand)
	{
		RubberBand = new QRubberBand(QRubberBand::Line, Target->parentWidget());
	}

	auto Geometry = _this->geometry();
	auto TopLeft = Target->mapTo(Target->parentWidget(), Geometry.topLeft());
	switch (HandlePosition)
	{
	case Qt::LeftEdge:
	case Qt::RightEdge: TopLeft.rx() += Pos; break;
	case Qt::TopEdge:
	case Qt::BottomEdge: TopLeft.ry() += Pos; break;
	}

	Geometry.moveTopLeft(TopLeft);
	RubberBand->setGeometry(Geometry);
	RubberBand->show();
}


//============================================================================
void ResizeHandlePrivate::doResizing(QMouseEvent* e, bool ForceResize)
{
    int pos = pick(e->pos()) - MouseOffset;
    auto OldGeometry = Target->geometry();
	auto NewGeometry = OldGeometry;
	switch (HandlePosition)
	{
	case Qt::LeftEdge:
		 {
			 NewGeometry.adjust(pos, 0, 0, 0);
			 int Size = qBound(MinSize, NewGeometry.width(), MaxSize);
			 pos += (NewGeometry.width() - Size);
			 NewGeometry.setWidth(Size);
			 NewGeometry.moveTopRight(OldGeometry.topRight());
		 }
		 break;


	case Qt::RightEdge:
		 {
			 NewGeometry.adjust(0, 0, pos, 0);
			 int Size = qBound(MinSize, NewGeometry.width(), MaxSize);
			 pos -= (NewGeometry.width() - Size);
			 NewGeometry.setWidth(Size);
		 }
		 break;

	case Qt::TopEdge:
	     {
			 NewGeometry.adjust(0, pos, 0, 0);
			 int Size = qBound(MinSize, NewGeometry.height(), MaxSize);
			 pos += (NewGeometry.height() - Size);
			 NewGeometry.setHeight(Size);
			 NewGeometry.moveBottomLeft(OldGeometry.bottomLeft());
		 }
		 break;

	case Qt::BottomEdge:
	     {
			 NewGeometry.adjust(0, 0, 0, pos);
			 int Size = qBound(MinSize, NewGeometry.height(), MaxSize);
			 pos -= (NewGeometry.height() - Size);
			 NewGeometry.setHeight(Size);
		 }
		 break;
	}

	if (_this->opaqueResize() || ForceResize)
	{
		Target->setGeometry(NewGeometry);
	}
	else
	{
		setRubberBand(pos);
	}
}


//============================================================================
CResizeHandle::CResizeHandle(Qt::Edge HandlePosition, QWidget* parent) :
	Super(parent),
	d(new ResizeHandlePrivate(this))
{
	d->Target = parent;
	setMinResizeSize(48);
	setHandlePosition(HandlePosition);
}


//============================================================================
CResizeHandle::~CResizeHandle()
{
	delete d;
}


//============================================================================
void CResizeHandle::mouseMoveEvent(QMouseEvent* e)
{
    if (!(e->buttons() & Qt::LeftButton))
    {
        return;
    }

    d->doResizing(e);
}


//============================================================================
void CResizeHandle::mousePressEvent(QMouseEvent* e)
{
    if (e->button() == Qt::LeftButton)
    {
        d->MouseOffset = d->pick(e->pos());
        d->Pressed = true;
        update();
    }
}


//============================================================================
void CResizeHandle::mouseReleaseEvent(QMouseEvent* e)
{
    if (!opaqueResize() && e->button() == Qt::LeftButton)
    {
        if (d->RubberBand)
        {
        	d->RubberBand->deleteLater();
        }
        d->doResizing(e, true);
    }
    if (e->button() == Qt::LeftButton)
    {
        d->Pressed = false;
        update();
    }
}


//============================================================================
void CResizeHandle::setHandlePosition(Qt::Edge HandlePosition)
{
	d->HandlePosition = HandlePosition;
	switch (d->HandlePosition)
	{
	case Qt::LeftEdge: // fall through
	case Qt::RightEdge: setCursor(Qt::SizeHorCursor); break;

	case Qt::TopEdge: // fall through
	case Qt::BottomEdge: setCursor(Qt::SizeVerCursor); break;
	}

	setMaxResizeSize(d->isHorizontal() ? parentWidget()->height() : parentWidget()->width());
	if (!d->isHorizontal())
	{
		setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
	}
	else
	{
		setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Expanding);
	}
}


//============================================================================
Qt::Edge CResizeHandle::handlePostion() const
{
	return d->HandlePosition;
}


//============================================================================
Qt::Orientation CResizeHandle::orientation() const
{
	switch (d->HandlePosition)
	{
	case Qt::LeftEdge: // fall through
	case Qt::RightEdge: return Qt::Horizontal;

	case Qt::TopEdge: // fall through
	case Qt::BottomEdge: return Qt::Vertical;
	}

	return Qt::Horizontal;
}


//============================================================================
QSize CResizeHandle::sizeHint() const
{
	QSize Result;
	switch (d->HandlePosition)
	{
	case Qt::LeftEdge: // fall through
	case Qt::RightEdge: Result = QSize(d->HandleWidth, d->Target->height()); break;

	case Qt::TopEdge: // fall through
	case Qt::BottomEdge: Result = QSize(d->Target->width(), d->HandleWidth); break;
	}

	return Result;
}


//============================================================================
bool CResizeHandle::isResizing() const
{
	return d->Pressed;
}


//============================================================================
void CResizeHandle::setMinResizeSize(int MinSize)
{
	d->MinSize = MinSize;
}


//============================================================================
void CResizeHandle::setMaxResizeSize(int MaxSize)
{
	d->MaxSize = MaxSize;
}


//============================================================================
void CResizeHandle::setOpaqueResize(bool opaque)
{
	d->OpaqueResize = opaque;
}


//============================================================================
bool CResizeHandle::opaqueResize() const
{
	return d->OpaqueResize;
}
} // namespace ads

//---------------------------------------------------------------------------
// EOF ResizeHandle.cpp