GPXSee/src/map/emptymap.cpp

#include <QtGlobal>
#include <QPainter>
#include "common/coordinates.h"
#include "common/rectc.h"
#include "common/wgs84.h"
#include "emptymap.h"


#define SCALE_MIN 0.5
#define SCALE_MAX 1.0E-6

static QPointF ll2m(const Coordinates &c)
{
	return QPointF(c.lon(), rad2deg(log(tan(M_PI/4.0 + deg2rad(c.lat())/2.0))));
}

static Coordinates m2ll(const QPointF &p)
{
	return Coordinates(p.x(), rad2deg(2 * atan(exp(deg2rad(p.y()))) - M_PI/2));
}


EmptyMap::EmptyMap(QObject *parent) : Map(parent)
{
	_scale = SCALE_MAX;
}

QRectF EmptyMap::bounds() const
{
	return QRectF(ll2xy(Coordinates(-180, 85)), ll2xy(Coordinates(180, -85)));
}

qreal EmptyMap::zoomFit(const QSize &size, const RectC &br)
{
	if (!br.isValid())
		_scale = SCALE_MAX;
	else {
		QRectF tbr(ll2m(br.topLeft()), ll2m(br.bottomRight()));
		QPointF sc(tbr.width() / size.width(), tbr.height() / size.height());
		_scale = qMax(sc.x(), sc.y());
	}

	_scale = qMax(_scale, SCALE_MAX);
	_scale = qMin(_scale, SCALE_MIN);

	return _scale;
}

qreal EmptyMap::zoomFit(qreal resolution, const Coordinates &c)
{
	_scale = (360.0 * resolution) / (WGS84_RADIUS * 2 * M_PI
	  * cos(deg2rad(c.lat())));

	_scale = qMax(_scale, SCALE_MAX);
	_scale = qMin(_scale, SCALE_MIN);

	return _scale;
}

qreal EmptyMap::resolution(const QPointF &p) const
{
	return (WGS84_RADIUS * 2 * M_PI * _scale / 360.0
	  * cos(2.0 * atan(exp(deg2rad(-p.y() * _scale))) - M_PI/2));
}

qreal EmptyMap::zoomIn()
{
	_scale = qMax(_scale / 2.0, SCALE_MAX);
	return _scale;
}

qreal EmptyMap::zoomOut()
{
	_scale = qMin(_scale * 2.0, SCALE_MIN);
	return _scale;
}

void EmptyMap::draw(QPainter *painter, const QRectF &rect)
{
	painter->fillRect(rect, _backgroundColor);
}

QPointF EmptyMap::ll2xy(const Coordinates &c) const
{
	QPointF m = ll2m(c);
	return QPointF(m.x() / _scale, m.y() / -_scale);
}

Coordinates EmptyMap::xy2ll(const QPointF &p) const
{
	QPointF m(p.x() * _scale, -p.y() * _scale);
	return m2ll(QPointF(p.x() * _scale, -p.y() * _scale));
}