osmscout::MercatorProjection Class Reference

#include <libosmscout/include/osmscout/projection/MercatorProjection.h>

Inheritance diagram for osmscout::MercatorProjection:

Collaboration diagram for osmscout::MercatorProjection:

Public Member Functions
	MercatorProjection ()=default
	MercatorProjection (const MercatorProjection &)=default
	MercatorProjection (MercatorProjection &&)=default
MercatorProjection &	operator= (const MercatorProjection &)=default
MercatorProjection &	operator= (MercatorProjection &&)=default
	~MercatorProjection () override=default
bool	CanBatch () const override
bool	IsValid () const override
bool	IsValidFor (const GeoCoord &coord) const override
bool	Set (const GeoCoord &coord, const Magnification &magnification, size_t width, size_t height)
bool	Set (const GeoCoord &coord, double angle, const Magnification &magnification, size_t width, size_t height)
bool	Set (const GeoCoord &coord, const Magnification &magnification, double dpi, size_t width, size_t height)
bool	Set (const GeoCoord &coord, double angle, const Magnification &magnification, double dpi, size_t width, size_t height)
bool	PixelToGeo (double x, double y, GeoCoord &coord) const override
bool	GeoToPixel (const GeoCoord &coord, Vertex2D &pixel) const override
bool	Move (double horizPixel, double vertPixel)
bool	MoveUp (double pixel)
bool	MoveDown (double pixel)
bool	MoveLeft (double pixel)
bool	MoveRight (double pixel)
bool	IsLinearInterpolationEnabled () const
void	SetLinearInterpolationUsage (bool useLinearInterpolation)
Public Member Functions inherited from osmscout::Projection
	Projection ()=default
	Projection (const Projection &)=default
	Projection (Projection &&)=default
Projection &	operator= (const Projection &)=default
Projection &	operator= (Projection &&)=default
virtual	~Projection ()=default
GeoCoord	GetCenter () const
double	GetAngle () const
size_t	GetWidth () const
size_t	GetHeight () const
ScreenBox	GetScreenBox () const
Magnification	GetMagnification () const
double	GetDPI () const
GeoBox	GetDimensions () const
double	GetPixelSize () const
double	GetMeterInPixel () const
double	GetMeterInMM () const
double	ConvertWidthToPixel (double width) const
double	ConvertPixelToWidth (double pixel) const
bool	BoundingBoxToPixel (const GeoBox &boundingBox, ScreenBox &screenBox) const

Static Public Attributes
static const double	MaxLat
static const double	MinLat
static const double	MaxLon
static const double	MinLon

Protected Member Functions
void	GeoToPixel (const BatchTransformer &transformData) const override

Protected Attributes
bool	valid =false
	projection is valid
double	latOffset =0.0
	Absolute and untransformed screen position of lat coordinate.
double	angleSin =0.0
double	angleCos =0.0
double	angleNegSin =0.0
double	angleNegCos =0.0
double	scale =1.0
double	scaleGradtorad =0.0
	Precalculated scale*Gradtorad.
double	scaledLatDeriv =0.0
	center scaled by gradtorad * scale
bool	useLinearInterpolation =false
	switch to enable linear interpolation of latitude to pixel computation
Protected Attributes inherited from osmscout::Projection
GeoCoord	center
	Coordinate of the center of the displayed area.
double	angle =0.0
	Display rotation angle in radians, canvas clockwise.
Magnification	magnification
	Current magnification.
double	dpi =0.0
	Screen DPI.
size_t	width =0
	Width of image.
size_t	height =0
	Height of image.
GeoBox	boundingBox
	Bounding box of the current projection on the ground.
double	pixelSize =0.0
	Size of a pixel in meter.
double	meterInPixel =0.0
	Number of on screen pixel for one meter on the ground.
double	meterInMM =0.0
	Number of on screen millimeters for one meter on the ground.

Detailed Description

Mercator projection that tries to render the resulting map in the same physical size on all devices. If the physical DPI of the device is correctly given, objects on any device has the same size. Bigger devices will show "more" map thus.

Scale is calculated based on the assumption that the original OpenStreetMap tiles were designed for 96 DPI displays.

Constructor & Destructor Documentation

MercatorProjection() [1/3]

osmscout::MercatorProjection::MercatorProjection ( )

default

MercatorProjection() [2/3]

osmscout::MercatorProjection::MercatorProjection ( const MercatorProjection & )

default

MercatorProjection() [3/3]

osmscout::MercatorProjection::MercatorProjection ( MercatorProjection && )

default

~MercatorProjection()

osmscout::MercatorProjection::~MercatorProjection ( )

overridedefault

Member Function Documentation

CanBatch()

bool osmscout::MercatorProjection::CanBatch ( ) const

inlineoverridevirtual

Implements osmscout::Projection.

GeoToPixel() [1/2]

void osmscout::MercatorProjection::GeoToPixel ( const BatchTransformer & transformData ) const

overrideprotectedvirtual

Implements osmscout::Projection.

GeoToPixel() [2/2]

bool osmscout::MercatorProjection::GeoToPixel ( const GeoCoord & coord, Vertex2D & pixel ) const

overridevirtual

Converts a geo coordinate to a pixel coordinate.

Return true on success, false if given coordinate is not valid for this projection.

Implements osmscout::Projection.

IsLinearInterpolationEnabled()

bool osmscout::MercatorProjection::IsLinearInterpolationEnabled ( ) const

inlinenodiscard

IsValid()

bool osmscout::MercatorProjection::IsValid ( ) const

inlineoverridevirtual

Implements osmscout::Projection.

IsValidFor()

bool osmscout::MercatorProjection::IsValidFor ( const GeoCoord & coord ) const

inlineoverridevirtual

Return true if given coordinate is valid for this projection

Implements osmscout::Projection.

Move()

bool osmscout::MercatorProjection::Move	(	double	horizPixel,
		double	vertPixel )

MoveDown()

bool osmscout::MercatorProjection::MoveDown ( double pixel )

inline

MoveLeft()

bool osmscout::MercatorProjection::MoveLeft ( double pixel )

inline

MoveRight()

bool osmscout::MercatorProjection::MoveRight ( double pixel )

inline

MoveUp()

bool osmscout::MercatorProjection::MoveUp ( double pixel )

inline

operator=() [1/2]

MercatorProjection & osmscout::MercatorProjection::operator= ( const MercatorProjection & )

default

operator=() [2/2]

MercatorProjection & osmscout::MercatorProjection::operator= ( MercatorProjection && )

default

PixelToGeo()

bool osmscout::MercatorProjection::PixelToGeo ( double x, double y, GeoCoord & coord ) const

overridevirtual

Converts a pixel coordinate to a geo coordinate.

Return true on success, false if returned coordinate is not valid for this projection.

Implements osmscout::Projection.

Set() [1/4]

bool osmscout::MercatorProjection::Set ( const GeoCoord & coord, const Magnification & magnification, double dpi, size_t width, size_t height )

inline

Set() [2/4]

bool osmscout::MercatorProjection::Set ( const GeoCoord & coord, const Magnification & magnification, size_t width, size_t height )

inline

Set() [3/4]

bool osmscout::MercatorProjection::Set	(	const GeoCoord &	coord,
		double	angle,
		const Magnification &	magnification,
		double	dpi,
		size_t	width,
		size_t	height )

Setup projection parameters.

Return true on success, false if arguments are not valid for Mercator projection, projection parameters are unchanged in such case.

Angle is in radians ([0..2*PI[)

Note that coord (center) have to be valid coordinate in Mercator projection. But it is possible setup dimensions (width and height) that projection will cover area bigger than the one valid for Mercator projection. Bounding box is adjusted then to be valid for projection.

In code:

projection.GetDimensions(bbox); projection.GeoToPixel(bbox.GetMinCoord(),x,y)

may be x >= 0

Set() [4/4]

bool osmscout::MercatorProjection::Set ( const GeoCoord & coord, double angle, const Magnification & magnification, size_t width, size_t height )

inline

SetLinearInterpolationUsage()

void osmscout::MercatorProjection::SetLinearInterpolationUsage ( bool useLinearInterpolation )

inline

Switch to enable/disable linear interpolation of latitude to pixel computation. It speedup GeoToPixel calculation with fractional error on small render area.

Member Data Documentation

angleCos

double osmscout::MercatorProjection::angleCos =0.0

protected

angleNegCos

double osmscout::MercatorProjection::angleNegCos =0.0

protected

angleNegSin

double osmscout::MercatorProjection::angleNegSin =0.0

protected

angleSin

double osmscout::MercatorProjection::angleSin =0.0

protected

latOffset

double osmscout::MercatorProjection::latOffset =0.0

protected

Absolute and untransformed screen position of lat coordinate.

MaxLat

const double osmscout::MercatorProjection::MaxLat

static

MaxLon

const double osmscout::MercatorProjection::MaxLon

static

MinLat

const double osmscout::MercatorProjection::MinLat

static

MinLon

const double osmscout::MercatorProjection::MinLon

static

scale

double osmscout::MercatorProjection::scale =1.0

protected

scaledLatDeriv

double osmscout::MercatorProjection::scaledLatDeriv =0.0

protected

center scaled by gradtorad * scale

precalculated derivation of "latToYPixel" function in projection

scaleGradtorad

double osmscout::MercatorProjection::scaleGradtorad =0.0

protected

Precalculated scale*Gradtorad.

useLinearInterpolation

bool osmscout::MercatorProjection::useLinearInterpolation =false

protected

switch to enable linear interpolation of latitude to pixel computation

valid

bool osmscout::MercatorProjection::valid =false

protected

projection is valid

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The documentation for this class was generated from the following file:

• libosmscout/include/osmscout/projection/MercatorProjection.h