TSLLatLongGridDataLayer Class Reference

Inheritance diagram for TSLLatLongGridDataLayer:

Detailed Description

This draws a Latitude / Longitude grid over a map data layer.

This adds special features to allow configuration of the rendering. Use the setFeatureRendering() method to configure the rendering options for these.

At present, the available feature names are:

• Line rendition styles:
  • "lonMajorDegree" : longitude lines (multiples of a degree)
  • "lonDegree" : longitude lines at degree intervals
  • "lonMinute" : longitude lines at minute intervals
  • "lonTenths" : longitude lines at tenth intervals
  • "latMajorDegree" : latitude lines (multiples of a degree)
  • "latDegree" : latitude lines at degree intervals
  • "latMinute" : latitude lines at minute intervals
  • "latTenths" : latitude lines at tenth intervals
• Text rendering styles:
  • "degreeLineLabel" : text style of the label applied to a line of latitude or longitude.
  • "subgridLineLabel" : text style of the label applied to a subgrid (minor) line, e.g. a minute or tenths line.

Label Positioning:

Line labels are setup by default to be positioned with latitude labels at the left hand side of the projection or screen and longitude labels at the bottom of the projection or screen. This can be modified by the user using the functions setLatitudeLabelPosition and setLongitudeLabelPosition. These functions take a bitmask value, see TSLGridLabelPosition, allowing a single option (e.g. latitude labels displayed on the RHS of the projection/screen) or a combination of options (e.g. latitude labels displayed on top and bottom of the projection/screen). The current values of the label position bitmasks can be obtained using the functions getLatitudeLabelPosition and getLongitudeLabelPosition.

The setSpacing() method with feature set to "lonMajorDegree" or "latMajorDegree" sets the distance between the major grid lines (in degrees). The default is 10 degrees.

The line rendering can be disabled by setting the edge style to 0. If the edge style is 0 then a symbol will be drawn if the feature rendering for a symbol is setup.

If the rendering for display of tenths and minutes are both setup, then neither is displayed.

The user can provide a TSLLatLongGridDataLayerFormatCallback to format the text drawn at each grid interval. If a callback is not supplied then it will default to decimal degrees. The user can also provide a TSLLatLongGridDataLayerFormatCallback to format the text drawn for subgrid labels. If a callback is not supplied then it will default to decimal degrees with a maximum of 3 decimal places.

Coordinate Systems:

The layer requires a Coordinate Systems to allow it to work out the grid points. The layer by default will use the Drawing Surface Coordinate System. This may be changed by the user by a call to addDataLayer with a coordinate system providing layer.

In both cases the Coordinate System must be correctly setup before the first draw of the grid layer or before calling addDataLayer as the layer takes a copy of the Coordinate System.

If the coordinate system is changed on the Drawing Surface or a map with a new coordinate system is loaded into the map data-layer then notifiedChanged should be called with true. This will cause the cache to be flushed and the Coordinate System to be queried again.

If you delete the map data-layer associated with the layer then you should call setDataLayer with NULL.

Public Types
enum	TSLSubGridLabelPositionEnum {   TSLSubGridLabelDefaultCentre = 0 , TSLSubGridLabelLHSBottom = 1 , TSLSubGridLabelRHSBottom = 2 , TSLSubGridLabelLHSTop = 3 ,   TSLSubGridLabelRHSTop = 4 }
enum	TSLGridLabelPosition {   TSLGridLabelLegacy = 0 , TSLGridLabelLHS = 1 , TSLGridLabelRHS = 2 , TSLGridLabelTop = 4 ,   TSLGridLabelBottom = 8 }
typedef TSLSubGridLabelPositionEnum	TSLSubGridLabelPosEnum
	deprecated

Public Member Functions
	TSLLatLongGridDataLayer ()
bool	getCentre (double &latitude, double &longitude) const
TSLLatLongGridDataLayerFormatCallback *	getFormatCallback (void **arg) const
TSLGridDetailLevelChangeEnum	getGridLevelChangeMode () const
TSLBitMask	getLatitudeLabelPosition () const
TSLBitMask	getLongitudeLabelPosition () const
TSLLatLongGridDataLayerFormatCallback *	getSubGridFormatCallback (void **arg) const
TSLSubGridLabelPositionEnum	getSubGridLabelPosition () const
bool	localDatum () const
void	localDatum (bool useLocalDatum)
void	setDataLayer (TSLDataLayer *dataLayer)
void	setFormatCallback (TSLLatLongGridDataLayerFormatCallback *callbackFunc, void *arg)
void	setGridLevelChangeMode (TSLGridDetailLevelChangeEnum mode=TSLGridLevelChangeAutomatic)
bool	setLatitudeLabelPosition (const TSLBitMask labelPosition=TSLGridLabelLHS)
bool	setLongitudeLabelPosition (const TSLBitMask labelPosition)
bool	setSpacing (const char *const feature, int spacing)
void	setSubGridFormatCallback (TSLLatLongGridDataLayerFormatCallback *callbackFunc, void *arg)
void	setSubGridLabelPosition (TSLSubGridLabelPositionEnum position=TSLSubGridLabelDefaultCentre)
bool	snap (TSLCoord *snap_pt, double &latitude, double &longitude, bool force_snap=false, bool snapToMiddle=false)
void	snapable (bool value)
bool	snapable () const
void	tickLength (int degrees, int tenthsMinutes)
void	ticks (bool ticks)
void *	operator new (size_t size) TSL_NO_THROW
void *	operator new (size_t size, char *filename, int line)
Public Member Functions inherited from TSLDataLayer
void	addDrawingCallback (TSLDataLayerDrawingCallback *drawingCallback)
bool	addFeatureRendering (const char *featureName, TSLFeatureID featureID)
bool	addLoader (TSLFileLoader *loader, TSLLoaderAppCallback callback, void *arg, TSLAllLoadedCallback allLoadedCallback=0, void *arg2=0)
bool	addPathList (const TSLPathList *path_list)
void	cancelFlashback ()
bool	clearFeatureRendering (const char *featureName, TSLFeatureID featureID)
TSLDataHandler *	createDataHandler (const char *config_file=0)
TSLHistoryVersion	currentVersion () const
TSLDataHandler *	dataHandler ()
const TSLDataHandler *	dataHandler () const
void	destroy ()
bool	entityIsVisible (const TSLEntity *entity, const TSLDrawingSurface *drawingSurface) const
const TSLFeatureClassList *	featureList () const
const TSLFeatureClassList *	featureList (const char *detailLayerName) const
bool	fileModificationTime (const char *filename, TSLTimeType &lastModificationTime)
TSLEntity *	findEntity (TSLTMC x, TSLTMC y, TSLTMC aperture, int depth, const char *featureName=0, int drawingSurfaceID=-1)
bool	findFile (const char *filename, TSLSimpleString &foundPath) const
void	flashbackToTimestamp (TSLHistoryTimestamp timestamp, TSLLayerArchiveCallback archiveCallback, void *arg=0)
void	flashbackToTimestamp (TSLHistoryTimestamp timestamp, TSLLayerArchiveTileCallback archiveTileCallback, void *arg=0)
void	flashbackToVersion (TSLHistoryVersion version, TSLLayerArchiveCallback archiveCallback, void *arg=0)
void	flashbackToVersion (TSLHistoryVersion version, TSLLayerArchiveTileCallback archiveTileCallback, void *arg=0)
bool	getActiveLayerName (const TSLEnvelope &extent, double screenResolution, TSLSimpleString &activeLayerName) const
TSLEntityIterator *	getEntityIterator (const char *detailLayer, TSLSelector *selector=NULL, TSLEnvelope *extent=NULL, bool splitOptimisedPrimitives=true)
bool	getFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributeInt attribute, int *result) const
bool	getFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributeDouble attribute, double *result) const
bool	getFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributeBool attribute, bool *result) const
bool	getFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributes *result) const
TSLFileLoader *	getLoader ()
bool	getMUExtent (double *x1, double *y1, double *x2, double *y2, int drawingSurfaceID=-1) const
bool	getTMCExtent (TSLTMC *x1, TSLTMC *y1, TSLTMC *x2, TSLTMC *y2, int drawingSurfaceID=-1) const
bool	getUUExtent (double *x1, double *y1, double *x2, double *y2, const TSLDrawingSurface *drawingSurface) const
bool	importHistory (TSLHistoryVersion mapVersion, TSLHistoryTimestamp timestamp, TSLHistoryImportSet *historySet)
bool	latLongToTMC (double latitude, double longitude, TSLTMC *x, TSLTMC *y, bool local=false) const
bool	latLongToTMC (int num, double *latitudes, double *longitudes, TSLTMC *xs, TSLTMC *ys, bool local=false) const
TSLDataLayerTypeEnum	layerType () const
bool	loadData (const char *filename)
bool	loadRendering (const char *filename)
void	notifyChanged (bool changed=true)
TSLMapQuery *	query (TSLTMC x1, TSLTMC y1, TSLTMC x2, TSLTMC y2, int depth=-1, const char *featureName=NULL, int drawingSurfaceID=-1) const
TSLMapQuery *	query (TSLTMC x1, TSLTMC y1, TSLTMC x2, TSLTMC y2, TSLSelector *selector, int drawingSurfaceID=-1) const
const TSLCoordinateSystem *	getCoordinateSystem () const
bool	queryVersionHistory (const TSLEnvelope &extent, TSLVersionHistorySet &history)
void	refreshFlashback ()
bool	removeData ()
void	releaseResources (int surfaceID)
bool	saveRendering (const char *filename, TSLMapLinkVersion ver=TSL_CURRENT_MAPLINK_VERSION)
bool	setCoordinateSystem (const TSLCoordinateSystem *coordinateSystem)
bool	setFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributeInt attribute, int value)
bool	setFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributeDouble attribute, double value)
bool	setFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributeBool attribute, bool value)
bool	setFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributes *value)
bool	TMCToLatLong (TSLTMC x, TSLTMC y, double *latitude, double *longitude, bool local=false, bool boundCheck=true) const
bool	TMCToLatLong (int num, TSLTMC *xs, TSLTMC *ys, double *latitudes, double *longitudes, bool local=false) const
const TSLVersionHistorySet *	versionHistory () const

Member Typedef Documentation

TSLSubGridLabelPosEnum

typedef TSLSubGridLabelPositionEnum TSLLatLongGridDataLayer::TSLSubGridLabelPosEnum

deprecated

Member Enumeration Documentation

TSLGridLabelPosition

enum TSLLatLongGridDataLayer::TSLGridLabelPosition

Bitmask defining the positions available for the display position of the Major and Degree level Grid labels.

Apart from the TSLGridLabelLegacy position which is mutually exclusive, the positions can be used individually or in combination with each other.

(LHS: Left Hand Side, RHS: Right Hand Side)

Enumerator
TSLGridLabelLegacy	Label is positioned as in older versions of MapLink (pre 7.0). If the map is fully contained by the display the label is positioned where the line intersects the left screen edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to a point midway up the display left edge and a twentieth of the display width across. If the map is not fully contained by the display, longitude labels are displayed along the latitude line closest to a point a tenth of the display height up the display left edge.
TSLGridLabelLHS	If the map is fully contained by the display the label is positioned where the line intersects the left display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display left edge and longitude labels are displayed along the latitude line closest to the midpoint of the display left edge.
TSLGridLabelRHS	If the map is fully contained by the display the label is positioned where the line intersects the right display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display right edge and longitude labels are displayed along the latitude line closest to the midpoint of the display right edge.
TSLGridLabelTop	If the map is fully contained by the display the label is positioned where the line intersects the top display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display top edge and longitude labels are displayed along the latitude line closest to the midpoint of the display top edge.
TSLGridLabelBottom	If the map is fully contained by the display the label is positioned where the line intersects the bottom display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display bottom edge and longitude labels are displayed along the latitude line closest to the midpoint of the display bottom edge.

TSLSubGridLabelPositionEnum

enum TSLLatLongGridDataLayer::TSLSubGridLabelPositionEnum

Enumeration defining the positions available for the display position of the SubGrid label.

(LHS: Left Hand Side, RHS: Right Hand Side)

Enumerator
TSLSubGridLabelDefaultCentre	Latitude/Longitude Label is positioned close to Sub Grid Centre
TSLSubGridLabelLHSBottom	Latitude Label is positioned at screen left, Longitude label is positioned at screen bottom
TSLSubGridLabelRHSBottom	Latitude Label is positioned at screen right, Longitude label is positioned at screen bottom
TSLSubGridLabelLHSTop	Latitude Label is positioned at screen left, Longitude label is positioned at screen top
TSLSubGridLabelRHSTop	Latitude Label is positioned at screen right, Longitude label is positioned at screen top

Constructor & Destructor Documentation

TSLLatLongGridDataLayer()

TSLLatLongGridDataLayer::TSLLatLongGridDataLayer

(

)

Member Function Documentation

getCentre()

bool TSLLatLongGridDataLayer::getCentre	(	double &	latitude,
		double &	longitude ) const

Gets the latitude and longitude of the centre of the last view displayed.

Parameters

latitude	[output] centre latitude.
longitude	[output] centre longitude.

Returns

true on success, false otherwise.

getFormatCallback()

TSLLatLongGridDataLayerFormatCallback * TSLLatLongGridDataLayer::getFormatCallback

(

void **

arg

)

const

Queries the data layer to see if a user defined callback, to format the text drawn at each grid interval, has been set.

Parameters

arg	If this parameter is provided, it will be pointed to the user defined value passed to the setFormatCallback method. If no callback has been set, it will be pointed at NULL

Returns

the user specified callback function if one has been provided, else NULL

getGridLevelChangeMode()

TSLGridDetailLevelChangeEnum TSLLatLongGridDataLayer::getGridLevelChangeMode

(

)

const

This method allows users to retrieve the current Grid Level Change Mode.

getLatitudeLabelPosition()

TSLBitMask TSLLatLongGridDataLayer::getLatitudeLabelPosition

(

)

const

This method allows users to retrieve the value of the bitmask used to determine the position of the latitude line labels. The positions available are:

• TSLGridLabelLegacy: Label is positioned as in older versions of MapLink (pre 7.0). If the map is fully contained by the display the label is positioned where the line intersects the left screen edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to a point midway up the display left edge and a twentieth of the display width across. If the map is not fully contained by the display, longitude labels are displayed along the latitude line closest to a point a tenth of the display height up the display left edge.
• TSLGridLabelLHS: If the map is fully contained by the display the label is positioned where the line intersects the left display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display left edge and longitude labels are displayed along the latitude line closest to the midpoint of the display left edge.
• TSLGridLabelRHS: If the map is fully contained by the display the label is positioned where the line intersects the right display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display right edge and longitude labels are displayed along the latitude line closest to the midpoint of the display right edge.
• TSLGridLabelTop: If the map is fully contained by the display the label is positioned where the line intersects the top display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display top edge and longitude labels are displayed along the latitude line closest to the midpoint of the display top edge.
• TSLGridLabelBottom: If the map is fully contained by the display the label is positioned where the line intersects the bottom display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display bottom edge and longitude labels are displayed along the latitude line closest to the midpoint of the display bottom edge.

Apart from the TSLGridLabelLegacy position which is mutually exclusive, the positions can be used individually or in combination with each other.

getLongitudeLabelPosition()

TSLBitMask TSLLatLongGridDataLayer::getLongitudeLabelPosition

(

)

const

This method allows users to retrieve the value of the bitmask used to determine the position of the longitude line labels. The positions available are:

• TSLGridLabelLegacy: Label is positioned as in older versions of MapLink (pre 7.0). If the map is fully contained by the display the label is positioned where the line intersects the left screen edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to a point midway up the display left edge and a twentieth of the display width across. If the map is not fully contained by the display, longitude labels are displayed along the latitude line closest to a point a tenth of the display height up the display left edge.
• TSLGridLabelLHS: If the map is fully contained by the display the label is positioned where the line intersects the left display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display left edge and longitude labels are displayed along the latitude line closest to the midpoint of the display left edge.
• TSLGridLabelRHS: If the map is fully contained by the display the label is positioned where the line intersects the right display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display right edge and longitude labels are displayed along the latitude line closest to the midpoint of the display right edge.
• TSLGridLabelTop: If the map is fully contained by the display the label is positioned where the line intersects the top display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display top edge and longitude labels are displayed along the latitude line closest to the midpoint of the display top edge.
• TSLGridLabelBottom: If the map is fully contained by the display the label is positioned where the line intersects the bottom display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display bottom edge and longitude labels are displayed along the latitude line closest to the midpoint of the display bottom edge.

Apart from the TSLGridLabelLegacy position which is mutually exclusive, the positions can be used individually or in combination with each other.

getSubGridFormatCallback()

TSLLatLongGridDataLayerFormatCallback * TSLLatLongGridDataLayer::getSubGridFormatCallback

(

void **

arg

)

const

Queries the data layer to see if a user defined callback, to format the text drawn for a subgrid label, has been set.

Parameters

arg	If this parameter is provided, it will be pointed to the user defined value passed to the setSubGridFormatCallback method. If no callback has been set, it will be pointed at NULL

Returns

the user specified callback function if one has been provided, else NULL

getSubGridLabelPosition()

TSLSubGridLabelPositionEnum TSLLatLongGridDataLayer::getSubGridLabelPosition

(

)

const

This method allows users to retrieve the enum denoting the position where the Sub Grid Label is displayed.

localDatum() [1/2]

bool TSLLatLongGridDataLayer::localDatum

(

)

const

This returns whether local or WGS84 datum is being used.

Returns true if local datum is used, false if WGS84 datum is used.

localDatum() [2/2]

void TSLLatLongGridDataLayer::localDatum

(

bool

useLocalDatum

)

This sets whether local or WGS84 datum is being used.

Parameters

useLocalDatum

Pass true to use local datum, false to use WGS84 datum

operator new() [1/2]

void * TSLLatLongGridDataLayer::operator new

(

size_t

size

)

Allocation override for API redirection

operator new() [2/2]

void * TSLLatLongGridDataLayer::operator new	(	size_t	size,
		char *	filename,
		int	line )

When included in an MFC application in debug mode, the debug new expects this to be here. Override it and return the same as the normal one. The library must include it when compiled in release mode, since the user's application may be in debug mode.

setDataLayer()

void TSLLatLongGridDataLayer::setDataLayer

(

TSLDataLayer *

dataLayer

)

This sets the map layer that the grid is to overlay.

You should call this method with the layer whenever the coordinate-system is changed. This will cause the grid cache to be flushed and re-calculated.

Parameters

dataLayer

The Coordinate Providing Data Layer for the grid to use for its latitude longitude conversions.

setFormatCallback()

void TSLLatLongGridDataLayer::setFormatCallback	(	TSLLatLongGridDataLayerFormatCallback *	callbackFunc,
		void *	arg )

This method allows users to provide a callback to format the text drawn at each grid interval. If a callback is not supplied then it will default to decimal degrees.

Parameters

callbackFunc	The callback to be used. If NULL is passed then the existing callback will be removed and will revert to the default functionality
arg	This user value will be passed to the callback function when it is called. It will remain in the ownership of the user.

setGridLevelChangeMode()

void TSLLatLongGridDataLayer::setGridLevelChangeMode

(

TSLGridDetailLevelChangeEnum

mode = TSLGridLevelChangeAutomatic

)

This method allows users to change the Grid Level Change Mode. The modes available are:

• TSLGridLevelChangeAutomatic - level changes are determined automatically by the TSLLatLongGridDataLayer
• TSLGridLevelChangeManual - level changes are determined by the user setting the rendering edge styles of the Latitude/Longitude Grid Lines, e.g. setting the value of the Tenths Longitude and Latitude edge styles to a value greater than 0 will enable the calculation of the Tenths grids.

NOTE: If the Manual mode is used then the User needs to be aware that setting of Sub Grids at too high a zoom level will seriously impinge on performance and memory usage.

Parameters

mode	The Change mode to be used. If NULL is passed then the default functionality i.e. level changes are determined automatically by the TSLLatLongGridDataLayer

setLatitudeLabelPosition()

bool TSLLatLongGridDataLayer::setLatitudeLabelPosition

(

const TSLBitMask

labelPosition = TSLGridLabelLHS

)

This method allows users to change the position of the latitude line labels. The positions available are:

• TSLGridLabelLegacy: Label is positioned as in older versions of MapLink (pre 7.0). If the map is fully contained by the display the label is positioned where the line intersects the left screen edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to a point midway up the display left edge and a twentieth of the display width across. If the map is not fully contained by the display, longitude labels are displayed along the latitude line closest to a point a tenth of the display height up the display left edge.
• TSLGridLabelLHS: If the map is fully contained by the display the label is positioned where the line intersects the left display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display left edge and longitude labels are displayed along the latitude line closest to the midpoint of the display left edge.
• TSLGridLabelRHS: If the map is fully contained by the display the label is positioned where the line intersects the right display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display right edge and longitude labels are displayed along the latitude line closest to the midpoint of the display right edge.
• TSLGridLabelTop: If the map is fully contained by the display the label is positioned where the line intersects the top display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display top edge and longitude labels are displayed along the latitude line closest to the midpoint of the display top edge.
• TSLGridLabelBottom: If the map is fully contained by the display the label is positioned where the line intersects the bottom display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display bottom edge and longitude labels are displayed along the latitude line closest to the midpoint of the display bottom edge.

Apart from the TSLGridLabelLegacy position which is mutually exclusive, the positions can be used individually or in combination with each other.

The default position for latitude labels is the TSLGridLabelLegacy, i.e. display left.

Parameters

labelPosition

The bitmask defining the position(s) at which to display the latitude line labels.

Returns

true on success, false if an invalid value is passed (an invalid value a value that has bits set that are not in the TSLGridLabelPosition).

setLongitudeLabelPosition()

bool TSLLatLongGridDataLayer::setLongitudeLabelPosition

(

const TSLBitMask

labelPosition

)

This method allows users to change the position of the longitude line labels. The positions available are:

• TSLGridLabelLegacy: Label is positioned as in older versions of MapLink (pre 7.0). If the map is fully contained by the display the label is positioned where the line intersects the left screen edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to a point midway up the display left edge and a twentieth of the display width across. If the map is not fully contained by the display, longitude labels are displayed along the latitude line closest to a point a tenth of the display height up the display left edge.
• TSLGridLabelLHS: If the map is fully contained by the display the label is positioned where the line intersects the left display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display left edge and longitude labels are displayed along the latitude line closest to the midpoint of the display left edge.
• TSLGridLabelRHS: If the map is fully contained by the display the label is positioned where the line intersects the right display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display right edge and longitude labels are displayed along the latitude line closest to the midpoint of the display right edge.
• TSLGridLabelTop: If the map is fully contained by the display the label is positioned where the line intersects the top display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display top edge and longitude labels are displayed along the latitude line closest to the midpoint of the display top edge.
• TSLGridLabelBottom: If the map is fully contained by the display the label is positioned where the line intersects the bottom display edge. If the map is not fully contained by the display, latitude labels are displayed along the longitude line closest to the midpoint of the display bottom edge and longitude labels are displayed along the latitude line closest to the midpoint of the display bottom edge.

Apart from the TSLGridLabelLegacy position which is mutually exclusive, the positions can be used individually or in combination with each other.

The default position for longitude labels is the TSLGridLabelLegacy, i.e. display bottom edge.

Parameters

labelPosition

The bitmask defining the position(s) at which to display the longitude line labels.

Returns

true on success, false if an invalid value is passed (an invalid value being a value that has bits set that are not in the TSLGridLabelPosition).

setSpacing()

bool TSLLatLongGridDataLayer::setSpacing	(	const char *const	feature,
		int	spacing )

Set the spacing between the major latitude and longitude grid lines.

The default spacing is 10 degrees.

Parameters

feature	either "lonMajorDegree" or "latMajorDegree"
spacing	between the grid lines in degrees (range 1 to 30)

Returns

true on success, false otherwise.

setSubGridFormatCallback()

void TSLLatLongGridDataLayer::setSubGridFormatCallback	(	TSLLatLongGridDataLayerFormatCallback *	callbackFunc,
		void *	arg )

This method allows users to provide a callback to format the text drawn at for a subgrid label. If a callback is not supplied then it will default to decimal degrees, with a maximum of 3 decimal places.

Parameters

callbackFunc	The callback to be used. If NULL is passed then the existing callback will be removed and will revert to the default functionality
arg	This user value will be passed to the callback function when it is called. It will remain in the ownership of the user.

setSubGridLabelPosition()

void TSLLatLongGridDataLayer::setSubGridLabelPosition

(

TSLSubGridLabelPositionEnum

position = TSLSubGridLabelDefaultCentre

)

This method allows users to change the position of the SubGrid label. The positions available are:

• TSLSubGridLabelDefaultCentre: Latitude/Longitude Label is positioned close to Sub Grid Centre
• TSLSubGridLabelLHSBottom: Latitude Label is positioned at screen left, Longitude label is positioned at screen bottom
• TSLSubGridLabelRHSBottom: Latitude Label is positioned at screen right, Longitude label is positioned at screen bottom
• TSLSubGridLabelLHSTop: Latitude Label is positioned at screen left, Longitude label is positioned at screen top
• TSLSubGridLabelRHSTop: Latitude Label is positioned at screen right, Longitude label is positioned at screen top

(LHS: Left Hand Side, RHS: Right Hand Side)

Parameters

position

The position enumeration defining the position at which to display the Sub Grid label. If NULL is passed then the default position is used.

snap()

bool TSLLatLongGridDataLayer::snap	(	TSLCoord *	snap_pt,
		double &	latitude,
		double &	longitude,
		bool	force_snap = false,
		bool	snapToMiddle = false )

This method returns the point snapped to given the initial position.

Parameters

snap_pt	on entry the point to snap, on exit this may be changed to the centre or lower left of the grid square.
latitude	[output] latitude of the snapped point
longitude	[output] longitude of the snapped point
force_snap	snap to the grid square even if snapable() would return false.
snapToMiddle	if true then snap the point to the middle of the square

Returns

true on success, false otherwise.

snapable() [1/2]

bool TSLLatLongGridDataLayer::snapable

(

)

const

Returns true if snap() snaps points to the nearest grid square, false otherwise.

snapable() [2/2]

void TSLLatLongGridDataLayer::snapable

(

bool

value

)

This controls whether snap() snaps points to the nearest grid square.

Parameters

value

Pass true if snap is to snap to the nearest grid square.

tickLength()

void TSLLatLongGridDataLayer::tickLength	(	int	degrees,
		int	tenthsMinutes )

Set the pixel size of the tick lengths.

Parameters

degrees	the length of the degree tick in pixels (default 8 pixels)
tenthsMinutes	the length of the tenths or minutes tick in pixels (default 2 pixels)

ticks()

void TSLLatLongGridDataLayer::ticks

(

bool

ticks

)

Draw ticks on the latitude and longitude lines.

Parameters

ticks

If the value is true then a tick is drawn every degree or 0.1 degree.