Class JXG.Coords

↳ JXG.Coords

This is the Coordinates class. All members a coordinate has to provide are defined here.

Defined in: coords.js.

Class Summary
Constructor Attributes	Constructor Name and Description
	JXG.Coords(method, coordinates, board, emitter) Constructs a new Coordinates object.

Field Summary
Field Attributes	Field Name and Description
	board Stores the board the object is used on.
	emitter If true, this coordinates object will emit update events every time the coordinates are set.
	scrCoords Stores coordinates for screen view as homogeneous coordinates.
	usrCoords Stores coordinates for user view as homogeneous coordinates.

Method Summary
Method Attributes	Method Name and Description
<private>	copy(obj, offset) Copy array, either scrCoords or usrCoords Uses slice() in case of standard arrays and set() in case of typed arrays.
	distance(coord_type, coordinates) Calculate distance of one point to another.
	isReal() Test if one of the usrCoords is NaN or the coordinates are infinite.
<private>	normalizeUsrCoords() Normalize homogeneous coordinates
<private>	screen2usr() Compute user coordinates out of given screen coordinates.
	setCoordinates(coord_type, coordinates, doRound, noevent) Set coordinates by either user coordinates or screen coordinates and recalculate the other one.
<private>	usr2screen(doRound) Compute screen coordinates out of given user coordinates.

Event Summary
Event Attributes	Event Name and Description
	update(ou, os) Triggered whenever the coordinates change.

Class Detail

JXG.Coords(method, coordinates, board, emitter)

Constructs a new Coordinates object.

Parameters:
{Number} method: The type of coordinates given by the user. Accepted values are COORDS_BY_SCREEN and COORDS_BY_USER.
{Array} coordinates: An array of affine coordinates.
{JXG.Board} board: A reference to a board.
{Boolean} emitter Optional, Default: true

Field Detail

{JXG.Board} board

Stores the board the object is used on.

{boolean} emitter

If true, this coordinates object will emit update events every time the coordinates are set.

Default Value:: true

{Array} scrCoords

Stores coordinates for screen view as homogeneous coordinates.

{Array} usrCoords

Stores coordinates for user view as homogeneous coordinates.

Method Detail

<private> {Array} copy(obj, offset)

Copy array, either scrCoords or usrCoords Uses slice() in case of standard arrays and set() in case of typed arrays.

Parameters:
{String} obj: Either 'scrCoords' or 'usrCoords'
{Number} offset: Offset, defaults to 0 if not given

Returns:: {Array} Returns copy of the coords array either as standard array or as typed array.

{Number} distance(coord_type, coordinates)

Calculate distance of one point to another.

Parameters:
{Number} coord_type: The type of coordinates used here. Possible values are JXG.COORDS_BY_USER and JXG.COORDS_BY_SCREEN.
{JXG.Coords} coordinates: The Coords object to which the distance is calculated.

Returns:: {Number} The distance

{Boolean} isReal()

Test if one of the usrCoords is NaN or the coordinates are infinite.

Returns:: {Boolean} true if the coordinates are finite, false otherwise.

<private> normalizeUsrCoords()

Normalize homogeneous coordinates

<private> screen2usr()

Compute user coordinates out of given screen coordinates.

{JXG.Coords} setCoordinates(coord_type, coordinates, doRound, noevent)

Set coordinates by either user coordinates or screen coordinates and recalculate the other one.

Parameters:
{Number} coord_type: The type of coordinates used here. Possible values are COORDS_BY_USER and COORDS_BY_SCREEN.
{Array} coordinates: An array of affine coordinates the Coords object is set to.
{Boolean} doRound Optional, Default: true: flag If true or null round the coordinates in usr2screen. This is used in smooth curve plotting. The IE needs rounded coordinates. Id doRound==false we have to round in updatePathString.
{Boolean} noevent Optional, Default: false

Returns:: {JXG.Coords} Reference to the coords object.

<private> usr2screen(doRound)

Compute screen coordinates out of given user coordinates.

Parameters:
doRound

Event Detail

update(ou, os)

Triggered whenever the coordinates change.

Parameters:
{Array} ou: Old user coordinates
{Array} os: Old screen coordinates

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Class JXG.Coords