Class Geometry

GoJS® Diagramming Components
version 4.0.0
by Northwoods Software®

The Geometry class is used to define the "shape" of a Shape. A Geometry can be simple straight lines, rectangles, or ellipses. A Geometry can also be an arbitrarily complex path, consisting of a list of PathFigures.

A Geometry must not be modified once it has been used by a Shape. However, a Geometry may be shared by multiple Shapes.

It is commonplace to create Geometries using geometry path string syntax: Geometry Path Strings. However it is much more efficient to create Geometries programmatically. One way to do that is illustrated by several of the samples that evaluate JavaScript such as:

new go.Geometry()
  .add(new go.PathFigure(p.x, p.y)
        .add(new go.PathSegment(go.SegmentType.Arc, -sweep/2, sweep, 0, 0, radius+layerThickness, radius+layerThickness))
        .add(new go.PathSegment(go.SegmentType.Line, q.x, q.y))
        .add(new go.PathSegment(go.SegmentType.Arc, sweep/2, -sweep, 0, 0, radius, radius).close()));

See samples that make use of Geometries in the samples index.

Index

Constructors

constructor

new Geometry(type?: GeometryType, init?: Partial<Geometry>): Geometry
Parameters
- Optionaltype: GeometryType
  Construct an empty Geometry. The geometry type must be a GeometryType. The default type is GeometryType.Path.
- Optionalinit: Partial<Geometry>
Returns Geometry

Accessors

`Readonly`bounds

get bounds(): Rect
This read-only property returns a rectangle that contains all points within the Geometry. The result will always contain the origin (0, 0).

Returns Rect

defaultStretch

get defaultStretch(): GeometryStretch
Gets or sets the Shape.geometryStretch value the Shape should use by default when the Shape.geometryStretch value is GeometryStretch.None. The default value is GeometryStretch.Fill. Some figure generators return a Geometry with this property set to GeometryStretch.Uniform, in order to preserve its aspect ratio when used by a Shape that may have different sizes.

Returns GeometryStretch

endX

get endX(): number
Gets or sets the ending X coordinate of the Geometry if it is of type Line, Rectangle, or Ellipse. The initial value is zero.

Returns number

endY

get endY(): number
Gets or sets the ending Y coordinate of the Geometry if it is of type Line, Rectangle, or Ellipse. The initial value is zero.

Returns number

figures

get figures(): List<PathFigure>
Gets or sets the List of PathFigures that describes the content of the path for Geometries of type Path.

Returns List<PathFigure>

spot1

get spot1(): Spot
Gets or sets the spot an "Auto" Panel will use for the top-left corner of any panel content when the Shape.spot1 value is Spot.Default. The default value is Spot.TopLeft, at the top-left point of the bounds of the Shape.

Returns Spot

spot2

get spot2(): Spot
Gets or sets the spot an "Auto" Panel will use for the bottom-right corner of any panel content when the Shape.spot2 value is Spot.Default. The default value is Spot.BottomRight, at the bottom-right point of the bounds of the Shape.

Returns Spot

startX

get startX(): number
Gets or sets the starting X coordinate of the Geometry if it is of type Line, Rectangle, or Ellipse. The initial value is zero.

Returns number

startY

get startY(): number
Gets or sets the starting Y coordinate of the Geometry if it is of type Line, Rectangle, or Ellipse. The initial value is zero.

Returns number

type

get type(): GeometryType
Gets or sets the type of the Geometry. The default type is GeometryType.Path.

Returns GeometryType

Methods

add

add(figure: PathFigure): this
Add a PathFigure to the figures list.
Parameters
- figure: PathFigure
  a newly allocated unshared PathFigure that will become owned by this Geometry
Returns this
this

computeBoundsWithoutOrigin

computeBoundsWithoutOrigin(result?: Rect): Rect
Computes the Geometry's bounds without adding an origin point, and returns those bounds as a rect. This method does not modify the Geometry or its bounds.
Parameters
- Optionalresult: Rect
  an optional Rect that is modified and returned
Returns Rect

containsPoint

containsPoint(p: Point, sw?: number): boolean
Returns true if the Geometry contains the point.
Parameters
- p: Point
  in local geometry coordinates
- Optionalsw: number
  half the stroke width that a Shape has or that you want to pretend it has
Returns boolean
since
2.2

`Virtual`copy

copy(): Geometry
Create a copy of this Geometry, with the same values and figures.

Returns Geometry

getAngleAlongPath

getAngleAlongPath(fraction: number): number
Returns the slope expressed as an angle at the fractional distance (0-1) along this Geometry's path, in local coordinates.
Parameters
- fraction: number
  A fractional amount between 0 and 1, inclusive.
Returns number
since
2.1

getFractionForPoint

getFractionForPoint(pt: Point): number
Returns the fractional distance (0-1) along this Geometry's path for a nearby point.
Parameters
- pt: Point
  A Point, in local coordinates, near this Geometry.
Returns number
A fractional amount between 0 and 1, inclusive.

since
2.1

getPointAlongPath

getPointAlongPath(fraction: number, result?: Point): Point
Returns the point at the fractional distance (0-1) along this Geometry's path.
Parameters
- fraction: number
  A fractional amount between 0 and 1, inclusive.
- Optionalresult: Point
  an optional Point that is modified and returned; otherwise it allocates and returns a new Point.
Returns Point
the Point, in local coordinates, of the fractional distance along the path.

since
2.1

normalize

normalize(): Point
Normalizes the Geometry points in place by ensuring the top-left bounds of the geometry lines up with (0, 0), returning the Point (x, y) amount it was shifted. After this method is called there will be no negative X or Y value for the Geometry's bounds, and no empty space at the top-left of the Geometry.

Returns Point

offset

offset(x: number, y: number): this
Offsets the Geometry in place by a given (x, y) amount
Parameters
- x: number
  The x-axis offset factor.
- y: number
  The y-axis offset factor.
Returns this
this

rotate

rotate(angle: number, x?: number, y?: number): this
Rotates the Geometry in place by a given angle, with optional x and y values to rotate the geometry about. If no x and y value are given, (0, 0) is used as the rotation point.
Parameters
- angle: number
  The angle to rotate by.
- Optionalx: number
  The optional X point to rotate the geometry about. If no point is given, this value is 0.
- Optionaly: number
  The optional Y point to rotate the geometry about. If no point is given, this value is 0.
Returns this
this

scale

scale(x: number, y: number): this
Scales the Geometry in place by a given (x, y) scale factor.

If you want to flip a Geometry horizontally, call geo.scale(-1, 1). If you want to flip a Geometry vertically, call geo.scale(1, -1).
Parameters
- x: number
  The x-axis scale factor.
- y: number
  The y-axis scale factor.
Returns this
this

`Static`fillPath

fillPath(str: string): string
Given a SVG or GoJS path string, returns a congruent path string with each pathfigure filled. For instance, "M0 0 L22 22 L33 0" would become "F M0 0 L22 22 L33 0".
Parameters
- str: string
Returns string

`Static`parse

parse(str: string, filled?: boolean): Geometry
Produce a Geometry from a string that uses an SVG-like compact path geometry syntax. The syntax accepts all SVG Path Syntax (SVG Path Syntax (w3.org)), as well as three GoJS-specific tokens. Specifically, the following tokens are allowed:
- M (x,y)+ - Move commands
- L (x,y)+, H (x)+, V (y)+ Lines commands, including horizontal and vertical lines
- C (x1 y1 x2 y2 x y)+, S (x2 y2 x y)+ Cubic bezier curves
- Q (x1 y1 x y)+, T (x y)+ Quadratic bezier curves
- A (rx ry x-axis-rotation large-arc-flag clockwise-flag x y)+ Arcs (following SVG arc conventions)
- Z Denotes that the previous subpath is closed
Additionally there are some tokens specific to GoJS:
- B (startAngle, sweepAngle, centerX, centerY, radius)+ Arcs following GoJS canvas arc conventions
- X Used before M-commands to denote separate PathFigures instead of a subpath
- F Denotes whether the current PathFigure is filled (true if F is present)
- F0 (instead of F) Denotes that the PathFigure should use the even-odd fill rule instead of the nonzero winding number rule (setting PathFigure.isEvenOdd)
- U Denotes that the PathFigure is not shadowed
See the Learn page on Geometry Parsing for more details.
Parameters
- str: string
- Optionalfilled: boolean
  whether figures should be filled. If true, all PathFigures in the string will be filled regardless of the presence of an "F" command or not. If false, all PathFigures will determine their own filled state by the presence of an "F" command or not. Default is false.
Returns Geometry

`Static`stringify

stringify(val: Geometry): string
This static function can be used to write out a Geometry as a string that can be read by Geometry.parse.

The string produced by this method is a superset of the SVG path string rules that contains some additional GoJS-specific tokens. See the Learn page on Geometry Parsing for more details.
Parameters
- val: Geometry
  a Geometry to be rendered as a string
Returns string

`Static`stringifyFixed

stringifyFixed(digits: number): (val: Geometry) => string
This static function returns a function that can be used as a back converter for a Binding to write out a Geometry as a string with its numbers at a fixed number of digits after the decimal point.

This is useful for limiting the size of JSON output and making it more legible. It might also be useful for regression testing.
Parameters
- digits: number
  must be a non-negative integer
Returns (val: Geometry) => string
a function that converts a Geometry to a string without so many decimals

since
3.0

Properties

`Static` `Readonly`Ellipse

Ellipse: Ellipse = GeometryType.Ellipse

deprecated

See GeometryType.Ellipse.

`Static` `Readonly`Line

Line: Line = GeometryType.Line

deprecated

See GeometryType.Line.

`Static` `Readonly`Path

Path: Path = GeometryType.Path

deprecated

See GeometryType.Path.

`Static` `Readonly`Rectangle

Rectangle: Rectangle = GeometryType.Rectangle

deprecated

See GeometryType.Rectangle.

Class Geometry

Index

Constructors

Accessors

Methods

Properties

Constructors

constructor

Parameters

Returns Geometry

Accessors

Readonlybounds

Returns Rect

defaultStretch

Returns GeometryStretch

endX

Returns number

endY

Returns number

figures

Returns List<PathFigure>

spot1

Returns Spot

spot2

Returns Spot

startX

Returns number

startY

Returns number

type

Returns GeometryType

Methods

add

Parameters

Returns this

computeBoundsWithoutOrigin

Parameters

Returns Rect

containsPoint

Parameters

Returns boolean

Virtualcopy

Returns Geometry

getAngleAlongPath

Parameters

Returns number

getFractionForPoint

Parameters

Returns number

getPointAlongPath

Parameters

Returns Point

normalize

Returns Point

offset

Parameters

Returns this

rotate

Parameters

Returns this

scale

Parameters

Returns this

StaticfillPath

Parameters

Returns string

Staticparse

Parameters

Returns Geometry

Staticstringify

Parameters

Returns string

StaticstringifyFixed

Parameters

Returns (val: Geometry) => string

Properties

Static ReadonlyEllipse

Static ReadonlyLine

Static ReadonlyPath

Static ReadonlyRectangle

`Readonly`bounds

`Virtual`copy

`Static`fillPath

`Static`parse

`Static`stringify

`Static`stringifyFixed

`Static` `Readonly`Ellipse

`Static` `Readonly`Line

`Static` `Readonly`Path

`Static` `Readonly`Rectangle