Geometry | GoJS API

Hierarchy

Geometry

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

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

Index

Constructors

constructor

Properties

Methods

Constants

Constructors

constructor

new Geometry(type?: EnumValue): Geometry

Parameters
- Optional type: EnumValue
  
  Construct an empty Geometry. The geometry type must be one of the following values: Geometry.Line, Geometry.Ellipse, Geometry.Rectangle, Geometry.Path. The default type is Geometry.Path.
Returns Geometry

Properties

Read-only 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).

defaultStretch: EnumValue

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

since
1.5

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.

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.

figures: List<PathFigure>

Gets or sets the List of PathFigures that describes the content of the path for Geometries of type Path.

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.

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.

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.

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.

type: EnumValue

Gets or sets the type of the Geometry. The default type is Geometry.Path. Other permissible values are Geometry.Line, Geometry.Ellipse, or Geometry.Rectangle.

Methods

add

add(figure: PathFigure): Geometry

Add a PathFigure to the figures list.

since
1.5

Parameters
- figure: PathFigure
  
  a newly allocated unshared PathFigure that will become owned by this Geometry
Returns Geometry
this

computeBoundsWithoutOrigin

computeBoundsWithoutOrigin(): 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.

since
1.1

Returns Rect

containsPoint

containsPoint(p: Point, sw?: number): boolean

Returns true if the Geometry contains the point.

since
2.2

Parameters
- p: Point
  
  in local geometry coordinates
- Optional sw: number
  
  half the stroke width that a Shape has or that you want to pretend it has
Returns boolean

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.

since
2.1

Parameters
- fraction: number
  
  A fractional amount between 0 and 1, inclusive.
Returns number

getFractionForPoint

getFractionForPoint(pt: Point): number

Returns the fractional distance (0-1) along this Geometry's path for a nearby point.

since
2.1

Parameters
- pt: Point
  
  A Point, in local coordinates, near this Geometry.
Returns number
A fractional amount between 0 and 1, inclusive.

getPointAlongPath

getPointAlongPath(fraction: number, result?: Point): Point

Returns the point at the fractional distance (0-1) along this Geometry's path.

since
2.1

Parameters
- fraction: number
  
  A fractional amount between 0 and 1, inclusive.
- Optional result: 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.

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.

since
1.1

Returns Point

offset

offset(x: number, y: number): Geometry

Offsets the Geometry in place by a given (x, y) amount

since
1.1

Parameters
- x: number
  
  The x-axis offset factor.
- y: number
  
  The y-axis offset factor.
Returns Geometry
this

rotate

rotate(angle: number, x?: number, y?: number): Geometry

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.

since
1.1

Parameters
- angle: number
  
  The angle to rotate by.
- Optional x: number
  
  The optional X point to rotate the geometry about. If no point is given, this value is 0.
- Optional y: number
  
  The optional Y point to rotate the geometry about. If no point is given, this value is 0.
Returns Geometry
this

scale

scale(x: number, y: number): Geometry

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).

since
1.1

Parameters
- x: number
  
  The x-axis scale factor.
- y: number
  
  The y-axis scale factor.
Returns Geometry
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".

since
1.1

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)
- U Denotes that the PathFigure is not shadowed
See the Introduction page on Geometry Parsing for more details.
Parameters
- str: string
- Optional filled: 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 Introduction page on Geometry Parsing for more details.

since
1.1

Parameters
- val: Geometry
Returns string

Constants

Static Ellipse: EnumValue

For drawing an ellipse fitting within a rectangle; a value for Geometry.type. The ellipse fits within the rectangle that goes from the point (startX, startY) to the point (endX, endY).

Static Line: EnumValue

For drawing a simple straight line; a value for Geometry.type. The line goes from the point (startX, startY) to the point (endX, endY).

Static Path: EnumValue

For drawing a complex path made of a list of PathFigures; a value for Geometry.type.

Static Rectangle: EnumValue

For drawing a rectangle; a value for Geometry.type. The rectangle goes from the point (startX, startY) to the point (endX, endY).

Hierarchy

Index

Constructors

Properties

Methods

Constants

Constructors

constructor

Parameters

Optional type: EnumValue

Returns Geometry

Properties

Read-only bounds: Rect

defaultStretch: EnumValue

endX: number

endY: number

figures: List<PathFigure>

spot1: Spot

spot2: Spot

startX: number

startY: number

type: EnumValue

Methods

add

Parameters

figure: PathFigure

Returns Geometry

computeBoundsWithoutOrigin

Returns Rect

containsPoint

Parameters

p: Point

Optional sw: number

Returns boolean

Virtual copy

Returns Geometry

getAngleAlongPath

Parameters

fraction: number

Returns number

getFractionForPoint

Parameters

pt: Point

Returns number

getPointAlongPath

Parameters

fraction: number

Optional result: Point

Returns Point

normalize

Returns Point

offset

Parameters

x: number

y: number

Returns Geometry

rotate

Parameters

angle: number

Optional x: number

Optional y: number

Returns Geometry

scale

Parameters

x: number

y: number

Returns Geometry

Static fillPath

Parameters

str: string

Returns string

Static parse

Parameters

str: string

Optional filled: boolean

Returns Geometry

Static stringify

Parameters

val: Geometry

Returns string