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# Class Geometry

### 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.

## Constructors

• new Geometry(type?: EnumValue): Geometry

## Properties

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

• Gets or sets the ending X coordinate of the Geometry if it is of type Line, Rectangle, or Ellipse. The initial value is zero.

• Gets or sets the ending Y coordinate of the Geometry if it is of type Line, Rectangle, or Ellipse. The initial value is zero.

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

• 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.

• 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.

• Gets or sets the starting X coordinate of the Geometry if it is of type Line, Rectangle, or Ellipse. The initial value is zero.

• Gets or sets the starting Y coordinate of the Geometry if it is of type Line, Rectangle, or Ellipse. The initial value is zero.

## Methods

• 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(): 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(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

• Create a copy of this Geometry, with the same values and figures.

#### Returns Geometry

• 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(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(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.

• 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

• 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(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

• 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

• 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

#### Returns string

• 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

• ##### 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

• 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

## Constants

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).

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

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

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