Provides the logic for the Sketch widget.

SketchViewModel simplifies the process of adding and updating graphics on a MapView or a SceneView. SketchViewModel is intended to be used with Graphics.

Known Limitations

• Graphics with polyline or polygon geometries can not be rotated or scaled in a SceneView.
• Graphics with geometries where hasZ is true will be ignored by update() in a SceneView.
• Multipoint geometry can only be created in a MapView.

Read more

Pointer and keyboard gestures for creating graphics with different geometries are described in the tables below.

Creating point graphics

Gesture	Action
Left-click	Adds a point graphic at the pointer location.
C	Adds a point graphic at the pointer location.

Creating polyline and polygon graphics

Gesture	Action
Left-click	Adds a vertex at the pointer location.
Left-drag	Adds a vertex for each pointer move.
F	Adds a vertex to the polyline or polygon graphic.
C	Completes the polyline or polygon graphic sketch.
Z	Incrementally undo actions recorded in the stack.
R	Incrementally redo actions recorded in the stack.
Spacebar+Left-drag	Pan the view while creating a polyline or polygon graphic.
Left-click on the first vertex	Completes the polygon graphic sketch.

Creating polygon graphics with predefined shapes

The following keyboard shortcuts apply when creating polygon graphics with predefined shapes.

Gesture	Action
Left-click+Drag	Creates a rectangle graphic with dimensions based on the bounding box between initial click and cursor location. Creates a circle graphic with radius based on the distance between initial click and cursor location.
Ctrl+Left-click+Drag	Changes the shape from a rectangle to a square or from a circle to an ellipse.
Alt+Left-click+Drag	Creates a rectangle graphic with a center at initial click, and dimensions based on the distance between the initial click to the cursor location. Creates a circle graphic with a radius based on the bounding box between the initial click and the cursor location.
Ctrl+Alt+Left-click+Drag	Combines the behavior described above.

Updating graphics

The Sketch widget provides users with the ability to move, rotate, scale or reshape graphics during an update operation. To begin updating, Left-click on a graphic. Use Shift+Left-click to add more graphics to the selection, for bulk updating. Once graphics are selected, the following actions can be performed.

Gesture	Action	Example
Left-click on a graphic	Select a graphic to move, rotate or scale.
Shift+Left-click graphics	Select multiple graphics to move, rotate or scale.
Drag graphic	Move the selected graphic.
Drag rotate handle	Rotate the selected graphic.
Drag scale handle	Scale the selected graphic.
Z	Incrementally undo actions recorded in the stack.
R	Incrementally redo actions recorded in the stack.
Left-click on view (not the graphic)	Complete the graphic update.
Press Delete key	Remove the selected graphic(s) from the layer.

The following update operations can be performed on a single polyline or polygon graphic:

Gesture	Action	Example
Left-click on a graphic	Select a graphic to move or reshape.
Drag graphic	Move the selected graphic.
Left-click on a ghost vertex	Add a new vertex.
Left-click on a vertex	Select a vertex.
Shift+Left-click on vertices	Select or unselect multiple vertices.
Drag vertex	Move the selected vertex or vertices.
Right-click on a vertex	Delete a vertex.
Select multiple vertices and press Backspace or Delete key	Delete multiple vertices.

The following update operations can be performed on a single graphic with point geometry in a SceneView, if the graphic uses a 3D object symbol layer:

Gesture	Action	Example
Left-click on a graphic	Select a graphic to move, rotate or scale.
Drag inner handle	Move the selected graphic.
Drag outer handle sideways	Rotate the selected graphic.
Drag outer handle inwards or outwards	Scale the selected graphic.

See also:

• Sketch

• Sketch.scss

• Sample - Sketch temporary geometries

• Sample - Sketch update validation

• Sample - Query statistics by geometry

• Sample - Filter features by geometry with SceneLayer

• Guide topic: Widget development - ViewModel pattern

Example:

// Create a new SketchViewModel and set
// its required parameters
var sketchVM = new SketchViewModel({
  layer: tempGraphicsLayer,
  view: view
});

// Listen to sketchViewModel's create event.
sketchVM.on("create", function(event) {
  // check if the create event's state has changed to complete indicating
  // the graphic create operation is completed.
  if (event.state === "complete") {
    // remove the graphic from the layer. Sketch adds
    // the completed graphic to the layer by default.
    polygonGraphicsLayer.remove(event.graphic);

    // use the graphic.geometry to query features that intersect it
    selectFeatures(event.graphic.geometry);
  }
});

Constructors

new SketchViewModel(properties)

Parameter:

properties Object optional See the properties for a list of all the properties that may be passed into the constructor.

Example:

// Typical usage
var sketch = new SketchViewModel({
  view: view,
  layer: graphicsLayer
});

Property Overview

Property Details

activeTool Stringreadonly

Since: ArcGIS API for JavaScript 4.10

When creating new graphics (for example after create() has been called), this property reflects the create tool being used. When updating graphics (for example after update() has been called), this property reflects the update tool being used. If no create or update operation is in progress, this is null.

Possible Values:"point"|"multipoint"|"polyline"|"polygon"|"circle"|"rectangle"|"move"|"transform"|"reshape"

createGraphic Graphicreadonly

Since: ArcGIS API for JavaScript 4.10

The graphic that is being created.

declaredClass Stringreadonly inherited

Since: ArcGIS API for JavaScript 4.7

The name of the class. The declared class name is formatted as esri.folder.className.

defaultCreateOptions Object

Since: ArcGIS API for JavaScript 4.14

Default create options set for the Sketch widget.

Property:

mode String optional Create operation mode how the graphic can be created. Possible Values: Value Description hybrid This is the default. Vertices are added while the pointer is clicked or dragged. Applies to and is the default for polygon and polyline. freehand Vertices are added while the pointer is dragged. Applies to polygon, polyline rectangle and circle. Default for rectangle and circle. click Vertices are added when the pointer is clicked.

defaultUpdateOptions Object

Since: ArcGIS API for JavaScript 4.10

Default update options set for the SketchViewModel. Update options set on this property will be overridden by options passed to the update() method.

Properties:

tool String optional Name of the update tool. The default tool is transform for graphics with polygon and polyline geometries and move for graphics with point and multipoint geometries. However, if a graphic with point geometry uses a 3D object symbol layer, the default tool is transform.

enableRotation Boolean optional Default Value:true Indicates if the rotation operation will be enabled when updating graphics. Only applies if tool is transform.

enableScaling Boolean optional Default Value:true Indicates if the scale operation will be enabled when updating graphics. Only applies if tool is transform.

multipleSelectionEnabled Boolean optional Default Value:true Indicates whether more than one selection can be made at once. This pertains to shift+click interaction with the transform tool.

preserveAspectRatio Boolean optional Default Value:false Indicates if the uniform scale operation will be enabled when updating graphics. enableScaling must be set true when setting this property to true. Only applies if tool is transform and is always true when transforming points that use a 3D object symbol layer.

toggleToolOnClick Boolean optional Default Value:true Indicates if the graphic being updated can be toggled between transform and reshape update options.

layer GraphicsLayer

Since: ArcGIS API for JavaScript 4.6

The GraphicsLayer associated with the SketchViewModel. The SketchViewModel adds new graphics to this layer or can only update graphics stored in this layer.

pointSymbol SimpleMarkerSymbol|PointSymbol3D

A SimpleMarkerSymbol or PointSymbol3D used for representing the point geometry that is being drawn. SimpleMarkerSymbol may also be used to symbolize point features in a SceneView. However, it is recommended you use PointSymbol3D instead.

The default value is the following:

{
  type: "simple-marker",
  style: "circle",
  size: 6,
  color: [255, 255, 255],
  outline: {
   color: [50, 50, 50],
    width: 1
  }
}

polygonSymbol SimpleFillSymbol|PolygonSymbol3D

A SimpleFillSymbol or PolygonSymbol3D used for representing the polygon geometry that is being drawn. SimpleFillSymbol may also be used to symbolize point features in a SceneView. However, it is recommended you use PolygonSymbol3D instead.

The default value is the following:

{
  type: "simple-fill",
  color: [150, 150, 150, 0.2],
  outline: {
   color: [50, 50, 50],
    width: 2
  }
}

polylineSymbol SimpleLineSymbol|LineSymbol3D

A SimpleLineSymbol or LineSymbol3D used for representing the polyline geometry that is being drawn. SimpleLineSymbol may also be used to symbolize polyline features in a SceneView. However, it is recommended you use LineSymbol3D instead.

The default value is the following:

{
  type: "simple-line",
  color: [130, 130, 130],
  width: 2
}

state Stringreadonly

The sketch view model's state.

Possible Values:"ready"|"disabled"|"active"

updateGraphics Collection<Graphic>readonly

Since: ArcGIS API for JavaScript 4.10

An array of graphics that are being updated by the SketchViewModel.

updateOnGraphicClick Boolean

Since: ArcGIS API for JavaScript 4.10

Indicates if a graphic can be selected to be updated. If false, graphics cannot selected to be updated. Set this property to false to add a custom hitTest logic for updating graphics.

view MapView|SceneView

The view in which geometries will be sketched by the user.

Method Overview

Method Details

cancel()

Since: ArcGIS API for JavaScript 4.10

Cancels the active operation and fires the create or update event and changes the event's state to cancel. If called in the middle of a create operation, cancel() discards the partially created graphic.

complete()

Since: ArcGIS API for JavaScript 4.6

Completes the active operation and fires the create or update event and changes the event's state to complete. If called in the middle of a create operation, complete() finishes the active create operation and keeps the valid geometry.

create(tool, createOptions)

Create a graphic with the geometry specified in the tool parameter. When the first vertex of the graphic is added, the create event will start firing. The provided tool will become the activeTool.

Parameters:

tool String Name of the create tool. Specifies the geometry for the graphic to be created. Possible Values: point | multipoint | polyline | polygon | rectangle | circle

createOptions Object optional Options for the graphic to be created. Specification: mode String optional Specifies how the graphic can be created. The create mode applies only when creating polygon, polyline, rectangle and circle geometries. Possible Values: Value Description hybrid Vertices are added while the pointer is clicked or dragged. Applies to and is the default for polygon and polyline. freehand Vertices are added while the pointer is dragged. Applies to polygon, polyline rectangle and circle. Default for rectangle and circle. click Vertices are added when the pointer is clicked.

Example:

// Call create method to create a polygon with freehand option.
sketchVM.create("polygon", {mode: "freehand"});

* // listen to create event, only respond when event's state changes to complete
sketchVM.on("create", function(event) {
  if (event.state === "complete") {
    // remove the graphic from the layer associated with the sketch widget
    // instead use the polygon that user created to query features that
    // intersect it.
    polygonGraphicsLayer.remove(event.graphic);
    selectFeatures(event.graphic.geometry);
  }
});

delete()

Since: ArcGIS API for JavaScript 4.14

Deletes the selected graphics used in the update workflow. Calling this method will fire the delete event.

Example:

// selected graphics can be deleted only when update event becomes active
sketch.on("update", function(event) {
  if (event.state === "active") {
    sketch.delete();
  }
});

// fires after delete method is called
// returns references to deleted graphics.
sketch.on("delete", function(event) {
  event.graphics.forEach(function(graphic){
    console.log("deleted", graphic)
  });
});

destroy()

Destroys the view model instance.

emit(type, event){Boolean}

Emits an event on the instance. This method should only be used when creating subclasses of this class.

Parameters:

type String The name of the event.

event Object optional The event payload.

Returns:

Type	Description
Boolean	true if a listener was notified

hasEventListener(type){Boolean}

Indicates whether there is an event listener on the instance that matches the provided event name.

Parameter:

type String The name of the event.

Returns:

Type	Description
Boolean	Returns true if the class supports the input event.

on(type, listener){Object}

Registers an event handler on the instance. Call this method to hook an event with a listener.

Parameters:

type String|String[] A event type, or an array of event types, to listen for.

listener Function The function to call when the event is fired.

Returns:

Type	Description
Object	Returns an event handler with a remove() method that can be called to stop listening for the event(s). Property Type Description remove Function When called, removes the listener from the event.

Example:

view.on("click", function(event){
  // event is the event handle returned after the event fires.
  console.log(event.mapPoint);
});

redo()

Since: ArcGIS API for JavaScript 4.9

Incrementally redo actions recorded in the stack. Calling this method will fire the redo event.

undo()

Since: ArcGIS API for JavaScript 4.9

Incrementally undo actions recorded in the stack. Calling this method will fire the undo event.

update(graphics, updateOptions){Promise<void>}

Since: ArcGIS API for JavaScript 4.10

Initializes an update operation for the specified graphic(s) and fires update event.

Parameters:

Specification:

graphics Graphic|Graphic[] A graphic or an array of graphics to be updated. Only graphics added to SketchViewModel's layer property can be updated.

updateOptions Object optional Update options for the graphics to be updated. Specification: tool String optional Name of the update tool. Specifies the update operation for the selected graphics. The provided tool will become the activeTool. Possible Values: Value Description transform This is the default tool for graphics with a polygon geometry, polyline geometry or graphics that use a 3D object symbol layer with a point geometry. It allows one or multiple graphics to be scaled, rotated and moved by default. Its default behavior can be changed by setting the enableRotation, enableScaling or preserveAspectRatio arguments when calling the update method or setting them on the defaultUpdateOptions property when the Sketch widget initializes. reshape This tool allows the entire graphic or individual vertices of the graphic to be moved. Vertices can be added or removed. This tool can only be used with a single graphic that has a polygon or polyline geometry. move This is the default tool for graphics with a point geometry that do not use a 3D object symbol layer. It should be used for specific cases where you just want to move selected polygon and polyline graphics without additional options. Additionally, the move tool does not support toggling to different modes, since the move operation is built into both the transform and reshape tools by default. enableRotation Boolean optional Default Value: true Indicates if the rotation operation will be enabled when updating graphics. Only applies if tool is transform. enableScaling Boolean optional Default Value: true Indicates if the scale operation will be enabled when updating graphics. Only applies if tool is transform. preserveAspectRatio Boolean optional Default Value: false Indicates if the uniform scale operation will be enabled when updating graphics. enableScaling must be set true when setting this property to true. Only applies if tool is transform and is always true when transforming points that use a 3D object symbol layer. toggleToolOnClick Boolean optional Default Value: true Indicates if the graphic being updated can be toggled between transform and reshape update options.

Returns:

Type	Description
Promise<void>	Resolves when the requested update tool has been loaded and is ready to use.

Examples:

// start update operation for the selected graphic
// with transform tool. Only allow uniform scaling operation.
sketchVM.update([selectedGraphic], {
  tool: "transform",
  enableRotation: false,
  enableScaling: true,
  preserveAspectRatio: true,
  toggleToolOnClick: false
});

// Listen to sketch's update event to validate graphic's
// location while it is being reshaped or moved
sketchViewModel.on("update", onGraphicUpdate);
function onGraphicUpdate(event) {
  // get the graphic as it is being updated
  const graphic = event.graphics[0];
  // check if the graphic is intersecting school buffers
  intersects = geometryEngine.intersects(buffers, graphic.geometry);

  // change the graphic symbol to valid or invalid symbol
  // depending the graphic location
  graphic.symbol = (intersects) ? invalidSymbol : validSymbol

  // check if the update event's the toolEventInfo.type is move-stop or reshape-stop
  // user finished moving or reshaping the graphic, call complete method.
  // This changes update event state to complete.
  const toolType = event.toolEventInfo.type;
  if (event.toolEventInfo && (toolType === "move-stop" || toolType === "reshape-stop")) {
    if (!intersects) {
      sketchViewModel.complete();
    }
  } else if ((event.state === "cancel" || event.state === "complete")) {
      // graphic update has been completed or cancelled
      // if the graphic is in a bad spot, call sketch's update method again
      // giving user a chance to correct the location of the graphic
      if ((!contains) || (intersects)) {
        sketchViewModel.update({
          tool: "reshape",
          graphics: [graphic],
          toggleToolOnClick: false
        });
      }
  }
}

Event Overview

{graphic: Graphic,state: String,tool: String,toolEventInfo: CreateToolEventInfo,type: "create"}

{graphics: Graphic[],tool: "move","reshape","transform",type: "delete"}

{graphics: Graphic[],tool: "point","multipoint","polyline","polygon","rectangle","circle","move","transform","reshape",type: "redo"}

{graphics: Graphic[],tool: "point","multipoint","polyline","polygon","rectangle","circle","move","transform","reshape",type: "undo"}

{graphics: Graphic[],state: "start","active","complete","cancel",tool: "move","transform","reshape",type: "update",toolEventInfo: UpdateToolEventInfo}

Event Details

create

Since: ArcGIS API for JavaScript 4.10

Fires when a user starts sketching a graphic, is actively sketching a graphic and completes sketching a graphic.

Properties:

graphic Graphic The graphic that is being created.

state String The current state of the event. Possible Values: Value Description start State changes to start when the first vertex is created. Not applicable when creating points. active State is active while graphic is being created. Not applicable when creating points. complete State changes to complete after the complete() method is called, when the user double clicks, presses the C key or clicks the first vertex of the polygon while creating a graphic. When point is created, the create event is fired with the complete state. cancel State changes to cancel if the create() or cancel() methods are called during the create operation and before the state changes to complete.

tool String Name of the create tool. Possible Values: point | multipoint | polyline | polygon | rectangle | circle

toolEventInfo CreateToolEventInfo Returns additional information associated with the create operation such as where the user is clicking the view or where the user is moving the cursor to. Value of this parameter changes to null when the create event's state changes to complete or cancel.

type String The type of the event. The value is always "create".

Example:

// Listen to sketch widget's create event.
sketchVM.on("create", function(event) {
  // check if the create event's state has changed to complete indicating
  // the graphic create operation is completed.
  if (event.state === "complete") {
    // remove the graphic from the layer. Sketch adds
    // the completed graphic to the layer by default.
    polygonGraphicsLayer.remove(event.graphic);

    // use the graphic.geometry to query features that intersect it
    selectFeatures(event.graphic.geometry);
  }
});

delete

Since: ArcGIS API for JavaScript 4.14

Fires when a user deletes selected graphics by clicking the Delete feature button on the Sketch widget or when delete() method is called.

Properties:

graphics Graphic[] An array of deleted graphics.

tool String Name of the tool that was active when graphics are deleted. Possible Values:"move"|"reshape"|"transform"

type String The type of the event. The value is always "delete".

redo

Since: ArcGIS API for JavaScript 4.10

Fires in response to redo action during creation of a new graphic or updating existing graphics.

Properties:

graphics Graphic[] An array of graphics that are being updated or created.

tool String Name of the create or update tool that is active. Possible Values:"point"|"multipoint"|"polyline"|"polygon"|"rectangle"|"circle"|"move"|"transform"|"reshape"

type String The type of the event. The value is always "redo".

undo

Since: ArcGIS API for JavaScript 4.10

Fires in response to undo action during creation of a new graphic or updating existing graphics.

Properties:

graphics Graphic[] An array of graphics that are being updated or created.

tool String Name of the create or update tool that is active. Possible Values:"point"|"multipoint"|"polyline"|"polygon"|"rectangle"|"circle"|"move"|"transform"|"reshape"

type String The type of the event. The value is always "undo".

update

Since: ArcGIS API for JavaScript 4.10

Fires when the user starts updating graphics, is actively updating graphics, and completes updating graphics.

Properties:

graphics Graphic[] An array of graphics that are being updated.

state String The state of the event. Possible Values: Value Description start State changes to start when a graphic is selected to be updated. active State is active while graphics are being updated and toolEventInfo parameter is not null. complete State changes to complete after graphics are updated. cancel State changes to cancel when graphics are selected and then unselected without any updates, or when the update(), create() or cancel() method is called before the update event's state changes to complete. Possible Values:"start"|"active"|"complete"|"cancel"

tool String Name of the update operation tool. Possible Values:"move"|"transform"|"reshape"

type String The type of the event. The value is always "update".

toolEventInfo UpdateToolEventInfo Update operation tool info. Returns additional information associated with the update operation that is taking place for selected graphics and what stage it is at. Value of this parameter changes to null when the update event's state changes to complete.

Example:

// Listen to SketchViewModel's update event to show relevant data in a chart
// as the graphics are being moved
sketchViewModel.on("update", onMove);

// Point graphics at the center and edge of the buffer polygon are being moved.
// Recalculate the buffer with updated geometry and run the query stats using
// the updated buffer and update the chart.
function onMove(event) {
  // If the edge graphic is moving, keep the center graphic
  // at its initial location. Only move edge graphic to resize the buffer.
  if (event.toolEventInfo && event.toolEventInfo.mover.attributes.edge) {
    const toolType = event.toolEventInfo.type;
    if (toolType === "move-start") {
      centerGeometryAtStart = centerGraphic.geometry;
    }
    // keep the center graphic at its initial location when edge point is moving
    else if (toolType === "move" || toolType === "move-stop") {
      centerGraphic.geometry = centerGeometryAtStart;
    }
  }

  // the center or edge graphic is being moved, recalculate the buffer
  const vertices = [
    [centerGraphic.geometry.x, centerGraphic.geometry.y],
    [edgeGraphic.geometry.x, edgeGraphic.geometry.y]
  ];

  // client-side stats query of features that intersect the buffer
  calculateBuffer(vertices);

  // user is clicking on the view... call update method with the center and edge graphics
  if ((event.state === "cancel" || event.state === "complete")) {
    sketchViewModel.update({
      tool: "move",
      graphics: [edgeGraphic, centerGraphic]
    });
  }
}