Magnifier

AMD: require(["esri/views/Magnifier"], (Magnifier) => { /* code goes here */ });
ESM: import Magnifier from "@arcgis/core/views/Magnifier.js";
Class: esri/views/Magnifier
Inheritance: MagnifierAccessor
Since: ArcGIS Maps SDK for JavaScript 4.19

The Magnifier allows end users to show a portion of the view as a magnified image. An instance of this class can be accessed through either MapView.magnifier or SceneView.magnifier.

magnifier-overlay

As you can see in the screenshot above, the Magnifier utilizes a default overlay image of a magnifier glass. The overlay image is set using the overlayUrl property. You can disable the overlay image by setting the Magnifier.overlayEnabled to false. The following demonstrates using a Magnifier without an overlay image.

magnifier-no-overlay

The Magnifier contains a default mask image, which is set using the maskUrl, and determines the visible area of the magnified image. Be default, the magnified area is in the shape of a circle. The following demonstrates an example of a mask image set in the shape of a square. Note that the overlayEnabled was set to false in this example as well to hide the overlay image, and only display the magnified area.

magnifier-maskUrl

See also
Example
view.when(() => {
  view.magnifier.visible = true;

  const offset = view.magnifier.size / 2;
  view.magnifier.offset = { x: offset, y: offset };

  //The magnifier will be displayed whenever the cursor hovers over the map.
  view.on("pointer-move", function (event) {
    view.magnifier.position = { x: event.x, y: event.y };
  });
});

Constructors

Magnifier

Constructor
new Magnifier(properties)
Parameter
properties Object
optional

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

Property Overview

Any properties can be set, retrieved or listened to. See the Working with Properties topic.
Show inherited properties Hide inherited properties
Name Type Summary Class

The name of the class.

Accessor

Controls the amount of magnification to display.

Magnifier

Indicates whether the mask image is enabled.

Magnifier

The mask url points to an image that determines the visible area of the magnified image (alpha channel).

Magnifier

The offset of the magnifier in pixels.

Magnifier

Indicates whether the overlay image is enabled.

Magnifier

The overlay url points to an image that is displayed on top of the magnified image.

Magnifier

The position of the magnifier in pixels.

Magnifier

The size of the magnifier in pixels.

Magnifier

Indicates whether the magnifier is visible.

Magnifier

Property Details

declaredClass

Inherited
Property
declaredClass Stringreadonly
Inherited from Accessor

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

factor

Property
factor Number

Controls the amount of magnification to display. The larger the value, the more augmented the magnified image appears.

Default Value:1.5

maskEnabled

Property
maskEnabled Boolean

Indicates whether the mask image is enabled.

Default Value:true

maskUrl

Property
maskUrl String

The mask url points to an image that determines the visible area of the magnified image (alpha channel). A default built-in circle mask with a diameter equal to the size of the magnifier is used when the maskUrl is null.

Default Value:null

offset

Property
offset ScreenPoint

The offset of the magnifier in pixels. The offset allows to adjust where the magnifier is drawn relative to its position.

Example
const offset = view.magnifier.size / 2;
view.magnifier.offset = { x: offset, y: offset };

overlayEnabled

Property
overlayEnabled Boolean

Indicates whether the overlay image is enabled.

Default Value:true

overlayUrl

Property
overlayUrl String

The overlay url points to an image that is displayed on top of the magnified image. Note that the overlay image is not affected by the maskUrl. A default built-in image of a magnifier glass is used when the overlayUrl is null.

Default Value:null

position

Property
position ScreenPoint

The position of the magnifier in pixels. The magnifier will not be displayed if the position is null.

Default Value:null

size

Property
size Number

The size of the magnifier in pixels.

Default Value:120

visible

Property
visible Boolean

Indicates whether the magnifier is visible.

Default Value:true

Method Overview

Show inherited methods Hide inherited methods
Name Return Type Summary Class

Adds one or more handles which are to be tied to the lifecycle of the object.

Accessor

Returns true if a named group of handles exist.

Accessor

Removes a group of handles owned by the object.

Accessor

Method Details

addHandles

Inherited
Method
addHandles(handleOrHandles, groupKey)
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, addHandles added at 4.25.

Adds one or more handles which are to be tied to the lifecycle of the object. The handles will be removed when the object is destroyed.

// Manually manage handles
const handle = reactiveUtils.when(
  () => !view.updating,
  () => {
    wkidSelect.disabled = false;
  },
  { once: true }
);

this.addHandles(handle);

// Destroy the object
this.destroy();
Parameters
handleOrHandles WatchHandle|WatchHandle[]

Handles marked for removal once the object is destroyed.

groupKey *
optional

Key identifying the group to which the handles should be added. All the handles in the group can later be removed with Accessor.removeHandles(). If no key is provided the handles are added to a default group.

hasHandles

Inherited
Method
hasHandles(groupKey){Boolean}
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, hasHandles added at 4.25.

Returns true if a named group of handles exist.

Parameter
groupKey *
optional

A group key.

Returns
Type Description
Boolean Returns true if a named group of handles exist.
Example
// Remove a named group of handles if they exist.
if (obj.hasHandles("watch-view-updates")) {
  obj.removeHandles("watch-view-updates");
}

removeHandles

Inherited
Method
removeHandles(groupKey)
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, removeHandles added at 4.25.

Removes a group of handles owned by the object.

Parameter
groupKey *
optional

A group key or an array or collection of group keys to remove.

Example
obj.removeHandles(); // removes handles from default group

obj.removeHandles("handle-group");
obj.removeHandles("other-handle-group");

Type Definitions

ScreenPoint

Type Definition
ScreenPoint

An object representing the location on the screen. The Magnifier.position represents an actual point on the screen, while the Magnifier.offset represents a location relative to the position of the magnifier.

Properties
x Number

The x coordinate.

y Number

The y coordinate.

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