Magnifier | API Reference | ArcGIS Maps SDK for JavaScript 4.31

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 Watch for changes topic.

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Type	Summary	Class
String	The name of the class.	Accessor
Number	Controls the amount of magnification to display.	Magnifier
Boolean	Indicates whether the mask image is enabled.	Magnifier
String	The mask url points to an image that determines the visible area of the magnified image (alpha channel).	Magnifier
ScreenPoint	The offset of the magnifier in pixels.	Magnifier
Boolean	Indicates whether the overlay image is enabled.	Magnifier
String	The overlay url points to an image that is displayed on top of the magnified image.	Magnifier
ScreenPoint	The position of the magnifier in pixels.	Magnifier
Number	The size of the magnifier in pixels.	Magnifier
Boolean	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

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Return Type	Summary	Class
	Adds one or more handles which are to be tied to the lifecycle of the object.	Accessor
Boolean	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.