Layers in Diagram Control

3 Jan 202316 minutes to read

Layer is used to organize related shapes on a diagram control. A layer is a named category of shapes. By assigning shapes to different layers, you can selectively view, remove, and lock different categories of shapes.

In diagram, Layers provide a way to change the properties of all shapes that have been assigned to that layer. The following properties can be set.

  • Visible
  • Lock
  • Objects
  • AddInfo

Visible

The layer’s visible property is used to control the visibility of the elements assigned to the layer.

import {
    Diagram,
    ConnectorModel,
    NodeModel,
    LayerModel
} from '@syncfusion/ej2-diagrams';
// A node is created and stored in nodes array.
let nodes: NodeModel[] = [{
        id: 'node1',
        width: 100,
        height: 100,
        offsetX: 100,
        offsetY: 100,
        annotations: [{
            content: 'Default Shape'
        }]
    },
    {
        id: 'node2',
        width: 100,
        height: 100,
        offsetX: 300,
        offsetY: 100,
        shape: {
            type: 'Path',
            data: 'M540.3643,137.9336L546.7973,159.7016L570.3633,159.7296L550.7723,171.9366L558.9053,194.9966L540.3643,' +
                '179.4996L521.8223,194.9966L529.9553,171.9366L510.3633,159.7296L533.9313,159.7016L540.3643,137.9336z'
        },
        annotations: [{
            content: 'Path Element'
        }]
    }
];
let connectors: ConnectorModel[] = [{
    id: 'connector1',
    type: 'Straight',
    sourcePoint: {
        x: 100,
        y: 300
    },
    targetPoint: {
        x: 200,
        y: 400
    },
}];
// initialize diagram component
let diagram: Diagram = new Diagram({
    width: '100%',
    height: '600px',
    connectors: connectors,
    nodes: nodes,
    layers: [{
            id: 'layer1',
            visible: true,
            objects: ['node1']
        }
    ]
});
// render initialized diagram
diagram.appendTo('#element');

Lock

The layer’s lock property is used to prevent or allow changes to the elements dimension and position.

import {
    Diagram,
    ConnectorModel,
    NodeModel,
    LayerModel
} from '@syncfusion/ej2-diagrams';
// A node is created and stored in nodes array.
let nodes: NodeModel[] = [{
        id: 'node1',
        width: 100,
        height: 100,
        offsetX: 100,
        offsetY: 100,
        annotations: [{
            content: 'Default Shape'
        }]
    },
    {
        id: 'node2',
        width: 100,
        height: 100,
        offsetX: 300,
        offsetY: 100,
        shape: {
            type: 'Path',
            data: 'M540.3643,137.9336L546.7973,159.7016L570.3633,159.7296L550.7723,171.9366L558.9053,194.9966L540.3643,' +
                '179.4996L521.8223,194.9966L529.9553,171.9366L510.3633,159.7296L533.9313,159.7016L540.3643,137.9336z'
        },
        annotations: [{
            content: 'Path Element'
        }]
    }
];
let connectors: ConnectorModel[] = [{
    id: 'connector1',
    type: 'Straight',
    sourcePoint: {
        x: 100,
        y: 300
    },
    targetPoint: {
        x: 200,
        y: 400
    },
}];
// initialize diagram component
let diagram: Diagram = new Diagram({
    width: '100%',
    height: '600px',
    connectors: connectors,
    nodes: nodes,
    layers: [{
            id: 'layer1',
            visible: true,
            objects: ['node1'],
            lock: true
        },
        {
            id: 'layer2',
            visible: true,
            objects: ['node2'],
            lock: false
        }
    ]
});
// render initialized diagram
diagram.appendTo('#element');

Objects

The layer’s objects property defines the diagram elements to the layer.

import {
    Diagram,
    ConnectorModel,
    NodeModel,
    LayerModel
} from '@syncfusion/ej2-diagrams';
// A node is created and stored in nodes array.
let nodes: NodeModel[] = [{
        id: 'node1',
        width: 100,
        height: 100,
        offsetX: 100,
        offsetY: 100,
        annotations: [{
            content: 'Default Shape'
        }]
    },
    {
        id: 'node2',
        width: 100,
        height: 100,
        offsetX: 300,
        offsetY: 100,
        shape: {
            type: 'Path',
            data: 'M540.3643,137.9336L546.7973,159.7016L570.3633,159.7296L550.7723,171.9366L558.9053,194.9966L540.3643,' +
                '179.4996L521.8223,194.9966L529.9553,171.9366L510.3633,159.7296L533.9313,159.7016L540.3643,137.9336z'
        },
        annotations: [{
            content: 'Path Element'
        }]
    }
];
let connectors: ConnectorModel[] = [{
    id: 'connector1',
    type: 'Straight',
    sourcePoint: {
        x: 100,
        y: 300
    },
    targetPoint: {
        x: 200,
        y: 400
    },
}];
// initialize diagram component
let diagram: Diagram = new Diagram({
    width: '100%',
    height: '600px',
    connectors: connectors,
    nodes: nodes,
    layers: [{
            id: 'layer1',
            visible: true,
            objects: ['node1', 'node2']
        },
        {
            id: 'layer2',
            visible: true,
            objects: ['node2']
        }
    ]
});
// render initialized diagram
diagram.appendTo('#element');

AddInfo

The addInfo property of layers allow you to maintain additional information to the layers.

import {
    Diagram,
    ConnectorModel,
    NodeModel,
    LayerModel
} from '@syncfusion/ej2-diagrams';
// A node is created and stored in nodes array.
let nodes: NodeModel[] = [{
        id: 'node1',
        width: 100,
        height: 100,
        offsetX: 100,
        offsetY: 100,
        annotations: [{
            content: 'Default Shape'
        }]
    },
    {
        id: 'node2',
        width: 100,
        height: 100,
        offsetX: 300,
        offsetY: 100,
        shape: {
            type: 'Path',
            data: 'M540.3643,137.9336L546.7973,159.7016L570.3633,159.7296L550.7723,171.9366L558.9053,194.9966L540.3643,' +
                '179.4996L521.8223,194.9966L529.9553,171.9366L510.3633,159.7296L533.9313,159.7016L540.3643,137.9336z'
        },
        annotations: [{
            content: 'Path Element'
        }]
    }
];
let connectors: ConnectorModel[] = [{
    id: 'connector1',
    type: 'Straight',
    sourcePoint: {
        x: 100,
        y: 300
    },
    targetPoint: {
        x: 200,
        y: 400
    },
}];
let addInfo: Object = { Description: 'Layer1' };
// initialize Diagram component
let diagram: Diagram = new Diagram({
    width: '100%',
    height: '600px',
    connectors: connectors,
    nodes: nodes,
    layers: [{
            id: 'layer1',
            visible: true,
            objects: ['node1', 'node2'],
            addInfo: addInfo
        },
        {
            id: 'layer2',
            visible: true,
            objects: ['node2']
        }
    ]
});

Add layer at runtime

Layers can be added at runtime by using the addLayer public method.

The layer’s ID property defines the ID of the layer, and its further used to find the layer at runtime and do any customization.

let diagramElement = document.getElementById('element');
let diagram: Object[] = diagramElement.ej2_instances[0];
// add the layers to the existing diagram layer collection
diagram.addLayer({
    id: 'newlayer',
    objects: [],
    visible: true,
    lock: false,
    zIndex: -1
}, [{
    type: 'Straight',
    sourcePoint: {
        x: 100,
        y: 300
    },
    targetPoint: {
        x: 200,
        y: 400
    }
}]);

Remove layer at runtime

Layers can be removed at runtime by using the removeLayer public method.

let diagramElement = document.getElementById('element');
let diagram: Object[] = diagramElement.ej2_instances[0];
// remove the diagram layers
diagram.removeLayer([diagram.model.layers[i]]);

moveObjects

Objects of the layers can be moved by using the moveObjects public method.

let diagramElement = document.getElementById('element');
let diagram: Object[] = diagramElement.ej2_instances[0];
// move the objects of diagram layers
diagram.moveObjects(['connector1'], 'layer2');

bringLayerForward

Layers can be moved forward at runtime by using the bringLayerForward public method.

let diagramElement = document.getElementById('element');
let diagram: Object[] = diagramElement.ej2_instances[0];
// move the layer forward
diagram.bringLayerForward('layer1');

sendLayerBackward

Layers can be moved backward at runtime by using the sendLayerBackward public method.

let diagramElement = document.getElementById('element');
let diagram: Object[] = diagramElement.ej2_instances[0];
// move the layer backward
diagram.sendLayerBackward('layer1');

cloneLayer

Layers can be cloned with its object by using the cloneLayer public method.

let diagramElement = document.getElementById('element');
let diagram: Object[] = diagramElement.ej2_instances[0];
// clone a layer with its object
diagram.cloneLayer('layer2');

getActiveLayer

To get the active layers back in diagram, use the getActiveLayer public method.

let diagramElement = document.getElementById('element');
let diagram: Object[] = diagramElement.ej2_instances[0];
// gets the active layer back
diagram.getActiveLayer();

setActiveLayer

Set the active layer by using the setActiveLayer public method.

let diagramElement = document.getElementById('element');
let diagram: Object[] = diagramElement.ej2_instances[0];
// set the active layer
//@param layerName defines the name of the layer which is to be active layer
diagram.setActiveLayer('layer2');