Scroll Settings in AngularJS Diagram

30 Jan 20235 minutes to read

The Diagram can be scrolled by using the vertical and horizontal scrollbars. In addition to the scrollbars, you can use mouse wheel to scroll the Diagram.
Diagram’s scrollSettings enables you to read the current scroll status, view port size, current zoom, and zoom factor. It also allows you to scroll the Diagram programmatically.

Get current scroll status

Scroll settings allows you to read the scroll status, view port size, and current zoom factor with a set of properties. To explore those properties, see Scroll Settings

Define scroll status

Diagram allows you to pan the Diagram before loading, so that any desired region of a large Diagram is made to view. You can programmatically pan the Diagram with the horizontalOffset and verticalOffset properties of scroll settings. The following code illustrates how to set pan the Diagram programmatically.

HTML

<div ng-controller="diagramCtrl">
    <ej-diagram id="diagram" e-height="600px" e-width="100%" e-scrollSettings="scrollSettings" e-pageSettings="pageSettings">
    </ej-diagram>
</div>

JAVASCRIPT

syncApp.controller('diagramCtrl', function($scope) {
      $scope.scrollSettings = {
          horizontalOffset: 100,
          verticalOffset: 50,
          zoomFactor: 0.2
      };
      $scope.pageSettings = {
          pageWidth: 500,
          pageHeight: 500
      };
  });

In the example given below, the vertical scroll bar is scrolled down by 50px and horizontal scroll bar is scrolled to right by 100px. 

AutoScroll

Autoscroll feature automatically scrolls the Diagram whenever the node or connector is moved beyond the boundary of the Diagram. So that, it is always visible during dragging, resizing, and multiple selection operations. Autoscroll is automatically triggered when any one of the following is done towards the edges of the Diagram.

• Node dragging, resizing
• Connection editing
• Rubber band selection
• Label dragging

Autoscroll border

The Autoscroll border is used to specify the maximum distance between the object and Diagram edge to trigger Autoscroll. The default value is set as 15 for all sides (left, right, top, and bottom) and it can be changed by using the autoScrollBorder property of page settings. The following code example illustrates how to set Autoscroll border. 

HTML

<div ng-controller="diagramCtrl">
    <ej-diagram id="diagram" e-height="600px" e-width="100%" e-pagesettings="pageSettings" pagesettings-autoscrollborder="pageSettings.autoScrollBorder">
    </ej-diagram>
</div>

JAVASCRIPT

syncApp.controller('diagramCtrl', function($scope) {
    $scope.pageSettings = {
        autoScrollBorder: {
            left: 150,
            top: 15,
            right: 15,
            bottom: 15
        }
    };
});

Scroll limit

The scroll limit allows you to define the scrollable region of the Diagram. It includes the following options.

• Allows to scroll in all directions without any restriction.
• Allows to scroll within the Diagram content.
• Allows to scroll within the specified scrollable area.

scrollLimit property of scroll settings helps to limit the scrolling. For the accepted values of the scrollLimit, refer to Scroll Limit.

The following code example illustrates how to specify the scroll limit.

JAVASCRIPT

syncApp.controller('diagramCtrl', function($scope) {
    $scope.pageSettings = {
        scrollLimit: "diagram"
    };
});

Scrollable Area

You can restrict scrolling beyond any particular rectangular area by using the scrollableArea property of scroll settings. To restrict scrolling beyond any custom region, you have to set the scrollLimit as “limited”. The following code example illustrates how to customize scrollable area.

HTML

<div ng-controller="diagramCtrl">
    <ej-diagram id="diagram" e-height="600px" e-width="100%" e-pagesettings="pageSettings" pagesettings-scrollablearea="pageSettings.scrollableArea" pagesettings-scrolllimit="pageSettings.scrollLimit">
    </ej-diagram>
</div>

JAVASCRIPT

syncApp.controller('diagramCtrl', function($scope) {
    $scope.pageSettings = {
        //Sets scroll limit as limited
        scrollLimit: "limited",
        //Sets the limited scrollable area
        scrollableArea: {
            x: 0,
            y: 0,
            width: 500,
            height: 500
        }
    }

});