{WebTwainObject}.Viewer

{WebTwainObject} denotes the WebTwain instance.

All APIs on this page support Android Service from version 18.2.

Methods

Properties

Events

bind()

Create a Dynamsoft Viewer instance and bind it to the WebTwain instance.

Syntax

bind(element: HTMLDivElement | HTMLElement) : boolean;

Parameters

element: Specify an HTML element to create the viewer.

Example

var DWObject;
Dynamsoft.DWT.CreateDWTObjectEx(
    {
        WebTwainId: "dwtControl"
    },
    function (obj) {
        DWObject = obj;
        DWObject.Viewer.bind("dwtcontrolContainer");
        DWObject.Viewer.width=600;
        DWObject.Viewer.height=800;
        DWObject.Viewer.show();    
    }, 
    function (err) {
        console.log(err);
    });

Availability

Usage notes

Replace the previous BindViewer method.

clearSelectedAreas()

Clear the selected area(s) on the current page.

Syntax

clearSelectedAreas(): boolean;

Availability

Example

DWObject.Viewer.clearSelectedAreas();

createCustomElement()

Add a custom page DIV element and specify its position and display order. Generate an independent CustomElement object.

Syntax

createCustomElement(
    element: HTMLDivElement,
    location?: string,
    ifFull?: boolean
): CustomElement;

Parameters

element: Specify the HTMLDivElement.

location: Define where to place the custom element. The allowed values are “left” and “right”, and the default value is “right”.

ifFull: The default value is false, that is, the created CustomElement is displayed according to the set area. If set to true, the main viewer will be covered by the CustomElement.

Arguments

CustomElement: Please refer to CustomElement.

Availability

Example

var myElement = document.createElement("div");
myElement.style = "width:100px;height:200px;background:red";
var customElement = DWObject.Viewer.createCustomElement(
  myElement,
  "right",
  false
);
customElement.show();

Usage notes

Only one CustomElement object can be created. If you try creating another one, you’ll get the error ‘A CustomElement already exists.’, and the existing CustomElement object will be returned.

If the width defined by the CustomElement object exceeds the width of the main viewer, the width of the main viewer is used.

The method unbind() will dispose all created CustomElement objects.

createImageEditor()

Generate an independent ImageEditor object.

Syntax

createImageEditor(
    editorSettings?: EditorSettings
): ImageEditor;

Parameters

editorSettings: Configure the object. Please refer to EditorSettings.

Arguments

ImageEditor: Please refer to ImageEditor.

Availability

Example

The example code shows 2 ways to use the API createImageEditor()

• v18.3
• v18.2

// Use default settings
var imageEditor = DWObject.Viewer.createImageEditor();
imageEditor.zoomOrigin = {x:"center", y:"center"};
imageEditor.show();

// Use default settings
var imageEditor = DWObject.Viewer.createImageEditor();
imageEditor.show();

• v18.3+
• v18.2

// Customize the editor
var editorSettings = {
  /* Show the editor within the DIV 'imageEditor'*/
  element: document.getElementById("imageEditor"),
  width: 600,
  height: 400,
  border: "1px solid rgb(204, 204, 204)",
  topMenuBorder: "",
  innerBorder: "",
  background: "rgb(255, 255, 255)",
  promptToSaveChange: true,
  buttons: {
    titles: {
      previous: "Previous Image",
      next: "Next Image",
      print: "Print Image",
      scan: "Scan Documents",
      load: "Load Local Images",
      rotateleft: "Rotate Left",
      rotate: "Rotate",
      rotateright: "Rotate Right",
      deskew: "Deskew",
      crop: "Crop Selected Area",
      cut: "Cut Selected Area",
      changeimagesize: "Change Image Size",
      flip: "Flip Image",
      mirror: "Mirror Image",
      zoomin: "Zoom In",
      originalsize: "Show Original Size",
      zoomout: "Zoom Out",
      stretch: "Stretch Mode",
      fit: "Fit Window",
      fitw: "Fit Horizontally",
      fith: "Fit Vertically",
      hand: "Hand Mode",
      rectselect: "Select Mode",
      zoom: "Click to Zoom In",
      restore: "Restore Original Image",
      save: "Save Changes",
      close: "Close the Editor",
      removeall: "Remove All Images",
      removeselected: "Remove All Selected Images",
    },
    visibility: {
      previous:true,
      next:true,
      scan: true,
      load: true,
      print: true,
      removeall: true,
      removeselected: true,
      rotateleft: true,
      rotate: true,
      rotateright: true,
      deskew: true,
      crop: true,
      cut: true,
      changeimagesize: true,
      flip: true,
      mirror: true,
      zoomin: true,
      originalsize: true,
      zoomout: true,
      stretch: true,
      fit: true,
      fitw: true,
      fith: true,
      hand: true,
      rectselect: true,
      zoom: true,
      restore: true,
      save: true,
      close: true,
    },
  },
  dialogText: {
    dlgRotateAnyAngle: [
      "Angle :",
      "Interpolation:",
      "Keep size",
      "  OK  ",
      "Cancel",
    ],
    dlgChangeImageSize: [
      "New Height :",
      "New Width :",
      "Interpolation method:",
      "  OK  ",
      "Cancel",
    ],
    saveChangedImage: [
      "You have changed the image, do you want to keep the change(s)?",
      "  Yes  ",
      "  No  ",
    ],
    selectSource: [
      "Select Source:",
      "Select",
      "Cancel",
      "There is no source available",
    ],
  },
  workMode:Dynamsoft.DWT.EnumDWT_WorkMode.balance,
  zoomOrigin: {
    x: "center",
    y: "center",
  },
};
//Create the editor
var imageEditor = DWObject.Viewer.createImageEditor(editorSettings);
imageEditor.show();

// Customize the editor
var editorSettings = {
  /* Show the editor within the DIV 'imageEditor'*/
  element: document.getElementById("imageEditor"),
  width: 600,
  height: 400,
  border: "1px solid rgb(204, 204, 204)",
  topMenuBorder: "",
  innerBorder: "",
  background: "rgb(255, 255, 255)",
  promptToSaveChange: true,
  buttons: {
    titles: {
      previous: "Previous Image",
      next: "Next Image",
      print: "Print Image",
      scan: "Scan Documents",
      load: "Load Local Images",
      rotateleft: "Rotate Left",
      rotate: "Rotate",
      rotateright: "Rotate Right",
      deskew: "Deskew",
      crop: "Crop Selected Area",
      cut: "Cut Selected Area",
      changeimagesize: "Change Image Size",
      flip: "Flip Image",
      mirror: "Mirror Image",
      zoomin: "Zoom In",
      originalsize: "Show Original Size",
      zoomout: "Zoom Out",
      stretch: "Stretch Mode",
      fit: "Fit Window",
      fitw: "Fit Horizontally",
      fith: "Fit Vertically",
      hand: "Hand Mode",
      rectselect: "Select Mode",
      zoom: "Click to Zoom In",
      restore: "Restore Original Image",
      save: "Save Changes",
      close: "Close the Editor",
      removeall: "Remove All Images",
      removeselected: "Remove All Selected Images",
    },
    visibility: {
      scan: true,
      load: true,
      print: true,
      removeall: true,
      removeselected: true,
      rotateleft: true,
      rotate: true,
      rotateright: true,
      deskew: true,
      crop: true,
      cut: true,
      changeimagesize: true,
      flip: true,
      mirror: true,
      zoomin: true,
      originalsize: true,
      zoomout: true,
      stretch: true,
      fit: true,
      fitw: true,
      fith: true,
      hand: true,
      rectselect: true,
      zoom: true,
      restore: true,
      save: true,
      close: true,
    },
  },
  dialogText: {
    dlgRotateAnyAngle: [
      "Angle :",
      "Interpolation:",
      "Keep size",
      "  OK  ",
      "Cancel",
    ],
    dlgChangeImageSize: [
      "New Height :",
      "New Width :",
      "Interpolation method:",
      "  OK  ",
      "Cancel",
    ],
    saveChangedImage: [
      "You have changed the image, do you want to keep the change(s)?",
      "  Yes  ",
      "  No  ",
    ],
    selectSource: [
      "Select Source:",
      "Select",
      "Cancel",
      "There is no source available",
    ],
  },
  workMode:Dynamsoft.DWT.EnumDWT_WorkMode.balance,
};
//Create the editor 
var imageEditor = DWObject.Viewer.createImageEditor(editorSettings);
imageEditor.show();

Usage notes

Replace the previous ShowImageEditor() method.

Only one ImageEditor object can be created. If you try creating it again, you’ll get the error ‘An ImageEditor already exists.’ and the existing ImageEditor object will be returned.

The method unbind() will dispose all created ImageEditor objects.

createThumbnailViewer()

Generate a independent ThumbnailViewer object.

Syntax

createThumbnailViewer(
    thumbnailViewerSettings?: ThumbnailViewerSettings
): ThumbnailViewer;

Parameters

thumbnailViewerSettings: Configure the ThumbnailViewer object. Please refer to ThumbnailViewerSettings.

Arguments

ThumbnailViewer: Please refer to ThumbnailViewer.

Availability

Example

The example code shows 2 ways to use the API createThumbnailViewer()

// Use default settings
var objThumbnailViewer = DWObject.Viewer.createThumbnailViewer();
objThumbnailViewer.background = "rgb(0,0,255)";
objThumbnailViewer.show();

// Customize the thumbnail viewer
var thumbnailViewerSettings = {
    location: 'left',
    size: '30%',
    columns: 1,
    rows: 3,
    scrollDirection: 'vertical', // 'horizontal'
    pageMargin: 10,
    background: "rgb(255, 255, 255)",
    border: '',
    allowKeyboardControl: true,
    allowPageDragging: true,
    allowResizing: false,
    pageBackground: "transparent",
    pageBorder: "1px solid rgb(238, 238, 238)",
    hoverBackground: "rgb(239, 246, 253)",
    hoverPageBorder: "1px solid rgb(238, 238, 238)",
    placeholderBackground: "rgb(251, 236, 136)",
    selectedPageBorder: "1px solid rgb(125,162,206)",
    selectedPageBackground: "rgb(199, 222, 252)"
}​​​​​​​;

var thumbnail = DWObject.Viewer.createThumbnailViewer(thumbnailViewerSettings);
thumbnail.show();

Usage notes

For the CheckboxSettings and PageNumberSettings interface, please refer to the APIs updateCheckboxStyle() and updatePageNumberStyle().

The following table shows the events available to a ThumbnailViewer object.

By default, scrolling the scroll bar on Thumbnail does not trigger the topchanged event.

Only one ThumbnailViewer object can be created. If you try creating it again, you will get the error ‘A ThumbnailViewer already exists.’ and the existing ThumbnailViewer object will be returned.

The method unbind() will dispose all created ThumbnailViewer objects.

first()

Show the first page and return the index which should be 0. If there is no page in the viewer, -1 is returned.

Syntax

first():number;

Availability

Example

DWObject.Viewer.first();

fitWindow()

Set how the page is fit in the viewer.

Syntax

fitWindow(
    type?: string
): void

Parameters

type: Specify how to fit. Allowed values are “width” and “height”

Availability

Example

DWObject.Viewer.fitWindow();

Usage notes

This API only works if the view mode of the viewer is set to -1 by -1 (singlePageMode is true).

The allowed values are

width: Fit the page vertically. height: Fit the page horizontally.

If no parameter is provided, it tries to fit the whole page within the viewer.

gotoPage()

Show the specified page and return its index.

Syntax

gotoPage(
    index: number
): number;

Parameters

index: Specify the page.

Availability

Example

DWObject.Viewer.gotoPage(0);

hide()

Hide the viewer.

Syntax

hide(): boolean;

Availability

Example

DWObject.Viewer.hide();

last()

Show the last page and return its index. If there is no page in the viewer, -1 is returned.

Syntax

last():number;

Availability

Example

DWObject.Viewer.last();

next()

Show the next page and return its index. If there is no page in the viewer, -1 is returned.

Syntax

next(): number;

Availability

Example

DWObject.SelectImages([3]); //Select the 4th page.
var currentIndex = DWObject.Viewer.next(); // return 4 which represents the 5th page.

previous()

Show the previous page and return its index. If there is no page in the viewer, -1 is returned.

Syntax

previous(): number;

Availability

Example

DWObject.SelectImages([3]); //Select the 4th page.
var currentIndex = DWObject.Viewer.previous(); // return 2 which represents the 3rd page.

render()

Refresh the viewer.

Syntax

render(): boolean;

Availability

Example

DWObject.Viewer.on("pageRendered", function (index) {
  console.log(index);
});

DWObject.Viewer.render(); //It will trigger the pageRendered event

setButtonClass()

Set the CSS class name of the specified button.

Syntax

setButtonClass(
    name: string,
    className: string
): boolean;

Parameters

name: Specify the button.

className: Specify the CSS class name.

Availability

Usage notes

Use this method to fine-tune the buttons in the viewer with CSS.

Example

DWObject.Viewer.setButtonClass("crop", "CropClass");

setSelectedAreas()

Set one or more rectangular area(s) on the current page.

Syntax

setSelectedAreas(
    areas: Area[]
): boolean;

Parameters

areas: Specify the rectangular area(s). Please refer to Area.

Availability

Usage notes

The coordinates are based on the size of the original page (instead of the size of the viewer).

This method only works when cursor is set to “crosshair”.

Example

DWObject.Viewer.setSelectedAreas([
  {
    left: 0,
    top: 0,
    right: 100,
    bottom: 100,
  },
  {
    left: 200,
    top: 200,
    right: 400,
    bottom: 500,
  },
]);

setViewMode()

Set the view mode of the viewer.

Syntax

setViewMode(
    columns: number,
    rows: number
): boolean;

Parameters

columns: Specify the number of images per column.

rows: Specify the number of images per row.

Availability

Usage notes

Setting the view mode as -1 by -1 is equivalent to setting singlePageMode to true.

Example

DWObject.Viewer.setViewMode(2, 2);

show()

Show the viewer.

Syntax

show(): boolean;

Availability

Example

DWObject.Viewer.show();

unbind()

Unbind and destroy the viewer.

Syntax

unbind(): boolean;

Availability

Usage notes

Replace the previous UnbindViewer method.

Example

DWObject.Viewer.unbind();

acceptDrop

Set whether to load files dropped over the viewer area. The default value is true.

Syntax

acceptDrop: boolean;

Availability

Example

DWObject.Viewer.acceptDrop = true;

allowSlide

Set whether to allow image navigation by swiping left or right on the viewer. The default value is true.

allowSlide: boolean;

Availability

Usage notes

This API only works if the view mode of the viewer is set to -1 by -1.

Example

DWObject.Viewer.allowSlide = true;

allowPageDragging

Set whether to allow page dragging to reorder the pages in the viewer. The default value is true.

allowPageDragging: boolean;

Availability

Example

DWObject.Viewer.setViewMode(2,2);
DWObject.Viewer.cursor = "pointer";
DWObject.Viewer.allowPageDragging = false; //Disable drag&drop.

background

Return or set the background of the viewer.

Syntax

background: string;

Availability

Usage notes

Replace the previous BackgroundColor method. Now you can specify the backgournd by CSS which may be a single color or even an image. Read more on the background shorthand CSS.

Example

DWObject.Viewer.background = "rgb(255, 255, 255)";

border

Return or set the border of the viewer.

Syntax

border: string;

Availability

Usage notes

The default value is “1px solid rgb(204, 204, 204)”. Now you can specify the border by CSS. Read more on the border shorthand CSS.

Example

DWObject.Viewer.border = "2px solid rgb(204, 204, 204)";

cursor

Return or set the shape of the cursor.

Syntax

cursor: string;

Availability

Usage Notes

The allowed values are:

Value	Description
default	The shape is .
crosshair	The shape is (default setting), you can select one or multiple area(s) on the page.
pointer	The shape is . If the displayed page is bigger than the viewer, the page can be moved.
zoom-in	The shape is , supports click the page to zoom in. Only works if the view mode of the viewer is set to -1 by -1.

If there are selected areas on the page, changing the cursor property will clear them.

Example

DWObject.Viewer.cursor = "crosshair";

height

Return or set the height of the viewer.

Syntax

height: number | string;

Availability

Usage Notes

If a number is assigned, it means that number of pixels (px). If a string is assigned, it is either a fixed size like “500px” or a dynamic size like “50%” which follows standard CSS rules.

When reading the property, the value is always in pixels no matter what value was set to it.

Example

DWObject.Viewer.height = 350;
DWObject.Viewer.height = "350px";
DWObject.Viewer.height = "100%";

idPostfix

Return the postfix of the Ids of the elements in the viewer.

Syntax

readonly idPostfix: string;

Availability

Example

var myViewerIdPostfix = DWObject.Viewer.idPostfix;

ifAutoScroll

Return or set whether to scroll the viewer automatically when new pages are imported. Default: true;

Syntax

ifAutoScroll: string;

Availability

Example

DWObject.Viewer.ifAutoScroll = false;

innerBorder

Return or set the inner border of the viewer.

Syntax

innerBorder: string;

Availability

Example

DWObject.Viewer.innerBorder = "1px solid rgb(204, 204, 204)";

Usage notes

The default value is null. You can specify the border by CSS. Read more on the border shorthand CSS.

pageMargin

Return or set the margin between images.

Syntax

pageMargin: number | string;

Availability

Usage Notes

The page margin is only effective when the view mode is not -1 * -1 (in other words, singlePageMode is false ).

Example

DWObject.Viewer.pageMargin = 10;

selectedAreaBorderColor

This API has been deprecated as of release 18.4.

Please use the updateSelectionBoxStyle() function.

Set the border color of the selected area. Also applies to the selection box on the video opened by the method showVideo.

Syntax

selectedAreaBorderColor: string;

Availability

Usage notes

The default value is “rgba(0, 0, 0, 1)”.

Example

DWObject.Viewer.selectedAreaBorderColor = "rgba(0, 0, 0, 1)";

selectedPageBackground

Set the selected page background color of the Thumbnail viewer.

Syntax

selectedPageBackground: string;

Availability

Usage notes

The default value is “rgb(199, 222, 252)”. You can specify the backgournd by CSS which may be a single color or even an image. Read more on the background shorthand CSS.

Example

DWObject.Viewer.selectedPageBackground = "rgb(255, 0, 0)";

selectedPageBorder

Return or set the border style for selected page(s).

Syntax

selectedPageBorder: string;

Availability

Usage Notes

This API is only effective when the view mode is not -1 * -1 (in other words, singlePageMode is false ).

The default value is “1px solid rgb(125, 162, 206)”. Now you can specify the border by CSS. Read more on the border shorthand CSS.

Example

DWObject.Viewer.selectedPageBorder = "3px solid rgb(125,162,206)";

selectionRectAspectRatio

Specify an aspect ratio to be used when selecting an rectangular area on a page.

Syntax

selectionRectAspectRatio: number | string;

Availability

Usage Notes

This API is only effective when drawing manually (it won’t work if the selection is done with the API setSelectedAreas()).

Example

DWObject.Viewer.selectionRectAspectRatio = 0.5;

singlePageMode

Set whether to use single page mode.

Syntax

singlePageMode: boolean;

Availability

Usage notes

The default value is false. If the thumbnail viewer is not shown, setting singlePageMode to true is equivalent to setting the view mode to -1 by -1. But if the thumbnail viewer is shown, singlePageMode will be changed to true automatically.

Example

// Use single page mode in the main viewer
DWObject.Viewer.singlePageMode = true;

// Use single page mode in the thumnail viewer
var objThumbnailViewer = DWObject.Viewer.createThumbnailViewer();
objThumbnailViewer.show();
DWObject.Viewer.singlePageMode = true;

updateSelectionBoxStyle()

Sets the graphical style for the selection box in the Viewer.

Syntax

updateSelectionBoxStyle(selectionBoxStyleSettings?: SelectionBoxStyleSettings): boolean;

Parameters selectionBoxStyleSettings: Selection box settings. Please refer to SelectionBoxStyleSettings for details.

Availability

Example

let styleSettings = {
    borderColor: "rgba(255, 105, 110, 1)",
    borderWidth:4,
    lineDash:[4,2],
    handleWidth:10,
    handleHeight:10,
    handleColor: "rgba(252, 92, 255, 1)",
}

DWObject.Viewer.updateSelectionBoxStyle(styleSettings);

Usage Notes If creating an ImageEditor object, the Viewer styling will be inherited by the ImageEditor on creation, but styles will be maintained seperately. That is to say that after creating the ImageEditor, changing one style will not affect the other.

width

Return or set the width of the viewer.

Syntax

width: number | string;

Availability

Usage Notes

If a number is assigned, it means that number of pixels (px). If a string is assigned, it is either a fixed size like “500px” or a dynamic size like “50%” which follows standard CSS rules.

When reading the property, the value is always in pixels no matter what value was set to it.

Example

DWObject.Viewer.width = 270;
DWObject.Viewer.width = "270px";
DWObject.Viewer.width = "100%";

zoom

Return or set the zoom factor, and then the current page will be enlarged or reduced.

Syntax

zoom: number;

Availability

Usage Notes

The zoom factor is only effective when the view mode is -1 * -1. Allowed values is from 0.02 to 65.

Example

DWObject.Viewer.zoom = 2.0;

autoChangeIndex

Set whether to make sure the first image in the viewer is always selected when scrolling through multiple images. The default value is false.

Syntax

autoChangeIndex: boolean;

Availability

Usage Notes

When set to true, the index in the upper left corner of the viewer will be selected when scrolling.

Example

DWObject.Viewer.autoChangeIndex = true;

updateCheckboxStyle()

Update checkbox style

Syntax

updateCheckboxStyle(checkboxSettings?: CheckboxSettings): boolean;

Parameters

checkboxSettings: Settings for checkboxes. Please refer to CheckboxSettings.

Availability

updatePageNumberStyle()

Update page number style

Syntax

updatePageNumberStyle(pageNumberSettings?: PageNumberSettings): boolean;

Parameters

pageNumberSettings: Settings for page numbers. Please refer to PageNumberSettings.

Availability

selectionMode

Return or set the selection mode used.

Syntax

selectionMode: Dynamsoft.DWT.EnumDWT_SelectionMode | number;

Availability

Usage notes

The default value is 0 (Single). Even if checkbox is used, only one image can be selected if the selection mode is set to 0 (Single).

Please refer to EnumDWT_SelectionMode.

Example

DWObject.Viewer.setViewMode(2,2);
DWObject.Viewer.cursor = "pointer";
DWObject.Viewer.updateCheckboxStyle({
    visibility:"visible",
});
DWObject.Viewer.selectionMode = Dynamsoft.DWT.EnumDWT_SelectionMode.Multiple; // Multiple Selection

zoomOrigin

Set the zoom origin.

Syntax

zoomOrigin: {x: string; y: string;};

Parameters

x: x-coordinate. Default is “center”, values: “left”, “right”, “center”.

y: y-coordinate. Default is “center”, values: “top”, “bottom”, “center”.

Availability

Usage notes

The default value is {x:"center", y:"center"}, which means the zoom origin is center point of the image.

Example

DWObject.Viewer.zoomOrigin = {x:"left", y:"top"}; // Set the zoom origin to top left corner.

Events

on()

Built-in callbacks that are triggered for a certain mouse event or keyboard event on a page.

Syntax

on(
    eventName: string,
    callback: (dwtEvent: ViewerEvent | KeyboardEvent, domEvent: MouseEvent) => void
): void;

Parameters

eventName: Specify the event. Value: click, contextmenu, dblclick, mousemove, mousedown, mouseup, mouseout, mouseover, keydown, keyup.

callback: Specify the callback.

• dwtEvent: The viewer-specific event object. Please refer to ViewerEvent and KeyboardEvent.
• domEvent: The original mouse event object. Please refer to MouseEvent.

Availability

Usage notes

The events mouseout, mouseover, keydown and keyup are only triggered on desktop browsers. The events click, dbclick, mousemove, pageAreaSelected, and pageAreaUnselected are supported in ActiveX.

Example

DWObject.Viewer.on("click", function (dwtEvent, domEvent) {
  console.log(dwtEvent, domEvent);
});

DWObject.Viewer.on("dblclick", function (dwtEvent, domEvent) {
  console.log(dwtEvent, domEvent);
});

DWObject.Viewer.on("contextmenu", function (dwtEvent, domEvent) {
  console.log(dwtEvent, domEvent);
});

DWObject.Viewer.on("mousemove", function (dwtEvent, domEvent) {
  console.log(dwtEvent, domEvent);
});

DWObject.Viewer.on("mousedown", function (dwtEvent, domEvent) {
  console.log(dwtEvent, domEvent);
});

DWObject.Viewer.on("mouseup", function (dwtEvent, domEvent) {
  console.log(dwtEvent, domEvent);
});

DWObject.Viewer.on("mouseout", function (dwtEvent, domEvent) {
  console.log(dwtEvent, domEvent);
});

DWObject.Viewer.on("mouseover", function (dwtEvent, domEvent) {
  console.log(dwtEvent, domEvent);
});

DWObject.Viewer.on("keydown", function (keyboardEvent) {
  console.log(keyboardEvent);
});

DWObject.Viewer.on("keyup", function (keyboardEvent) {
  console.log(keyboardEvent);
});

off()

Unbind event listener(s) from the specified viewer event.

Syntax

off(
    eventName: string,
    callback?: () => void
): void;

Parameters

eventName: Specify the event.

callback: Specify the listener to remove

Availability

Example

DWObject.Viewer.off("pageAreaSelected");

Usage notes

If no listener is specified, all listeners will be removed.

pageAreaSelected

This event is triggered when user selects an area (draws a rectangle) or move a selected area on the current page.

Syntax

on('pageAreaSelected',
    (index: number, rect: rect[])=> void
): void;

Parameters

index: The index of the current page.

rect: Some attribute values of the selected area. Please refer to rect.

Availability

Example

DWObject.Viewer.on("pageAreaSelected", function (sImageIndex, rect) {
  console.log(sImageIndex);
});

DWObject.Viewer.off("pageAreaSelected");

pageAreaUnselected

This event is triggered when selected area(s) get cleared (when the user clicks outside of the drawn rectangle).

Syntax

on('pageAreaUnselected',
    (index: number) => void
): void;

Parameters

index: The index of the current page.

Availability

Example

DWObject.Viewer.on("pageAreaUnselected", function (sImageIndex) {
  console.log(
    "The selected areas on the page with index " +
      sImageIndex +
      " have been cleared"
  );
});

DWObject.Viewer.off("pageAreaUnselected");

pageRendered

This event is triggered when a page is rendered.

Syntax

on('pageRendered',
    (index: number) => void
): void;

Parameters

index: The index of the current page.

Availability

Example

DWObject.Viewer.on("pageRendered", function (index) {
  console.log(index);
});
DWObject.Viewer.render(); //It will trigger the pageRendered event

resize

This event is triggered when width & height of the viewer has been changed.

Syntax

on('resize',
    (width: number, height: number) => void
): void;

Parameters

width: The new width of the viewer.

height: The new height of the viewer.

Availability

Example

DWObject.Viewer.on("resize", function (width, height) {
  console.log(width, height);
});
DWObject.Viewer.width = 100;