---
layout: default-layout
needAutoGenerateSidebar: true
# noTitleIndex: true
title: Dynamic Web TWAIN SDK API Reference - Input and Output APIs
keywords: Dynamic Web TWAIN, Documentation, API Reference, IO APIs
breadcrumbText: IO
description: Dynamic Web TWAIN SDK Documentation | API Reference | IO APIs Page
---
# {WebTwainObject} IO
The properties and methods on this page live in the namespace {WebTwainObject}. {WebTwainObject} denotes the `WebTwain` instance. Learn about [how to create a web twain object](/_articles/extended-usage/advanced-initialization.md#instantiating-webtwain-without-onwebtwainready).
**Methods**
**Input Methods**
| [`LoadImage()`](#loadimage) | [`LoadImageEx()`](#loadimageex) | [`LoadImageFromBase64Binary()`](#loadimagefrombase64binary) | [`LoadImageFromBinary()`](#loadimagefrombinary) |
| [`LoadDibFromClipboard()`](#loaddibfromclipboard) | [`FTPDownload()`](#ftpdownload) | [`FTPDownloadEx()`](#ftpdownloadex) | [`HTTPDownload()`](#httpdownload) |
| [`HTTPDownloadEx()`](#httpdownloadex) | [`HTTPDownloadThroughPost()`](#httpdownloadthroughpost) | [`loadFromLocalStorage()`](#loadfromlocalstorage) |
**Output Methods**
| [`ConvertToBase64()`](#converttobase64) | [`ConvertToBlob()`](#converttoblob) | [`FTPUpload()`](#ftpupload) |
| [`FTPUploadEx()`](#ftpuploadex) | [`FTPUploadAllAsMultiPageTIFF()`](#ftpuploadallasmultipagetiff) | [`FTPUploadAllAsPDF()`](#ftpuploadallaspdf) |
| [`FTPUploadAsMultiPagePDF()`](#ftpuploadasmultipagepdf) | [`FTPUploadAsMultiPageTIFF()`](#ftpuploadasmultipagetiff) | [`HTTPUpload()`](#httpupload) |
| [`HTTPUploadThroughPutEx()`](#httpuploadthroughputex) | [`HTTPUploadThroughPost()`](#httpuploadthroughpost) | [`HTTPUploadThroughPostEx()`](#httpuploadthroughpostex) |
| [`HTTPUploadAllThroughPostAsMultiPageTIFF()`](#httpuploadallthroughpostasmultipagetiff) | [`HTTPUploadAllThroughPostAsPDF()`](#httpuploadallthroughpostaspdf) | [`HTTPUploadThroughPostAsMultiPagePDF()`](#httpuploadthroughpostasmultipagepdf) |
| [`HTTPUploadThroughPostAsMultiPageTIFF()`](#httpuploadthroughpostasmultipagetiff) | [`OutputSelectedAreaAsync()`](#outputselectedareaasync) | [`SaveAsBMP()`](#saveasbmp) |
| [`SaveAsJPEG()`](#saveasjpeg) | [`SaveAsPDF()`](#saveaspdf) | [`SaveAsPNG()`](#saveaspng) |
| [`SaveAsTIFF()`](#saveastiff) | [`SaveSelectedImagesAsMultiPagePDF()`](#saveselectedimagesasmultipagepdf) | [`SaveSelectedImagesAsMultiPageTIFF()`](#saveselectedimagesasmultipagetiff) |
| [`SaveAllAsMultiPageTIFF()`](#saveallasmultipagetiff) | [`SaveAllAsPDF()`](#saveallaspdf) | [`httpUploadBlob()`](#httpuploadblob) |
| [`saveBlob()`](#saveblob) | [`saveToLocalStorage()`](#savetolocalstorage) |
**Other Methods**
| [`ClearTiffCustomTag()`](#cleartiffcustomtag) | [`SetTiffCustomTag()`](#settiffcustomtag) | [`ClearAllHTTPFormField()`](#clearallhttpformfield) | [`SetHTTPFormField()`](#sethttpformfield) |
| [`SetHTTPHeader()`](#sethttpheader) | [`SetUploadSegment()`](#setuploadsegment) | [`ShowFileDialog()`](#showfiledialog) | [`Print()`](#print) |
| [`PrintEx()`](#printex) | [`createLocalStorage()`](#createlocalstorage) | [`localStorageExist()`](#localstorageexist) | [`removeLocalStorage()`](#removelocalstorage) |
**Properties**
| [`FTPPassword`](#ftppassword) | [`FTPPort`](#ftpport) | [`FTPUserName`](#ftpusername) | [`IfPASVMode`](#ifpasvmode) |
| [`HttpFieldNameOfUploadedImage`](#httpfieldnameofuploadedimage) | [`HTTPPort`](#httpport) | [`IfSSL`](#ifssl) | [`HTTPPostResponseString`](#httppostresponsestring) |
| [`IfShowFileDialog`](#ifshowfiledialog) | [`IfShowCancelDialogWhenImageTransfer`](#ifshowcanceldialogwhenimagetransfer) | [`IfShowProgressBar`](#ifshowprogressbar) | [`JPEGQuality`](#jpegquality) |
| [`IfTiffMultiPage`](#iftiffmultipage) | [`TIFFCompressionType`](#tiffcompressiontype) | [`MaxUploadImageSize`](#maxuploadimagesize) | [`IfSortBySelectionOrder`](#ifsortbyselectionorder) |
**Events**
| [`OnGetFilePath`](#ongetfilepath) | [`OnPostLoad`](#onpostload) | [`OnInternetTransferPercentage`](#oninternettransferpercentage) |
---
## LoadImage()
Load image(s) specified by its absolute path.
**Syntax**
```javascript
LoadImage(
fileName: string
): boolean;
// Call this API asynchronously to avoid blocking the browser's main thread
LoadImage(
fileName: string,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`fileName`: The path of the image to load.
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Example**
```javascript
DWTObject.LoadImage(
"C:\\test\\DWT.jpg",
function () {
console.log("success");
},
function (errorCode, errorString) {
console.log(errorString);
},
);
```
---
## LoadImageEx()
Load image(s) specified by its absolute path.
**Syntax**
```javascript
LoadImageEx(
fileName: string,
type: Dynamsoft.DWT.EnumDWT_ImageType | number
): boolean;
// Call this API asynchronously to avoid blocking the browser's main thread
LoadImageEx(
fileName: string,
type: Dynamsoft.DWT.EnumDWT_ImageType | number,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`fileName`: The path of the image to load.
`type`: The format of the image. Please refer to [`EnumDWT_ImageType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_imagetype).
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Usage Notes**
You can set [`IfShowFileDialog`](/_articles/info/api/WebTwain_IO.md#ifshowfiledialog) before calling this API to enable/disable "Open File" dialog.
**Example**
```javascript
DWTObject.IfShowFileDialog = true; //"Open File" dialog will be opened.
DWTObject.LoadImageEx(
"", //file name can be empty if "Open File" dialog is called.
Dynamsoft.DWT.EnumDWT_ImageType.IT_JPG,
function () {
console.log("success");
},
function (errorCode, errorString) {
console.log(errorString);
},
);
```
```javascript
DWTObject.IfShowFileDialog = false; //Default value is true.
DWTObject.LoadImageEx(
"C:\\test\\DWT.jpg",
Dynamsoft.DWT.EnumDWT_ImageType.IT_JPG,
function () {
console.log("success");
},
function (errorCode, errorString) {
console.log(errorString);
},
);
```
**Remark**
[Load Guide](/_articles/general-usage/scanner-image-acquisition.md#load-files)
---
## LoadImageFromBase64Binary()
Load image(s) from a base64 string.
**Syntax**
```javascript
LoadImageFromBase64Binary(
imageData: string,
imageType: Dynamsoft.DWT.EnumDWT_ImageType
): boolean;
// Call this API asynchronously to avoid blocking the browser's main thread
LoadImageFromBase64Binary(
imageData: string,
imageType: Dynamsoft.DWT.EnumDWT_ImageType,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`imageData`: The image data which is a base64 string without the data URI scheme.
`imageType`: The format of the image. Please refer to [`EnumDWT_ImageType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_imagetype).
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Usage Notes**
You may leverage [`ConvertToBase64()`](/_articles/info/api/WebTwain_IO.md#converttobase64) to get a base64 string.
**Example**
```javascript
DWTObject.ConvertToBase64(
[0, 1, 2],
Dynamsoft.DWT.EnumDWT_ImageType.IT_PDF,
function (result, indices, type) {
DWTObject.LoadImageFromBase64Binary(
result.getData(0, result.getLength()),
Dynamsoft.DWT.EnumDWT_ImageType.IT_PDF,
function () {
console.log("success");
},
function (errorCode, errorString) {
console.log(errorString);
},
);
},
function (errorCode, errorString) {
console.log(errorString);
},
);
```
**Remark**
[Load Guide](/_articles/general-usage/scanner-image-acquisition.md#load-files-in-binary-or-base64-string-format)
---
## LoadImageFromBinary()
Load image(s) from a binary object (Blob or ArrayBuffer).
**Syntax**
```javascript
LoadImageFromBinary(
imageData: Blob | ArrayBuffer,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`imageData`: The image data.
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v16.0+ |
v16.0+ |
v16.0+ |
v16.0+ |
**Usage Notes**
You may leverage [`ConvertToBlob()`](/_articles/info/api/WebTwain_IO.md#converttoblob) to get a Blob object.
**Example**
```javascript
DWTObject.ConvertToBlob(
[0, 1, 2],
Dynamsoft.DWT.EnumDWT_ImageType.IT_PDF,
function (result, indices, type) {
DWTObject.LoadImageFromBinary(
result,
function () {
console.log("success");
},
function (errorCode, errorString) {
console.log(errorString);
},
);
},
function (errorCode, errorString) {
console.log(errorString);
},
);
```
**Remark**
[Load Guide](/_articles/general-usage/scanner-image-acquisition.md#load-files-in-binary-or-base64-string-format)
---
## LoadDibFromClipboard()
Load an image from the system clipboard. The image must be in DIB format.
**Syntax**
```javascript
LoadDibFromClipboard(): boolean;
// Call this API asynchronously to avoid blocking the browser's main thread
LoadDibFromClipboard(
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Usage Notes**
If called without any callback functions, these methods (except for [`LoadImageFromBinary()`](/_articles/info/api/WebTwain_IO.md#loadimagefrombinary) ) become synchronously and return a boolean value to indicate whether it succeeded.
However, calling them asynchronously is recommended.
---
## OnGetFilePath
This event is triggered when [`ShowFileDialog()`](/_articles/info/api/WebTwain_IO.md#showfiledialog) is called or when [`LoadImageEx()`](/_articles/info/api/WebTwain_IO.md#loadimageex) is called with [`IfShowFileDialog`](/_articles/info/api/WebTwain_IO.md#ifshowfiledialog) set to true.
**Syntax**
```javascript
RegisterEvent(
"OnGetFilePath",
function (
isSave: number,
filesCount: number,
index: number,
directory: string,
fileName: string
) {}
);
```
**Parameters**
`isSave`: Whether or not the event is triggered after a save-file dialog was shown. `0` means false, `1` means true.
`filesCount`: How many files were selected.
`index`: The index of the current image.
`directory`: The parent directory of currently selected file(s), "\\\\" is not included. If the method [`ShowFileDialog()`](/_articles/info/api/WebTwain_IO.md#showfiledialog) failed, the initial directory path set in the [`ShowFileDialog()`](/_articles/info/api/WebTwain_IO.md#showfiledialog) method is returned.
`fileName`: The current file name.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Example**
```javascript
DWTObject.RegisterEvent("OnGetFilePath", function (isSave, filesCount, index, directory, filename) {
alert(
"isSave:" +
isSave +
" fileCount: " +
filesCount +
" index: " +
index +
" directory: " +
directory +
"\\" +
filename,
);
});
```
---
## OnPostLoad
This event is triggered when a file is loaded in the following cases:
- A file is dragged and dropped into the viewer
- A file is loaded using [`LoadImageFromBase64Binary()`](/_articles/info/api/WebTwain_IO.md#loadimagefrombase64binary) or [`LoadImageFromBinary()`](/_articles/info/api/WebTwain_IO.md#loadimagefrombinary)
- A local file is loaded using [`LoadImage()`](/_articles/info/api/WebTwain_IO.md#loadimage) or [`LoadImageEx()`](/_articles/info/api/WebTwain_IO.md#loadimageex)
- A remote file is downloaded using network methods like [`HTTPDownload()`](/_articles/info/api/WebTwain_IO.md#httpdownload)
Note: The event fires regardless of the operation's success.
**Syntax**
```javascript
RegisterEvent(
"OnPostLoad",
function (path: string, fileName: string, fileType: string) {}
);
```
**Parameters**
`path`: The path of the source. For example, "C:\\Users\\[username]\\Downloads". It is empty if the file is dragged and dropped.
`fileName`: The name of the loaded file. For example, "image1.jpg".
`fileType`: The file type. Please refer to [`EnumDWT_ImageType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_imagetype).
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Example**
```javascript
DWTObject.RegisterEvent("OnPostLoad", function (path, name, type) {
alert(path + "\\" + name);
});
```
---
## FTPDownload()
Download the specified file via FTP.
**Syntax**
```javascript
FTPDownload(
host: string,
path: string,
successCallback: () => void,
failureCallBack: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`host`: The FTP Host.
`path`: Specify the file to download.
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v4.0+ |
v4.0+ |
v4.0+ |
v4.0+ |
---
## FTPDownloadEx()
Download the specified file via FTP.
**Syntax**
```javascript
FTPDownloadEx(
host: string,
path: string,
type: Dynamsoft.DWT.EnumDWT_ImageType | number,
successCallback: () => void,
failureCallBack: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`host`: The FTP Host.
`path`: Specify the file to download.
`type`: The format of the file. Please refer to [`EnumDWT_ImageType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_imagetype).
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v4.0+ |
v4.0+ |
v4.0+ |
v4.0+ |
**Example**
```javascript
/* The sample file path is:
* "ftp://192.168.8.20/files/sample.pdf"
*/
var onSuccess = function () {
console.log("Downloaded a file successfully!");
};
var onFailure = function (errorCode, errorString) {
console.log(errorString);
};
DWTObject.FTPPort = 21;
DWTObject.FTPUserName = "FTPUser";
DWTObject.FTPPassword = "SomePassword";
DWTObject.FTPDownloadEx(
"192.168.8.20",
"/files/sample.pdf",
Dynamsoft.DWT.EnumDWT_ImageType.IT_PDF,
onSuccess,
onFailure,
);
```
---
## FTPUpload()
Upload the specified image via FTP.
**Syntax**
```javascript
FTPUpload(
host: string,
index: number,
path: string,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`host`: The FTP Host.
`index`: Specify the index of the image in the buffer. The index is 0-based.
`path`: The path to save the file.
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v4.0+ |
v4.0+ |
v4.0+ |
v4.0+ |
**Example**
```javascript
var onSuccess = function () {
console.log("Uploaded a file successfully!");
};
var onFailure = function (errorCode, errorString) {
console.log(errorString);
};
DWTObject.FTPUserName = "test";
DWTObject.FTPPort = 21;
DWTObject.FTPPassword = "test";
DWTObject.FTPUpload(
"192.168.8.222", //The FTP Host
0, // The index of the image
"test.pdf", // The path & name of the file
onSuccess, // Callback in case of success
onFailure, // Callback in case of failure
);
```
---
## FTPUploadEx()
Upload the specified image via FTP.
**Syntax**
```javascript
FTPUploadEx(
host: string,
index: number,
path: string,
type: Dynamsoft.DWT.EnumDWT_ImageType | number,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`host`: The FTP Host.
`index`: Specify the index of the image in the buffer. The index is 0-based.
`path`: The path to save the file.
`type`: The format of the file. Please refer to [`EnumDWT_ImageType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_imagetype).
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.0+ |
v5.0+ |
v5.0+ |
v5.0+ |
---
## FTPUploadAllAsMultiPageTIFF()
Upload all images as a multi-page TIFF via FTP.
**Syntax**
```javascript
FTPUploadAllAsMultiPageTIFF(
host: string,
path: string,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`host`: The FTP Host.
`path`: Specify the path to save the file.
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v4.0+ |
v4.0+ |
v4.0+ |
v4.0+ |
---
## FTPUploadAllAsPDF()
Upload all images as a multi-page PDF via FTP.
**Syntax**
```javascript
FTPUploadAllAsPDF(
host: string,
path: string,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`host`: The FTP Host.
`path`: Specify the path to save the file.
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v4.0+ |
v4.0+ |
v4.0+ |
v4.0+ |
---
## FTPUploadAsMultiPagePDF()
Upload selected images as a multi-page PDF via FTP.
**Syntax**
```javascript
FTPUploadAsMultiPagePDF(
host: string,
path: string,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`host`: The FTP Host.
`path`: Specify the path to save the file.
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v6.0+ |
v6.0+ |
v6.0+ |
v6.0+ |
---
## FTPUploadAsMultiPageTIFF()
Upload selected images as a multi-page TIFF via FTP.
**Syntax**
```javascript
FTPUploadAsMultiPageTIFF(
host: string,
path: string,
type: Dynamsoft.DWT.EnumDWT_ImageType | number,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`host`: The FTP Host.
`path`: Specify the path to save the file.
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v6.0+ |
v6.0+ |
v6.0+ |
v6.0+ |
---
## FTPUserName
The user name to connect to the FTP.
**Syntax**
```javascript
FTPUserName: string;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.2+ |
v5.2+ |
v5.2+ |
v5.2+ |
---
## FTPPassword
The password to connect to the FTP.
**Syntax**
```javascript
FTPPassword: string;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.2+ |
v5.2+ |
v5.2+ |
v5.2+ |
---
## FTPPort
The port to connect to the FTP.
**Syntax**
```javascript
FTPPort: number;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.2+ |
v5.2+ |
v5.2+ |
v5.2+ |
---
## IfPASVMode
Return or set whether to use passive mode when connect to the FTP.
**Syntax**
```javascript
IfPASVMode: boolean;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v6.0+ |
v6.0+ |
v6.0+ |
v6.0+ |
---
## HTTPPassword
Return or set the password used to log into the HTTP server.
**Syntax**
```javascript
HTTPPassword: string;
```
---
## HTTPUserName
Return or set the user name used to log into the HTTP server.
**Syntax**
```javascript
HTTPUserName: string;
```
---
## HTTPDownload()
Download the specified file via a HTTP Get request.
**Syntax**
```javascript
HTTPDownload(
host: string,
path: string,
successCallback: () => void,
failureCallback: (
errorCode: number,
errorString: string) => void
): void;
```
**Parameters**
`host`: The HTTP Host.
`path`: Specify the path of the file to download.
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v4.0+ |
v4.0+ |
v4.0+ |
v4.0+ |
**Example**
```javascript
/* The sample file path is:
* "http://localhost:300/files/sample.tif"
*/
var onSuccess = function () {
console.log("Downloaded a file successfully!");
};
var onFailure = function (errorCode, errorString) {
console.log(errorString);
};
DWTObject.HTTPPort = 300;
DWTObject.HTTPDownload("localhost", "/files/sample.tif", onSuccess, onFailure);
```
**Remark**
[Download Guide](/_articles/general-usage/scanner-image-acquisition.md#download)
---
## HTTPDownloadEx()
Download the specified file via a HTTP Get request.
**Syntax**
```javascript
HTTPDownloadEx(
host: string,
path: string,
type: Dynamsoft.DWT.EnumDWT_ImageType | number,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`host`: The HTTP Host.
`path`: Specify the path of the file to download.
`type`: The format of the file. Please refer to [`EnumDWT_ImageType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_imagetype).
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.0+ |
v5.0+ |
v5.0+ |
v5.0+ |
**Usage Notes**
If you want to use this method to upload / download files through HTTPS, please don't forget to set [`IfSSL`](/_articles/info/api/WebTwain_IO.md#ifssl) to true and set the correct [`HTTPPort`](/_articles/info/api/WebTwain_IO.md#httpport).
**Example**
In this example, the URL points to a server-side script.
The server-side script can be written in any language and in any logic as long as it returns a file. Please refer to [Download-Server-Script](/_articles/general-usage/server-side-scripting.md#download-a-file).
```javascript
/* The sample file path is:
* "http://localhost:300/files/sample.tif"
*/
var onSuccess = function () {
console.log("Downloaded a file successfully!");
};
var onFailure = function (errorCode, errorString) {
console.log(errorString);
};
DWTObject.HTTPPort = 300;
DWTObject.HTTPDownloadEx(
"localhost",
"/getFile.aspx",
Dynamsoft.DWT.EnumDWT_ImageType.IT_TIF,
onSuccess,
onFailure,
);
```
**Remark**
[Download Guide](/_articles/general-usage/scanner-image-acquisition.md#download)
---
## HTTPDownloadThroughPost()
Download the specified file via a HTTP Post request.
**Syntax**
```javascript
HTTPDownloadThroughPost(
host: string,
path: string,
type: Dynamsoft.DWT.EnumDWT_ImageType | number,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string, response?: any) => void,
): void;
```
**Parameters**
`host`: The HTTP Host.
`path`: Specify the path of the file to download.
`type`: The format of the file. Please refer to [`EnumDWT_ImageType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_imagetype).
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
- `response`: The response from your server.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.0+ |
v5.0+ |
v5.0+ |
v5.0+ |
---
## HTTPUpload()
Upload the specified image(s) via a HTTP Post.
**Syntax**
```javascript
HTTPUpload(
URL: string,
indices: number[],
type: Dynamsoft.DWT.EnumDWT_ImageType | number,
dataFormat: Dynamsoft.DWT.EnumDWT_UploadDataFormat | number,
fileName: string,
onEmptyResponse: () => void,
onServerReturnedSomething: (errorCode: number, errorString: string, response: string) => void
): void;
```
```javascript
HTTPUpload(
URL: string,
indices: number[],
type: Dynamsoft.DWT.EnumDWT_ImageType | number,
dataFormat: Dynamsoft.DWT.EnumDWT_UploadDataFormat | number,
onEmptyResponse: () => void,
onServerReturnedSomething: (errorCode: number, errorString: string, response: string) => void
): void;
```
**Parameters**
`URL`: The server-side script to receive the post. For the sample code of Server Script, please refer to [Upload-Server-Script](/_articles/general-usage/server-side-scripting.md#how-to-process-uploaded-files).
`indices`: Specify the image(s).
`type`: The format of the file. Please refer to [`EnumDWT_ImageType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_imagetype).
`dataFormat`: Whether to upload the file as binary or a base64 string. Please refer to [`EnumDWT_UploadDataFormat`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_uploaddataformat).
`fileName`: The file name. Additionally, if `fileName` specifies the extension of the file,
- If the extension is not the same as the format of the file which is specified by `type`, the extra extension will be added to the file name.
- e.g. if `fileName` is set to `"test.jpg"`, and `type` is `Dynamsoft.DWT.EnumDWT_ImageType.IT_PDF`, then the final file name would be `test.jpg.pdf` and the file format would be PDF.
- If the extension is the same as the format of the file which is specified by `type`, the file name equals to the string which is specified by `fileName`.
- e.g. if `fileName` is set to `"test.pdf"`, and `type` is `Dynamsoft.DWT.EnumDWT_ImageType.IT_PDF`, then the final file name would be `test.pdf` and the file format would be PDF.
`onEmptyResponse`: A callback function that is executed if the response is empty.
`onServerReturnedSomething`: A callback function that is executed if the response is not empty. The accepted response type is `string`.
- `errorCode` The error code.
- `errorString` The error string.
- `response` The response string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v12.0+ |
v12.0+ |
v12.0+ |
v12.0+ |
**Usage Notes**
If you want to use this method to upload / download files through HTTPS, please don't forget to set [`IfSSL`](/_articles/info/api/WebTwain_IO.md#ifssl) to true and set the correct [`HTTPPort`](/_articles/info/api/WebTwain_IO.md#httpport).
**Example**
```javascript
DWTObject.HTTPUpload(
"https://www.dynamsoft.com/SaveToFile.aspx",
[0, 1],
Dynamsoft.DWT.EnumDWT_ImageType.IT_PDF,
Dynamsoft.DWT.EnumDWT_UploadDataFormat.Binary,
"test.pdf",
OnEmptyResponse,
OnServerReturnedSomething,
);
function OnEmptyResponse() {
console.log("Success");
}
function OnServerReturnedSomething(errCode, errString, responseStr) {
console.log(errString);
}
```
**Remark**
[Upload Guide](/_articles/general-usage/image-export/index.md#upload)
---
## HTTPUploadThroughPutEx()
Upload the specified image via a HTTP Put request.
**Syntax**
```javascript
HTTPUploadThroughPutEx(
host: string,
index: number,
path: string,
type: Dynamsoft.DWT.EnumDWT_ImageType | number,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`host`: The HTTP Host.
`index`: Specify the image.
`path`: Specify the path to put the file.
`type`: The format of the file. Please refer to [`EnumDWT_ImageType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_imagetype).
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.0+ |
v5.0+ |
v5.0+ |
v5.0+ |
---
## HTTPUploadThroughPost()
Upload the specified image via a HTTP Post request.
**Syntax**
```javascript
HTTPUploadThroughPost(
host: string,
index: number,
target: string,
fileName: string,
onEmptyResponse: () => void,
onServerReturnedSomething: (errorCode: number, errorString: string, response: string) => void
): void;
```
**Parameters**
`host`: The HTTP Host.
`index`: Specify the image.
`target`: The target where the request is sent. For the sample code of Server Script, please refer to [Upload-Server-Script](/_articles/general-usage/server-side-scripting.md#how-to-process-uploaded-files).
`fileName`: The file name.
`onEmptyResponse`: A callback function that is executed if the response is empty.
`onServerReturnedSomething`: A callback function that is executed if the response is not empty.
- `errorCode`: The error code.
- `errorString`: The error string.
- `response`: The response string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v4.0+ |
v4.0+ |
v4.0+ |
v4.0+ |
**Usage Notes**
If you want to use this method to upload / download files through HTTPS, please don't forget to set [`IfSSL`](/_articles/info/api/WebTwain_IO.md#ifssl) to true and set the correct [`HTTPPort`](/_articles/info/api/WebTwain_IO.md#httpport).
**Example**
```javascript
var strHTTPServer = location.hostname; //The name of the HTTP server. For example: "www.dynamsoft.com";
var CurrentPathName = unescape(location.pathname);
var CurrentPath = CurrentPathName.substring(0, CurrentPathName.lastIndexOf("/") + 1);
var strActionPage = CurrentPath + "SaveToFile.aspx";
DWTObject.IfSSL = false; // Set whether SSL is used
DWTObject.HTTPPort = location.port == "" ? 100 : location.port;
var Digital = new Date();
var uploadfilename = Digital.getMilliseconds();
DWTObject.HTTPUploadThroughPost(
strHTTPServer,
DWTObject.CurrentImageIndexInBuffer,
strActionPage,
uploadfilename + ".jpg",
function () {
console.log("Empty response");
},
function (errorCode, errorString, response) {
console.log(response);
},
);
```
---
## HTTPUploadThroughPostEx()
Upload the specified image in a specific image format via a HTTP Post request.
**Syntax**
```javascript
HTTPUploadThroughPostEx(
host: string,
index: number,
target: string,
fileName: string,
type: Dynamsoft.DWT.EnumDWT_ImageType | number,
onEmptyResponse: () => void,
onServerReturnedSomething: (
errorCode: number,
errorString: string,
response: string) => void
): void;
```
**Parameters**
`host`: The HTTP Host.
`index`: Specify the image.
`target`: The target where the request is sent. For the sample code of Server Script, please refer to [Upload-Server-Script](/_articles/general-usage/server-side-scripting.md#how-to-process-uploaded-files).
`fileName`: The file name.
`type`: The format of the file. Please refer to [`EnumDWT_ImageType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_imagetype).
`onEmptyResponse`: A callback function that is executed if the response is empty.
`onServerReturnedSomething`: A callback function that is executed if the response is not empty.
- `errorCode`: The error code.
- `errorString`: The error string.
- `response`: The response string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.0+ |
v5.0+ |
v5.0+ |
v5.0+ |
**Usage Notes**
If you want to use this method to upload / download files through HTTPS, please don't forget to set [`IfSSL`](/_articles/info/api/WebTwain_IO.md#ifssl) to true and set the correct [`HTTPPort`](/_articles/info/api/WebTwain_IO.md#httpport).
---
## HTTPUploadAllThroughPostAsMultiPageTIFF()
Upload all images in the buffer as a TIFF file via a HTTP Post request.
**Syntax**
```javascript
HTTPUploadAllThroughPostAsMultiPageTIFF(
host: string,
target: string,
fileName: string,
onEmptyResponse: () => void,
onServerReturnedSomething: (
errorCode: number,
errorString: string,
response: string) => void
): void;
```
**Parameters**
`host`: The HTTP Host.
`target`: The target where the request is sent. For the sample code of Server Script, please refer to [Upload-Server-Script](/_articles/general-usage/server-side-scripting.md#how-to-process-uploaded-files).
`fileName`: The file name.
`onEmptyResponse`: A callback function that is executed if the response is empty.
`onServerReturnedSomething`: A callback function that is executed if the response is not empty.
- `errorCode`: The error code.
- `errorString`: The error string.
- `response`: The response string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v4.0+ |
v4.0+ |
v4.0+ |
v4.0+ |
**Usage Notes**
If you want to use this method to upload / download files through HTTPS, please don't forget to set [`IfSSL`](/_articles/info/api/WebTwain_IO.md#ifssl) to true and set the correct [`HTTPPort`](/_articles/info/api/WebTwain_IO.md#httpport).
---
## HTTPUploadAllThroughPostAsPDF()
Upload all images in the buffer as a PDF file via a HTTP Post request.
**Syntax**
```javascript
HTTPUploadAllThroughPostAsPDF(
host: string,
target: string,
fileName: string,
onEmptyResponse: () => void,
onServerReturnedSomething: (
errorCode: number,
errorString: string,
response: string) => void
): void;
```
**Parameters**
`host`: The HTTP Host.
`target`: The target where the request is sent. For the sample code of Server Script, please refer to [Upload-Server-Script](/_articles/general-usage/server-side-scripting.md#how-to-process-uploaded-files).
`fileName`: The file name.
`onEmptyResponse`: A callback function that is executed if the response is empty.
`onServerReturnedSomething`: A callback function that is executed if the response is not empty.
- `errorCode`: The error code.
- `errorString`: The error string.
- `response`: The response string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.0+ |
v5.0+ |
v5.0+ |
v5.0+ |
**Usage Notes**
If you want to use this method to upload / download files through HTTPS, please don't forget to set [`IfSSL`](/_articles/info/api/WebTwain_IO.md#ifssl) to true and set the correct [`HTTPPort`](/_articles/info/api/WebTwain_IO.md#httpport).
---
## HTTPUploadThroughPostAsMultiPagePDF()
Upload all selected images in the buffer as a PDF file via a HTTP Post request.
**Syntax**
```javascript
HTTPUploadThroughPostAsMultiPagePDF(
host: string,
target: string,
fileName: string,
onEmptyResponse: () => void,
onServerReturnedSomething: (
errorCode: number,
errorString: string,
response: string) => void
): void;
```
**Parameters**
`host`: The HTTP Host.
`target`: The target where the request is sent. For the sample code of Server Script, please refer to [Upload-Server-Script](/_articles/general-usage/server-side-scripting.md#how-to-process-uploaded-files).
`fileName`: The file name.
`onEmptyResponse`: A callback function that is executed if the response is empty.
`onServerReturnedSomething`: A callback function that is executed if the response is not empty.
- `errorCode`: The error code.
- `errorString`: The error string.
- `response`: The response string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v6.0+ |
v6.0+ |
v6.0+ |
v6.0+ |
**Usage Notes**
If you want to use this method to upload / download files through HTTPS, please don't forget to set [`IfSSL`](/_articles/info/api/WebTwain_IO.md#ifssl) to true and set the correct [`HTTPPort`](/_articles/info/api/WebTwain_IO.md#httpport).
---
## HTTPUploadThroughPostAsMultiPageTIFF()
Upload all selected images in the buffer as a TIFF file via a HTTP Post request.
**Syntax**
```javascript
HTTPUploadThroughPostAsMultiPageTIFF(
host: string,
target: string,
fileName: string,
onEmptyResponse: () => void,
onServerReturnedSomething: (
errorCode: number,
errorString: string,
response: string) => void
): void;
```
**Parameters**
`host`: The HTTP Host.
`target`: The target where the request is sent. For the sample code of Server Script, please refer to [Upload-Server-Script](/_articles/general-usage/server-side-scripting.md#how-to-process-uploaded-files).
`fileName`: The file name.
`onEmptyResponse`: A callback function that is executed if the response is empty.
`onServerReturnedSomething`: A callback function that is executed if the response is not empty.
- `errorCode`: The error code.
- `errorString`: The error string.
- `response`: The response string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v6.0+ |
v6.0+ |
v6.0+ |
v6.0+ |
**Usage Notes**
If you want to use this method to upload / download files through HTTPS, please don't forget to set [`IfSSL`](/_articles/info/api/WebTwain_IO.md#ifssl) to true and set the correct [`HTTPPort`](/_articles/info/api/WebTwain_IO.md#httpport).
---
## httpUploadBlob()
Upload images which are in blob format.
**Syntax**
```typescript
httpUploadBlob(
URL: string,
blobData: Blob,
fileName: string,
optionConfig?:{
responseType?: Dynamsoft.DWT.EnumDWT_ResponseType,
formFields?:{
name: string,
value: Blob | string,
fileName?: string
}[],
headers?:{
name: string,
value: string
}[]
}
): Promise;
```
**Parameters**
`URL`: The server-side script to receive the post. For the sample code of Server Script, please refer to [Upload-Server-Script](/_articles/general-usage/server-side-scripting.md#how-to-process-uploaded-files).
`blobData`: The blob data of the image to upload.
`fileName`: The file name. Additionally, if `fileName` specifies the extension of the file,
- If the extension is not the same as the blob type, the extra extension will be added to the file name.
- e.g. if `fileName` is set to `"test.jpg"`, and blob type is `application/pdf`, then the final file name would be `test.jpg.pdf` and the file format would be PDF.
- If the extension is the same as the blob type, the file name equals to the string which is specified by `fileName`.
- e.g. if `fileName` is set to `"test.pdf"`, and blob type is `application/pdf`, then the final file name would be `test.pdf` and the file format would be PDF.
`optionConfig`:
- `responseType`: The response type. Please refer to [`EnumDWT_ResponseType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_responsetype).
- `formFields`: The fields to the HTTP Post Form.
- `name`: The name of field.
- `value`: The value of field.
- `fileName`: Specify the file name, if `value` is `Blob`.
- `headers`: The headers to the HTTP Post Form.
- `name`: The name of header.
- `value`: The value of header.
**Return Values**
A Promise object of the response that is resolved based on the `responseType` parameter.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v18.5+ |
v18.5+ |
v18.5+ |
v18.5+ |
**Usage notes**
Supported blob type: `image/jpeg`, `image/png`, `image/bmp`, `image/tiff`, `application/pdf`, `image/jpg`, `image/tif`.
---
## HttpFieldNameOfUploadedImage
Return or set the field name for the uploaded file. By default, it's "RemoteFile".
**Syntax**
```javascript
HttpFieldNameOfUploadedImage: string;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v6.0+ |
v6.0+ |
v6.0+ |
v6.0+ |
---
## HTTPPort
Return or set the HTTP Port. The default value is `80`.
**Syntax**
```javascript
HTTPPort: number;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v4.2.1+ |
v4.2.1+ |
v4.2.1+ |
v4.2.1+ |
---
## IfSSL
Return or set whether to use SSL in HTTP requests. The default value is `false`.
**Syntax**
```javascript
IfSSL: boolean;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.2+ |
v5.2+ |
v5.2+ |
v5.2+ |
---
## HTTPPostResponseString
Return the response string of the latest HTTP Post request.
**Syntax**
```javascript
readonly HTTPPostResponseString: string;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v3.0.3+ |
v3.0.3+ |
v3.0.3+ |
v3.0.3+ |
---
## MaxUploadImageSize
Return or set the maximum allowed size of a file to upload (in bytes). The default value is `-1` which indicates there is no limit over the upload size. The value should be equal or smaller than `2147483647` which essentially means `2 GB`.
**Syntax**
```javascript
MaxUploadImageSize: number;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.2+ |
v5.2+ |
v5.2+ |
v5.2+ |
---
## OnInternetTransferPercentage
This event is triggered multiple times during a HTTP upload or download request.
**Syntax**
```javascript
RegisterEvent("OnInternetTransferPercentage", function (percentage: number) {});
```
**Parameters**
`percentage`: Return the progress by percentage.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.0+ |
v5.0+ |
v5.0+ |
v5.0+ |
---
## ConvertToBase64()
Convert the specified images to a base64 string.
**Syntax**
```javascript
ConvertToBase64(
indices: number[],
type: Dynamsoft.DWT.EnumDWT_ImageType | number,
successCallback: (result: Base64Result, indices: number[], type: number) => void,
failureCallBack: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`indices`: Specify one or multiple images.
`type`: The file type. Please refer to [`EnumDWT_ImageType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_imagetype).
`successCallback`: A callback function that is executed if the request succeeds.
- `result`: The resulting base64 string. Please refer to [`Base64Result`](/_articles/info/api/interfaces.md#base64result).
- `indices`: The indices of the converted images.
- `type`: The file type.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v12.0+ |
v12.0+ |
v12.0+ |
v12.1+ |
**Usage Notes**
`getData()` returns the pure base64 string without the data URI scheme. For example, "/9j/4AAQSkZJRgABA...". If you want to use the string, you probably need to add the scheme. For example, "data:image/png; base64, /9j/4AAQSkZJRgABA...".
**Example**
Convert the first three images in the buffer to `base64`, and print to the browser console.
```javascript
DWTObject.ConvertToBase64(
[0, 1, 2],
Dynamsoft.DWT.EnumDWT_ImageType.IT_PDF,
function (result, indices, type) {
console.log(result.getData(0, result.getLength()));
},
function (errorCode, errorString) {
console.log(errorString);
},
);
```
Convert all the images in the buffer to a `base64` PDF, and print the `base64` string to the browser console.
```javascript
// Index array of all images in buffer in ascending order
bufferIndices = Array.from({ length: DWTObject.HowManyImagesInBuffer },
(value, index) => index);
DWTObject.ConvertToBase64(
bufferIndices,
Dynamsoft.DWT.EnumDWT_ImageType.IT_PDF, // Encode image as PDF
(base64Result, indices) => {
console.log(base64Result.getData(0, base64Result.getLength())));
},
(errorCode, errorString) => {
console.log(errorString);
})
```
---
## ConvertToBlob()
Convert the specified images to a blob.
**Syntax**
```javascript
ConvertToBlob(
indices: number[],
type: Dynamsoft.DWT.EnumDWT_ImageType | number,
successCallback: (result: Blob, indices: number[], type: number) => void,
failureCallBack: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`indices`: Specify one or multiple images.
`type`: The file type. Please refer to [`EnumDWT_ImageType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_imagetype).
`successCallback`: A callback function that is executed if the request succeeds.
- `result`: The resulting blob.
- `indices`: The indices of the converted images.
- `type`: The file type.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v13.0+ |
v13.0+ |
v13.0+ |
v13.0+ |
**Example**
```javascript
DWTObject.ConvertToBlob(
[0, 1, 2],
Dynamsoft.DWT.EnumDWT_ImageType.IT_PDF,
function (result, indices, type) {
console.log(result.size);
},
function (errorCode, errorString) {
console.log(errorString);
},
);
```
---
## OutputSelectedAreaAsync()
Copy selected area to Blob or base64.
**Syntax**
```typescript
OutputSelectedAreaAsync(
index: number,
area: {
x: number,
y: number,
width: number,
height: number
},
type: Dynamsoft.DWT.EnumDWT_ImageType | number,
imageFormatType: Dynamsoft.DWT.EnumDWT_ImageFormatType | number
): Promise < Blob | string > ;
```
**Parameters**
`index`: Image to be copied from.
`area`: Area of image to be copied. X,Y is top left corner origin, width and height is size of area to be copied
`type`: The target image type of the blob/base64 (See [`Dynamsoft.DWT.EnumDWT_ImageType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_imagetype) for allowable types).
`imageFormatType`: Specify if the return should be Blob or base64 string ([`Dynamsoft.DWT.EnumDWT_ImageFormatType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_imageformattype) for values)
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v18.4+ |
v18.4+ |
v18.4+ |
v18.4+ |
**Example**
Output the square portion of page index 0 in the buffer with its top left corner at pixel coordinates (50, 50), with height and width 100. Pass it to the console as a `base64` string, and also load it back into the WebTwain buffer as a separate page.
```js
DWTObject.OutputSelectedAreaAsync(
0,
{ x: 50, y: 50, width: 100, height: 100 },
Dynamsoft.DWT.EnumDWT_ImageType.IT_JPG,
Dynamsoft.DWT.EnumDWT_ImageFormatType.Base64,
).then((base64) => {
console.log(base64);
DWTObject.LoadImageFromBase64Binary(base64, Dynamsoft.DWT.EnumDWT_ImageType.IT_JPG);
});
```
---
## SaveAsBMP()
Save the specified image as a BMP file.
**Syntax**
```javascript
SaveAsBMP(
fileName: string,
index: number
): boolean;
// Call this API asynchronously to avoid blocking the browser's main thread
SaveAsBMP(
fileName: string,
index: number,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`fileName`: The name to save to (or specify the absolute path).
`index`: The index which specifies the image to save.
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v11.0+ |
v11.0+ |
v12.1+ |
**Usage Notes**
If you would like to save images by showing the 'Save File' dialog box, you can set [`IfShowFileDialog`](/_articles/info/api/WebTwain_IO.md#ifshowfiledialog) to `true`.
---
## SaveAsJPEG()
Save the specified image as a JPEG file.
**Syntax**
```javascript
SaveAsJPEG(
fileName: string,
index: number
): boolean;
// Call this API asynchronously to avoid blocking the browser's main thread
SaveAsJPEG(
fileName: string,
index: number,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`fileName`: The name to save to (or specify the absolute path).
`index`: The index which specifies the image to save.
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Usage notes**
If you would like to save images by showing the 'Save File' dialog box, you can set [`IfShowFileDialog`](/_articles/info/api/WebTwain_IO.md#ifshowfiledialog) to `true`.
---
## SaveAsPDF()
Save the specified image as a PDF file.
**Syntax**
```javascript
SaveAsPDF(
fileName: string,
index: number
): boolean;
// Call this API asynchronously to avoid blocking the browser's main thread
SaveAsPDF(
fileName: string,
index: number,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`fileName`: The name to save to (or specify the absolute path).
`index`: The index which specifies the image to save.
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Usage notes**
Learn about [how to config PDF save settings](/_articles/info/api/Addon_PDF.md#writesetup).
If you would like to save images by showing the 'Save File' dialog box, you can set [`IfShowFileDialog`](/_articles/info/api/WebTwain_IO.md#ifshowfiledialog) to `true`.
---
## SaveAsPNG()
Save the specified image as a PNG file.
**Syntax**
```javascript
SaveAsPNG(
fileName: string,
index: number
): boolean;
// Call this API asynchronously to avoid blocking the browser's main thread
SaveAsPNG(
fileName: string,
index: number,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`fileName`: The name to save to (or specify the absolute path).
`index`: The index which specifies the image to save.
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Usage notes**
If you would like to save images by showing the 'Save File' dialog box, you can set [`IfShowFileDialog`](/_articles/info/api/WebTwain_IO.md#ifshowfiledialog) to true.
---
## SaveAsTIFF()
Save the specified image as a TIFF file.
**Syntax**
```javascript
SaveAsTIFF(
fileName: string,
index: number
): boolean;
// Call this API asynchronously to avoid blocking the browser's main thread
SaveAsTIFF(
fileName: string,
index: number,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Parameters**
`fileName`: The name to save to (or specify the absolute path).
`index`: The index which specifies the image to save.
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Usage notes**
If you would like to save images by showing the 'Save File' dialog box, you can set [`IfShowFileDialog`](/_articles/info/api/WebTwain_IO.md#ifshowfiledialog) to true.
---
## SaveAllAsMultiPageTIFF()
Saves all the images in buffer as a multi-page TIFF file.
**Syntax**
```javascript
SaveAllAsMultiPageTIFF(
fileName: string
): boolean;
// Call this API asynchronously to avoid blocking the browser's main thread
SaveAllAsMultiPageTIFF(
fileName: string,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`fileName`: The name to save to (or specify the absolute path).
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode` The error code.
- `errorString` The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Usage notes**
{% comment %}If you are using WASM mode on the desktop, the image will always be saved to the Downloads folder even if you specify an absolute path.{% endcomment %}
If you would like to save images by showing the 'Save File' dialog box, you can set [`IfShowFileDialog`](/_articles/info/api/WebTwain_IO.md#ifshowfiledialog) to true.
---
## SaveAllAsPDF()
Saves all the images in buffer as a multi-page PDF file.
**Syntax**
```javascript
SaveAllAsPDF(
fileName: string
): boolean;
// Call this API asynchronously to avoid blocking the browser's main thread
SaveAllAsPDF(
fileName: string,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`fileName`: The name to save to (or specify the absolute path).
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Usage notes**
Learn about [how to config PDF save settings](/_articles/info/api/Addon_PDF.md#writesetup).
If you would like to save images by showing the 'Save File' dialog box, you can set [`IfShowFileDialog`](/_articles/info/api/WebTwain_IO.md#ifshowfiledialog) to true.
---
## SaveSelectedImagesAsMultiPagePDF()
Saves all selected images in buffer as a multi-page PDF file.
**Syntax**
```javascript
SaveSelectedImagesAsMultiPagePDF(
fileName: string
): boolean;
// Call this API asynchronously to avoid blocking the browser's main thread
SaveSelectedImagesAsMultiPagePDF(
fileName: string,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`fileName`: The name to save to (or specify the absolute path).
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Usage notes**
Learn about [how to config PDF save settings](/_articles/info/api/Addon_PDF.md#write-setup).
If you would like to save images by showing the 'Save File' dialog box, you can set [`IfShowFileDialog`](/_articles/info/api/WebTwain_IO.md#ifshowfiledialog) to `true`.
---
## SaveSelectedImagesAsMultiPageTIFF()
Saves all selected images in buffer as a multi-page TIFF file.
**Syntax**
```javascript
SaveSelectedImagesAsMultiPageTIFF(
fileName: string
): boolean;
// Call this API asynchronously to avoid blocking the browser's main thread
SaveSelectedImagesAsMultiPageTIFF(
fileName: string,
successCallback: () => void,
failureCallback: (errorCode: number, errorString: string) => void
): void;
```
**Parameters**
`fileName`: The name to save to (or specify the absolute path).
`successCallback`: A callback function that is executed if the request succeeds.
`failureCallback`: A callback function that is executed if the request fails.
- `errorCode`: The error code.
- `errorString`: The error string.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Usage notes**
If called without any callback functions, these methods become synchronously and return a boolean value to indicate whether it succeeded. However, calling them asynchronously is recommended.
If you would like to save images by showing the 'Save File' dialog box, you can set [`IfShowFileDialog`](/_articles/info/api/WebTwain_IO.md#ifshowfiledialog) to `true`.
---
## saveBlob()
Save image which are in blob format.
**Syntax**
```typescript
saveBlob(
fileName: string,
blobData: Blob,
): Promise;
```
**Parameters**
`fileName`: The file name. Additionally, if `fileName` specifies the extension of the file,
- If the extension is not the same as the blob type, the extra extension will be added to the file name.
- e.g. if `fileName` is set to `"test.jpg"`, and blob type is `application/pdf`, then the final file name would be `test.jpg.pdf` and the file format would be PDF.
- If the extension is the same as the blob type, the file name equals to the string which is specified by `fileName`.
- e.g. if `fileName` is set to `"test.pdf"`, and blob type is `application/pdf`, then the final file name would be `test.pdf` and the file format would be PDF.
`blobData`: The blob data of the image to save.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v18.5+ |
v18.5+ |
v18.5+ |
v18.5+ |
**Usage notes**
Supported blob type: `image/jpeg`, `image/png`, `image/bmp`, `image/tiff`, `application/pdf`, `image/jpg`, `image/tif`.
---
## ClearTiffCustomTag()
Clear the content of all custom tiff tags.
**Syntax**
```javascript
ClearTiffCustomTag(): boolean;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
---
## SetTiffCustomTag()
Sets a custom tiff tag (up to 32 tags). The string to be set in a tag can be base64 encoded.
**Syntax**
```javascript
SetTiffCustomTag(
id: number,
content: string,
useBase64Encoding: boolean
): boolean;
```
**Parameters**
`id`: The id of the custom tag.
`content`: The content of the tag.
`useBase64Encoding`: Whether the content is encoded.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Usage notes**
The method `SetTiffCustomTag()` sets one or up to 32 tags to be added to a TIFF file when generating it. The content of the tags can be plain text or a base64-encoded string. If it's encoded, it'll be decoded when generating the TIFF file.
To make sure you don't included unwanted tags, call [`ClearTiffCustomTag()`](/_articles/info/api/WebTwain_IO.md#cleartiffcustomtag) to clear old tags before setting up new ones.
**Example**
```javascript
DWTObject.ClearTiffCustomTag();
DWTObject.SetTiffCustomTag(700, "Created By DWT", false);
DWTObject.SaveAsTIFF("C:\\DWT.tiff", 0);
```
---
## ClearAllHTTPFormField()
Clear all the custom fields from the HTTP Post Form.
**Syntax**
```javascript
ClearAllHTTPFormField(): boolean;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.0+ |
v5.0+ |
v5.0+ |
v5.0+ |
---
## SetHTTPFormField()
Add a custom field to the HTTP Post Form. Or add a binary file to the HTTP Post Form.
**Syntax**
```javascript
SetHTTPFormField(
name: string,
value: string
): boolean;
```
```javascript
SetHTTPFormField(
name: string,
content: Blob,
fileName?: string
): boolean;
```
**Parameters**
`name`: The name of the field.
`value`: The value of the field.
`content`: The content of the file.
`fileName`: The name of the file.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.0+ |
v5.0+ |
v5.0+ |
v5.0+ |
---
## SetHTTPHeader()
Add a custom header to the HTTP Post Form.
**Syntax**
```javascript
SetHTTPHeader(
name: string,
value: string
): boolean;
```
**Parameters**
`name`: The name of the header.
`value`: The value of the header.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v12.0+ |
v12.0+ |
v12.0+ |
v12.0+ |
---
## SetUploadSegment()
Set the segmentation threshold and segment size.
**Syntax**
```javascript
SetUploadSegment(
threshold: number,
size: number
): boolean;
```
**Parameters**
`threshold`: Specify the threshold (in MB).
`size`: Specify the segment size (in KB).
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v12.1+ |
v12.1+ |
v12.1+ |
v12.1+ |
---
## IfShowFileDialog
Return or set whether to show open/save file dialog when saving images in the buffer or loading images from a local directory.
**Syntax**
```javascript
IfShowFileDialog: boolean;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v11.0+ |
v11.0+ |
v12.1+ |
---
## IfShowCancelDialogWhenImageTransfer
Return or set whether to show the progress of an operation with a button to cancel it.
**Syntax**
```javascript
IfShowCancelDialogWhenImageTransfer: boolean;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v5.2+ |
v5.2+ |
v5.2+ |
v5.2+ |
**Usage Notes**
This API is only valid if [`IfShowProgressBar`](/_articles/info/api/WebTwain_IO.md#ifshowprogressbar) is set to `true`.
---
## IfShowProgressBar
Return or set whether the progress bar will be displayed during any encoding, decoding, or transfer activities.
**Syntax**
```javascript
IfShowProgressBar: boolean;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
---
## ShowFileDialog()
Show the system's save-file dialog or open-file dialog.
**Syntax**
```javascript
ShowFileDialog(
isSave: boolean,
filter: string,
filterIndex: number,
defaultExtension: string,
initialDirectory: string,
allowMultiSelect: boolean,
showOverwritePrompt: boolean,
flag: number
): boolean;
```
**Parameters**
`isSave`: Whether to show a save-file dialog or an open-file dialog.
`filter`: The filter pattern like `JPG` or `*.jpg`. See usage notes below for details.
`filterIndex`: The default file type `filter` selected in the open-file dialog. The filters are 1-indexed. Default value: 1.
`defaultExtension`: Extension to be appended to the file name. Only valid in a save-file dialog.
`initialDirectory`: The initial directory that the dialog opens.
`allowMultiSelect`: Whether or not multiple files can be selected at the same time. Only valid in an open-file dialog.
`showOverwritePrompt`: Whether to display a prompt if saving a file which would overwrite an existing file (only valid for Windows).
`flag`: If set to 0, `allowMultiSelect` and `showOverwritePrompt` take effect. Otherwise, ignore those two parameters.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v10.0+ |
v11.0+ |
v12.1+ |
**Usage notes**
The `filter` is a concatenation of **pattern strings** of valid file extensions. Each pattern string has a **text label**. The text label precedes the pattern string and is separated by a pipe `|`. The pattern string is a combination of semicolon-separated valid file extensions with asterisks.
For example, the following is a single entry that allows JPG, PNG, and TIF: `JPG, PNG and TIF|*.jpg;*png;*.tif`. You can concatenate multiple combinations separated by pipes `|`, e.g. `BMP|*.bmp|TIF|*.tif|JPG|*.jpg|PNG|*.png|PDF|*.pdf` creates one entry for each of the five file types instead of combining multiple file types into one entry.
The open-file dialog display the combinations in order in the file type drop-down. You can use the `filterIndex` argument to set the default combination to use (1-indexed). On macOS, the string is different, e.g. `JPG, PNG , TIF`. To show all files, use `All Files | *.*`. Do not include spaces in the pattern string.
This method triggers the [`OnGetFilePath`](/_articles/info/api/WebTwain_IO.md#ongetfilepath) event even when it fails. If multiple files are selected, the event triggers multiple times.
**Example**
```javascript
DWTObject.RegisterEvent("OnGetFilePath", function (isSave, filesCount, index, directory, fileName) {
alert(" directory: " + directory + "\\" + fileName);
});
//On macOS
DWTObject.ShowFileDialog(
false,
"TIF,TIFF,JPG,JPEG,PNG,PDF",
1,
"",
"",
true,
false,
0,
);
//On Windows
DWTObject.ShowFileDialog(
false,
"BMP,TIF,JPG,PNG,PDF|*.bmp;*.tif;*.png;*.jpg;*.pdf;*.tiff;*.jpeg",
1,
"",
"",
true,
false,
0,
);
```
---
## Print()
> [!NOTE]
> This API has been deprecated as of release 19.3. Please use the [`PrintEX()`](#printex) function.
Export all image data in the buffer to a new browser window and use the browser's built-in print feature to print the image(s).
**Syntax**
```javascript
Print(useOSPrintWindow?: boolean): boolean;
```
**Parameters**
`useOSPrintWindow`: Whether to use the print feature of the operating system instead.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v11.0+ |
v11.0+ |
v12.1+ |
---
## PrintEx()
Print selected image(s).
**Syntax**
```javascript
PrintEx(indices: number[], settings?: PrintSettings): boolean;
```
**Parameters**
`indices`: Specify the image.
`settings`: Settings for printing. Refer to [`PrintSettings`](/_articles/info/api/interfaces.md#printsettings). (Only available since v19.3.)
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v17.0+ |
v17.0+ |
v17.0+ |
v17.0+ |
---
## createLocalStorage()
Create a storage folder locally to save the cache of encrypted images.
**Syntax**
```typescript
createLocalStorage(
settings?: {
password?: string;
}
): Promise;
```
**Parameters**
`settings`:
- `password`: Specify the password which is used to protect the storage folder. Up to 32 characters.
**Return value**
A Promise object which will be resolved with the uid string which will be used as the storage folder's name when the folder is created successfully.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v18.5+ |
v18.5+ |
v18.5+ |
v18.5+ |
**Usage notes**
- If `password` is not specified, the returned `uid` string will be set as the password of the storage folder.
- The local directory of the created storage folder is under the service's [installation folder](/_articles/extended-usage/dynamsoft-service-configuration.md#installation-folder).
- The creation will not be successful, if the remaining disk space is less than
| System | Remaining Disk Space |
| ----------- | -------------------- |
| Windows x86 | < 1.2GB |
| Windows x64 | < 4GB |
| macOS 32bit | < 1.2GB |
| macOS 64bit | < 4GB |
| Linux | < 4GB |
---
## localStorageExist()
Determine whether the storage folder exists or not.
**Syntax**
```typescript
localStorageExist(uid: string):Promise;
```
**Parameters**
`uid`: Specify the uid of the storage folder to determine.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v18.5+ |
v18.5+ |
v18.5+ |
v18.5+ |
---
## saveToLocalStorage()
Save encrypted image caches to the specified storage folder.
**Syntax**
```typescript
saveToLocalStorage(
settings:{
uid: string;
password?: string;
maxThreads?: number;
indices?: number[];
}
): Promise;
```
**Parameters**
`settings`:
- `uid`: Specify the storage folder to save the images cache.
- `password`: The password of the specified storage folder.
- `maxThreads`: The maximum number of threads used for saving. You can set this to improve the speed. The default value is 1. Available for v19.4+. Windows only.
- `indices`: Specify the indices to save.
- If not set, means all images in buffer.
- If set to `[]`, all cache in the specified storage folder will be clear.
**Return value**
A Promise object which will be resolved with the array of image ids which are saved to the storage folder successfully.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v18.5+ |
v18.5+ |
v18.5+ |
v18.5+ |
**Usage notes**
- Each time this method is called successfully, the original cache in the specified folder will be overwritten by the new cache.
- The remaining disk space is calculated before saving each encrypted image caches. Subsequent saves will not be successful, if the remaining disk space is less than
| System | Remaining Disk Space |
| ----------- | -------------------- |
| Windows x86 | < 1.2GB |
| Windows x64 | < 4GB |
| macOS 32bit | < 1.2GB |
| macOS 64bit | < 4GB |
| Linux | < 4GB |
---
## loadFromLocalStorage()
Load image from the specified storage folder.
**Syntax**
```typescript
loadFromLocalStorage (
settings:{
uid: string;
password?:string;
maxThreads?: number;
}
): Promise<{oriImageId: string, newImageId: string}[]>;
```
**Parameters**
`settings`:
- `uid`: Specify the storage folder to load the images.
- `password`: The password of the specified storage folder.
- `maxThreads`: The maximum number of threads used for loading. You can set this to improve the speed. The default value is 1. Available for v19.4+. Windows only.
**Return value**
A Promise object which will be resolved with the array of object which contains the original image id (in storage folder) and the new image id (in Web TWAIN buffer) of the loaded image.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v18.5+ |
v18.5+ |
v18.5+ |
v18.5+ |
---
## removeLocalStorage()
Remove the specified storage folder.
**Syntax**
```typescript
removeLocalStorage(
settings:{
uid: string;
password?: string;
}
): Promise;
```
**Parameters**
`settings`:
- `uid`: Specify the storage folder to remove.
- `password`: The password of the specified storage folder.
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v18.5+ |
v18.5+ |
v18.5+ |
v18.5+ |
---
## JPEGQuality
Return or set the quality for JPEG compression.
**Syntax**
```javascript
JPEGQuality: number;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v11.0+ |
v11.0+ |
v12.1+ |
**Usage notes**
The default value of `JPEGQuality` property is 80.
The valid range is 0-100. The higher the `JPEGQuality` property, the better the quality and the bigger the size of the file.
---
## IfTiffMultiPage
Return or set whether to append to or replace an existing TIFF file with the same name.
**Syntax**
```javascript
IfTiffMultiPage: boolean;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v11.0+ |
v11.0+ |
v12.1+ |
**Usage notes**
When you save a new image in the same name of an existing TIFF file:
1. If this property is true, the new image will be added to the existing file.
2. If this property is false, the new image will replace the existing file.
---
## TIFFCompressionType
Return or set the compression type for TIFF files. Please refer to [`EnumDWT_TIFFCompressionType`](/_articles/info/api/Dynamsoft_Enum.md#dynamsoftdwtenumdwt_tiffcompressiontype).
**Syntax**
```javascript
TIFFCompressionType: Dynamsoft.DWT.EnumDWT_TIFFCompressionType | number;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v10.0+ |
v11.0+ |
v11.0+ |
v12.1+ |
**Usage notes**
When set to `TIFF_AUTO` (0), 1-bit images will be compressed in `TIFF_T6` (4) while images with other bit depth will be compressed in `TIFF_LZW` (5).
When set to `TIFF_JPEG` (7), 1-bit images will be compressed in `TIFF_T6` (4), color images or grey images (8-bit or higher) in `TIFF_JPEG` (7) standard, and other images by `TIFF_LZW` (5).
`TIFF_T4` (3) and `TIFF_FAX3` (3) are two names for the same compression type. So are `TIFF_T6` (4) and `TIFF_FAX4` (4).
`TIFF_RLE` (2), `TIFF_T4` (3), `TIFF_FAX3` (3) and `TIFF_PACKBITS` (32773) only support compression of 1-bit images. `TIFF_JPEG` (7) supports compression of 8-bit above color images and 8-bit grey images.
When `TIFF_JPEG` (7) is used, you can use [`JPEGQuality`](/_articles/info/api/WebTwain_IO.md#jpegquality) to further reduce the size of the TIFF file.
## IfSortBySelectionOrder
Whether to load the files by the selection order when load files by open file dialog.
**Syntax**
```javascript
IfSortBySelectionOrder: boolean;
```
**Availability**
| H5(Windows) |
H5(macOS/TWAIN) |
H5(macOS/ICA) |
H5(Linux) |
| v18.5+ |
v18.5+ |
v18.5+ |
v18.5+ |