總覽：

Aspose.Pdf for Android 的其中一些高級功能：

平臺獨立性：

Aspose.Pdf for Android 可以被用于如下平臺：

支持的文件格式：

 Aspose.Pdf for Android 除了讓你操作PDF文檔，還能轉換各種文件格式為PDF或將PDF文件呈現為各種輸出格式。如下表格簡述了支持類型：

常規用途：

• 創建新的PDF文檔；

• 轉換圖像為PDF；

• 添加文本和圖像到PDF文檔；

• 當添加文本到PDF文檔時，操作文本的樣式及格式。

• 插入、提取、分離和連接PDF文檔；

• 在生成PDF期間添加頁眉和頁腳；

• 創建、導入、導出或刪除書簽；

• 添加、修改、提取或刪除附件和注釋；

• 在PDF生成期間或之后，添加、更新、移除安全限制。

• 在創建PDF時設置PDF加密和密碼；

• 加密、解密、添加或移除PDF密碼信息；

• 從FDF、XML和XFDF創建、更新、移除、導入或導出表單字段數據。

• 從PDF文檔添加或移除水印；

• 創建多個基于列的PDF文檔；

• 設置PDF文檔的頁面邊界、尺寸、方向、轉換類型、縮放系數和外觀；

• 分離PDF文檔為單頁文檔。

PDF文檔創建和操作功能：

Aspose.Pdf for Android提供創建新的和操作現有PDF文檔的功能。有了Aspose.Pdf for Android你可以轉換圖像或簡單文本文件為PDF格式，也可以在生成PDF期間指定XMP元數據、作者詳細資料、創建者詳細資料和標題信息。

 Aspose.Pdf for Android功能相當豐富。允許你在同一個文檔中為不同的標題指定不同的書簽級別，設置壓縮機別，默認文檔打開行為（適合頁面還是適合框），文檔打開方式或甚至縮略圖/書簽的外觀。你可以設置頁面方向，定義文檔縮放系數。

當你需要編輯或操作現有PDF文檔時，Aspose.Pdf for Android允許你連接或合并PDF文檔，附加新的頁面到現有PDF文件，提取頁面、插入頁面在特殊的位置，分離一個PDF為兩個或更多PDF文檔，或創建n-up's（頁數多于單頁）和小冊子。

你還可以添加XMP元數據信息諸如CreateDate、CreatorTool、ModifyDate 和MetaDataDate 到PDF文檔或改變現有元信息如標題、作者名、頁眉、關鍵字等等。

部分和段落功能：

Aspose.Pdf for Android允許你指定一個文檔中每一頁的頁面/邊緣尺寸，還可以設置頁面背景圖像、頁眉和頁腳。

其它功能包括：創建、更新或刪除書簽、創建或刪除文件附件和注釋。添加浮框絕對定位的浮動框而非浮動圖層。

圖形圖像功能：

Aspose.Pdf for Android 支持很多不同的圖形，圖形可以被繪制于坐標指定的任何頁面位置，圖形還可以被按需旋轉和縮放。

Aspose.Pdf for Android 圖像可以從磁盤或內存插入到文檔中，web圖像可以通過提供其URL被添加，連同常見圖像類型、CCITT（fax）圖像、多頁TIFF圖像和透明GIF圖像也被支持。

你可以以原始尺寸或自定義尺寸將圖像放置在主文檔部分、表格單元格內或頁眉/頁腳部分。連同添加圖像的功能，你可以替換、提取或刪除PDF文檔中現有的圖像。當生成新的PDF文檔或替換現有文檔時，還能將圖像作為水印添加。

超鏈接和附件功能：

Aspose.Pdf for Android 允許你添加超鏈接快捷方式到PDF文檔中的其它頁面。超鏈接到其它PDF文檔的頁面，超鏈接到無PDF文件以及超鏈接到web地址，連同超鏈接創建，即能夠從PDF文檔中提取超鏈接。

能夠能夠添加、更新、導入導出或刪除附件和注釋。任何類型的圖像都可以附加于PDF文檔和注釋類型諸如多邊形、折線、彈窗、插入符號、自由文本等等。你可以指定注釋彈窗的具體位置和尺寸，還可以指定圖標類型、坐標和不透明度值。

表單字段功能：

Aspose.Pdf for Android 為表單字段處理提供高級功能。你能夠添加表單字段到PDF文檔或者以編程方式移動、重命名、移除和復制表單字段。Aspose.Pdf for Android還能指定表單屬性諸如READ_ONLY、REQUIRED、NO_EXPORT、HIDDEN、NOZOOM或者你可以輕易指定視覺屬性，如字段對齊、邊界峰哥、按鈕峰哥、字體尺寸、文本顏色、文本編碼等等。

安全性：

Aspose.Pdf for Android提供40位或128位PDF文檔加密，PDF文檔中的內容修改（如內容復制、PDF打印、注釋修改等）都可以被限制。還允許你通過使用PKCS#1、PKCS#7 和PKCS#7分離的簽名類型和數字證書來更深層地提升PDF安全機制，可以指定證書級別并設置圖形外觀。

Common Uses

• Creating new PDF documents.
• Converting an image to PDF.
• Adding text and images to a PDF document.
• Manipulating text styles and formatting when adding it to a PDF document.
• Inserting, extracting, splitting, and concatenating PDF documents.
• Adding headers and footers during PDF generation.
• Creating, importing, exporting and deleting ;bookmarks.
• Adding, modifying, extracting and deleting attachments and annotations from PDF creation.
• Adding, updating, removing security constraints during and after PDF generation.
• Setting PDF encryption and passwords during PDF creation.
• Encrypting, decrypting, adding and removing password information from PDF document.
• Creating, updating, removing, importing and exporting form field data from FDF, XML and XFDF files.
• Add and remove watermarks from PDF document
• Creating multiple column based PDF documents.
• Setting page margin, size, orientation, transition type, zoom factor and appearance of PDF documents.
• Splitting PDF document into single page documents.

PDF Document Creation and Manipulation Features

Aspose.Pdf for Android offers the capability to create new and manipulate existing PDF documents. With Aspose.Pdf you can transform image or simple text files into PDF format. You can also specify XMP metadata, author details, creator details, and title information during PDF generation. 

Aspose.Pdf for Android is feature rich. It allows you to specify different bookmark levels for different headings in a document, set the compression level of the document, default document open action (fit to page or fit box), document open mode or even the appearance to thumbnails or bookmarks. You can also set page orientation from portrait to landscape and define the document zoom factor. To control how the file displays you can specify different page transition effects such as dissolve or box.

This component is a good choice when you need to edit or manipulate existing PDF documents. It allows you to concatenate or merge PDF documents, append new pages to an existing PDF file, extract pages, insert pages at a particular location in an existing PDF file, split one PDF into two or more PDF documents or create n-up's (number of pages over single page) and booklets.

With this robust product, you can also add XMP metadata information such as CreateDate, CreatorTool, ModifyDate and MetaDataDate to PDF documents or change existing meta information like title, author name, header, keywords, subject etc.

Section and Paragraph Features

Aspose.Pdf for Android allows you to specify page size and the page margin size of each page in a document. Page background images, page header and footer sections can also be set. 

Other features include: create, update or delete bookmarks, create or delete file attachments and annotations, add floating box with absolute positioning rather than flow layout and much more.

Text Features

With Aspose.Pdf for Android text alignment, for example right, left, center, justify or full justify, can be applied to text within a PDF document. You can create left hanging text paragraphs, preserve whitespace in text, set or inherit text format from child nodes of the PDF DOM (Document Object Model), formatting the text in all segments of a document. You can even change text to underline, over-line or strikeout.

As well as specifying horizontal text alignment, you can also specify vertical alignment of text segments, for example baseline or topline. Text foreground and background colors can be changed, you can use replaceable symbols which allow you to change the corresponding text content at runtime. 

Right-to-left languages such as Arabic, Hebrew and Urdu are supported. Nonetheless, text extraction, replacement and insertion of new text inside an existing PDF document, are some of the great features features offered by this component.

Graph and Imaging Capabilities

Aspose.Pdf for Android provides support for many different types of graph, graphs can be drawn on any page location specified by coordinates and graphs can be also rotated and scaled to suit your requirements.

With Aspose.Pdf for Android, images can be inserted into documents from disk or memory, web images can also be added by providing their URL. Along with conventional image types, CCITT (fax) images, multi-page TIFF images and transparent GIF images are also supported.

You get the capability to place image in its original size or you can specify custom dimensions and place it inside main document section, inside a table cell or in the header or footer sections. Along with the feature of adding images, you can also replace, extract or delete images already present in a PDF document. Get the privilege to add images as watermark when generating a new PDF document or place one over an existing document.

Hyperlink and Attachments Features

Aspose.Pdf for Android allows you to add hyperlink shortcuts to other pages within a PDF document, hyperlinks to pages in other PDF documents, hyperlinks to non-PDF files as well as hyperlinks to web locations. Along with hyperlink creation, get the capabilities to extract hyperlinks from a PDF document. 

Get the power to add, update, import, export or delete attachments and annotations. Files of any type can be attached to a PDF document and annotation types such as polygon, polyline, pop-up, rubber stamp, caret, free text and many more can be added. You can specify the exact position and the size of the note's popup window. You may also specify icon type, coordinates and opacity values. 

Form Field Features

Aspose.Pdf for Android provides advanced features for form field processing. With this single product, you get the capabilities to add form fields to the PDF document or you can programmatically move, rename, remove and copy form fields across PDF documents, set JavaScript for buttons and flatten form fields. Aspose.Pdf is also great when it comes to specifying field attributes such as READ_ONLY, REQUIRED, NO_EXPORT, HIDDEN, NOZOOM or you can easily specify visual attributes such as field Alignment, BorderStyle, ButtonStyle, FontSize, TextColor, TextEncoding or define custom positioning to place form fields at absolute position within document.

Platform Independence

Aspose.Pdf for Android is compatible with Android 2.0 OS and higher.

Security Features

Aspose.Pdf for Android offers the facility to encrypt PDF documents with either 40-bit or 128-bit encryption, master and user passwords can also be set for further PDF security. Content modification in PDF documents such as content copying, PDF printing, form field completion, degraded printing, annotation modification as well as PDF document assembly can all be restricted by using Aspose.Pdf for Android.

 This component also allows you to further improve PDF security mechanism by using PKCS#1, PKCS#7 and PKCS#7 detached signature types and with the use of digital certificate. You may also specify the certificate level and set the graphical appearance of the signature.