pdftron.PDF Namespace

• Glyphs in the font are selected by single-byte Character codes obtained from a string that is shown by the text-showing operators. Logically, these codes index into a table of 256 glyphs; the mapping from codes to glyphs is called the font's encoding. Each font program has a built-in encoding. Under some circumstances, the encoding can be altered by means described in Section 5.5.5 "Character Encoding" in PDF Reference Manual.
• Each glyph has a single set of metrics. Therefore simple fonts support only horizontal writing mode.

The Optimizer class provides functionality for optimizing/shrinking output PDF files.

'pdftron.PDF.Optimizer' is an optional PDFNet Add-On utility class that can be used to optimize PDF documents by reducing the file size, removing redundant information, and compressing data streams using the latest in image compression technology. PDF Optimizer can compress and shrink PDF file size with the following operations:

• Remove duplicated fonts, images, ICC profiles, and any other data stream.
• Optionally convert high-quality or print-ready PDF files to small, efficient and web-ready PDF.
• Optionally down-sample large images to a given resolution.
• Optionally compress or recompress PDF images using JBIG2 and JPEG2000 compression formats.
• Compress uncompressed streams and remove unused PDF objects.

• A series of objects representing the objects drawn on the page (See Element and ElementReader class for examples of how to extract page content).
• A list of resources used in drawing the page
• Annotations
• Beads, private metadata, optional thumbnail image, etc.

PDF page labels can be used to describe a page. This is used to allow for non-sequential page numbering or the addition of arbitrary labels for a page (such as the inclusion of Roman numerals at the beginning of a book). PDFNet PageLabel object can be used to specify the numbering style to use (for example, upper- or lower-case Roman, decimal, and so forth), the starting number for the first page, and an arbitrary prefix to be pre-appended to each number (for example, "A-" to generate "A-1", "A-2", "A-3", and so forth.)

PageLabel corresponds to the PDF Page Label object (Section 8.3.1, 'Page Labels' in the PDF Reference Manual.

Each page in a PDF document is identified by an integer page index that expresses the page's relative position within the document. In addition, a document may optionally define page labels to identify each page visually on the screen or in print. Page labels and page indices need not coincide: the indices are fixed, running consecutively through the document starting from 1 for the first page, but the labels can be specified in any way that is appropriate for the particular document. For example, if the document begins with 12 pages of front matter numbered in roman numerals and the remainder of the document is numbered in Arabic, the first page would have a page index of 1 and a page label of i, the twelfth page would have index 12 and label xii, and the thirteenth page would have index 13 and label 1.

For purposes of page labeling, a document can be divided into labeling ranges, each of which is a series of consecutive pages using the same numbering system. Pages within a range are numbered sequentially in ascending order. A page's label consists of a numeric portion based on its position within its labeling range, optionally preceded by a label prefix denoting the range itself. For example, the pages in an appendix might be labeled with decimal numeric portions prefixed with the string "A-" and the resulting page labels would be "A-1", "A-2",

Examples

doc.SetPageLabel(1, PageLabel::Create(doc, PageLabel::e_roman_uppercase, "My Prefix ", 1));

PageLabel L2 = PageLabel::Create(doc, PageLabel::e_decimal, "My Prefix ", 4);
doc.SetPageLabel(4, L2);

PageLabel L3 = PageLabel::Create(doc, PageLabel::e_alphabetic_uppercase, "My Prefix ", 1);
doc.SetPageLabel(7, L3);

PageLabel label = new PageLabel();
for (int i=1; i<=doc.GetPageCount(); ++i) {
label = doc.GetPageLabel(i);
if (label.IsValid()) {
string title = label.GetLabelTitle(i);
}

• To access pages use pdfdoc.getPageIterator() or pdfdoc.PageFind(page_num).
• To access form fields use pdfdoc.GetFieldIterator() or pdfdoc.FieldFind(name).
• To access document's meta-data use pdfdoc.GetDocInfo().
• To access the outline tree use pdfdoc.GetFirstBookmark().
• To access low-level Document Catalog use pdfdoc.GetRoot().

PDF Redactor is a separately licensable Add-on that offers options to remove (not just covering or obscuring) content within a region of PDF. With printed pages, redaction involves blacking-out or cutting-out areas of the printed page. With electronic documents that use formats such as PDF, redaction typically involves removing sensitive content within documents for safe distribution to courts, patent and government institutions, the media, customers, vendors or any other audience with restricted access to the content.

The redaction process in PDFNet consists of two steps:

a) Content identification: A user applies redact annotations that specify the pieces or regions of content that should be removed. The content for redaction can be identified either interactively (e.g. using 'pdftron.PDF.PDFViewCtrl' as shown in PDFView sample) or programmatically (e.g. using 'pdftron.PDF.TextSearch' or 'pdftron.PDF.TextExtractor'). Up until the next step is performed, the user can see, move and redefine these annotations.

b) Content removal: Using 'pdftron.PDF.Redactor.Redact()' the user instructs PDFNet to apply the redact regions, after which the content in the area specified by the redact annotations is removed. The redaction function includes number of options to control the style of the redaction overlay (including color, text, font, border, transparency, etc.).

PDFTron Redactor makes sure that if a portion of an image, text, or vector graphics is contained in a redaction region, that portion of the image or path data is destroyed and is not simply hidden with clipping or image masks. PDFNet API can also be used to review and remove metadata and other content that can exist in a PDF document, including XML Forms Architecture (XFA) content and Extensible Metadata Platform (XMP) content.

• In Function-based (type 1) shadings, the color at every point in the domain is defined by a specified mathematical function. The function need not be smooth or continuous. This is the most general of the available shading types, and is useful for shadings that cannot be adequately described with any of the other types.
• Axial shadings (type 2) define a color blend along a line between two points, optionally extended beyond the boundary points by continuing the boundary colors.
• Radial shadings (type 3) define a color blend that varies between two circles. Shadings of this type are commonly used to depict three-dimensional spheres and cones.
• Free-form Gouraud-shaded triangle mesh shadings (type 4) and lattice gouraud shadings (type 5) are commonly used to represent complex colored and shaded three-dimensional shapes. The area to be shaded is defined by a path composed entirely of triangles. The color at each vertex of the triangles is specified, and a technique known as Gouraud interpolation is used to color the interiors. The interpolation functions defining the shading may be linear or nonlinear.

• Colors are specified for each corner of the unit square, and bilinear interpolation is used to fill in colors over the entire unit square
• Coordinates are mapped from the unit square into a four-sided patch whose sides are not necessarily linear. The mapping is continuous: the corners of the unit square map to corners of the patch and the sides of the unit square map to sides of the patch.
• Tensor-product patch mesh shadings (type 7) are identical to type 6 (Coons mesh), except that they are based on a bicubic tensor-product patch defined by 16 control points, instead of the 12 control points that define a Coons patch. The shading Patterns dictionaries representing the two patch types differ only in the value of the Type entry and in the number of control points specified for each patch in the data stream. Although the Coons patch is more concise and easier to use, the tensor- product patch affords greater control over color mapping.

Stamper is a utility class that can be used to PDF pages with text, images, or with other PDF content in only a few lines of code.

Although Stamper is very simple to use compared to ElementBuilder/ElementWriter it is not as powerful or flexible. In case you need full control over PDF creation use ElementBuilder/ElementWriter to add new content to existing PDF pages as shown in the ElementBuilder sample project.

• Converting PDF pages to text or XML for content repurposing.
• Searching PDF pages for specific words or keywords.
• Indexing large PDF repositories for indexing or content.

• Classifying or summarizing PDF documents based on their text content.
• Finding specific words for content editing purposes (such as splitting pages.

• Normalize all text content to Unicode.
• Extract inferred logical structure (word by word, line by line, or paragraph by paragraph).
• Extract positioning information for every line, word, or a glyph.
• Extract style information (such as information about the font, font size, font styles, etc) for every line, word, or a glyph.
• Control the content analysis process. A number of options (such as removal of text obscured by images) is available to let the user direct the flow of content recognition algorithms that will meet their requirements.
• Offer utility methods to convert PDF page content to text, XML, or HTML.

Remarks

Examples

//... Initialize PDFNet ...
PDFDoc doc = new PDFDoc(filein);
doc.initSecurityHandler();
Page page = doc.pageBegin().current();
TextExtractor txt = new TextExtractor();
txt.begin(page, 0, TextExtractor.ProcessingFlags.e_remove_hidden_text);
string text = txt.getAsText();
// or traverse words one by one...
TextExtractor.Word word;
for (TextExtractor.Line line = txt.GetFirstLine(); line.IsValid(); line=line.GetNextLine()) {
for (word=line.GetFirstWord(); word.IsValid(); word=word.GetNextWord()) {
string w = word.GetString();
}
}

• Guide users of a PDF viewer (e.g. implemented by PDFViewCtrl) to places where they are intersted in;
• Find interested PDF documents which contain certain patterns;
• Extract interested information (e.g., credit card numbers) from a set of files;
• Extract Highlight information (refer to the Highlights class for details) from files for external use.
• Since hyphens ('-') are frequently used in PDF documents to concatenate the two broken pieces of a word at the end of a line, for example "TextSearch is powerful for finding patterns in PDF files; yes, it is really pow- erful." a search for "powerful" should return both instances. However, not all end-of-line hyphens are hyphens added to connect a broken word; some of them could be "real" hyphens. In addition, an input search pattern may also contain hyphens that complicate the situation. To tackle this problem, the following conventions are adopted:
  1. When in the verbatim search mode and the pattern contains no hyphen, a matching string is returned if it is exactly the same or it contains end-of-line or start-of-line hyphens. For example, as mentioned above, a search for "powerful" would return both instances.
  2. When in verbatim search mode and the pattern contains one or multiple hyphens, a matching string is returned only if the string matches the pattern exactly. For example, a search for "pow-erful" will only return the second instance, and a search for "power-ful" will return nothing.
  3. When searching using regular expressions, hyphens are not taken care implicitly. Users should take care of it themselves. For example, in order to find both the "powerful" instances, the input pattern can be "pow-{0,1}erful".

Examples

   //... Initialize PDFNet ...
PDFDoc doc = new PDFDoc(filein);
doc.initSecurityHandler();
int mode = TextSearch.e_whole_word | TextSearch.e_page_stop;
UString pattern("joHn sMiTh");
TextSearch txt_search = new TextSearch();

//PDFDoc doesn't allow simultaneous access from different threads. If this
//document could be used from other threads (e.g., the rendering thread inside
//PDFView/PDFViewCtrl, if used), it is good practice to lock it.
//Notice: don't forget to call doc.Unlock() to avoid deadlock.
doc.Lock(); 
txt_search.Begin( doc, pattern, mode, -1, -1 );
while ( true )
{
    TextSearch.ResultCode result = txt_search.Run();
    if ( result.GetCode() == TextSearchResult.e_found )
    {
        Console.WriteLine("found one instance: " + result.GetResultStr());
    }
    else
    {
        break;
    }
}

//unlock the document to avoid deadlock.
doc.UnLock();