com.lowagie.text.pdf

## Class PdfPageEventHelper

- java.lang.Object
- - com.lowagie.text.pdf.PdfPageEventHelper

All Implemented Interfaces:
  PdfPageEvent

Direct Known Subclasses:
  FieldPositioningEvents, IndexEvents

    public class PdfPageEventHelper
    extends java.lang.Object
    implements PdfPageEvent

Helps the use of `PdfPageEvent` by implementing all the interface methods. A class can extend `PdfPageEventHelper` and only implement the needed methods.

Note: do not use Document.add() inside a page event.

Author:
  Paulo Soares (psoares@consiste.pt)

### Constructor Summary

Constructors
Constructor and Description
`PdfPageEventHelper()`

### Method Summary

Methods
`void` `onChapter(PdfWriter writer, Document document, float paragraphPosition, Paragraph title)` Called when a Chapter is written.
`void` `onChapterEnd(PdfWriter writer, Document document, float position)` Called when the end of a Chapter is reached.
`void` `onCloseDocument(PdfWriter writer, Document document)` Called when the document is closed.
`void` `onEndPage(PdfWriter writer, Document document)` Called when a page is finished, just before being written to the document.
`void` `onGenericTag(PdfWriter writer, Document document, Rectangle rect, java.lang.String text)` Called when a `Chunk` with a generic tag is written.
`void` `onOpenDocument(PdfWriter writer, Document document)` Called when the document is opened.
`void` `onParagraph(PdfWriter writer, Document document, float paragraphPosition)` Called when a Paragraph is written.
`void` `onParagraphEnd(PdfWriter writer, Document document, float paragraphPosition)` Called when a Paragraph is written.
`void` `onSection(PdfWriter writer, Document document, float paragraphPosition, int depth, Paragraph title)` Called when a Section is written.
`void` `onSectionEnd(PdfWriter writer, Document document, float position)` Called when the end of a Section is reached.
`void` `onStartPage(PdfWriter writer, Document document)` Called when a page is initialized.

### Methods inherited from class java.lang.Object

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

### Constructor Detail

#### PdfPageEventHelper

    public PdfPageEventHelper()

### Method Detail

#### onOpenDocument

    public void onOpenDocument(PdfWriter writer,
                      Document document)

Called when the document is opened.

Specified by:
  `onOpenDocument` in interface `PdfPageEvent`
Parameters:
  `writer` - the `PdfWriter` for this document
  `document` - the document

#### onStartPage

    public void onStartPage(PdfWriter writer,
                   Document document)

Called when a page is initialized.

Note that if even if a page is not written this method is still called. It is preferable to use `onEndPage` to avoid infinite loops.

Specified by:
  `onStartPage` in interface `PdfPageEvent`
Parameters:
  `writer` - the `PdfWriter` for this document
  `document` - the document

#### onEndPage

    public void onEndPage(PdfWriter writer,
                 Document document)

Called when a page is finished, just before being written to the document.

Specified by:
  `onEndPage` in interface `PdfPageEvent`
Parameters:
  `writer` - the `PdfWriter` for this document
  `document` - the document

#### onCloseDocument

    public void onCloseDocument(PdfWriter writer,
                       Document document)

Called when the document is closed.

Note that this method is called with the page number equal to the last page plus one.

Specified by:
  `onCloseDocument` in interface `PdfPageEvent`
Parameters:
  `writer` - the `PdfWriter` for this document
  `document` - the document

#### onParagraph

    public void onParagraph(PdfWriter writer,
                   Document document,
                   float paragraphPosition)

Called when a Paragraph is written.

`paragraphPosition` will hold the height at which the paragraph will be written to. This is useful to insert bookmarks with more control.

Specified by:
  `onParagraph` in interface `PdfPageEvent`
Parameters:
  `writer` - the `PdfWriter` for this document
  `document` - the document
  `paragraphPosition` - the position the paragraph will be written to

#### onParagraphEnd

    public void onParagraphEnd(PdfWriter writer,
                      Document document,
                      float paragraphPosition)

Called when a Paragraph is written.

`paragraphPosition` will hold the height of the end of the paragraph.

Specified by:
  `onParagraphEnd` in interface `PdfPageEvent`
Parameters:
  `writer` - the `PdfWriter` for this document
  `document` - the document
  `paragraphPosition` - the position of the end of the paragraph

#### onChapter

    public void onChapter(PdfWriter writer,
                 Document document,
                 float paragraphPosition,
                 Paragraph title)

Called when a Chapter is written.

`position` will hold the height at which the chapter will be written to.

Specified by:
  `onChapter` in interface `PdfPageEvent`
Parameters:
  `writer` - the `PdfWriter` for this document
  `document` - the document
  `paragraphPosition` - the position the chapter will be written to
  `title` - the title of the Chapter

#### onChapterEnd

    public void onChapterEnd(PdfWriter writer,
                    Document document,
                    float position)

Called when the end of a Chapter is reached.

`position` will hold the height of the end of the chapter.

Specified by:
  `onChapterEnd` in interface `PdfPageEvent`
Parameters:
  `writer` - the `PdfWriter` for this document
  `document` - the document
  `position` - the position of the end of the chapter.

#### onSection

    public void onSection(PdfWriter writer,
                 Document document,
                 float paragraphPosition,
                 int depth,
                 Paragraph title)

Called when a Section is written.

`position` will hold the height at which the section will be written to.

Specified by:
  `onSection` in interface `PdfPageEvent`
Parameters:
  `writer` - the `PdfWriter` for this document
  `document` - the document
  `paragraphPosition` - the position the section will be written to
  `depth` - the number depth of the Section
  `title` - the title of the section

#### onSectionEnd

    public void onSectionEnd(PdfWriter writer,
                    Document document,
                    float position)

Called when the end of a Section is reached.

`position` will hold the height of the section end.

Specified by:
  `onSectionEnd` in interface `PdfPageEvent`
Parameters:
  `writer` - the `PdfWriter` for this document
  `document` - the document
  `position` - the position of the end of the section

#### onGenericTag

    public void onGenericTag(PdfWriter writer,
                    Document document,
                    Rectangle rect,
                    java.lang.String text)

Called when a `Chunk` with a generic tag is written.

It is useful to pinpoint the `Chunk` location to generate bookmarks, for example.

Specified by:
  `onGenericTag` in interface `PdfPageEvent`
Parameters:
  `writer` - the `PdfWriter` for this document
  `document` - the document
  `rect` - the `Rectangle` containing the `Chunk`
  `text` - the text of the tag