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## org.faceless.pdf2
Class PageExtractor

    java.lang.Object
      org.faceless.pdf2.PageExtractor

    public class PageExtractor

extends Object

This class enables the extraction of text and images from a `PDFPage`. You can get one by calling the `PDFParser.getPageExtractor(int)` method, assuming the PDF has the rights to let you extract text and/or images.

Once you've got one, you can extract the text of the page as a `StringBuffer` by calling `getTextAsStringBuffer()`. Note that extracting text from PDF's is not an exact science - the internals of a PDF allow text to be displayed in any order, and features like superscript, subscript, rotated text and so on which are easy to display in PDF can only be approximated in plain text.

Features like tables etc. have to be determined using heuristics, and some PDF's are encoded in a way that makes extracting their text almost impossible (storing each letter as an image, for example).

Depending on how the font has been stored, the library may replace unknown characters with a Unicode character in the private range (U+EF00 - U+EFFF). These replacements will be consistent, so if you find that U+EF01 is in fact the letter 'A', you can easily run a `String.replace()` on the string to correct the letters

Extracting BitMap images is a much simpler process. The `PageExtractor.Image` class represents an image on the current page. There is one instance for each time an image is drawn, although as an image is repeated each instance may contain the same `RenderedImage`. You can retrieve the list of images by calling the `getImages()` method.

This class requires the Extended Edition plus Viewer license to operate. Although it may be freely used in the trial version of the library, the extracted text will have the letter 'e' replaced with the letter 'a'.

Since:
  2.6.2

Nested Class Summary
`class` | `PageExtractor.Image` A class representing a bitmap image which is extracted from the `PageExtractor`.
`class` | `PageExtractor.Text` A class representing a piece of text which is extracted from the `PageExtractor`.

Method Summary
`static Collection` | `cropText(Collection all, Shape shape)` Given a Collection of `PageExtractor.Text` items, as returned by `getMatchingText()`, `getTextUnordered()` or `getTextInDisplayOrder()`, return a new Collection which contains only Text that falls completely inside the specified `Shape`.
`Collection` | `getImages()` Return every `PageExtractor.Image` on the page, in the order they were added to the page.
`Collection` | `getMatchingText(Pattern pattern)` Return a Collection of `PageExtractor.Text` items on this page that match the specified Regular Expression.
`Collection` | `getMatchingText(String query)` Return a Collection of `PageExtractor.Text` items on this page that are equal to the specified substring.
`Collection` | `getMatchingText(String[] queries)` Return a Collection of `PageExtractor.Text` items on this page that are equals to one of the specified substrings.
`Collection` | `getMatchingText(String[] queries, boolean caseinsensitive)` Return a Collection of `PageExtractor.Text` items on this page that are equals to one of the specified substrings.
`PDFPage` | `getPage()` Return the `PDFPage` this PageExtractor relates to
`AttributedString` | `getStyledText(PageExtractor.Text first, int firstchar, PageExtractor.Text last, int lastchar, boolean displayorder)` Return an AttributedString containing a contiguous range of text from this PageExtractor.
`StringBuffer` | `getText(PageExtractor.Text first, int firstchar, PageExtractor.Text last, int lastchar, boolean displayorder)` Return a StringBuffer containing a contiguous range of text from this PageExtractor.
`StringBuffer` | `getTextAsStringBuffer()` Parse and return all the text on the page as a StringBuffer.
`StringBuffer` | `getTextAsStringBuffer(float x1, float y1, float x2, float y2)` Parse and return the text in the specified area on the page as a String.
`Collection` | `getTextInDisplayOrder()` Return every `PageExtractor.Text` item on the page, in the order they are displayed on the screen - so the first item in the returned collection will nearest to the top left of the page.
`Collection` | `getTextUnordered()` Return every `PageExtractor.Text` item on the page, in the order they were added to the page.
`boolean` | `isExtracted()` Return true if the extraction has been run, false otherwise.
`void` | `setOption(String key, String value)` Set an option to control text extraction.
`void` | `setSpaceTolerance(double zero, double one, double many)` Set the "space tolerance" - tunable parameters for the extractor to determine when two adjacent phrases of text are to be separated by zero, one or more than one space.

Methods inherited from class java.lang.Object
`equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Method Detail

### isExtracted

    public boolean isExtracted()

  Return true if the extraction has been run, false otherwise.

  Since:
    2.11.7

### setOption

    public void setOption(String key,
                          String value)

  Set an option to control text extraction. These options are useful for specific cases, such as when working with the Adobe Highlight File Format but probably won't be required for general use. The following options are recognised.

  IgnoreArtifacts | all | regex | Set to all to ignore any text flagged as an "artifact" in the PDF stream, or set to a regular expression to match against artifacts to be ignored.
  RawText | true | false | Set to true to prevent any post-processing of the extracted text. If this option is set, `getTextInDisplayOrder`, `getTextAsStringBuffer` and similar methods cannot be used - only `getTextUnordered()` will work

  Since:
    2.11.12

### setSpaceTolerance

    public void setSpaceTolerance(double zero,
                                  double one,
                                  double many)

  Set the "space tolerance" - tunable parameters for the extractor to determine when two adjacent phrases of text are to be separated by zero, one or more than one space. Typically this won't need to be tuned by the end user, but if you find the spacing between the extracted text is less than ideal, you can tune it to some degree with this method. The perfect value will depend on the font, the language, layout, line justification and kerning.

  The values are multipliers of the width of the "space" character - so 1 means "the width of one space". Typically the parameter to tune is "one", within a rough range of 0.25 to 0.7 - reduce it if you find words are being joined together, and increase it if words are being split into two. it.

  Parameters:
    `zero` - how far apart two characters should be in order for them to be joined by zero spaces. The default value is -0.5
    `one` - at least how far apart two characters must be in order to be joined by one space. The default value is 0.666.
    `many` - at least how far apart two characters must be in order to be considered separate pieces of text. The default value is 1.5
  Since:
    2.11.2

### getImages

    public Collection getImages()

  Return every `PageExtractor.Image` on the page, in the order they were added to the page. Some images may be displayed more than once, in which case the value returned by `PageExtractor.Image.getImage()` will be identical.

  Returns:
    an unmodifiable collection of `PageExtractor.Image` elements.

### getTextUnordered

    public Collection getTextUnordered()

  Return every `PageExtractor.Text` item on the page, in the order they were added to the page. The ordering may not be consistant with the order items are positioned on screen.

  Returns:
    an unmodifiable collection of `PageExtractor.Text` elements.

### getTextInDisplayOrder

    public Collection getTextInDisplayOrder()

  Return every `PageExtractor.Text` item on the page, in the order they are displayed on the screen - so the first item in the returned collection will nearest to the top left of the page.

  Returns:
    an unmodifiable collection of `PageExtractor.Text` elements.

### getMatchingText

    public Collection getMatchingText(String query)

  Return a Collection of `PageExtractor.Text` items on this page that are equal to the specified substring. The Text items returned from `getTextInDisplayOrder()` are searched and possibly substrings extracted from them to create this collection. In this case the co-ordinates of the returned Text items will reflect the substring not the original Text object.

  As an example, the following method could be used to search a PDF for a specified word and add a "highlight" annotation over it. The PDF can then be rendered or saved as normal.

       void highlightWords(PDF pdf, String word) {
         PDFParser parser = new PDFParser(pdf);
         for (int i=0;i<pdf.getNumberOfPages();i++) {
           PageExtractor extractor = parser.getPageExtractor(i);
           Collection co = extractor.getMatchingText(word);
           for (Iterator j = co.iterator();j.hasNext();) {
             PageExtractor.Text text = (PageExtractor.Text)j.next();
             AnnotationMarkup annot = text.createAnnotationMarkup("Highlight");
             text.getPage().getAnnotations().add(annot);
           }
         }
       }

  Parameters:
    `query` - the String to search for
  Returns:
    a Collection of `PageExtractor.Text` objects.
  Since:
    2.6.12

### getMatchingText

    public Collection getMatchingText(String[] queries)

  Return a Collection of `PageExtractor.Text` items on this page that are equals to one of the specified substrings. This method runs exactly like `getMatchingText(String)` but allows more than one substring to be matched.

  Parameters:
    `queries` - a list of zero or more Strings to search for
  Returns:
    a Collection of `PageExtractor.Text` objects.
  Since:
    2.8.1

### getMatchingText

    public Collection getMatchingText(String[] queries,
                                      boolean caseinsensitive)

  Return a Collection of `PageExtractor.Text` items on this page that are equals to one of the specified substrings. This method runs exactly like `getMatchingText(String)` but allows more than one substring to be matched.

  Parameters:
    `queries` - a list of zero or more Strings to search for
    `caseinsensitive` - whether the search should be performed with regard to case
  Returns:
    a Collection of `PageExtractor.Text` objects.
  Since:
    2.11.1

### getMatchingText

    public Collection getMatchingText(Pattern pattern)

  Return a Collection of `PageExtractor.Text` items on this page that match the specified Regular Expression. This is likely to be more efficient than the version of this method that takes multiple-strings.

  Parameters:
    `pattern` - the `Pattern` to search for
  Returns:
    a Collection of `PageExtractor.Text` objects.
  Since:
    2.11

### getTextAsStringBuffer

    public StringBuffer getTextAsStringBuffer()

  Parse and return all the text on the page as a StringBuffer. Text will be converted back to it's normalized form, and newlines and spaces will be inserted in an approximation of the original layout.

### getTextAsStringBuffer

    public StringBuffer getTextAsStringBuffer(float x1,
                                              float y1,
                                              float x2,
                                              float y2)

  Parse and return the text in the specified area on the page as a String. Text will be converted back to its normalized form, and newlines and spaces will be inserted in an approximation of the original layout. The co-ordinates define the start position of any phrases that are to be returned.

  Parameters:
    `x1` - the left-most X co-ordinate of the text
    `y1` - the top-most Y co-ordinate of the text
    `x2` - the right-most X co-ordinate of the text
    `y2` - the bottom-most Y co-ordinate of the text
  Returns:
    a StringBuffer containing all the text within the specified rectangle

### getText

    public StringBuffer getText(PageExtractor.Text first,
                                int firstchar,
                                PageExtractor.Text last,
                                int lastchar,
                                boolean displayorder)

  Return a StringBuffer containing a contiguous range of text from this PageExtractor. The range is specified by giving a starting and ending `PageExtractor.Text` object, and the offsets into those strings. This method is chiefly intended for use with a GUI that allows a range of text to be selected.

  Parameters:
    `first` - the first Text from this PageExtractor to be extracted
    `firstchar` - the index of the first character from "first" to be extracted
    `last` - the last Text from this PageExtractor to be extracted
    `lastchar` - the index after the index of the last character from "last" to be extracted
    `displayorder` - if true, the iteration from first to last will go in display order, right to left and top to bottom. If false, the iteration will run in the order the text items exist in the document.
  Since:
    2.10.3

### getStyledText

    public AttributedString getStyledText(PageExtractor.Text first,
                                          int firstchar,
                                          PageExtractor.Text last,
                                          int lastchar,
                                          boolean displayorder)

  Return an AttributedString containing a contiguous range of text from this PageExtractor. The range is specified by giving a starting and ending `PageExtractor.Text` object, and the offsets into those strings. This method is chiefly intended for use with a GUI that allows a range of text to be selected.

  Parameters:
    `first` - the first Text from this PageExtractor to be extracted
    `firstchar` - the first character from "first" to be extracted
    `last` - the last Text from this PageExtractor to be extracted
    `lastchar` - the index after the index of the last character from "last" to be extracted
    `displayorder` - if true, the iteration from first to last will go in display order, right to left and top to bottom. If false, the iteration will run in the order the text items exist in the document.
  Since:
    2.11.19

### getPage

    public PDFPage getPage()

  Return the `PDFPage` this PageExtractor relates to

  Since:
    2.10.3

### cropText

    public static Collection cropText(Collection all,
                                      Shape shape)

  Given a Collection of `PageExtractor.Text` items, as returned by `getMatchingText()`, `getTextUnordered()` or `getTextInDisplayOrder()`, return a new Collection which contains only Text that falls completely inside the specified `Shape`. For example, to get all the text in a specific rectangle:

       Shape rect = new Rectangle2D.Float(0, 0, 100, 100);
       Collection all = extractor.trimToShape(extractor.getTextUnordered(), rect);

  Parameters:
    `all` - a Collection of Text objects
    `shape` - the Shape to trim the text to
  Returns:
    a new Collection of Text items where every item is completely inside the specified shape
  Since:
    2.11.8

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