Package org.apache.pdfbox.text
Class PDFTextStripper
java.lang.Object
org.apache.pdfbox.contentstream.PDFStreamEngine
org.apache.pdfbox.text.PDFTextStripper
- Direct Known Subclasses:
PDFTextStripperByArea
This class will take a pdf document and strip out all of the text and ignore the formatting and such. Please note; it
is up to clients of this class to verify that a specific user has the correct permissions to extract text from the
PDF document.
The basic flow of this process is that we get a document and use a series of processXXX() functions that work on
smaller and smaller chunks of the page. Eventually, we fully process each page and then print it.
- Author:
- Ben Litchfield
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected ArrayList<List<TextPosition>>
The charactersByArticle is used to extract text by article divisions.protected PDDocument
protected final String
The platform's line separator.protected Writer
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprotected float
computeFontHeight
(PDFont font) Compute the font height.protected void
End an article.protected void
endDocument
(PDDocument document) This method is available for subclasses of this class.protected void
End a page.boolean
This will tell if the text stripper should add some more text formatting.Returns the string which will be used at the end of an article.Returns the string which will be used at the beginning of an article.float
Get the current character width-based tolerance value that is being used to estimate where spaces in text should be added.protected List<List<TextPosition>>
Character strings are grouped by articles.protected int
Get the current page number that is being processed.float
the minimum whitespace, as a multiple of the max height of the current characters beyond which the current line start is considered to be a paragraph start.Get the bookmark where text extraction should end, inclusive.int
This will get the last page that will be extracted.float
returns the multiple of whitespace character widths for the current text which the current line start can be indented from the previous line start beyond which the current line start is considered to be a paragraph start.This will get the line separator.returns a list of regular expression Patterns representing different common list item formats.protected Writer
The output stream that is being written to.Returns the string which will be used at the end of a page.Returns the string which will be used at the beginning of a page.Returns the string which will be used at the end of a paragraph.Returns the string which will be used at the beginning of a paragraph.boolean
This will tell if the text stripper should separate by beads.boolean
This will tell if the text stripper should sort the text tokens before writing to the stream.float
Get the current space width-based tolerance value that is being used to estimate where spaces in text should be added.Get the bookmark where text extraction should start, inclusive.int
This is the page that the text extraction will start on.boolean
getText
(PDDocument doc) This will return the text of a document.This will get the word separator.protected static Pattern
matchPattern
(String string, List<Pattern> patterns) iterates over the specified list of Patterns until it finds one that matches the specified string.void
processPage
(PDPage page) This will process the contents of a page.protected void
processPages
(PDPageTree pages) This will process all of the pages and the text that is in them.protected void
This will process a TextPosition object and add the text to the list of characters on a page.void
setAddMoreFormatting
(boolean newAddMoreFormatting) There will some additional text formatting be added if addMoreFormatting is set to true.void
setArticleEnd
(String articleEndValue) Sets the string which will be used at the end of an article.void
setArticleStart
(String articleStartValue) Sets the string which will be used at the beginning of an article.void
setAverageCharTolerance
(float averageCharToleranceValue) Set the character width-based tolerance value that is used to estimate where spaces in text should be added.void
setDropThreshold
(float dropThresholdValue) sets the minimum whitespace, as a multiple of the max height of the current characters beyond which the current line start is considered to be a paragraph start.void
setEndBookmark
(PDOutlineItem aEndBookmark) Set the bookmark where the text extraction should stop.void
setEndPage
(int endPageValue) This will set the last page to be extracted by this class.void
setIndentThreshold
(float indentThresholdValue) sets the multiple of whitespace character widths for the current text which the current line start can be indented from the previous line start beyond which the current line start is considered to be a paragraph start.void
setLineSeparator
(String separator) Set the desired line separator for output text.protected void
setListItemPatterns
(List<Pattern> patterns) use to supply a different set of regular expression patterns for matching list item starts.void
setPageEnd
(String pageEndValue) Sets the string which will be used at the end of a page.void
setPageStart
(String pageStartValue) Sets the string which will be used at the beginning of a page.void
Sets the string which will be used at the end of a paragraph.void
Sets the string which will be used at the beginning of a paragraph.void
setShouldSeparateByBeads
(boolean aShouldSeparateByBeads) Set if the text stripper should group the text output by a list of beads.void
setSortByPosition
(boolean newSortByPosition) The order of the text tokens in a PDF file may not be in the same as they appear visually on the screen.void
setSpacingTolerance
(float spacingToleranceValue) Set the space width-based tolerance value that is used to estimate where spaces in text should be added.void
setStartBookmark
(PDOutlineItem aStartBookmark) Set the bookmark where text extraction should start, inclusive.void
setStartPage
(int startPageValue) This will set the first page to be extracted by this class.void
setSuppressDuplicateOverlappingText
(boolean suppressDuplicateOverlappingTextValue) By default the text stripper will attempt to remove text that overlapps each other.void
setWordSeparator
(String separator) Set the desired word separator for output text.protected void
Called when a glyph is to be processed.protected void
Start a new article, which is typically defined as a column on a single page (also referred to as a bead).protected void
startArticle
(boolean isLTR) Start a new article, which is typically defined as a column on a single page (also referred to as a bead).protected void
startDocument
(PDDocument document) This method is available for subclasses of this class.protected void
Start a new page.protected void
writeCharacters
(TextPosition text) Write the string in TextPosition to the output stream.protected void
Write the line separator value to the output stream.protected void
This will print the text of the processed page to "output".protected void
Write something (if defined) at the end of a page.protected void
Write something (if defined) at the start of a page.protected void
Write something (if defined) at the end of a paragraph.protected void
writes the paragraph separator string to the output.protected void
Write something (if defined) at the start of a paragraph.protected void
writeString
(String text) Write a Java string to the output stream.protected void
writeString
(String text, List<TextPosition> textPositions) Write a Java string to the output stream.void
writeText
(PDDocument doc, Writer outputStream) This will take a PDDocument and write the text of that document to the print writer.protected void
Write the word separator value to the output stream.Methods inherited from class org.apache.pdfbox.contentstream.PDFStreamEngine
addOperator, applyTextAdjustment, beginMarkedContentSequence, beginText, decreaseLevel, endMarkedContentSequence, endText, getAppearance, getCurrentPage, getGraphicsStackSize, getGraphicsState, getInitialMatrix, getLevel, getResources, getTextLineMatrix, getTextMatrix, increaseLevel, operatorException, processAnnotation, processChildStream, processOperator, processOperator, processSoftMask, processTilingPattern, processTilingPattern, processTransparencyGroup, processType3Stream, registerOperatorProcessor, restoreGraphicsStack, restoreGraphicsState, saveGraphicsStack, saveGraphicsState, setLineDashPattern, setTextLineMatrix, setTextMatrix, showAnnotation, showFontGlyph, showFontGlyph, showForm, showGlyph, showText, showTextString, showTextStrings, showTransparencyGroup, showType3Glyph, showType3Glyph, transformedPoint, transformWidth, unsupportedOperator
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Field Details
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LINE_SEPARATOR
The platform's line separator. -
charactersByArticle
The charactersByArticle is used to extract text by article divisions. For example a PDF that has two columns like a newspaper, we want to extract the first column and then the second column. In this example the PDF would have 2 beads(or articles), one for each column. The size of the charactersByArticle would be 5, because not all text on the screen will fall into one of the articles. The five divisions are shown below Text before first article first article text text between first article and second article second article text text after second article Most PDFs won't have any beads, so charactersByArticle will contain a single entry. -
document
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output
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Constructor Details
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PDFTextStripper
Instantiate a new PDFTextStripper object.- Throws:
IOException
- If there is an error loading the properties.
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Method Details
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getText
This will return the text of a document. See writeText.
NOTE: The document must not be encrypted when coming into this method.IMPORTANT: By default, text extraction is done in the same sequence as the text in the PDF page content stream. PDF is a graphic format, not a text format, and unlike HTML, it has no requirements that text one on page be rendered in a certain order. The order is the one that was determined by the software that created the PDF. To get text sorted from left to right and top to botton, use
setSortByPosition(boolean)
.- Parameters:
doc
- The document to get the text from.- Returns:
- The text of the PDF document.
- Throws:
IOException
- if the doc state is invalid or it is encrypted.
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writeText
This will take a PDDocument and write the text of that document to the print writer.- Parameters:
doc
- The document to get the data from.outputStream
- The location to put the text.- Throws:
IOException
- If the doc is in an invalid state.
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processPages
This will process all of the pages and the text that is in them.- Parameters:
pages
- The pages object in the document.- Throws:
IOException
- If there is an error parsing the text.
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startDocument
This method is available for subclasses of this class. It will be called before processing of the document start.- Parameters:
document
- The PDF document that is being processed.- Throws:
IOException
- If an IO error occurs.
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endDocument
This method is available for subclasses of this class. It will be called after processing of the document finishes.- Parameters:
document
- The PDF document that is being processed.- Throws:
IOException
- If an IO error occurs.
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processPage
This will process the contents of a page.- Parameters:
page
- The page to process.- Throws:
IOException
- If there is an error processing the page.
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startArticle
Start a new article, which is typically defined as a column on a single page (also referred to as a bead). This assumes that the primary direction of text is left to right. Default implementation is to do nothing. Subclasses may provide additional information.- Throws:
IOException
- If there is any error writing to the stream.
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startArticle
Start a new article, which is typically defined as a column on a single page (also referred to as a bead). Default implementation is to do nothing. Subclasses may provide additional information.- Parameters:
isLTR
- true if primary direction of text is left to right.- Throws:
IOException
- If there is any error writing to the stream.
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endArticle
End an article. Default implementation is to do nothing. Subclasses may provide additional information.- Throws:
IOException
- If there is any error writing to the stream.
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startPage
Start a new page. Default implementation is to do nothing. Subclasses may provide additional information.- Parameters:
page
- The page we are about to process.- Throws:
IOException
- If there is any error writing to the stream.
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endPage
End a page. Default implementation is to do nothing. Subclasses may provide additional information.- Parameters:
page
- The page we are about to process.- Throws:
IOException
- If there is any error writing to the stream.
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writePage
This will print the text of the processed page to "output". It will estimate, based on the coordinates of the text, where newlines and word spacings should be placed. The text will be sorted only if that feature was enabled.- Throws:
IOException
- If there is an error writing the text.
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writeLineSeparator
Write the line separator value to the output stream.- Throws:
IOException
- If there is a problem writing out the line separator to the document.
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writeWordSeparator
Write the word separator value to the output stream.- Throws:
IOException
- If there is a problem writing out the word separator to the document.
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writeCharacters
Write the string in TextPosition to the output stream.- Parameters:
text
- The text to write to the stream.- Throws:
IOException
- If there is an error when writing the text.
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writeString
Write a Java string to the output stream. The default implementation will ignore thetextPositions
and just callswriteString(String)
.- Parameters:
text
- The text to write to the stream.textPositions
- The TextPositions belonging to the text.- Throws:
IOException
- If there is an error when writing the text.
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writeString
Write a Java string to the output stream.- Parameters:
text
- The text to write to the stream.- Throws:
IOException
- If there is an error when writing the text.
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processTextPosition
This will process a TextPosition object and add the text to the list of characters on a page. It takes care of overlapping text.- Parameters:
text
- The text to process.
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getStartPage
public int getStartPage()This is the page that the text extraction will start on. The pages start at page 1. For example in a 5 page PDF document, if the start page is 1 then all pages will be extracted. If the start page is 4 then pages 4 and 5 will be extracted. The default value is 1.- Returns:
- Value of property startPage.
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setStartPage
public void setStartPage(int startPageValue) This will set the first page to be extracted by this class.- Parameters:
startPageValue
- New value of 1-based startPage property.
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getEndPage
public int getEndPage()This will get the last page that will be extracted. This is inclusive, for example if a 5 page PDF an endPage value of 5 would extract the entire document, an end page of 2 would extract pages 1 and 2. This defaults to Integer.MAX_VALUE such that all pages of the pdf will be extracted.- Returns:
- Value of property endPage.
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setEndPage
public void setEndPage(int endPageValue) This will set the last page to be extracted by this class.- Parameters:
endPageValue
- New value of 1-based endPage property.
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setLineSeparator
Set the desired line separator for output text. The line.separator system property is used if the line separator preference is not set explicitly using this method.- Parameters:
separator
- The desired line separator string.
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getLineSeparator
This will get the line separator.- Returns:
- The desired line separator string.
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getWordSeparator
This will get the word separator.- Returns:
- The desired word separator string.
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setWordSeparator
Set the desired word separator for output text. The PDFBox text extraction algorithm will output a space character if there is enough space between two words. By default a space character is used. If you need and accurate count of characters that are found in a PDF document then you might want to set the word separator to the empty string.- Parameters:
separator
- The desired page separator string.
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getSuppressDuplicateOverlappingText
public boolean getSuppressDuplicateOverlappingText()- Returns:
- Returns the suppressDuplicateOverlappingText.
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getCurrentPageNo
protected int getCurrentPageNo()Get the current page number that is being processed.- Returns:
- A 1 based number representing the current page.
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getOutput
The output stream that is being written to.- Returns:
- The stream that output is being written to.
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getCharactersByArticle
Character strings are grouped by articles. It is quite common that there will only be a single article. This returns a List that contains List objects, the inner lists will contain TextPosition objects.- Returns:
- A double List of TextPositions for all text strings on the page.
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setSuppressDuplicateOverlappingText
public void setSuppressDuplicateOverlappingText(boolean suppressDuplicateOverlappingTextValue) By default the text stripper will attempt to remove text that overlapps each other. Word paints the same character several times in order to make it look bold. By setting this to false all text will be extracted, which means that certain sections will be duplicated, but better performance will be noticed.- Parameters:
suppressDuplicateOverlappingTextValue
- The suppressDuplicateOverlappingText to set.
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getSeparateByBeads
public boolean getSeparateByBeads()This will tell if the text stripper should separate by beads.- Returns:
- If the text will be grouped by beads.
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setShouldSeparateByBeads
public void setShouldSeparateByBeads(boolean aShouldSeparateByBeads) Set if the text stripper should group the text output by a list of beads. The default value is true!- Parameters:
aShouldSeparateByBeads
- The new grouping of beads.
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getEndBookmark
Get the bookmark where text extraction should end, inclusive. Default is null.- Returns:
- The ending bookmark.
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getStartBookmark
Get the bookmark where text extraction should start, inclusive. Default is null.- Returns:
- The starting bookmark.
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getAddMoreFormatting
public boolean getAddMoreFormatting()This will tell if the text stripper should add some more text formatting.- Returns:
- true if some more text formatting will be added
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setAddMoreFormatting
public void setAddMoreFormatting(boolean newAddMoreFormatting) There will some additional text formatting be added if addMoreFormatting is set to true. Default is false.- Parameters:
newAddMoreFormatting
- Tell PDFBox to add some more text formatting
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getSortByPosition
public boolean getSortByPosition()This will tell if the text stripper should sort the text tokens before writing to the stream.- Returns:
- true If the text tokens will be sorted before being written.
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setSortByPosition
public void setSortByPosition(boolean newSortByPosition) The order of the text tokens in a PDF file may not be in the same as they appear visually on the screen. For example, a PDF writer may write out all text by font, so all bold or larger text, then make a second pass and write out the normal text.
The default is to not sort by position.
A PDF writer could choose to write each character in a different order. By default PDFBox does not sort the text tokens before processing them due to performance reasons.- Parameters:
newSortByPosition
- Tell PDFBox to sort the text positions.
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getSpacingTolerance
public float getSpacingTolerance()Get the current space width-based tolerance value that is being used to estimate where spaces in text should be added. Note that the default value for this has been determined from trial and error.- Returns:
- The current tolerance / scaling factor
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setSpacingTolerance
public void setSpacingTolerance(float spacingToleranceValue) Set the space width-based tolerance value that is used to estimate where spaces in text should be added. Note that the default value for this has been determined from trial and error. Setting this value larger will reduce the number of spaces added.- Parameters:
spacingToleranceValue
- tolerance / scaling factor to use
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getAverageCharTolerance
public float getAverageCharTolerance()Get the current character width-based tolerance value that is being used to estimate where spaces in text should be added. Note that the default value for this has been determined from trial and error.- Returns:
- The current tolerance / scaling factor
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setAverageCharTolerance
public void setAverageCharTolerance(float averageCharToleranceValue) Set the character width-based tolerance value that is used to estimate where spaces in text should be added. Note that the default value for this has been determined from trial and error. Setting this value larger will reduce the number of spaces added.- Parameters:
averageCharToleranceValue
- average tolerance / scaling factor to use
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getIndentThreshold
public float getIndentThreshold()returns the multiple of whitespace character widths for the current text which the current line start can be indented from the previous line start beyond which the current line start is considered to be a paragraph start.- Returns:
- the number of whitespace character widths to use when detecting paragraph indents.
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setIndentThreshold
public void setIndentThreshold(float indentThresholdValue) sets the multiple of whitespace character widths for the current text which the current line start can be indented from the previous line start beyond which the current line start is considered to be a paragraph start. The default value is 2.0.- Parameters:
indentThresholdValue
- the number of whitespace character widths to use when detecting paragraph indents.
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getDropThreshold
public float getDropThreshold()the minimum whitespace, as a multiple of the max height of the current characters beyond which the current line start is considered to be a paragraph start.- Returns:
- the character height multiple for max allowed whitespace between lines in the same paragraph.
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setDropThreshold
public void setDropThreshold(float dropThresholdValue) sets the minimum whitespace, as a multiple of the max height of the current characters beyond which the current line start is considered to be a paragraph start. The default value is 2.5.- Parameters:
dropThresholdValue
- the character height multiple for max allowed whitespace between lines in the same paragraph.
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getParagraphStart
Returns the string which will be used at the beginning of a paragraph.- Returns:
- the paragraph start string
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setParagraphStart
Sets the string which will be used at the beginning of a paragraph.- Parameters:
s
- the paragraph start string
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getParagraphEnd
Returns the string which will be used at the end of a paragraph.- Returns:
- the paragraph end string
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setParagraphEnd
Sets the string which will be used at the end of a paragraph.- Parameters:
s
- the paragraph end string
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getPageStart
Returns the string which will be used at the beginning of a page.- Returns:
- the page start string
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setPageStart
Sets the string which will be used at the beginning of a page.- Parameters:
pageStartValue
- the page start string
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getPageEnd
Returns the string which will be used at the end of a page.- Returns:
- the page end string
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setPageEnd
Sets the string which will be used at the end of a page.- Parameters:
pageEndValue
- the page end string
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getArticleStart
Returns the string which will be used at the beginning of an article.- Returns:
- the article start string
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setArticleStart
Sets the string which will be used at the beginning of an article.- Parameters:
articleStartValue
- the article start string
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getArticleEnd
Returns the string which will be used at the end of an article.- Returns:
- the article end string
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setArticleEnd
Sets the string which will be used at the end of an article.- Parameters:
articleEndValue
- the article end string
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writeParagraphSeparator
writes the paragraph separator string to the output.- Throws:
IOException
- if something went wrong
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writeParagraphStart
Write something (if defined) at the start of a paragraph.- Throws:
IOException
- if something went wrong
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writeParagraphEnd
Write something (if defined) at the end of a paragraph.- Throws:
IOException
- if something went wrong
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writePageStart
Write something (if defined) at the start of a page.- Throws:
IOException
- if something went wrong
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writePageEnd
Write something (if defined) at the end of a page.- Throws:
IOException
- if something went wrong
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setListItemPatterns
use to supply a different set of regular expression patterns for matching list item starts.- Parameters:
patterns
- list of patterns
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getListItemPatterns
returns a list of regular expression Patterns representing different common list item formats. For example numbered items of form:- some text
- more text
- some text
- more text
This method returns a list of such regular expression Patterns.
- Returns:
- a list of Pattern objects.
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matchPattern
iterates over the specified list of Patterns until it finds one that matches the specified string. Then returns the Pattern.Order of the supplied list of patterns is important as most common patterns should come first. Patterns should be strict in general, and all will be used with case sensitivity on.
- Parameters:
string
- the string to be searchedpatterns
- list of patterns- Returns:
- matching pattern
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showGlyph
protected void showGlyph(Matrix textRenderingMatrix, PDFont font, int code, String unicode, Vector displacement) throws IOException Called when a glyph is to be processed. The heuristic calculations here were originally written by Ben Litchfield for PDFStreamEngine.- Overrides:
showGlyph
in classPDFStreamEngine
- Parameters:
textRenderingMatrix
- the current text rendering matrix, Trmfont
- the current fontcode
- internal PDF character code for the glyphunicode
- the Unicode text for this glyph, or null if the PDF does provide itdisplacement
- the displacement (i.e. advance) of the glyph in text space- Throws:
IOException
- if the glyph cannot be processed
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computeFontHeight
Compute the font height. Override this if you want to use own calculations.- Parameters:
font
- the font.- Returns:
- the font height.
- Throws:
IOException
- if there is an error while getting the font bounding box.
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