com.itextpdf.text.pdf.parser

Class LocationTextExtractionStrategy

java.lang.Object

com.itextpdf.text.pdf.parser.LocationTextExtractionStrategy

All Implemented Interfaces:

RenderListener, TextExtractionStrategy

public class LocationTextExtractionStrategy
extends Object
implements TextExtractionStrategy

Development preview - this class (and all of the parser classes) are still experiencing heavy development, and are subject to change both behavior and interface.
A text extraction renderer that keeps track of relative position of text on page The resultant text will be relatively consistent with the physical layout that most PDF files have on screen.
This renderer keeps track of the orientation and distance (both perpendicular and parallel) to the unit vector of the orientation. Text is ordered by orientation, then perpendicular, then parallel distance. Text with the same perpendicular distance, but different parallel distance is treated as being on the same line.
This renderer also uses a simple strategy based on the font metrics to determine if a blank space should be inserted into the output.

Since:

5.0.2

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LocationTextExtractionStrategy.TextChunk Represents a chunk of text, it's orientation, and location relative to the orientation vector
static interface	LocationTextExtractionStrategy.TextChunkFilter Specifies a filter for filtering LocationTextExtractionStrategy.TextChunk objects during text extraction
static interface	LocationTextExtractionStrategy.TextChunkLocation
static class	LocationTextExtractionStrategy.TextChunkLocationDefaultImp
static interface	LocationTextExtractionStrategy.TextChunkLocationStrategy

Constructor Summary

Constructors

Constructor and Description
LocationTextExtractionStrategy() Creates a new text extraction renderer.
LocationTextExtractionStrategy(LocationTextExtractionStrategy.TextChunkLocationStrategy strat) Creates a new text extraction renderer, with a custom strategy for creating new TextChunkLocation objects based on the input of the TextRenderInfo.

Method Summary

Modifier and Type	Method and Description
void	beginTextBlock() Called when a new text block is beginning (i.e.
void	endTextBlock() Called when a text block has ended (i.e.
String	getResultantText() Returns the result so far.
String	getResultantText(LocationTextExtractionStrategy.TextChunkFilter chunkFilter) Gets text that meets the specified filter If multiple text extractions will be performed for the same page (i.e. for different physical regions of the page), filtering at this level is more efficient than filtering using FilteredRenderListener - but not nearly as powerful because most of the RenderInfo state is not captured in LocationTextExtractionStrategy.TextChunk
protected boolean	isChunkAtWordBoundary(LocationTextExtractionStrategy.TextChunk chunk, LocationTextExtractionStrategy.TextChunk previousChunk) Determines if a space character should be inserted between a previous chunk and the current chunk.
void	renderImage(ImageRenderInfo renderInfo) no-op method - this renderer isn't interested in image events
void	renderText(TextRenderInfo renderInfo) Called when text should be rendered

Methods inherited from class java.lang.Object

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

Constructor Detail

LocationTextExtractionStrategy

public LocationTextExtractionStrategy()

Creates a new text extraction renderer.

LocationTextExtractionStrategy

public LocationTextExtractionStrategy(LocationTextExtractionStrategy.TextChunkLocationStrategy strat)

Creates a new text extraction renderer, with a custom strategy for creating new TextChunkLocation objects based on the input of the TextRenderInfo.

Parameters:

strat - the custom strategy

Method Detail

beginTextBlock

public void beginTextBlock()

Description copied from interface: RenderListener

Called when a new text block is beginning (i.e. BT)

Specified by:

beginTextBlock in interface RenderListener

See Also:

RenderListener.beginTextBlock()

endTextBlock

public void endTextBlock()

Description copied from interface: RenderListener

Called when a text block has ended (i.e. ET)

Specified by:

endTextBlock in interface RenderListener

See Also:

RenderListener.endTextBlock()

isChunkAtWordBoundary

protected boolean isChunkAtWordBoundary(LocationTextExtractionStrategy.TextChunk chunk,
                                        LocationTextExtractionStrategy.TextChunk previousChunk)

Determines if a space character should be inserted between a previous chunk and the current chunk. This method is exposed as a callback so subclasses can fine time the algorithm for determining whether a space should be inserted or not. By default, this method will insert a space if the there is a gap of more than half the font space character width between the end of the previous chunk and the beginning of the current chunk. It will also indicate that a space is needed if the starting point of the new chunk appears *before* the end of the previous chunk (i.e. overlapping text).

Parameters:

chunk - the new chunk being evaluated

previousChunk - the chunk that appeared immediately before the current chunk

Returns:

true if the two chunks represent different words (i.e. should have a space between them). False otherwise.

getResultantText

public String getResultantText(LocationTextExtractionStrategy.TextChunkFilter chunkFilter)

Gets text that meets the specified filter If multiple text extractions will be performed for the same page (i.e. for different physical regions of the page), filtering at this level is more efficient than filtering using FilteredRenderListener - but not nearly as powerful because most of the RenderInfo state is not captured in LocationTextExtractionStrategy.TextChunk

Parameters:

chunkFilter - the filter to to apply

Returns:

the text results so far, filtered using the specified filter

getResultantText

public String getResultantText()

Returns the result so far.

Specified by:

getResultantText in interface TextExtractionStrategy

Returns:

a String with the resulting text.

renderText

public void renderText(TextRenderInfo renderInfo)

Description copied from interface: RenderListener

Called when text should be rendered

Specified by:

renderText in interface RenderListener

Parameters:

renderInfo - information specifying what to render

See Also:

RenderListener.renderText(com.itextpdf.text.pdf.parser.TextRenderInfo)

renderImage

public void renderImage(ImageRenderInfo renderInfo)

no-op method - this renderer isn't interested in image events

Specified by:

renderImage in interface RenderListener

Parameters:

renderInfo - information specifying what to render

Since:

5.0.1

See Also:

RenderListener.renderImage(com.itextpdf.text.pdf.parser.ImageRenderInfo)