Class JBIG2Page

java.lang.Object

org.apache.pdfbox.jbig2.JBIG2Page

class JBIG2Page
extends Object

This class represents a JBIG2 page.

Field Summary

Fields

Modifier and Type	Field	Description
private final JBIG2Document	document
private int	finalHeight
private int	finalWidth
private Bitmap	pageBitmap	The page bitmap that represents the page buffer
private final int	pageNumber	NOTE: page number != segmentList index
private int	resolutionX
private int	resolutionY
private final Map<Integer, SegmentHeader>	segments	This list contains all segments of this page, sorted by segment number in ascending order.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	JBIG2Page(JBIG2Document document, int pageNumber)

Method Summary

Modifier and Type	Method	Description
protected void	add(SegmentHeader segment)	Adds a SegmentHeader into the page's segments map.
protected void	clearPageData()	Reset memory-critical parts of page.
private void	clearSegmentData()	Resets the memory-critical segments to force on-demand-decoding and to avoid holding the segments' bitmap too long.
private ArrayList<SegmentData>	collectPageStripes()
private void	composePageBitmap()	This method composes the segments' bitmaps to a page and stores the page as a Bitmap
private int	countRegions()	This method counts the regions segments.
private void	createNormalPage(PageInformation pageInformation)
private void	createPage(PageInformation pageInformation)
private void	createStripedPage(PageInformation pageInformation)
private boolean	fitsPage(PageInformation pageInformation, Bitmap regionBitmap)	Check if we have only one region that forms the complete page.
protected Bitmap	getBitmap()	This method returns the decoded bitmap if present.
private CombinationOperator	getCombinationOperator(PageInformation pi, CombinationOperator newOperator)	This method checks and sets, which combination operator shall be used.
protected int	getHeight()	Returns the final height of the page.
protected SegmentHeader	getPageInformationSegment()	Returns the associated page information segment.
protected int	getResolutionX()
protected int	getResolutionY()
SegmentHeader	getSegment(int number)	This method searches for a segment specified by its number.
protected int	getWidth()
String	toString()

Methods inherited from class Object

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

Field Details

segments

private final Map<Integer, SegmentHeader> segments

This list contains all segments of this page, sorted by segment number in ascending order.

pageNumber

private final int pageNumber

NOTE: page number != segmentList index

pageBitmap

private Bitmap pageBitmap

The page bitmap that represents the page buffer

finalHeight

private int finalHeight

finalWidth

private int finalWidth

resolutionX

private int resolutionX

resolutionY

private int resolutionY

document

private final JBIG2Document document

Constructor Details

JBIG2Page

protected JBIG2Page(JBIG2Document document,
 int pageNumber)

Method Details

getSegment

public SegmentHeader getSegment(int number)

This method searches for a segment specified by its number.

Parameters:

number - - Segment number of the segment to search.

Returns:

The retrieved SegmentHeader or null if not available.

getPageInformationSegment

protected SegmentHeader getPageInformationSegment()

Returns the associated page information segment.

Returns:

The associated PageInformation segment or null if not available.

getBitmap

protected Bitmap getBitmap()
                    throws JBIG2Exception,
IOException

This method returns the decoded bitmap if present. Otherwise the page bitmap will be composed before returning the result.

Returns:

pageBitmap - The result of decoding a page

Throws:

JBIG2Exception

IOException

composePageBitmap

private void composePageBitmap()
                        throws IOException,
JBIG2Exception

This method composes the segments' bitmaps to a page and stores the page as a Bitmap

Throws:

IOException

JBIG2Exception

createPage

private void createPage(PageInformation pageInformation)
                 throws IOException,
IntegerMaxValueException,
InvalidHeaderValueException

Throws:

IOException

IntegerMaxValueException

InvalidHeaderValueException

createNormalPage

private void createNormalPage(PageInformation pageInformation)
                       throws IOException,
IntegerMaxValueException,
InvalidHeaderValueException

Throws:

IOException

IntegerMaxValueException

InvalidHeaderValueException

fitsPage

private boolean fitsPage(PageInformation pageInformation,
 Bitmap regionBitmap)

Check if we have only one region that forms the complete page. If the dimension equals the page's dimension set the region's bitmap as the page's bitmap. Otherwise we have to blit the smaller region's bitmap into the page's bitmap (see Issue 6).

Parameters:

pageInformation -

regionBitmap -

Returns:

createStripedPage

private void createStripedPage(PageInformation pageInformation)
                        throws IOException,
IntegerMaxValueException,
InvalidHeaderValueException

Throws:

IOException

IntegerMaxValueException

InvalidHeaderValueException

collectPageStripes

private ArrayList<SegmentData> collectPageStripes()

countRegions

private int countRegions()

This method counts the regions segments. If there is only one region, the bitmap of this segment is equal to the page bitmap and blitting is not necessary.

Returns:

Amount of regions.

getCombinationOperator

private CombinationOperator getCombinationOperator(PageInformation pi,
 CombinationOperator newOperator)

This method checks and sets, which combination operator shall be used.

Parameters:

pi - - PageInformation object

newOperator - - The combination operator, specified by actual segment

Returns:

the new combination operator

add

protected void add(SegmentHeader segment)

Adds a SegmentHeader into the page's segments map.

Parameters:

segment - - The segment to be added.

clearSegmentData

private void clearSegmentData()

Resets the memory-critical segments to force on-demand-decoding and to avoid holding the segments' bitmap too long.

clearPageData

protected void clearPageData()

Reset memory-critical parts of page.

getHeight

protected int getHeight()
                 throws IOException,
JBIG2Exception

Returns the final height of the page.

Returns:

The final height of the page.

Throws:

IOException

JBIG2Exception

getWidth

protected int getWidth()

getResolutionX

protected int getResolutionX()

getResolutionY

protected int getResolutionY()

toString

public String toString()

Overrides:

toString in class Object