org.sejda.sambox.contentstream

Class PDFStreamEngine

java.lang.Object

org.sejda.sambox.contentstream.PDFStreamEngine

Direct Known Subclasses:

PDFGraphicsStreamEngine, PDFTextStreamEngine

public abstract class PDFStreamEngine
extends Object

Processes a PDF content stream and executes certain operations. Provides a callback interface for clients that want to do things with the stream.

Author:

Ben Litchfield

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	PDFStreamEngine() Creates a new PDFStreamEngine.

Method Summary

Modifier and Type	Method and Description
void	addOperator(OperatorProcessor op) Adds an operator processor to the engine.
boolean	addOperatorIfAbsent(OperatorProcessor op) Adds an operator processor to the engine if there isn't an operator already associated with the PDF operator.
protected void	applyTextAdjustment(float tx, float ty) Applies a text position adjustment from the TJ operator.
void	beginMarkedContentSequence(COSName tag, COSDictionary properties) Called when a marked content group begins
void	beginText() Called when the BT operator is encountered.
void	decreaseLevel() Decrease the level.
void	endMarkedContentSequence() Called when a a marked content group ends
void	endText() Called when the ET operator is encountered.
PDAppearanceStream	getAppearance(PDAnnotation annotation) Returns the appearance stream to process for the given annotation.
PDPage	getCurrentPage() Returns the current page.
int	getGraphicsStackSize()
PDGraphicsState	getGraphicsState()
Matrix	getInitialMatrix() Gets the stream's initial matrix.
int	getLevel() Get the current level.
PDResources	getResources()
Matrix	getTextLineMatrix()
Matrix	getTextMatrix()
void	increaseLevel() Increase the level.
protected void	operatorException(Operator operator, List<COSBase> operands, IOException e) Called when an exception is thrown by an operator.
protected void	processAnnotation(PDAnnotation annotation, PDAppearanceStream appearance) Process the given annotation with the specified appearance stream.
protected void	processChildStream(PDContentStream contentStream, PDPage page) Process a child stream of the given page.
protected void	processOperator(Operator operator, List<COSBase> operands) This is used to handle an operation.
void	processOperator(String operation, List<COSBase> arguments) This is used to handle an operation.
void	processPage(PDPage page) This will initialise and process the contents of the stream.
protected void	processSoftMask(PDTransparencyGroup group) Processes a soft mask transparency group stream.
void	processStream(PDContentStream contentStream) Process a content stream.
protected void	processTilingPattern(PDTilingPattern tilingPattern, PDColor color, PDColorSpace colorSpace) Process the given tiling pattern.
protected void	processTilingPattern(PDTilingPattern tilingPattern, PDColor color, PDColorSpace colorSpace, Matrix patternMatrix) Process the given tiling pattern.
protected void	processTransparencyGroup(PDTransparencyGroup group) Processes a transparency group stream.
protected void	processType3Stream(PDType3CharProc charProc, Matrix textRenderingMatrix) Processes a Type 3 character stream.
protected void	restoreGraphicsStack(Deque<PDGraphicsState> snapshot) Restores the entire graphics stack.
void	restoreGraphicsState() Pops the current graphics state from the stack.
protected Deque<PDGraphicsState>	saveGraphicsStack() Saves the entire graphics stack.
void	saveGraphicsState() Pushes the current graphics state to the stack.
void	setLineDashPattern(COSArray array, int phase)
void	setTextLineMatrix(Matrix value)
void	setTextMatrix(Matrix value)
void	showAnnotation(PDAnnotation annotation) Shows the given annotation.
protected void	showFontGlyph(Matrix textRenderingMatrix, PDFont font, int code, String unicode, Vector displacement) Called when a glyph is to be processed.This method is intended for overriding in subclasses, the default implementation does nothing.
void	showForm(PDFormXObject form) Shows a form from the content stream.
protected void	showGlyph(Matrix textRenderingMatrix, PDFont font, int code, String unicode, Vector displacement) Called when a glyph is to be processed.This method is intended for overriding in subclasses, the default implementation does nothing.
protected void	showText(byte[] string) Process text from the PDF Stream.
void	showTextString(byte[] string) Called when a string of text is to be shown.
void	showTextStrings(COSArray array) Called when a string of text with spacing adjustments is to be shown.
void	showTransparencyGroup(PDTransparencyGroup form) Shows a transparency group from the content stream.
protected void	showType3Glyph(Matrix textRenderingMatrix, PDType3Font font, int code, String unicode, Vector displacement) Called when a glyph is to be processed.This method is intended for overriding in subclasses, the default implementation does nothing.
Point2D.Float	transformedPoint(float x, float y) Transforms a point using the CTM.
protected float	transformWidth(float width) Transforms a width using the CTM.
protected void	unsupportedOperator(Operator operator, List<COSBase> operands) Called when an unsupported operator is encountered.

Methods inherited from class java.lang.Object

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

Constructor Detail

PDFStreamEngine

protected PDFStreamEngine()

Creates a new PDFStreamEngine.

Method Detail

addOperator

public final void addOperator(OperatorProcessor op)

Adds an operator processor to the engine.

Parameters:

op - operator processor

addOperatorIfAbsent

public final boolean addOperatorIfAbsent(OperatorProcessor op)

Adds an operator processor to the engine if there isn't an operator already associated with the PDF operator.

Parameters:

op - operator processor

Returns:

true if the operator is added, false if not (there's already an operator associated)

processPage

public void processPage(PDPage page)
                 throws IOException

This will initialise and process the contents of the stream.

Parameters:

page - the page to process

Throws:

IOException - if there is an error accessing the stream

showTransparencyGroup

public void showTransparencyGroup(PDTransparencyGroup form)
                           throws IOException

Shows a transparency group from the content stream.

Parameters:

form - transparency group (form) XObject

Throws:

IOException - if the transparency group cannot be processed

showForm

public void showForm(PDFormXObject form)
              throws IOException

Shows a form from the content stream.

Parameters:

form - form XObject

Throws:

IOException - if the form cannot be processed

processSoftMask

protected void processSoftMask(PDTransparencyGroup group)
                        throws IOException

Processes a soft mask transparency group stream.

Parameters:

group -

Throws:

IOException

processTransparencyGroup

protected void processTransparencyGroup(PDTransparencyGroup group)
                                 throws IOException

Processes a transparency group stream.

Parameters:

group -

Throws:

IOException

processType3Stream

protected void processType3Stream(PDType3CharProc charProc,
                                  Matrix textRenderingMatrix)
                           throws IOException

Processes a Type 3 character stream.

Parameters:

charProc - Type 3 character procedure

textRenderingMatrix - the Text Rendering Matrix

Throws:

IOException

processAnnotation

protected void processAnnotation(PDAnnotation annotation,
                                 PDAppearanceStream appearance)
                          throws IOException

Process the given annotation with the specified appearance stream.

Parameters:

annotation - The annotation containing the appearance stream to process.

appearance - The appearance stream to process.

Throws:

IOException

processTilingPattern

protected final void processTilingPattern(PDTilingPattern tilingPattern,
                                          PDColor color,
                                          PDColorSpace colorSpace)
                                   throws IOException

Process the given tiling pattern.

Parameters:

tilingPattern - the tiling pattern

color - color to use, if this is an uncoloured pattern, otherwise null.

colorSpace - color space to use, if this is an uncoloured pattern, otherwise null.

Throws:

IOException

processTilingPattern

protected final void processTilingPattern(PDTilingPattern tilingPattern,
                                          PDColor color,
                                          PDColorSpace colorSpace,
                                          Matrix patternMatrix)
                                   throws IOException

Process the given tiling pattern. Allows the pattern matrix to be overridden for custom rendering.

Parameters:

tilingPattern - the tiling pattern

color - color to use, if this is an uncoloured pattern, otherwise null.

colorSpace - color space to use, if this is an uncoloured pattern, otherwise null.

patternMatrix - the pattern matrix, may be overridden for custom rendering.

Throws:

IOException

showAnnotation

public void showAnnotation(PDAnnotation annotation)
                    throws IOException

Shows the given annotation.

Parameters:

annotation - An annotation on the current page.

Throws:

IOException - If an error occurred reading the annotation

getAppearance

public PDAppearanceStream getAppearance(PDAnnotation annotation)

Returns the appearance stream to process for the given annotation. May be used to render a specific appearance such as "hover".

Parameters:

annotation - The current annotation.

Returns:

The stream to process.

processChildStream

protected void processChildStream(PDContentStream contentStream,
                                  PDPage page)
                           throws IOException

Process a child stream of the given page. Cannot be used with #processPage(PDPage).

Parameters:

contentStream - the child content stream

Throws:

IOException - if there is an exception while processing the stream

processStream

public void processStream(PDContentStream contentStream)
                   throws IOException

Process a content stream.

Parameters:

contentStream - the content stream

Throws:

IOException - if there is an exception while processing the stream

beginText

public void beginText()
               throws IOException

Called when the BT operator is encountered. This method is for overriding in subclasses, the default implementation does nothing.

Throws:

IOException - if there was an error processing the text

endText

public void endText()
             throws IOException

Called when the ET operator is encountered. This method is for overriding in subclasses, the default implementation does nothing.

Throws:

IOException - if there was an error processing the text

showTextString

public void showTextString(byte[] string)
                    throws IOException

Called when a string of text is to be shown.

Parameters:

string - the encoded text

Throws:

IOException - if there was an error showing the text

showTextStrings

public void showTextStrings(COSArray array)
                     throws IOException

Called when a string of text with spacing adjustments is to be shown.

Parameters:

array - array of encoded text strings and adjustments

Throws:

IOException - if there was an error showing the text

applyTextAdjustment

protected void applyTextAdjustment(float tx,
                                   float ty)
                            throws IOException

Applies a text position adjustment from the TJ operator. May be overridden in subclasses.

Parameters:

tx - x-translation

ty - y-translation

Throws:

IOException

showText

protected void showText(byte[] string)
                 throws IOException

Process text from the PDF Stream. You should override this method if you want to perform an action when encoded text is being processed.

Parameters:

string - the encoded text

Throws:

IOException - if there is an error processing the string

showGlyph

protected void showGlyph(Matrix textRenderingMatrix,
                         PDFont font,
                         int code,
                         String unicode,
                         Vector displacement)
                  throws IOException

Called when a glyph is to be processed.This method is intended for overriding in subclasses, the default implementation does nothing.

Parameters:

textRenderingMatrix - the current text rendering matrix, T_rm

font - the current font

code - internal PDF character code for the glyph

unicode - the Unicode text for this glyph, or null if the PDF does provide it

displacement - the displacement (i.e. advance) of the glyph in text space

Throws:

IOException - if the glyph cannot be processed

showFontGlyph

protected void showFontGlyph(Matrix textRenderingMatrix,
                             PDFont font,
                             int code,
                             String unicode,
                             Vector displacement)
                      throws IOException

Called when a glyph is to be processed.This method is intended for overriding in subclasses, the default implementation does nothing.

Parameters:

textRenderingMatrix - the current text rendering matrix, T_rm

font - the current font

code - internal PDF character code for the glyph

unicode - the Unicode text for this glyph, or null if the PDF does provide it

displacement - the displacement (i.e. advance) of the glyph in text space

Throws:

IOException - if the glyph cannot be processed

showType3Glyph

protected void showType3Glyph(Matrix textRenderingMatrix,
                              PDType3Font font,
                              int code,
                              String unicode,
                              Vector displacement)
                       throws IOException

Called when a glyph is to be processed.This method is intended for overriding in subclasses, the default implementation does nothing.

Parameters:

textRenderingMatrix - the current text rendering matrix, T_rm

font - the current font

code - internal PDF character code for the glyph

unicode - the Unicode text for this glyph, or null if the PDF does provide it

displacement - the displacement (i.e. advance) of the glyph in text space

Throws:

IOException - if the glyph cannot be processed

beginMarkedContentSequence

public void beginMarkedContentSequence(COSName tag,
                                       COSDictionary properties)

Called when a marked content group begins

Parameters:

tag - content tag

properties - optional properties

endMarkedContentSequence

public void endMarkedContentSequence()

Called when a a marked content group ends

processOperator

public void processOperator(String operation,
                            List<COSBase> arguments)
                     throws IOException

This is used to handle an operation.

Parameters:

operation - The operation to perform.

arguments - The list of arguments.

Throws:

IOException - If there is an error processing the operation.

processOperator

protected void processOperator(Operator operator,
                               List<COSBase> operands)
                        throws IOException

This is used to handle an operation.

Parameters:

operator - The operation to perform.

operands - The list of arguments.

Throws:

IOException - If there is an error processing the operation.

unsupportedOperator

protected void unsupportedOperator(Operator operator,
                                   List<COSBase> operands)
                            throws IOException

Called when an unsupported operator is encountered.

Parameters:

operator - The unknown operator.

operands - The list of operands.

Throws:

IOException

operatorException

protected void operatorException(Operator operator,
                                 List<COSBase> operands,
                                 IOException e)
                          throws IOException

Called when an exception is thrown by an operator.

Parameters:

operator - The unknown operator.

operands - The list of operands.

Throws:

IOException

saveGraphicsState

public void saveGraphicsState()

Pushes the current graphics state to the stack.

restoreGraphicsState

public void restoreGraphicsState()

Pops the current graphics state from the stack.

saveGraphicsStack

protected final Deque<PDGraphicsState> saveGraphicsStack()

Saves the entire graphics stack.

restoreGraphicsStack

protected final void restoreGraphicsStack(Deque<PDGraphicsState> snapshot)

Restores the entire graphics stack.

getGraphicsStackSize

public int getGraphicsStackSize()

Returns:

Returns the size of the graphicsStack.

getGraphicsState

public PDGraphicsState getGraphicsState()

Returns:

Returns the graphicsState.

getTextLineMatrix

public Matrix getTextLineMatrix()

Returns:

Returns the textLineMatrix.

setTextLineMatrix

public void setTextLineMatrix(Matrix value)

Parameters:

value - The textLineMatrix to set.

getTextMatrix

public Matrix getTextMatrix()

Returns:

Returns the textMatrix.

setTextMatrix

public void setTextMatrix(Matrix value)

Parameters:

value - The textMatrix to set.

setLineDashPattern

public void setLineDashPattern(COSArray array,
                               int phase)

Parameters:

array - dash array

phase - dash phase

getResources

public PDResources getResources()

Returns:

the stream' resources. This is mainly to be used by the OperatorProcessor classes

getCurrentPage

public PDPage getCurrentPage()

Returns the current page.

getInitialMatrix

public Matrix getInitialMatrix()

Gets the stream's initial matrix.

transformedPoint

public Point2D.Float transformedPoint(float x,
                                      float y)

Transforms a point using the CTM.

transformWidth

protected float transformWidth(float width)

Transforms a width using the CTM.

getLevel

public int getLevel()

Get the current level. This can be used to decide whether a recursion has done too deep and an operation should be skipped to avoid a stack overflow.

Returns:

the current level.

increaseLevel

public void increaseLevel()

Increase the level. Call this before running a potentially recursive operation.

decreaseLevel

public void decreaseLevel()

Decrease the level. Call this after running a potentially recursive operation. A log message is shown if the level is below 0. This can happen if the level is not decreased after an operation is done, e.g. by using a "finally" block.