Package org.apache.pdfbox.rendering

Class GroupGraphics

java.lang.Object

java.awt.Graphics

java.awt.Graphics2D

org.apache.pdfbox.rendering.GroupGraphics

class GroupGraphics
extends Graphics2D

Graphics implementation for non-isolated transparency groups.

Non-isolated groups require that the group backdrop (copied from parent group or page) is used as the initial contents of the image to which the group is rendered. This allows blend modes to blend the group contents with the graphics behind the group. Finally when the group rendering is done, backdrop removal must be computed (see removeBackdrop). It ensures the backdrop is not rendered twice on the parent but it leaves the effects of blend modes.

This class renders the group contents to two images. groupImage is initialized with the backdrop and group contents are drawn over it. groupAlphaImage is initially fully transparent and it accumulates the total alpha of the group contents excluding backdrop.

If a non-isolated group uses only the blend mode Normal, it can be optimized and rendered like an isolated group; backdrop usage and removal are not needed.

Field Summary

Fields

Modifier and Type	Field	Description
private final Graphics2D	alphaG2D
private final BufferedImage	groupAlphaImage
private final Graphics2D	groupG2D
private final BufferedImage	groupImage

Constructor Summary

Constructors

Modifier	Constructor	Description
(package private)	GroupGraphics(BufferedImage groupImage, Graphics2D groupGraphics)
private	GroupGraphics(BufferedImage groupImage, Graphics2D groupGraphics, BufferedImage groupAlphaImage, Graphics2D alphaGraphics)

Method Summary

Modifier and Type	Method	Description
void	addRenderingHints(Map<?,?> hints)
private int	backdropRemoval(int groupRGB, int backdropRGB, int shift, float alphaFactor)	Computes the backdrop removal equation.
void	clearRect(int x, int y, int width, int height)
void	clip(Shape s)
void	clipRect(int x, int y, int width, int height)
void	copyArea(int x, int y, int width, int height, int dx, int dy)
Graphics	create()
void	dispose()
void	draw(Shape s)
void	drawArc(int x, int y, int width, int height, int startAngle, int arcAngle)
void	drawGlyphVector(GlyphVector g, float x, float y)
void	drawImage(BufferedImage img, BufferedImageOp op, int x, int y)
boolean	drawImage(Image img, int dx1, int dy1, int dx2, int dy2, int sx1, int sy1, int sx2, int sy2, Color bgcolor, ImageObserver observer)
boolean	drawImage(Image img, int dx1, int dy1, int dx2, int dy2, int sx1, int sy1, int sx2, int sy2, ImageObserver observer)
boolean	drawImage(Image img, int x, int y, int width, int height, Color bgcolor, ImageObserver observer)
boolean	drawImage(Image img, int x, int y, int width, int height, ImageObserver observer)
boolean	drawImage(Image img, int x, int y, Color bgcolor, ImageObserver observer)
boolean	drawImage(Image img, int x, int y, ImageObserver observer)
boolean	drawImage(Image img, AffineTransform xform, ImageObserver obs)
void	drawLine(int x1, int y1, int x2, int y2)
void	drawOval(int x, int y, int width, int height)
void	drawPolygon(int[] xPoints, int[] yPoints, int nPoints)
void	drawPolyline(int[] xPoints, int[] yPoints, int nPoints)
void	drawRenderableImage(RenderableImage img, AffineTransform xform)
void	drawRenderedImage(RenderedImage img, AffineTransform xform)
void	drawRoundRect(int x, int y, int width, int height, int arcWidth, int arcHeight)
void	drawString(String str, float x, float y)
void	drawString(String str, int x, int y)
void	drawString(AttributedCharacterIterator iterator, float x, float y)
void	drawString(AttributedCharacterIterator iterator, int x, int y)
void	fill(Shape s)
void	fillArc(int x, int y, int width, int height, int startAngle, int arcAngle)
void	fillOval(int x, int y, int width, int height)
void	fillPolygon(int[] xPoints, int[] yPoints, int nPoints)
void	fillRect(int x, int y, int width, int height)
void	fillRoundRect(int x, int y, int width, int height, int arcWidth, int arcHeight)
Color	getBackground()
Shape	getClip()
Rectangle	getClipBounds()
Color	getColor()
Composite	getComposite()
GraphicsConfiguration	getDeviceConfiguration()
Font	getFont()
FontMetrics	getFontMetrics(Font f)
FontRenderContext	getFontRenderContext()
Paint	getPaint()
Object	getRenderingHint(RenderingHints.Key hintKey)
RenderingHints	getRenderingHints()
Stroke	getStroke()
AffineTransform	getTransform()
boolean	hit(Rectangle rect, Shape s, boolean onStroke)
(package private) void	removeBackdrop(BufferedImage backdrop, int offsetX, int offsetY)	Computes backdrop removal.
void	rotate(double theta)
void	rotate(double theta, double x, double y)
void	scale(double sx, double sy)
void	setBackground(Color color)
void	setClip(int x, int y, int width, int height)
void	setClip(Shape clip)
void	setColor(Color c)
void	setComposite(Composite comp)
void	setFont(Font font)
void	setPaint(Paint paint)
void	setPaintMode()
void	setRenderingHint(RenderingHints.Key hintKey, Object hintValue)
void	setRenderingHints(Map<?,?> hints)
void	setStroke(Stroke s)
void	setTransform(AffineTransform tx)
void	setXORMode(Color c1)
void	shear(double shx, double shy)
void	transform(AffineTransform tx)
void	translate(double tx, double ty)
void	translate(int x, int y)

Methods inherited from class java.awt.Graphics2D

draw3DRect, fill3DRect

Methods inherited from class java.awt.Graphics

create, drawBytes, drawChars, drawPolygon, drawRect, fillPolygon, finalize, getClipBounds, getClipRect, getFontMetrics, hitClip, toString

Methods inherited from class java.lang.Object

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

Field Details

groupImage

private final BufferedImage groupImage

groupAlphaImage

private final BufferedImage groupAlphaImage

groupG2D

private final Graphics2D groupG2D

alphaG2D

private final Graphics2D alphaG2D

Constructor Details

GroupGraphics

GroupGraphics(BufferedImage groupImage,
 Graphics2D groupGraphics)

GroupGraphics

private GroupGraphics(BufferedImage groupImage,
 Graphics2D groupGraphics,
 BufferedImage groupAlphaImage,
 Graphics2D alphaGraphics)

Method Details

clearRect

public void clearRect(int x,
 int y,
 int width,
 int height)

Specified by:

clearRect in class Graphics

clipRect

public void clipRect(int x,
 int y,
 int width,
 int height)

Specified by:

clipRect in class Graphics

copyArea

public void copyArea(int x,
 int y,
 int width,
 int height,
 int dx,
 int dy)

Specified by:

copyArea in class Graphics

create

public Graphics create()

Specified by:

create in class Graphics

dispose

public void dispose()

Specified by:

dispose in class Graphics

drawArc

public void drawArc(int x,
 int y,
 int width,
 int height,
 int startAngle,
 int arcAngle)

Specified by:

drawArc in class Graphics

drawImage

public boolean drawImage(Image img,
 int x,
 int y,
 Color bgcolor,
 ImageObserver observer)

Specified by:

drawImage in class Graphics

drawImage

public boolean drawImage(Image img,
 int x,
 int y,
 ImageObserver observer)

Specified by:

drawImage in class Graphics

drawImage

public boolean drawImage(Image img,
 int x,
 int y,
 int width,
 int height,
 Color bgcolor,
 ImageObserver observer)

Specified by:

drawImage in class Graphics

drawImage

public boolean drawImage(Image img,
 int x,
 int y,
 int width,
 int height,
 ImageObserver observer)

Specified by:

drawImage in class Graphics

drawImage

public boolean drawImage(Image img,
 int dx1,
 int dy1,
 int dx2,
 int dy2,
 int sx1,
 int sy1,
 int sx2,
 int sy2,
 Color bgcolor,
 ImageObserver observer)

Specified by:

drawImage in class Graphics

drawImage

public boolean drawImage(Image img,
 int dx1,
 int dy1,
 int dx2,
 int dy2,
 int sx1,
 int sy1,
 int sx2,
 int sy2,
 ImageObserver observer)

Specified by:

drawImage in class Graphics

drawLine

public void drawLine(int x1,
 int y1,
 int x2,
 int y2)

Specified by:

drawLine in class Graphics

drawOval

public void drawOval(int x,
 int y,
 int width,
 int height)

Specified by:

drawOval in class Graphics

drawPolygon

public void drawPolygon(int[] xPoints,
 int[] yPoints,
 int nPoints)

Specified by:

drawPolygon in class Graphics

drawPolyline

public void drawPolyline(int[] xPoints,
 int[] yPoints,
 int nPoints)

Specified by:

drawPolyline in class Graphics

drawRoundRect

public void drawRoundRect(int x,
 int y,
 int width,
 int height,
 int arcWidth,
 int arcHeight)

Specified by:

drawRoundRect in class Graphics

drawString

public void drawString(AttributedCharacterIterator iterator,
 int x,
 int y)

Specified by:

drawString in class Graphics2D

drawString

public void drawString(String str,
 int x,
 int y)

Specified by:

drawString in class Graphics2D

fillArc

public void fillArc(int x,
 int y,
 int width,
 int height,
 int startAngle,
 int arcAngle)

Specified by:

fillArc in class Graphics

fillOval

public void fillOval(int x,
 int y,
 int width,
 int height)

Specified by:

fillOval in class Graphics

fillPolygon

public void fillPolygon(int[] xPoints,
 int[] yPoints,
 int nPoints)

Specified by:

fillPolygon in class Graphics

fillRect

public void fillRect(int x,
 int y,
 int width,
 int height)

Specified by:

fillRect in class Graphics

fillRoundRect

public void fillRoundRect(int x,
 int y,
 int width,
 int height,
 int arcWidth,
 int arcHeight)

Specified by:

fillRoundRect in class Graphics

getClip

public Shape getClip()

Specified by:

getClip in class Graphics

getClipBounds

public Rectangle getClipBounds()

Specified by:

getClipBounds in class Graphics

getColor

public Color getColor()

Specified by:

getColor in class Graphics

getFont

public Font getFont()

Specified by:

getFont in class Graphics

getFontMetrics

public FontMetrics getFontMetrics(Font f)

Specified by:

getFontMetrics in class Graphics

setClip

public void setClip(int x,
 int y,
 int width,
 int height)

Specified by:

setClip in class Graphics

setClip

public void setClip(Shape clip)

Specified by:

setClip in class Graphics

setColor

public void setColor(Color c)

Specified by:

setColor in class Graphics

setFont

public void setFont(Font font)

Specified by:

setFont in class Graphics

setPaintMode

public void setPaintMode()

Specified by:

setPaintMode in class Graphics

setXORMode

public void setXORMode(Color c1)

Specified by:

setXORMode in class Graphics

translate

public void translate(int x,
 int y)

Specified by:

translate in class Graphics2D

addRenderingHints

public void addRenderingHints(Map<?,?> hints)

Specified by:

addRenderingHints in class Graphics2D

clip

public void clip(Shape s)

Specified by:

clip in class Graphics2D

draw

public void draw(Shape s)

Specified by:

draw in class Graphics2D

drawGlyphVector

public void drawGlyphVector(GlyphVector g,
 float x,
 float y)

Specified by:

drawGlyphVector in class Graphics2D

drawImage

public void drawImage(BufferedImage img,
 BufferedImageOp op,
 int x,
 int y)

Specified by:

drawImage in class Graphics2D

drawImage

public boolean drawImage(Image img,
 AffineTransform xform,
 ImageObserver obs)

Specified by:

drawImage in class Graphics2D

drawRenderableImage

public void drawRenderableImage(RenderableImage img,
 AffineTransform xform)

Specified by:

drawRenderableImage in class Graphics2D

drawRenderedImage

public void drawRenderedImage(RenderedImage img,
 AffineTransform xform)

Specified by:

drawRenderedImage in class Graphics2D

drawString

public void drawString(AttributedCharacterIterator iterator,
 float x,
 float y)

Specified by:

drawString in class Graphics2D

drawString

public void drawString(String str,
 float x,
 float y)

Specified by:

drawString in class Graphics2D

fill

public void fill(Shape s)

Specified by:

fill in class Graphics2D

getBackground

public Color getBackground()

Specified by:

getBackground in class Graphics2D

getComposite

public Composite getComposite()

Specified by:

getComposite in class Graphics2D

getDeviceConfiguration

public GraphicsConfiguration getDeviceConfiguration()

Specified by:

getDeviceConfiguration in class Graphics2D

getFontRenderContext

public FontRenderContext getFontRenderContext()

Specified by:

getFontRenderContext in class Graphics2D

getPaint

public Paint getPaint()

Specified by:

getPaint in class Graphics2D

getRenderingHint

public Object getRenderingHint(RenderingHints.Key hintKey)

Specified by:

getRenderingHint in class Graphics2D

getRenderingHints

public RenderingHints getRenderingHints()

Specified by:

getRenderingHints in class Graphics2D

getStroke

public Stroke getStroke()

Specified by:

getStroke in class Graphics2D

getTransform

public AffineTransform getTransform()

Specified by:

getTransform in class Graphics2D

hit

public boolean hit(Rectangle rect,
 Shape s,
 boolean onStroke)

Specified by:

hit in class Graphics2D

rotate

public void rotate(double theta)

Specified by:

rotate in class Graphics2D

rotate

public void rotate(double theta,
 double x,
 double y)

Specified by:

rotate in class Graphics2D

scale

public void scale(double sx,
 double sy)

Specified by:

scale in class Graphics2D

setBackground

public void setBackground(Color color)

Specified by:

setBackground in class Graphics2D

setComposite

public void setComposite(Composite comp)

Specified by:

setComposite in class Graphics2D

setPaint

public void setPaint(Paint paint)

Specified by:

setPaint in class Graphics2D

setRenderingHint

public void setRenderingHint(RenderingHints.Key hintKey,
 Object hintValue)

Specified by:

setRenderingHint in class Graphics2D

setRenderingHints

public void setRenderingHints(Map<?,?> hints)

Specified by:

setRenderingHints in class Graphics2D

setStroke

public void setStroke(Stroke s)

Specified by:

setStroke in class Graphics2D

setTransform

public void setTransform(AffineTransform tx)

Specified by:

setTransform in class Graphics2D

shear

public void shear(double shx,
 double shy)

Specified by:

shear in class Graphics2D

transform

public void transform(AffineTransform tx)

Specified by:

transform in class Graphics2D

translate

public void translate(double tx,
 double ty)

Specified by:

translate in class Graphics2D

removeBackdrop

void removeBackdrop(BufferedImage backdrop,
 int offsetX,
 int offsetY)

Computes backdrop removal. The backdrop removal equation is given in section 11.4.4 in the PDF 32000-1:2008 standard. It returns the final color C for each pixel in the group:
C = Cn + (Cn - C0) * (alpha0 / alphagn - alpha0)
where
Cn is the group color including backdrop (read from groupImage),
C0 is the backdrop color,
alpha0 is the backdrop alpha,
alphagn is the group alpha excluding backdrop (read the alpha channel from groupAlphaImage)

The alpha of the result is equal to alphagn, i.e., the alpha channel of groupAlphaImage.

The backdrop image may be much larger than groupImage if, for example, the current page is used as the backdrop. Only a specific rectangular region of backdrop is used in the backdrop removal: upper-left corner is at (offsetX, offsetY); width and height are equal to those of groupImage.

Parameters:

backdrop - group backdrop

offsetX - backdrop left X coordinate

offsetY - backdrop upper Y coordinate

backdropRemoval

private int backdropRemoval(int groupRGB,
 int backdropRGB,
 int shift,
 float alphaFactor)

Computes the backdrop removal equation. C = Cn + (Cn - C0) * (alpha0 / alphagn - alpha0)