Package com.jhlabs.image

Class PerspectiveFilter

java.lang.Object

com.jhlabs.image.AbstractBufferedImageOp

com.jhlabs.image.TransformFilter

com.jhlabs.image.PerspectiveFilter

All Implemented Interfaces:

java.awt.image.BufferedImageOp, java.lang.Cloneable

public class PerspectiveFilter
extends TransformFilter

A filter which performs a perspective distortion on an image. Coordinates are treated as if the image was a unit square, i.e. the bottom-right corner of the image is at (1, 1). The filter maps the unit square onto an arbitrary convex quadrilateral or vice versa.

Field Summary

Fields inherited from class com.jhlabs.image.TransformFilter

BILINEAR, CLAMP, edgeAction, interpolation, NEAREST_NEIGHBOUR, originalSpace, RGB_CLAMP, transformedSpace, WRAP, ZERO

Constructor Summary

Constructors

Constructor	Description
PerspectiveFilter()	Construct a PerspectiveFilter.
PerspectiveFilter(float x0, float y0, float x1, float y1, float x2, float y2, float x3, float y3)	Construct a PerspectiveFilter.

Method Summary

Modifier and Type	Method	Description
java.awt.image.BufferedImage	filter(java.awt.image.BufferedImage src, java.awt.image.BufferedImage dst)
java.awt.geom.Rectangle2D	getBounds2D(java.awt.image.BufferedImage src)
boolean	getClip()
float	getOriginX()	Get the origin of the output image.
float	getOriginY()	Get the origin of the output image.
java.awt.geom.Point2D	getPoint2D(java.awt.geom.Point2D srcPt, java.awt.geom.Point2D dstPt)
void	quadToUnitSquare(float x0, float y0, float x1, float y1, float x2, float y2, float x3, float y3)	Set the transform to map a quadrilateral onto the unit square.
void	setClip(boolean clip)
void	setCorners(float x0, float y0, float x1, float y1, float x2, float y2, float x3, float y3)	Set the new positions of the image corners.
java.lang.String	toString()
protected void	transformInverse(int x, int y, float[] out)	Inverse transform a point.
protected void	transformSpace(java.awt.Rectangle rect)	Forward transform a rectangle.
void	unitSquareToQuad(float x0, float y0, float x1, float y1, float x2, float y2, float x3, float y3)	Set the transform to map the unit square onto a quadrilateral.

Methods inherited from class com.jhlabs.image.TransformFilter

filterPixelsNN, getEdgeAction, getInterpolation, setEdgeAction, setInterpolation

Methods inherited from class com.jhlabs.image.AbstractBufferedImageOp

clone, createCompatibleDestImage, getRenderingHints, getRGB, setRGB, stringToColor

Methods inherited from class java.lang.Object

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

Constructor Detail

PerspectiveFilter

public PerspectiveFilter()

Construct a PerspectiveFilter.

PerspectiveFilter

public PerspectiveFilter(float x0,
                         float y0,
                         float x1,
                         float y1,
                         float x2,
                         float y2,
                         float x3,
                         float y3)

Construct a PerspectiveFilter.

Parameters:

x0 - the new position of the top left corner

y0 - the new position of the top left corner

x1 - the new position of the top right corner

y1 - the new position of the top right corner

x2 - the new position of the bottom right corner

y2 - the new position of the bottom right corner

x3 - the new position of the bottom left corner

y3 - the new position of the bottom left corner

Method Detail

setClip

public void setClip(boolean clip)

getClip

public boolean getClip()

setCorners

public void setCorners(float x0,
                       float y0,
                       float x1,
                       float y1,
                       float x2,
                       float y2,
                       float x3,
                       float y3)

Set the new positions of the image corners. This is the same as unitSquareToQuad, but the coordinates are in image pixels, not relative to the unit square. This method is provided as a convenience.

Parameters:

x0 - the new position of the top left corner

y0 - the new position of the top left corner

x1 - the new position of the top right corner

y1 - the new position of the top right corner

x2 - the new position of the bottom right corner

y2 - the new position of the bottom right corner

x3 - the new position of the bottom left corner

y3 - the new position of the bottom left corner

unitSquareToQuad

public void unitSquareToQuad(float x0,
                             float y0,
                             float x1,
                             float y1,
                             float x2,
                             float y2,
                             float x3,
                             float y3)

Set the transform to map the unit square onto a quadrilateral. When filtering, all coordinates will be scaled by the size of the image.

Parameters:

x0 - the new position of the top left corner

y0 - the new position of the top left corner

x1 - the new position of the top right corner

y1 - the new position of the top right corner

x2 - the new position of the bottom right corner

y2 - the new position of the bottom right corner

x3 - the new position of the bottom left corner

y3 - the new position of the bottom left corner

quadToUnitSquare

public void quadToUnitSquare(float x0,
                             float y0,
                             float x1,
                             float y1,
                             float x2,
                             float y2,
                             float x3,
                             float y3)

Set the transform to map a quadrilateral onto the unit square. When filtering, all coordinates will be scaled by the size of the image.

Parameters:

x0 - the old position of the top left corner

y0 - the old position of the top left corner

x1 - the old position of the top right corner

y1 - the old position of the top right corner

x2 - the old position of the bottom right corner

y2 - the old position of the bottom right corner

x3 - the old position of the bottom left corner

y3 - the old position of the bottom left corner

filter

public java.awt.image.BufferedImage filter(java.awt.image.BufferedImage src,
                                           java.awt.image.BufferedImage dst)

Specified by:

filter in interface java.awt.image.BufferedImageOp

Overrides:

filter in class TransformFilter

transformSpace

protected void transformSpace(java.awt.Rectangle rect)

Description copied from class: TransformFilter

Forward transform a rectangle. Used to determine the size of the output image.

Overrides:

transformSpace in class TransformFilter

Parameters:

rect - the rectangle to transform

getOriginX

public float getOriginX()

Get the origin of the output image. Use this for working out where to draw your new image.

Returns:

the X origin.

getOriginY

public float getOriginY()

Get the origin of the output image. Use this for working out where to draw your new image.

Returns:

the Y origin.

getBounds2D

public java.awt.geom.Rectangle2D getBounds2D(java.awt.image.BufferedImage src)

Specified by:

getBounds2D in interface java.awt.image.BufferedImageOp

Overrides:

getBounds2D in class AbstractBufferedImageOp

getPoint2D

public java.awt.geom.Point2D getPoint2D(java.awt.geom.Point2D srcPt,
                                        java.awt.geom.Point2D dstPt)

Specified by:

getPoint2D in interface java.awt.image.BufferedImageOp

Overrides:

getPoint2D in class AbstractBufferedImageOp

transformInverse

protected void transformInverse(int x,
                                int y,
                                float[] out)

Description copied from class: TransformFilter

Inverse transform a point. This method needs to be overriden by all subclasses.

Specified by:

transformInverse in class TransformFilter

Parameters:

x - the X position of the pixel in the output image

y - the Y position of the pixel in the output image

out - the position of the pixel in the input image

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object