Package org.apache.pdfbox.jbig2.image

Class Resizer

java.lang.Object

org.apache.pdfbox.jbig2.image.Resizer

class Resizer
extends java.lang.Object

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	Resizer.Mapping
private static class	Resizer.Order	Order in which to apply filter

Field Summary

Fields

Modifier and Type	Field	Description
private int[]	bitsPerChannel	Number of bits per channel
private boolean	coerce	Should filters be simplified if possible?
(package private) static boolean	debug
private static double	EPSILON	Error tolerance
private int[]	finalShift
private Resizer.Mapping	mappingX
private Resizer.Mapping	mappingY
private static int[]	NO_SHIFT
private Resizer.Order	order	The order in which data is processed.
private boolean	trimZeros	Should zeros be trimmed in x filter weight tables?
private int	weightBits	Number of bits in filter coefficients
private int	weightOne

Constructor Summary

Constructors

Constructor	Description
Resizer(double scale)	Creates an instance of Resizer with one scale factor for both x and y directions.
Resizer(double scaleX, double scaleY)	Creates an instance of Resizer with a scale factor for each direction.

Method Summary

Modifier and Type	Method	Description
private static Scanline	createScanline(java.lang.Object src, java.lang.Object dst, int length)
private Weighttab[]	createXWeights(java.awt.Rectangle srcBounds, java.awt.Rectangle dstBounds, ParameterizedFilter filter)
private static boolean	isInteger(double x)	Is x an integer?
void	resize(java.lang.Object src, java.awt.Rectangle srcBounds, java.lang.Object dst, java.awt.Rectangle dstBounds, Filter xFilter, Filter yFilter)
private void	resizeXfirst(java.lang.Object src, java.awt.Rectangle srcBounds, java.lang.Object dst, java.awt.Rectangle dstBounds, ParameterizedFilter xFilter, ParameterizedFilter yFilter)	Filtered zoom, x direction filtering before y direction filtering
private void	resizeYfirst(java.lang.Object src, java.awt.Rectangle srcBounds, java.lang.Object dst, java.awt.Rectangle dstBounds, ParameterizedFilter xFilter, ParameterizedFilter yFilter)	Filtered zoom, y direction filtering before x direction filtering
private ParameterizedFilter	simplifyFilter(ParameterizedFilter filter, double scale, double offset)	Checks if our discrete sampling of an arbitrary continuous filter, parameterized by the filter spacing (ParameterizedFilter.scale), its radius (ParameterizedFilter.support), and the scale and offset of the coordinate mapping, causes the filter to reduce to point sampling.

Methods inherited from class java.lang.Object

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

Field Detail

EPSILON

private static final double EPSILON

Error tolerance

See Also:

Constant Field Values

weightBits

private int weightBits

Number of bits in filter coefficients

weightOne

private int weightOne

bitsPerChannel

private int[] bitsPerChannel

Number of bits per channel

NO_SHIFT

private static final int[] NO_SHIFT

finalShift

private int[] finalShift

debug

static final boolean debug

See Also:

Constant Field Values

coerce

private final boolean coerce

Should filters be simplified if possible?

See Also:

Constant Field Values

order

private final Resizer.Order order

The order in which data is processed.

See Also:

Resizer.Order

trimZeros

private final boolean trimZeros

Should zeros be trimmed in x filter weight tables?

See Also:

Constant Field Values

mappingX

private final Resizer.Mapping mappingX

mappingY

private final Resizer.Mapping mappingY

Constructor Detail

Resizer

public Resizer(double scale)

Creates an instance of Resizer with one scale factor for both x and y directions.

Parameters:

scale - the scale factor for x and y direction

Resizer

public Resizer(double scaleX,
               double scaleY)

Creates an instance of Resizer with a scale factor for each direction.

Parameters:

scaleX - the scale factor for x direction

scaleY - the scale factor for y direction

Method Detail

isInteger

private static boolean isInteger(double x)

Is x an integer?

Parameters:

x - the double to check

Returns:

true if x is an integer, false if not.

createXWeights

private Weighttab[] createXWeights(java.awt.Rectangle srcBounds,
                                   java.awt.Rectangle dstBounds,
                                   ParameterizedFilter filter)

simplifyFilter

private ParameterizedFilter simplifyFilter(ParameterizedFilter filter,
                                           double scale,
                                           double offset)

Checks if our discrete sampling of an arbitrary continuous filter, parameterized by the filter spacing (ParameterizedFilter.scale), its radius (ParameterizedFilter.support), and the scale and offset of the coordinate mapping, causes the filter to reduce to point sampling.

It reduces if support is less than 1 pixel or if integer scale and translation, and filter is cardinal.

Parameters:

filter - the parameterized filter instance to be simplified

scale - the scale of the coordinate mapping

offset - the offset of the coordinate mapping

resizeXfirst

private void resizeXfirst(java.lang.Object src,
                          java.awt.Rectangle srcBounds,
                          java.lang.Object dst,
                          java.awt.Rectangle dstBounds,
                          ParameterizedFilter xFilter,
                          ParameterizedFilter yFilter)

Filtered zoom, x direction filtering before y direction filtering

Note: when calling createXWeights(Rectangle, Rectangle, ParameterizedFilter), we can trim leading and trailing zeros from the x weight buffers as an optimization, but not for y weight buffers since the split formula is anticipating a constant amount of buffering of source scanlines; trimming zeros in y weight could cause feedback.

resizeYfirst

private void resizeYfirst(java.lang.Object src,
                          java.awt.Rectangle srcBounds,
                          java.lang.Object dst,
                          java.awt.Rectangle dstBounds,
                          ParameterizedFilter xFilter,
                          ParameterizedFilter yFilter)

Filtered zoom, y direction filtering before x direction filtering

resize

public void resize(java.lang.Object src,
                   java.awt.Rectangle srcBounds,
                   java.lang.Object dst,
                   java.awt.Rectangle dstBounds,
                   Filter xFilter,
                   Filter yFilter)

Parameters:

src - Source object

srcBounds - Bounds of the source object

dst - Destination object

dstBounds - Bounds of the destination object

xFilter - The filter used for x direction filtering

yFilter - The filter used for y direction filtering

createScanline

private static Scanline createScanline(java.lang.Object src,
                                       java.lang.Object dst,
                                       int length)