Class GeneralFilter

java.lang.Object

VASSAL.tools.image.GeneralFilter

public final class GeneralFilter
extends Object

GeneralFilter is a pluggable image resampler.

GeneralFilter up- or down-samples images or parts of images using any one of the various filters contained in it as internal classes.

GeneralFilter is based on filter_rcg.c, which contains modifications made by Ray Gardener to filter.c, originally by Dale Schumacher. filter.c appeared in

Dale Schumacher. "General Filtered Image Rescaling". Graphics Gems III. David Kirk, ed. Academic Press. 1994. pp. 8–16, 414–424.

and the source for filter.c and filter_rcg.c are available here. Both filter.c and filter_rcg.c are in the Public Domain.

The filters provided here are intended for scaling, though other filters could be created which resample in other ways.

Author:

Joel Uckelman

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	GeneralFilter.BellFilter	A Bell filter.
static final class	GeneralFilter.BoxFilter	A box filter.
static final class	GeneralFilter.BSplineFilter	A B-spline filter.
static class	GeneralFilter.Filter	The abstract base class for filters.
static final class	GeneralFilter.HermiteFilter	A Hermite filter.
static final class	GeneralFilter.Lanczos3Filter	A Lanczos filter with radius 3.
static final class	GeneralFilter.MitchellFilter	A Mitchell filter.
static final class	GeneralFilter.TriangleFilter	A triangle, or bilinear, filter.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	OPAQUE
static final int	TRANS_PREMULT
static final int	TRANS_UNPREMULT

Method Summary

Modifier and Type	Method	Description
static void	resample(int[] src_data, boolean src_data_consecutive, int sx0, int sy0, int sx1, int sy1, int sw, int sh, int src_type, int srcWidth, int srcHeight, int[] dst_data, int dx0, int dy0, int dx1, int dy1, int dw, int dh, int dstWidth, int dstHeight, float xscale, float yscale, GeneralFilter.Filter filter)
static void	zoom(WritableRaster dstR, Rectangle dst_fr, BufferedImage srcI, GeneralFilter.Filter filter)	Filters a portion of the source image.
static BufferedImage	zoom(Rectangle dst, BufferedImage src, GeneralFilter.Filter filter)	Filters the entire source image.

Methods inherited from class java.lang.Object

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

Field Details

OPAQUE

public static final int OPAQUE

See Also:

• Constant Field Values

TRANS_PREMULT

public static final int TRANS_PREMULT

See Also:

• Constant Field Values

TRANS_UNPREMULT

public static final int TRANS_UNPREMULT

See Also:

• Constant Field Values

Method Details

zoom

public static BufferedImage zoom(Rectangle dst,
 BufferedImage src,
 GeneralFilter.Filter filter)

Filters the entire source image. This is a convenience function which calls zoom(WritableRaster, Rectangle, BufferedImage, Filter), setting the destination rectangle as the bounds of the destination tile.

Parameters:

dst - the destination rectangle

src - the source image

filter - the filter to apply

Throws:

ClassCastException - if src does not store its data in a DataBufferInt

zoom

public static void zoom(WritableRaster dstR,
 Rectangle dst_fr,
 BufferedImage srcI,
 GeneralFilter.Filter filter)

Filters a portion of the source image.

Parameters:

dstR - the destination tile to calculate

dst_fr - the bounds of the whole destination image

srcI - the source image

filter - the filter to apply

Throws:

ClassCastException - if srcI does not store its data in a DataBufferInt

resample

public static void resample(int[] src_data,
 boolean src_data_consecutive,
 int sx0,
 int sy0,
 int sx1,
 int sy1,
 int sw,
 int sh,
 int src_type,
 int srcWidth,
 int srcHeight,
 int[] dst_data,
 int dx0,
 int dy0,
 int dx1,
 int dy1,
 int dw,
 int dh,
 int dstWidth,
 int dstHeight,
 float xscale,
 float yscale,
 GeneralFilter.Filter filter)