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java.lang.Object | +--javax.media.jai.Warp
A description of an image warp.
The central method of a Warp is
warpSparseRect(), which returns the source pixel positions
for a specified (subdivided) rectangular region of the output.
As in the Interpolation class, pixel positions are
represented using scaled integer coordinates, yielding subpixel
accuracy but still allowing the use of integer arithmetic. The
degree of precision is set by means of the
getSubSampleBitsH() and getSubSampleBitsV
parameters to the warpRect() method.
Interpolation,
WarpAffine,
WarpGrid,
WarpPerspective,
WarpPolynomial,
WarpQuadratic,
WarpCubic,
WarpGeneralPolynomial,
WarpOpImage, Serialized Form| Constructor Summary | |
protected |
Warp()
Default constructor. |
| Method Summary | |
Point2D |
mapDestPoint(Point2D destPt)
Computes the source point corresponding to the supplied point. |
Rectangle |
mapDestRect(Rectangle destRect)
Computes a Rectangle that is guaranteed to enclose the region of the source that is required in order to produce a given rectangular output region. |
Point2D |
mapSourcePoint(Point2D sourcePt)
Computes the destination point corresponding to the supplied point. |
Rectangle |
mapSourceRect(Rectangle sourceRect)
Computes a rectangle that is guaranteed to enclose the region of the destination that can potentially be affected by the pixels of a rectangle of a given source. |
float[] |
warpPoint(int x,
int y,
float[] destRect)
Computes the source subpixel position for a given destination pixel. |
int[] |
warpPoint(int x,
int y,
int subsampleBitsH,
int subsampleBitsV,
int[] destRect)
Computes the source subpixel position for a given destination pixel. |
float[] |
warpRect(int x,
int y,
int width,
int height,
float[] destRect)
Computes the source subpixel positions for a given rectangular destination region. |
int[] |
warpRect(int x,
int y,
int width,
int height,
int subsampleBitsH,
int subsampleBitsV,
int[] destRect)
Computes the source subpixel positions for a given rectangular destination region. |
abstract float[] |
warpSparseRect(int x,
int y,
int width,
int height,
int periodX,
int periodY,
float[] destRect)
This method is must be implemented in all concrete subclasses. |
int[] |
warpSparseRect(int x,
int y,
int width,
int height,
int periodX,
int periodY,
int subsampleBitsH,
int subsampleBitsV,
int[] destRect)
Computes the source subpixel positions for a given rectangular destination region, subsampled with an integral period. |
| Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
protected Warp()
| Method Detail |
public int[] warpRect(int x,
int y,
int width,
int height,
int subsampleBitsH,
int subsampleBitsV,
int[] destRect)
subsampleBitsH and
subsampleBitsV parameters.
The integral destination rectangle coordinates should be considered pixel indices. The continuous plane of pixels locates each pixel index at a half-pixel location. For example, destination pixel (0,0) is located at the real location (0.5, 0.5). Thus pixels are considered to have a dimension of (1.0 x 1.0) with their "energy" concentrated in a "delta function" at relative coordinates (0.5, 0.5).
Destination to source mappings must keep this (0.5, 0.5) pixel center in mind when formulating transformation functions. Given integral destination pixel indices as an input, the fractional source location, as calculated by functions X(xDst,yDst), Y(xDst,yDst) is given by:
Xsrc = X(xDst+0.5, yDst+0.5) - 0.5
Ysrc = Y(xDst+0.5, yDst+0.5) - 0.5
The subtraction of 0.5 in the above formula produces the source pixel indices (in fractional form) needed to implement the various types of interpolation algorithms.
All of the Sun-supplied warp mapping functions perform the above final subtraction, since they have no knowledge of what interpolation algorithm will be used by a WarpOpImage implementation.
As a convenience, an implementation is provided for this
method that calls warpSparseRect(). Subclasses
may wish to provide their own implementations for better
performance.
x - The minimum X coordinate of the destination region.y - The minimum Y coordinate of the destination region.width - The width of the destination region. Must be positive.height - The height of the destination region. Must be positive.subsampleBitsH - The desired fixed-point precision of the
output X coordinates. Must be positive.subsampleBitsV - The desired fixed-point precision of the
output Y coordinates. Must be positive.destRect - An int array containing at least
2*width*height elements, or
null. If null, a new array
will be constructed.null, or a new int array
of length 2*width*height otherwise.
public float[] warpRect(int x,
int y,
int width,
int height,
float[] destRect)
As a convenience, an implementation is provided for this
method that calls warpSparseRect(). Subclasses
may wish to provide their own implementations for better
performance.
x - The minimum X coordinate of the destination region.y - The minimum Y coordinate of the destination region.width - The width of the destination region.height - The height of the destination region.destRect - A float array containing at least
2*width*height elements, or
null. If null, a new array
will be constructed.destRect parameter if
it is non-null, or a new float
array of length 2*width*height otherwise.IllegalArgumentException - if destRect is too small.
public int[] warpPoint(int x,
int y,
int subsampleBitsH,
int subsampleBitsV,
int[] destRect)
subsampleBitsH and
subsampleBitsV parameters.
As a convenience, an implementation is provided for this
method that calls warpSparseRect(). Subclasses
may wish to provide their own implementations for better
performance.
x - The minimum X coordinate of the destination region.y - The minimum Y coordinate of the destination region.subsampleBitsH - The desired fixed-point precision of the
output X coordinates.subsampleBitsV - The desired fixed-point precision of the
output Y coordinates.destRect - An int array containing at least 2
elements, or null. If null, a
new array will be constructed.null, or a new int array
of length 2 otherwise.IllegalArgumentException - if destRect is too small.
public float[] warpPoint(int x,
int y,
float[] destRect)
As a convenience, an implementation is provided for this
method that calls warpSparseRect(). Subclasses
may wish to provide their own implementations for better
performance.
x - The minimum X coordinate of the destination region.y - The minimum Y coordinate of the destination region.destRect - A float array containing at least
2 elements, or null. If null,
a new array will be constructed.destRect parameter if
it is non-null, or a new
float array of length 2 otherwise.IllegalArgumentException - if destRect is too small.
public int[] warpSparseRect(int x,
int y,
int width,
int height,
int periodX,
int periodY,
int subsampleBitsH,
int subsampleBitsV,
int[] destRect)
subsampleBitsH and subsampleBitsV
parameters.
As a convenience, an implementation is provided for this
method that calls warpSparseRect() with a
float destRect parameter. Subclasses
may wish to provide their own implementations for better
performance.
x - the minimum X coordinate of the destination region.y - the minimum Y coordinate of the destination region.width - the width of the destination region.height - the height of the destination region.periodX - the horizontal sampling period.periodY - the horizontal sampling period.subsampleBitsH - The desired fixed-point precision of the
output X coordinates.subsampleBitsV - The desired fixed-point precision of the
output Y coordinates.destRect - An int array containing at least
2*((width+periodX-1)/periodX)*((height+periodY-1)/periodY)
elements, or null. If null, a
new array will be constructed.destRect parameter if
it is non-null, or a new int
array otherwise.IllegalArgumentException - if destRect is too small.
public abstract float[] warpSparseRect(int x,
int y,
int width,
int height,
int periodX,
int periodY,
float[] destRect)
This method is must be implemented in all concrete subclasses.
x - The minimum X coordinate of the destination region.y - The minimum Y coordinate of the destination region.width - The width of the destination region.height - The height of the destination region.periodX - The horizontal sampling period.periodY - The vertical sampling period.destRect - A float array containing at least
2*((width+periodX-1)/periodX)*
((height+periodY-1)/periodY)
elements, or null. If null, a
new array will be constructed.destRect parameter if
it is non-null, or a new
float array otherwise.public Rectangle mapSourceRect(Rectangle sourceRect)
WarpOpImage method,
this routine may return null
if it is infeasible to compute such a bounding box.
The default implementation in this class returns null.
sourceRect - The Rectangle in source coordinates.Rectangle in the destination coordinate
system that enclose the region that can potentially be
affected by the pixels of a rectangle of a given source,
or null.public Rectangle mapDestRect(Rectangle destRect)
destRect - The Rectangle in destination coordinates.Rectangle in the source coordinate
system that is guaranteed to contain all pixels
referenced by the output of warpRect() on
the destination region, or null.IllegalArgumentException - if destRect is
null.public Point2D mapDestPoint(Point2D destPt)
This method returns the value of pt in the following
code snippet:
float[] sourceXY = warpSparseRect((int)destPt.getX(),
(int)destPt.getY(),
1, 1, 1, 1, null);
Point2D pt = (Point2D)destPt.clone();
pt.setLocation(sourceXY[0], sourceXY[1]);
Subclasses requiring different behavior should override this
method. This would be the case for those which desire a more
precise mapping.destPt - the position in destination image coordinates
to map to source image coordinates.Point2D of the same class as
destPt.IllegalArgumentException - if destPt is
null.public Point2D mapSourcePoint(Point2D sourcePt)
This method returns null. Subclasses requiring
different behavior should override this method.
sourcePt - the position in source image coordinates
to map to destination image coordinates.null.IllegalArgumentException - if sourcePt is
null.
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