jj2000.j2k.image.input
Class ImgReader

java.lang.Object
  |
  +--jj2000.j2k.image.input.ImgReader

All Implemented Interfaces:

BlkImgDataSrc, ImgData

Direct Known Subclasses:

ImgReaderPGM, ImgReaderPGX, ImgReaderPPM

public abstract class ImgReader

extends java.lang.Object

implements BlkImgDataSrc

This is the generic interface to be implemented by all image file (or other resource) readers for different image file formats.

An ImgReader behaves as an ImgData object. Whenever image data is requested through the getInternCompData() or getCompData() methods, the image data will be read (if it is not buffered) and returned. Implementing classes should not buffer large amounts of data, so as to reduce memory usage.

This class sets the image origin to (0,0). All default implementations of the methods assume this.

This class provides default implementations of many methods. These default implementations assume that there is no tiling (i.e., the only tile is the entire image), that the image origin is (0,0) in the canvas system and that there is no component subsampling (all components are the same size), but they can be overloaded by the implementating class if need be.

Field Summary

protected int	h The height of the image
protected int	nc The number of components in the image
protected int	w The width of the image

Constructor Summary

ImgReader()

Method Summary

abstract void	close() Closes the underlying file or network connection from where the image data is being read.
int	getCompImgHeight(int c) Returns the height in pixels of the specified component in the overall image.
int	getCompImgWidth(int c) Returns the width in pixels of the specified component in the overall image.
int	getCompSubsX(int c) Returns the component subsampling factor in the horizontal direction, for the specified component.
int	getCompSubsY(int c) Returns the component subsampling factor in the vertical direction, for the specified component.
int	getCompULX(int c) Returns the horizontal coordinate of the upper-left corner of the specified component in the current tile.
int	getCompULY(int c) Returns the vertical coordinate of the upper-left corner of the specified component in the current tile.
int	getImgHeight() Returns the overall height of the image in pixels.
int	getImgULX() Returns the horizontal coordinate of the image origin, the top-left corner, in the canvas system, on the reference grid.
int	getImgULY() Returns the vertical coordinate of the image origin, the top-left corner, in the canvas system, on the reference grid.
int	getImgWidth() Returns the overall width of the image in pixels.
int	getNomTileHeight() Returns the nominal tiles height
int	getNomTileWidth() Returns the nominal tiles width
int	getNumComps() Returns the number of components in the image.
int	getNumTiles() Returns the total number of tiles in the image.
Coord	getNumTiles(Coord co) Returns the number of tiles in the horizontal and vertical directions.
Coord	getTile(Coord co) Returns the coordinates of the current tile.
int	getTileCompHeight(int t, int c) Returns the height in pixels of the specified tile-component.
int	getTileCompWidth(int t, int c) Returns the width in pixels of the specified tile-component.
int	getTileHeight() Returns the overall height of the current tile in pixels, assuming there is no-tiling.
int	getTileIdx() Returns the index of the current tile, relative to a standard scan-line order.
int	getTilePartULX() Returns the horizontal tile partition offset in the reference grid
int	getTilePartULY() Returns the vertical tile partition offset in the reference grid
int	getTileWidth() Returns the width of the current tile in pixels, assuming there is no-tiling.
abstract boolean	isOrigSigned(int c) Returns true if the data read was originally signed in the specified component, false if not.
void	nextTile() Advances to the next tile, in standard scan-line order (by rows then columns).
void	setTile(int x, int y) Changes the current tile, given the new coordinates.

Methods inherited from class java.lang.Object

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

Methods inherited from interface jj2000.j2k.image.BlkImgDataSrc

getCompData, getFixedPoint, getInternCompData

Methods inherited from interface jj2000.j2k.image.ImgData

getNomRangeBits

Field Detail

w

protected int w

The width of the image

h

protected int h

The height of the image

nc

protected int nc

The number of components in the image

Constructor Detail

ImgReader

public ImgReader()

Method Detail

close

public abstract void close()
                    throws java.io.IOException

Closes the underlying file or network connection from where the image data is being read.

Throws:

java.io.IOException - If an I/O error occurs.

getTileWidth

public int getTileWidth()

Returns the width of the current tile in pixels, assuming there is no-tiling. Since no-tiling is assumed this is the same as the width of the image. The value of w is returned.

Specified by:

getTileWidth in interface ImgData

Returns:

The total image width in pixels.

getTileHeight

public int getTileHeight()

Returns the overall height of the current tile in pixels, assuming there is no-tiling. Since no-tiling is assumed this is the same as the width of the image. The value of h is returned.

Specified by:

getTileHeight in interface ImgData

Returns:

The total image height in pixels.

getNomTileWidth

public int getNomTileWidth()

Returns the nominal tiles width

Specified by:

getNomTileWidth in interface ImgData

getNomTileHeight

public int getNomTileHeight()

Returns the nominal tiles height

Specified by:

getNomTileHeight in interface ImgData

getImgWidth

public int getImgWidth()

Returns the overall width of the image in pixels. This is the image's width without accounting for any component subsampling or tiling. The value of w is returned.

Specified by:

getImgWidth in interface ImgData

Returns:

The total image's width in pixels.

getImgHeight

public int getImgHeight()

Returns the overall height of the image in pixels. This is the image's height without accounting for any component subsampling or tiling. The value of h is returned.

Specified by:

getImgHeight in interface ImgData

Returns:

The total image's height in pixels.

getNumComps

public int getNumComps()

Returns the number of components in the image. The value of nc is returned.

Specified by:

getNumComps in interface ImgData

Returns:

The number of components in the image.

getCompSubsX

public int getCompSubsX(int c)

Returns the component subsampling factor in the horizontal direction, for the specified component. This is, approximately, the ratio of dimensions between the reference grid and the component itself, see the 'ImgData' interface desription for details.

Specified by:

getCompSubsX in interface ImgData

Parameters:

c - The index of the component (between 0 and C-1)

Returns:

The horizontal subsampling factor of component 'c'

See Also:

ImgData

getCompSubsY

public int getCompSubsY(int c)

Returns the component subsampling factor in the vertical direction, for the specified component. This is, approximately, the ratio of dimensions between the reference grid and the component itself, see the 'ImgData' interface desription for details.

Specified by:

getCompSubsY in interface ImgData

Parameters:

c - The index of the component (between 0 and C-1)

Returns:

The vertical subsampling factor of component 'c'

See Also:

ImgData

getTileCompWidth

public int getTileCompWidth(int t,
                            int c)

Returns the width in pixels of the specified tile-component. This default implementation assumes no tiling and no component subsampling (i.e., all components, or components, have the same dimensions in pixels).

Specified by:

getTileCompWidth in interface ImgData

Parameters:

t - Tile index

c - The index of the component, from 0 to C-1.

Returns:

The width in pixels of component c in tilet.

getTileCompHeight

public int getTileCompHeight(int t,
                             int c)

Returns the height in pixels of the specified tile-component. This default implementation assumes no tiling and no component subsampling (i.e., all components, or components, have the same dimensions in pixels).

Specified by:

getTileCompHeight in interface ImgData

Parameters:

t - The tile index

c - The index of the component, from 0 to C-1.

Returns:

The height in pixels of component c in tile t.

getCompImgWidth

public int getCompImgWidth(int c)

Returns the width in pixels of the specified component in the overall image. This default implementation assumes no component, or component, subsampling (i.e. all components have the same dimensions in pixels).

Specified by:

getCompImgWidth in interface ImgData

Parameters:

c - The index of the component, from 0 to C-1.

Returns:

The width in pixels of component c in the overall image.

getCompImgHeight

public int getCompImgHeight(int c)

Returns the height in pixels of the specified component in the overall image. This default implementation assumes no component, or component, subsampling (i.e. all components have the same dimensions in pixels).

Specified by:

getCompImgHeight in interface ImgData

Parameters:

c - The index of the component, from 0 to C-1.

Returns:

The height in pixels of component c in the overall image.

setTile

public void setTile(int x,
                    int y)

Changes the current tile, given the new coordinates. An IllegalArgumentException is thrown if the coordinates do not correspond to a valid tile. This default implementation assumes no tiling so the only valid arguments are x=0, y=0.

Specified by:

setTile in interface ImgData

Parameters:

x - The horizontal coordinate of the tile.

y - The vertical coordinate of the new tile.

nextTile

public void nextTile()

Advances to the next tile, in standard scan-line order (by rows then columns). A NoNextElementException is thrown if the current tile is the last one (i.e. there is no next tile). This default implementation assumes no tiling, so NoNextElementException() is always thrown.

Specified by:

nextTile in interface ImgData

getTile

public Coord getTile(Coord co)

Returns the coordinates of the current tile. This default implementation assumes no-tiling, so (0,0) is returned.

Specified by:

getTile in interface ImgData

Parameters:

co - If not null this object is used to return the information. If null a new one is created and returned.

Returns:

The current tile's coordinates.

getTileIdx

public int getTileIdx()

Returns the index of the current tile, relative to a standard scan-line order. This default implementations assumes no tiling, so 0 is always returned.

Specified by:

getTileIdx in interface ImgData

Returns:

The current tile's index (starts at 0).

getCompULX

public int getCompULX(int c)

Returns the horizontal coordinate of the upper-left corner of the specified component in the current tile.

Specified by:

getCompULX in interface ImgData

Parameters:

c - The component index.

getCompULY

public int getCompULY(int c)

Returns the vertical coordinate of the upper-left corner of the specified component in the current tile.

Specified by:

getCompULY in interface ImgData

Parameters:

c - The component index.

getTilePartULX

public int getTilePartULX()

Returns the horizontal tile partition offset in the reference grid

Specified by:

getTilePartULX in interface ImgData

getTilePartULY

public int getTilePartULY()

Returns the vertical tile partition offset in the reference grid

Specified by:

getTilePartULY in interface ImgData

getImgULX

public int getImgULX()

Returns the horizontal coordinate of the image origin, the top-left corner, in the canvas system, on the reference grid.

Specified by:

getImgULX in interface ImgData

Returns:

The horizontal coordinate of the image origin in the canvas system, on the reference grid.

getImgULY

public int getImgULY()

Returns the vertical coordinate of the image origin, the top-left corner, in the canvas system, on the reference grid.

Specified by:

getImgULY in interface ImgData

Returns:

The vertical coordinate of the image origin in the canvas system, on the reference grid.

getNumTiles

public Coord getNumTiles(Coord co)

Returns the number of tiles in the horizontal and vertical directions. This default implementation assumes no tiling, so (1,1) is always returned.

Specified by:

getNumTiles in interface ImgData

Parameters:

co - If not null this object is used to return the information. If null a new one is created and returned.

Returns:

The number of tiles in the horizontal (Coord.x) and vertical (Coord.y) directions.

getNumTiles

public int getNumTiles()

Returns the total number of tiles in the image. This default implementation assumes no tiling, so 1 is always returned.

Specified by:

getNumTiles in interface ImgData

Returns:

The total number of tiles in the image.

isOrigSigned

public abstract boolean isOrigSigned(int c)

Returns true if the data read was originally signed in the specified component, false if not.

Parameters:

c - The index of the component, from 0 to C-1.

Returns:

true if the data was originally signed, false if not.