jj2000.j2k.image.input
Class ImgReader

java.lang.Object
  |
  +--jj2000.j2k.image.input.ImgReader
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 getCompHeight(int c)
          Returns the height in pixels of the specified component in the current tile.
 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 getCompWidth(int n)
          Returns the width in pixels of the specified component in the current tile.
 int getHeight()
          Returns the overall height of the current tile in pixels, assuming there is no-tiling.
 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 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 getTileIdx()
          Returns the index of the current tile, relative to a standard scan-line order.
 Coord getTileOff(Coord co, int c)
          Returns the horizontal and vertical offset of the upper-left corner of the current tile, in the specified component, relative to the canvas origin, in the component coordinates (not in the reference grid coordinates).
 int getULX(int c)
          Returns the horizontal coordinate of the upper-left corner of the active tile, with respect to the canvas origin, in the component coordinates, for the specified component.
 int getULY(int c)
          Returns the vertical coordinate of the upper-left corner of the active tile, with respect to the canvas origin, in the component coordinates, for the specified component.
 int getWidth()
          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, registerNatives, toString, wait, wait, wait
 

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.

getWidth

public int getWidth()
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.
Returns:
The total image width in pixels.

getHeight

public int getHeight()
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.
Returns:
The total image height in pixels.

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.
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.
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.
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.
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.
Parameters:
c - The index of the component (between 0 and C-1)
Returns:
The vertical subsampling factor of component 'c'
See Also:
ImgData

getCompWidth

public int getCompWidth(int n)
Returns the width in pixels of the specified component in the current tile. This default implementation assumes no tiling and no component subsampling (i.e., all components, or components, have the same dimensions in pixels).
Parameters:
c - The index of the component, from 0 to C-1.
Returns:
The width in pixels of component n in the current tile.

getCompHeight

public int getCompHeight(int c)
Returns the height in pixels of the specified component in the current tile. This default implementation assumes no tiling and no component subsampling (i.e., all components, or components, have the same dimensions in pixels).
Parameters:
c - The index of the component, from 0 to C-1.
Returns:
The height in pixels of component c in the current tile.

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).
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).
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.
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.

getTile

public Coord getTile(Coord co)
Returns the coordinates of the current tile. This default implementation assumes no-tiling, so (0,0) is returned.
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.
Returns:
The current tile's index (starts at 0).

getTileOff

public Coord getTileOff(Coord co,
                        int c)
Returns the horizontal and vertical offset of the upper-left corner of the current tile, in the specified component, relative to the canvas origin, in the component coordinates (not in the reference grid coordinates). These are the coordinates of the current tile's (not active tile) upper-left corner relative to the canvas.

This default implementation assumes no tiling and that the partitioning origin is the canvas origin, so (0,0) is always returned.

Parameters:
co - If not null the object is used to return the values, if null a new one is created and returned.
c - The index of the component (between 0 and C-1)
Returns:
The horizontal and vertical offsets of the upper-left corner of the current tile, for the specified component, relative to the canvas origin, in the component coordinates.

getULX

public int getULX(int c)
Returns the horizontal coordinate of the upper-left corner of the active tile, with respect to the canvas origin, in the component coordinates, for the specified component.
Parameters:
c - The index of the component (between 0 and C-1)
Returns:
The horizontal coordinate of the upper-left corner of the active tile, with respect to the canvas origin, for component 'c', in the component coordinates.

getULY

public int getULY(int c)
Returns the vertical coordinate of the upper-left corner of the active tile, with respect to the canvas origin, in the component coordinates, for the specified component.
Parameters:
c - The index of the component (between 0 and C-1)
Returns:
The vertical coordinate of the upper-left corner of the active tile, with respect to the canvas origin, for component 'c', in the component coordinates.

getImgULX

public int getImgULX()
Returns the horizontal coordinate of the image origin, the top-left corner, in the canvas system, on the reference grid.
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.
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.
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.
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.