Class ImgReader

java.lang.Object
jj2000.j2k.image.input.ImgReader
All Implemented Interfaces:
BlkImgDataSrc, ImgData
Direct Known Subclasses:
ImgReaderPGM

public abstract class ImgReader extends 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

    Fields
    Modifier and Type
    Field
    Description
    protected int
    The height of the image
    protected int
    The number of components in the image
    protected int
    The width of the image
  • Constructor Summary

    Constructors
    Constructor
    Description
     
  • Method Summary

    Modifier and Type
    Method
    Description
    abstract void
    Closes the underlying file or network connection from where the image data is being read.
    int
    Returns the height in pixels of the specified component in the overall image.
    int
    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
    Returns the overall height of the image in pixels.
    int
    Returns the horizontal coordinate of the image origin, the top-left corner, in the canvas system, on the reference grid.
    int
    Returns the vertical coordinate of the image origin, the top-left corner, in the canvas system, on the reference grid.
    int
    Returns the overall width of the image in pixels.
    int
    Returns the nominal tiles height
    int
    Returns the nominal tiles width
    int
    Returns the number of components in the image.
    int
    Returns the total number of tiles in the image.
    Returns the number of tiles in the horizontal and vertical directions.
    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
    Returns the overall height of the current tile in pixels, assuming there is no-tiling.
    int
    Returns the index of the current tile, relative to a standard scan-line order.
    int
    Returns the horizontal tile partition offset in the reference grid
    int
    Returns the vertical tile partition offset in the reference grid
    int
    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
    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 Details

    • 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 Details

    • ImgReader

      public ImgReader()
  • Method Details

    • close

      public abstract void close() throws IOException
      Closes the underlying file or network connection from where the image data is being read.
      Throws:
      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:
    • 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:
    • 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 Point getTile(Point 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 Point getNumTiles(Point 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 (Point.x) and vertical (Point.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.