org.geotoolkit.image.io.plugin
Class WorldFileImageReader

Object
  ImageReader
      SpatialImageReader
          ImageReaderAdapter
              WorldFileImageReader

All Implemented Interfaces:

Disposable, Localized, WarningProducer

public class WorldFileImageReader
extends ImageReaderAdapter

Reader for the World File format. This reader wraps an other image reader for an "ordinary" image format, like TIFF, PNG or JPEG. This WorldFileImageReader delegates the reading of pixel values to the wrapped reader, and additionally looks for two small text files in the same directory than the image file, with the same filename but a different extension:

• A text file containing the coefficients of the affine transform mapping pixel coordinates to geodesic coordinates. The reader expects one coefficient per line, in the same order than the one expected by the AffineTransform(double[]) constructor, which is scaleX, shearY, shearX, scaleY, translateX, translateY. This reader looks for a file having the following extensions, in preference order:

  1. The first letter of the image file extension, followed by the last letter of the image file extension, followed by 'w'. Example: "tfw" for "tiff" images, and "jgw" for "jpeg" images.
  2. The extension of the image file with a 'w' appended.
  3. The "tfw extension.

• A text file containing the Coordinate Reference System (CRS) definition in Well Known Text (WKT) syntax. This reader looks for a file having the ".prj" extension.

Every text file are expected to be encoded in ISO-8859-1 (a.k.a. ISO-LATIN-1) and every numbers are expected to be formatted in US locale.

Since:

3.08 (derived from 3.07)

Version:

3.08

Author:

Martin Desruisseaux (Geomatys)

See Also:

World File Format Description, WorldFileImageWriter

Module:

coverage/geotk-coverageio (download)

View source code for this class

Nested Class Summary

static class

WorldFileImageReader.Spi Service provider interface (SPI) for WorldFileImageReaders.

Field Summary

Fields inherited from class ImageReaderAdapter

main

Fields inherited from class ImageReader

availableLocales, ignoreMetadata, input, locale, minIndex, originatingProvider, progressListeners, seekForwardOnly, updateListeners, warningListeners, warningLocales

Fields inherited from interface WarningProducer

LOGGER

Constructor Summary

WorldFileImageReader(WorldFileImageReader.Spi provider)
Constructs a new image reader.

WorldFileImageReader(WorldFileImageReader.Spi provider, ImageReader main)
Constructs a new image reader wrapping the given reader.

Method Summary

protected void	close() Closes the input streams created by this reader.
protected Object	createInput(String readerID) Creates the input to be given to the reader identified by the given argument.
protected SpatialMetadata	createMetadata(int imageIndex) Creates a new stream or image metadata.

Methods inherited from class ImageReaderAdapter

abort, addIIOReadProgressListener, addIIOReadUpdateListener, addIIOReadWarningListener, canReadRaster, dispose, finalize, getAspectRatio, getAvailableLocales, getDefaultReadParam, getDimension, getGridEnvelope, getHeight, getImageMetadata, getImageTypes, getLocale, getNumBands, getNumImages, getNumThumbnails, getRawImageType, getStreamMetadata, getThumbnailHeight, getThumbnailWidth, getTileGridXOffset, getTileGridYOffset, getTileHeight, getTileWidth, getWidth, hasColors, hasThumbnails, initialize, isImageTiled, isRandomAccessEasy, read, read, readAsRenderedImage, readerSupportsThumbnails, readRaster, readThumbnail, readTile, readTileRaster, removeAllIIOReadProgressListeners, removeAllIIOReadUpdateListeners, removeAllIIOReadWarningListeners, removeIIOReadProgressListener, removeIIOReadUpdateListener, removeIIOReadWarningListener, reset, setLocale

Methods inherited from class SpatialImageReader

checkBandIndex, checkImageIndex, collapseNoDataValues, getDestination, getImageType, getRawDataType, setInput, warningOccurred

Methods inherited from class ImageReader

abortRequested, checkReadParamBandSettings, clearAbortRequest, computeRegions, getDestination, getFormatName, getImageMetadata, getInput, getMinIndex, getOriginatingProvider, getSourceRegion, getStreamMetadata, isIgnoringMetadata, isSeekForwardOnly, processImageComplete, processImageProgress, processImageStarted, processImageUpdate, processPassComplete, processPassStarted, processReadAborted, processSequenceComplete, processSequenceStarted, processThumbnailComplete, processThumbnailPassComplete, processThumbnailPassStarted, processThumbnailProgress, processThumbnailStarted, processThumbnailUpdate, processWarningOccurred, processWarningOccurred, readAll, readAll, setInput, setInput

Methods inherited from class Object

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

Constructor Detail

WorldFileImageReader

public WorldFileImageReader(WorldFileImageReader.Spi provider)
                     throws IOException

Constructs a new image reader. The provider argument is mandatory for this constructor. If the provider is unknown, use the next constructor below instead.

Parameters:

provider - The ImageReaderSpi that is constructing this object.

Throws:

IOException - If an error occurred while creating the main reader.

WorldFileImageReader

public WorldFileImageReader(WorldFileImageReader.Spi provider,
                            ImageReader main)

Constructs a new image reader wrapping the given reader.

Parameters:

provider - The ImageReaderSpi that is constructing this object, or null.

main - The reader to use for reading the pixel values.

Method Detail

createInput

protected Object createInput(String readerID)
                      throws IOException

Creates the input to be given to the reader identified by the given argument. If the readerID argument is "main" (ignoring case), then this method delegates to the super-class method. Otherwise this method returns an input which is typically a File or URL having the same name than the input of this reader, but a different extension. The new extension is determined from the readerID argument, which can be:

• "tfw" for the World File. The extension of the returned input may be "tfw" (most common), "jgw", "pgw" or other suffix depending on the extension of this reader input, and depending which file has been determined to exist. See the class javadoc for more details.

• "prj" for Map Projection file. The extension of the returned input is "prj".

Subclasses can override this method for specifying a different main ("main"), World File ("tfw") or Map Projection ("prj") input. They can also invoke this method with other identifiers than the three above-cited ones, in which case this method uses the given identifier as the extension of the returned input. However the default WorldFileImageReader implementation uses only "main", "tfw" and "prj".

Overrides:

createInput in class ImageReaderAdapter

Parameters:

readerID - "main" for the main input, "tfw" for the World File input, or "prj" for the Map Projection input. Other identifiers are allowed but subclass-specific.

Returns:

The given kind of input typically as a File or URL object, or null if there is no input for the given identifier.

Throws:

IOException - If an error occurred while creating the input.

See Also:

WorldFileImageWriter.createOutput(String)

createMetadata

protected SpatialMetadata createMetadata(int imageIndex)
                                  throws IOException

Creates a new stream or image metadata. This method first delegates to the main reader as documented in the super-class method, then completes the metadata with information read from the World File and Map Projection files.

The World File and Map Projection files are determined by calls to the createInput(String) method with "tfw" and "prj" argument values. Subclasses can override the later method if they want to specify different files to be read.

Overrides:

createMetadata in class ImageReaderAdapter

Parameters:

imageIndex - -1 for stream metadata, or the image index for image metadata.

Returns:

The requested metadata, or null if none.

Throws:

IOException - If an error occurred while reading metadata.

close

protected void close()
              throws IOException

Closes the input streams created by this reader. This method is automatically invoked when a new input is set, or when the reader is reset or disposed.

Overrides:

close in class ImageReaderAdapter

Throws:

IOException - if an error occurred while closing the stream.