ecar.pojo
Class ImageInfo

java.lang.Object
  ecar.pojo.ImageInfo

public class ImageInfo
extends java.lang.Object

Get file format, image resolution, number of bits per pixel and optionally number of images, comments and physical resolution from JPEG, GIF, BMP, PCX, PNG, IFF, RAS, PBM, PGM, PPM and PSD files (or input streams).

Use the class like this:

 ImageInfo ii = new ImageInfo();
 ii.setInput(in); // in can be InputStream or RandomAccessFile
 ii.setDetermineImageNumber(true); // default is false
 ii.setCollectComments(true); // default is false
 if (!ii.check()) {
   System.err.println("Not a supported image file format.");
   return;
 }
 System.out.println(ii.getFormatName() + ", " + ii.getMimeType() + ", " + ii.getWidth() + " x " + ii.getHeight() + " pixels, " + ii.getBitsPerPixel() + " bits per pixel, " + ii.getNumberOfImages() + " image(s), " + ii.getNumberOfComments() + " comment(s).");
 // there are other properties, check out the API documentation
 

You can also use this class as a command line program. Call it with a number of image file names and URLs as parameters:

   java ImageInfo *.jpg *.png *.gif http://somesite.tld/image.jpg
 

or call it without parameters and pipe data to it:

   java ImageInfo < image.jpg
 

Known limitations:

• When the determination of the number of images is turned off, GIF bits per pixel are only read from the global header. For some GIFs, local palettes change this to a typically larger value. To be certain to get the correct color depth, call setDetermineImageNumber(true) before calling check(). The complete scan over the GIF file will take additional time.
• Transparency information is not included in the bits per pixel count. Actually, it was my decision not to include those bits, so it's a feature! ;-)

Requirements:

• Java 1.1 or higher

The latest version can be found at http://schmidt.devlib.org/image-info/.

Written by Marco Schmidt.

This class is contributed to the Public Domain. Use it at your own risk.

Last modification 2005-07-26.

History:

• 2001-08-24 Initial version.
• 2001-10-13 Added support for the file formats BMP and PCX.
• 2001-10-16 Fixed bug in read(int[], int, int) that returned
• 2002-01-22 Added support for file formats Amiga IFF and Sun Raster (RAS).
• 2002-01-24 Added support for file formats Portable Bitmap / Graymap / Pixmap (PBM, PGM, PPM) and Adobe Photoshop (PSD). Added new method getMimeType() to return the MIME type associated with a particular file format.
• 2002-03-15 Added support to recognize number of images in file. Only works with GIF. Use setDetermineImageNumber(boolean) with true as argument to identify animated GIFs ( getNumberOfImages() will return a value larger than 1).
• 2002-04-10 Fixed a bug in the feature 'determine number of images in animated GIF' introduced with version 1.1. Thanks to Marcelo P. Lima for sending in the bug report. Released as 1.1.1.
• 2002-04-18 Added setCollectComments(boolean). That new method lets the user specify whether textual comments are to be stored in an internal list when encountered in an input image file / stream. Added two methods to return the physical width and height of the image in dpi: getPhysicalWidthDpi() and getPhysicalHeightDpi(). If the physical resolution could not be retrieved, these methods return -1.
• 2002-04-23 Added support for the new properties physical resolution and comments for some formats. Released as 1.2.
• 2002-06-17 Added support for SWF, sent in by Michael Aird. Changed checkJpeg() so that other APP markers than APP0 will not lead to a failure anymore. Released as 1.3.
• 2003-07-28 Bug fix - skip method now takes return values into consideration. Less bytes than necessary may have been skipped, leading to flaws in the retrieved information in some cases. Thanks to Bernard Bernstein for pointing that out. Released as 1.4.
• 2004-02-29 Added support for recognizing progressive JPEG and interlaced PNG and GIF. A new method isProgressive() returns whether ImageInfo has found that the storage type is progressive (or interlaced). Thanks to Joe Germuska for suggesting the feature. Bug fix: BMP physical resolution is now correctly determined. Released as 1.5.
• 2004-11-30 Bug fix: recognizing progressive GIFs (interlaced in GIF terminology) did not work (thanks to Franz Jeitler for pointing this out). Now it should work, but only if the number of images is determined. This is because information on interlacing is stored in a local image header. In theory, different images could be stored interlaced and non-interlaced in one file. However, I think that's unlikely. Right now, the last image in the GIF file that is examined by ImageInfo is used for the "progressive" status.
• 2005-01-02 Some code clean up (unused methods and variables commented out, missing javadoc comments, etc.). Thanks to George Sexton for a long list. Removed usage of Boolean.toString because it's a Java 1.4+ feature (thanks to Gregor Dupont). Changed delimiter character in compact output from semicolon to tabulator (for better integration with cut(1) and other Unix tools). Added some points to the 'Known issues' section of the website. Released as 1.6.
• 2005-07-26 Removed code to identify Flash (SWF) files. Has repeatedly led to problems and support requests, and I don't know the format and don't have the time and interest to fix it myself. I repeatedly included fixes by others which didn't work for some people. I give up on SWF. Please do not contact me about it anymore. Set package of ImageInfo class to org.devlib.schmidt.imageinfo (a package was repeatedly requested by some users). Released as 1.7.

Author:

Marco Schmidt

Field Summary

private int	bitBuf
private int	bitPos
private int	bitsPerPixel
private boolean	collectComments
private java.util.Vector	comments
private boolean	determineNumberOfImages
private java.io.DataInput	din
private int	format
static int	FORMAT_BMP Return value of getFormat() for BMP streams.
static int	FORMAT_GIF Return value of getFormat() for GIF streams.
static int	FORMAT_IFF Return value of getFormat() for IFF streams.
static int	FORMAT_JPEG Return value of getFormat() for JPEG streams.
private static java.lang.String[]	FORMAT_NAMES The names of all supported file formats.
static int	FORMAT_PBM Return value of getFormat() for PBM streams.
static int	FORMAT_PCX Return value of getFormat() for PCX streams.
static int	FORMAT_PGM Return value of getFormat() for PGM streams.
static int	FORMAT_PNG Return value of getFormat() for PNG streams.
static int	FORMAT_PPM Return value of getFormat() for PPM streams.
static int	FORMAT_PSD Return value of getFormat() for PSD streams.
static int	FORMAT_RAS Return value of getFormat() for RAS streams.
private int	height
private java.io.InputStream	in
private static java.lang.String[]	MIME_TYPE_STRINGS The names of the MIME types for all supported file formats.
private int	numberOfImages
private int	physicalHeightDpi
private int	physicalWidthDpi
private boolean	progressive
private int	width

Constructor Summary

ImageInfo()

Method Summary

private void	addComment(java.lang.String s)
boolean	check() Call this method after you have provided an input stream or file using setInput(InputStream) or setInput(DataInput).
private boolean	checkBmp()
private boolean	checkGif()
private boolean	checkIff()
private boolean	checkJpeg()
private boolean	checkPcx()
private boolean	checkPng()
private boolean	checkPnm(int id)
private boolean	checkPsd()
private boolean	checkRas()
private static boolean	determineVerbosity(java.lang.String[] args) Run over String list, return false iff at least one of the arguments equals -c.
private static boolean	equals(byte[] a1, int offs1, byte[] a2, int offs2, int num)
int	getBitsPerPixel() If check() was successful, returns the image's number of bits per pixel.
java.lang.String	getComment(int index) Returns the index'th comment retrieved from the file.
int	getFormat() If check() was successful, returns the image format as one of the FORMAT_xyz constants from this class.
java.lang.String	getFormatName() If check() was successful, returns the image format's name.
int	getHeight() If check() was successful, returns one the image's vertical resolution in pixels.
private static int	getIntBigEndian(byte[] a, int offs)
private static int	getIntLittleEndian(byte[] a, int offs)
java.lang.String	getMimeType() If check() was successful, returns a String with the MIME type of the format.
int	getNumberOfComments() If check() was successful and setCollectComments(boolean) was called with true as argument, returns the number of comments retrieved from the input image stream / file.
int	getNumberOfImages() Returns the number of images in the examined file.
int	getPhysicalHeightDpi() Returns the physical height of this image in dots per inch (dpi).
float	getPhysicalHeightInch() If check() was successful, returns the physical width of this image in dpi (dots per inch) or -1 if no value could be found.
int	getPhysicalWidthDpi() If check() was successful, returns the physical width of this image in dpi (dots per inch) or -1 if no value could be found.
float	getPhysicalWidthInch() Returns the physical width of an image in inches, or -1.0f if width information is not available.
private static int	getShortBigEndian(byte[] a, int offs)
private static int	getShortLittleEndian(byte[] a, int offs)
int	getWidth() If check() was successful, returns one the image's horizontal resolution in pixels.
boolean	isProgressive() Returns whether the image is stored in a progressive (also called: interlaced) way.
static void	main(java.lang.String[] args) To use this class as a command line application, give it either some file names as parameters (information on them will be printed to standard output, one line per file) or call it with no parameters.
private static void	print(java.lang.String sourceName, ImageInfo ii, boolean verbose)
private static void	printCompact(java.lang.String sourceName, ImageInfo imageInfo)
private static void	printLine(int indentLevels, java.lang.String text, float value, float minValidValue)
private static void	printLine(int indentLevels, java.lang.String text, int value, int minValidValue)
private static void	printLine(int indentLevels, java.lang.String text, java.lang.String value)
private static void	printVerbose(java.lang.String sourceName, ImageInfo ii)
private int	read()
private int	read(byte[] a)
private int	read(byte[] a, int offset, int num)
private java.lang.String	readLine()
private java.lang.String	readLine(java.lang.StringBuffer sb)
private int	readSBits(int numBits) Read a signed integer value from input.
private long	readUBits(int numBits)
void	redimensionaImagem(int limite)
private static void	run(java.lang.String sourceName, java.io.InputStream in, ImageInfo imageInfo, boolean verbose)
void	setCollectComments(boolean newValue) Specify whether textual comments are supposed to be extracted from input.
void	setDetermineImageNumber(boolean newValue) Specify whether the number of images in a file is to be determined - default is false.
void	setInput(java.io.DataInput dataInput) Set the input stream to the argument stream (or file).
void	setInput(java.io.InputStream inputStream) Set the input stream to the argument stream (or file).
private void	setPhysicalHeightDpi(int newValue)
private void	setPhysicalWidthDpi(int newValue)
private void	skip(int num)
void	zoomImagem(java.lang.String zoom)

Methods inherited from class java.lang.Object

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

Field Detail

FORMAT_JPEG

public static final int FORMAT_JPEG

Return value of getFormat() for JPEG streams. ImageInfo can extract physical resolution and comments from JPEGs (only from APP0 headers). Only one image can be stored in a file. It is determined whether the JPEG stream is progressive (see isProgressive()).

See Also:

Constant Field Values

FORMAT_GIF

public static final int FORMAT_GIF

Return value of getFormat() for GIF streams. ImageInfo can extract comments from GIFs and count the number of images (GIFs with more than one image are animations). It is determined whether the GIF stream is interlaced (see isProgressive()).

See Also:

Constant Field Values

FORMAT_PNG

public static final int FORMAT_PNG

Return value of getFormat() for PNG streams. PNG only supports one image per file. Both physical resolution and comments can be stored with PNG, but ImageInfo is currently not able to extract those. It is determined whether the PNG stream is interlaced (see isProgressive()).

See Also:

Constant Field Values

FORMAT_BMP

public static final int FORMAT_BMP

Return value of getFormat() for BMP streams. BMP only supports one image per file. BMP does not allow for comments. The physical resolution can be stored.

See Also:

Constant Field Values

FORMAT_PCX

public static final int FORMAT_PCX

Return value of getFormat() for PCX streams. PCX does not allow for comments or more than one image per file. However, the physical resolution can be stored.

See Also:

Constant Field Values

FORMAT_IFF

public static final int FORMAT_IFF

Return value of getFormat() for IFF streams.

See Also:

Constant Field Values

FORMAT_RAS

public static final int FORMAT_RAS

Return value of getFormat() for RAS streams. Sun Raster allows for one image per file only and is not able to store physical resolution or comments.

See Also:

Constant Field Values

FORMAT_PBM

public static final int FORMAT_PBM

Return value of getFormat() for PBM streams.

See Also:

Constant Field Values

FORMAT_PGM

public static final int FORMAT_PGM

Return value of getFormat() for PGM streams.

See Also:

Constant Field Values

FORMAT_PPM

public static final int FORMAT_PPM

Return value of getFormat() for PPM streams.

See Also:

Constant Field Values

FORMAT_PSD

public static final int FORMAT_PSD

Return value of getFormat() for PSD streams.

See Also:

Constant Field Values

FORMAT_NAMES

private static final java.lang.String[] FORMAT_NAMES

The names of all supported file formats. The FORMAT_xyz int constants can be used as index values for this array.

MIME_TYPE_STRINGS

private static final java.lang.String[] MIME_TYPE_STRINGS

The names of the MIME types for all supported file formats. The FORMAT_xyz int constants can be used as index values for this array.

width

private int width

height

private int height

bitsPerPixel

private int bitsPerPixel

progressive

private boolean progressive

format

private int format

in

private java.io.InputStream in

din

private java.io.DataInput din

collectComments

private boolean collectComments

comments

private java.util.Vector comments

determineNumberOfImages

private boolean determineNumberOfImages

numberOfImages

private int numberOfImages

physicalHeightDpi

private int physicalHeightDpi

physicalWidthDpi

private int physicalWidthDpi

bitBuf

private int bitBuf

bitPos

private int bitPos

Constructor Detail

ImageInfo

public ImageInfo()

Method Detail

addComment

private void addComment(java.lang.String s)

check

public boolean check()

Call this method after you have provided an input stream or file using setInput(InputStream) or setInput(DataInput). If true is returned, the file format was known and information on the file's content can be retrieved using the various getXyz methods.

Returns:

if information could be retrieved from input

checkBmp

private boolean checkBmp()
                  throws java.io.IOException

Throws:

java.io.IOException

checkGif

private boolean checkGif()
                  throws java.io.IOException

Throws:

java.io.IOException

checkIff

private boolean checkIff()
                  throws java.io.IOException

Throws:

java.io.IOException

checkJpeg

private boolean checkJpeg()
                   throws java.io.IOException

Throws:

java.io.IOException

checkPcx

private boolean checkPcx()
                  throws java.io.IOException

Throws:

java.io.IOException

checkPng

private boolean checkPng()
                  throws java.io.IOException

Throws:

java.io.IOException

checkPnm

private boolean checkPnm(int id)
                  throws java.io.IOException

Throws:

java.io.IOException

checkPsd

private boolean checkPsd()
                  throws java.io.IOException

Throws:

java.io.IOException

checkRas

private boolean checkRas()
                  throws java.io.IOException

Throws:

java.io.IOException

determineVerbosity

private static boolean determineVerbosity(java.lang.String[] args)

Run over String list, return false iff at least one of the arguments equals -c.

Parameters:

args - string list to check

equals

private static boolean equals(byte[] a1,
                              int offs1,
                              byte[] a2,
                              int offs2,
                              int num)

getBitsPerPixel

public int getBitsPerPixel()

If check() was successful, returns the image's number of bits per pixel. Does not include transparency information like the alpha channel.

Returns:

number of bits per image pixel

getComment

public java.lang.String getComment(int index)

Returns the index'th comment retrieved from the file.

Parameters:

index - int index of comment to return

Throws:

java.lang.IllegalArgumentException - if index is smaller than 0 or larger than or equal to the number of comments retrieved

See Also:

getNumberOfComments()

getFormat

public int getFormat()

If check() was successful, returns the image format as one of the FORMAT_xyz constants from this class. Use getFormatName() to get a textual description of the file format.

Returns:

file format as a FORMAT_xyz constant

getFormatName

public java.lang.String getFormatName()

If check() was successful, returns the image format's name. Use getFormat() to get a unique number.

Returns:

file format name

getHeight

public int getHeight()

If check() was successful, returns one the image's vertical resolution in pixels.

Returns:

image height in pixels

getIntBigEndian

private static int getIntBigEndian(byte[] a,
                                   int offs)

getIntLittleEndian

private static int getIntLittleEndian(byte[] a,
                                      int offs)

getMimeType

public java.lang.String getMimeType()

If check() was successful, returns a String with the MIME type of the format.

Returns:

MIME type, e.g. image/jpeg

getNumberOfComments

public int getNumberOfComments()

If check() was successful and setCollectComments(boolean) was called with true as argument, returns the number of comments retrieved from the input image stream / file. Any number >= 0 and smaller than this number of comments is then a valid argument for the getComment(int) method.

Returns:

number of comments retrieved from input image

getNumberOfImages

public int getNumberOfImages()

Returns the number of images in the examined file. Assumes that setDetermineImageNumber(true); was called before a successful call to check(). This value can currently be only different from 1 for GIF images.

Returns:

number of images in file

getPhysicalHeightDpi

public int getPhysicalHeightDpi()

Returns the physical height of this image in dots per inch (dpi). Assumes that check() was successful. Returns -1 on failure.

Returns:

physical height (in dpi)

See Also:

getPhysicalWidthDpi(), getPhysicalHeightInch()

getPhysicalHeightInch

public float getPhysicalHeightInch()

If check() was successful, returns the physical width of this image in dpi (dots per inch) or -1 if no value could be found.

Returns:

physical height (in dpi)

See Also:

getPhysicalHeightDpi(), getPhysicalWidthDpi(), getPhysicalWidthInch()

getPhysicalWidthDpi

public int getPhysicalWidthDpi()

If check() was successful, returns the physical width of this image in dpi (dots per inch) or -1 if no value could be found.

Returns:

physical width (in dpi)

See Also:

getPhysicalHeightDpi(), getPhysicalWidthInch(), getPhysicalHeightInch()

getPhysicalWidthInch

public float getPhysicalWidthInch()

Returns the physical width of an image in inches, or -1.0f if width information is not available. Assumes that check() has been called successfully.

Returns:

physical width in inches or -1.0f on failure

See Also:

getPhysicalWidthDpi(), getPhysicalHeightInch()

getShortBigEndian

private static int getShortBigEndian(byte[] a,
                                     int offs)

getShortLittleEndian

private static int getShortLittleEndian(byte[] a,
                                        int offs)

getWidth

public int getWidth()

If check() was successful, returns one the image's horizontal resolution in pixels.

Returns:

image width in pixels

isProgressive

public boolean isProgressive()

Returns whether the image is stored in a progressive (also called: interlaced) way.

Returns:

true for progressive/interlaced, false otherwise

main

public static void main(java.lang.String[] args)

To use this class as a command line application, give it either some file names as parameters (information on them will be printed to standard output, one line per file) or call it with no parameters. It will then check data given to it via standard input.

Parameters:

args - the program arguments which must be file names

print

private static void print(java.lang.String sourceName,
                          ImageInfo ii,
                          boolean verbose)

printCompact

private static void printCompact(java.lang.String sourceName,
                                 ImageInfo imageInfo)

printLine

private static void printLine(int indentLevels,
                              java.lang.String text,
                              float value,
                              float minValidValue)

printLine

private static void printLine(int indentLevels,
                              java.lang.String text,
                              int value,
                              int minValidValue)

printLine

private static void printLine(int indentLevels,
                              java.lang.String text,
                              java.lang.String value)

printVerbose

private static void printVerbose(java.lang.String sourceName,
                                 ImageInfo ii)

read

private int read()
          throws java.io.IOException

Throws:

java.io.IOException

read

private int read(byte[] a)
          throws java.io.IOException

Throws:

java.io.IOException

read

private int read(byte[] a,
                 int offset,
                 int num)
          throws java.io.IOException

Throws:

java.io.IOException

readLine

private java.lang.String readLine()
                           throws java.io.IOException

Throws:

java.io.IOException

readLine

private java.lang.String readLine(java.lang.StringBuffer sb)
                           throws java.io.IOException

Throws:

java.io.IOException

readUBits

private long readUBits(int numBits)
                throws java.io.IOException

Throws:

java.io.IOException

readSBits

private int readSBits(int numBits)
               throws java.io.IOException

Read a signed integer value from input.

Parameters:

numBits - number of bits to read

Throws:

java.io.IOException

run

private static void run(java.lang.String sourceName,
                        java.io.InputStream in,
                        ImageInfo imageInfo,
                        boolean verbose)

setCollectComments

public void setCollectComments(boolean newValue)

Specify whether textual comments are supposed to be extracted from input. Default is false. If enabled, comments will be added to an internal list.

Parameters:

newValue - if true, this class will read comments

See Also:

getNumberOfComments(), getComment(int)

setDetermineImageNumber

public void setDetermineImageNumber(boolean newValue)

Specify whether the number of images in a file is to be determined - default is false. This is a special option because some file formats require running over the entire file to find out the number of images, a rather time-consuming task. Not all file formats support more than one image. If this method is called with true as argument, the actual number of images can be queried via getNumberOfImages() after a successful call to check().

Parameters:

newValue - will the number of images be determined?

See Also:

getNumberOfImages()

setInput

public void setInput(java.io.DataInput dataInput)

Set the input stream to the argument stream (or file). Note that RandomAccessFile implements DataInput.

Parameters:

dataInput - the input stream to read from

setInput

public void setInput(java.io.InputStream inputStream)

Set the input stream to the argument stream (or file).

Parameters:

inputStream - the input stream to read from

setPhysicalHeightDpi

private void setPhysicalHeightDpi(int newValue)

setPhysicalWidthDpi

private void setPhysicalWidthDpi(int newValue)

skip

private void skip(int num)
           throws java.io.IOException

Throws:

java.io.IOException

redimensionaImagem

public void redimensionaImagem(int limite)

zoomImagem

public void zoomImagem(java.lang.String zoom)