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, PSD and SWF 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:
The latest version can be found at http://www.geocities
.com/marcoschmidt.geo/image-info.html.
Written by Marco Schmidt.
This class is contributed to the Public Domain. Use it at your own risk.
Last modification 2005-01-02.
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 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.