Image Processing and Graphics

Grayscale Image Processing

A C++ class library to do many boring and exciting things with grayscale images:

Elementary pixel operations: assigning, subtracting, adding, etc. a value to all pixels; comparing every pixel with a value; assigning, adding, subtracting, comparing two images; computing image extrema, various norms and ``scalar'' products.
Operations on square or rectangular parts of an image without much fuss, and without moving a lot of stuff around.
Reading and writing PGM, XWD and Group G (grayscale) TIFF 6.0 file formats with automatic recognition of the input image file format. When reading a TIFF file, we can look up the value of a private or non-mandatory tag. Likewise, we can add any optional or private tag into the TIFF file being created. We can also iterate over and clone TIFF IFD entries.
Squeezing, stretching and coercing images. The latter operation is an assignment of one image to another no matter what their dimensions are. The source image would be shrunk or stretched to fit. Any dimension ratios are possible.
Iterators for ``sweeping'' image processing: that is, for an operation that involves every pixel in a systematic way. Rather than writing a loop over all image rows and columns, we merely specify an action to perform on the current pixel. The package would take care of the iteration, which is more efficient than a for() loop.
Image streams: objects Image_istream and Image_iostream are safe pixel pointers. They permit arbitrary iterations on an image. Image streams are just as efficient as the naked pointers, yet they are safe.
Lazy images: objects that represent a ``recipe'' for making images. Rather than passing an image object as a return value of a function, we return a lazy image instead. The full image would be rolled out only when and where it is needed.
Image filtering. The package supports several image filtering techniques: convolutional, median, and morphological. The filters are optimized and done in-place. It seems that it takes noticeably more time to read an image than to filter it. A convolution or a median filters can be applied to rows only, to columns only, or to both rows and columns. A general, non-separable 2D filtration is supported as well.
Non-deterministic 3x3-averaging that may spare some pixels. The probability of pixel's survival depends on how much it sticks out of its neighborhood.
Lookup table substitutions are powerful and fast. See the README file for a few examples.
Fractal cloud generator of plasma fractals. It is implemented as a LazyImage.

Every feature of the package is tested in the included validation code. The README file tells far much more about the features and how to use them.

Platforms

i686/FreeBSD 4.0, gcc 2.95.2
various commercial UNIX flavors (Sun Ultra-2/Solaris 2.6, HP-UX B.10.10) with gcc 2.95.2
i686/Linux 2.2.14, gcc 2.95.2
Mac and PowerMac, Win95/WinNT

License

Public Domain

Version

The current version is 2.4, December 2000.

References

The README file [plain text file]

grayimage.tar.gz [258K]
Complete source code and the validation/sample code

Handling TIFF files in Scheme

Advanced i/o and arithmetic compression classlib is required as a dependency

Sample GUI Class library

A C++ wrapper around a platform-independent XVT GUI engine (with a distinct Windows flavor). The cornerstone class XVTBasicWindow does all the registration chores, receives events firsthand and handles them roughly, using appropriate (virtual) handlers for finer processing. The class also has methods to handle checkbox, button, list, and other controls. The package then defines a number of classes to :

handle modal and modeless dialogs, windows with subwindows and controls
display a grayscale image with high fidelity (which involves a lot of playing with CLUT tables)
manipulate color cells of CLUT, relying solely on Xlib
implement a rubber rectangle

Platforms

SunOS and Solaris 2.x, HP-UX, g++ v2.6.3

Version

The current version is 1.2, September 1994.

References

xvt_c++wrap.tar.gz [28K]
Complete source code. The archive also includes the verification code for all features.

XVT library is required to actually run the code
< http://www.xvt.com/>

Last updated January 1, 2006

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