    Version Notes
    =============

    1.37   10 July 06
           [After v.36 was released, Jeff Breidenbach built a Debian
           distribution of Leptonica based on v.36, and you can now get Leptonica
           as a Debian package.  Use "apt-cache search leptonica" to see
           what is available.]  The libraries are now combined into a single
           library (liblept.a, liblept.so) and the function prototypes are
           also in a single file (leptprotos.h).  cextract was found not
           to work on recent versions of linux that support 64 bit data types,
           and it is no longer distributed with leptonica.  Instead, I wrote
           a prototype extractor in leptonica (xtractprotos).  When you
           'make allprotos', it now uses this program.  The shared libraries
           now have major and minor numbers corresponding to the version.

    1.36   17 Jun 06
           Line graphics generation (graphics.c) reorganized; separated out pta
           generation from rendering.  Can now render with alpha blending.
           Examples of use are given in prog/graphicstest.c.
           Sort functions for basic geometrical objects now have the option
           of returning a numa giving the sort order on the original array.
           The pixa sort can sort with either clones or copies of the pix.

    1.35   21 May 06
           The efficiency of the multipage jbig unsupervised classifier is
           significantly improved due to a NumaHash struture implemented
           by Adam Langley.  Functions for computing runlength in 1 bpp
           images have been added.

    1.34   7 May 06
           Completely rewrote the jbig unsupervised classifier.
           It now works on multiple pages, and is more accurate in performing
           visually lossless substitutions.  You can classify by connected
           components, characters, or words.  The old data structures
           and interfaces have been removed.  New unpackers from 1 to 2 and
           1 to 4 bpp, with and without colormaps in the dest.

    1.33   18 Mar 06
           Generalized color snap to have different src and target colors,
           and to include colormaps (blend.c).  Distribute into root directory
           that specifies the version number (e.g., 1.33).  Add color
           space conversion between rgb and hsv.  Re-bundle thresholding
           code from (binarize*.c, dibitize*.c) to grayquant*.c.
           pixThreshold8() now also quantizes 8 bpp --> 8 bpp.
           High-level pixRotate() that optionally expands image sufficiently
           so that no pixels are lost in any sequence of rotations (rotate.c).
           Generalize shear to specify color of pixels brought in, including
           for in-place operation (shear.c, rotateshear.c).  Faster version of
           color rotation by area mapping, both about center and about UL corner.
           You can now use the standard color rotator (pixRotateAM) and get
           nearly the same speed as with the "Fast" one.

    1.32   4 Feb 06
           Ability to specify a sequence of binary morphological
           (& binary reduction/expansion) operations in a single
           function (morphseq.c).  Fast downscaling combined with conversion
           from rbg to gray and to binary (scale.c).  Utility for
           segmenting images by color (colorseg.c).

    1.31   7 Jan 06
           Remove more complicated functions that threshold to 2 bpp,
           retaining the simplest interface.  Retest all thresholding and
           dithering.  Add "ascii" write of PNM.  Improve graphics writing
           of lines; generalize to colormaps.  New colorization functions
           (paintcmap.c, blend.c).

    1.30   22 Dec 05
           Remove most instances of fprintf(stderr, ...), except within
           DEBUG or encapsulated in error, warning or info macros.
           As a result, there is no output to stderr if NO_CONSOLE_IO is defined.
           Adaptive mapping to make bg uniform (adaptmap.c).  A few bug fixes.
           New PostScript output functions for embedding PS files
           (prog/converttops).  Generalized some image enhancement functions.
           New functions for generating hit-miss sels.

    1.29   12 Nov 05
           More flexible blending of two images, with and without colormaps
           (see blend.c).  Painting colormapped images through masks, etc
           (see paintcmap.c).  More flexible interface for gamma and
           contrast enhancement (see enhance.c).

    1.28   8 Oct 05
           Removed all pix colormaps for 1 bpp.  Allow programmatic resetting
           of binary morphology boundary conditions.  Added (yet) another
           simple octcube color quantizer.  New colormap operations.

    1.27   24 Sept 05
           Renamed many of the enums and typedefs to avoid namespace
           collisions.  This includes structs and typedefs for BMP.
           Interface change to pixClipRectangle(); apologies to everyone
           whose code is broken by these changes -- I hope it's worth it.
           Removed colormap.h; simplified all colormap usage, hiding details
           from all but a few colormap functions.  Am now saving file format
           in the pix when an image is read, and can by default write
           out in this format.  Resolution info added for jpeg and png.
           Added L_INFO* macros and l_info* fctns for printing
           (e.g., debugging) info.  Suggestions and code kindly
           supplied by Dave Bryan, who helped solve compatibility issues
           with MINGW32 (e.g., in timing and directory functions).
           Added some blending and linear TRC functions.
           Generalized pixEqual() to include all cases with and without
           colormaps.  New regression tests in prog: ioformats, equaltest.

    1.26   24 July 05
           Generalized affine pointwise to do interpolation as well as
           sampling.  For both projective and bilinear transforms,
           implemented using both sampling and interpolation.
           Added function to remove keystoning by computing the necessary
           projective transform and doing it.  Also find baselines in text images.
           Added downscaling using accurate area-mapping over subpixels.

    1.25   25 June 05
           Better endian conversion fctns for 2 and 4 byte words.
           Remove colormaps before converting by thresholds.
           Added functions to read header parameters for png and tiff.

    1.24   5 June 05
           Added image splitting to allow printing in tiles (as several pages).
           Added new octree quantization function to generate 4 and 8 bpp
           colormapped output (not dithered).  Fixed bmp resolution.
           Added new flag for colormap removal (using dest depth based on
           src colormap).  Added I/O tests (prog/ioformats.c)

    1.23   10 Apr 05
           Added thresholding from 8 bpp to 2 and 4 bpp, allowing specification
           of both the number of output levels and whether or not a colormap
           is made.

    1.22   27 Mar 05
           Add pointer queue facility.  To demonstrate it, you can now
           generate a binary maze using a cellular automaton and find
           the shortest path between two points in the maze.  Add heap
           of pointers (keyed on the first field), which is used to
           implement a priority queue.  This is applied to search for
           a "least cost" path on a grayscale image (a generalization
           of a binary maze).

    1.21   28 Feb 05
           Read/write of colormaps to file.  For gplot, add a new
           latex output terminal.  Bring ptrs into 21st century by
           including stdint.h, and using uintptr_t for the ptr address
           arithmetic in arrayaccess.*.  This seems to be OK back to
           RH 7.0, but if you run into trouble with an earlier
           C compiler, let me know.  Also, use enums for global
           constants whenever possible, and qualify named constants
           (e.g., ADD --> ARITH_ADD, HORIZ --> MORPH_HORIZ) to avoid
           possible interactions with other libraries.

    1.20   31 January 05
           Speed up of tiffio and pngio with byte swap generating new pix.
           In textops.c, ability to split string into paragraphs,
           in preparation for more general typesetting.
           Automatic hit-miss Sel generation for pattern matching.
           Fast downscaling using a lowpass filter and subsampling.
           Generalization of several grayscale and color operations
           to work on colormapped images.  Improved scale-to-gray and
           scaling reduction operations to be antialiased for best results.

    1.19   30 November 04
           Additions to fileIO: (1) new jpeg reading options, such as
           returning warnings and scaled raster; (2) ability to write
           custom tiff flags.  Better tiling functions.
           Edge extraction, both with grayscale morphology
           and clipped convolution filters.  More general painting
           through a binary mask: pixSetMaskedGeneral().
           Unpacking from binary to 8, 16 and 32 bpp.  Thresholding
           and dithering from 8 bpp to 2 bpp ("dibitization").  New bitmap
           font facility, using a single rendered font in a variety of
           sizes: allows painting the text on an image (binary, gray, RGB).
           (People have asked for the ability to write text on images).

    1.18   25 August 04
           Changed typedefs of built-in types to avoid possible conflicts.
           Cleaned up and tested all programs in the prog directory.
           Simplified and fixed the pixSetMasked() and pixCombineMasked()
           functions.

    1.17   31 May 04
           Implemented distance function for 16 bpp.  We can now generate
           out 16 bpp PNG.  Simple programs for generating PS from a
           directory of g4tiff or jpeg images.  Changed implementation of
           erosion to allow either asymmetric or symmetric boundary conditions.
           The distinction is described on the binary morphology web page.
           Allow read/write of multipage TIFF files.  Implemented
           read/write of PNM files.

    1.16   31 March 04
           New depth conversion functions, improved conversion to false color,
           new contour rendering (onto 1 bpp or onto the src grayscale image),
           new orthogonal rotations, better interface for doing arithmetic
           on 2-d arrays using a pix, improved distance function.

    1.15   31 January 04
           Fast interpolated color rotation with 4x4 subpixels; has
           nearly the accuracy of the slower method using 16x16 subpixels.
           Demonstration of line removal from grayscale sketch in
           prog/lineremoval.c.  Conversion of grayscale to false color.
           Fixed shear and rotation functions to handle angle = 0.0 properly.
           Other small fixes and interface improvements.

    1.14   30 November 03
           Small implementation changes to list.c.  Better sorting
           routines for number arrays (numa), plus sorting for box
           arrays (boxa) and pix arrays (pixa).  PostScript wrapper
           for jpeg.  Better handling of colormaps, and a simple
           function to convert an RGB pix with not more than 256
           colors to the smallest colormapped pix.  PS output wrappers
           for JFIF JPEG and TIFF G4 files.  Comments compatible
           with doxygen for automatic documentation.

    1.13   31 October 03
           Cleaned up documentation in src.  Made libraries and test programs
           ANSI C++ compliant.  Added special cases to rasterops for
           alignment to word boundaries.  Fixed pngio.c to work with
           most recent libpng (1.2.5).

    1.12   30 June 03
           Implemented border chain representation from a binary image,
           writes/reads a compressed version, and renders the original
           image back from the borders.   Also writes outline file out
           in svg format.  Number arrays (numa) and point arrays (pta)
           are also extended to 2nd level arrays (numaa, ptaa).
           Serialized I/O for boxa, pta, and pixa.

    1.11   31 May 03
           Implemented generic list handling, for doubly-linked
           list cons cells and arbitrary objects.

    1.10   14 Apr 03
           Implemented simple image enhancements in gray and color:
           gamma correction, contrast enhancement, unsharp masking.
           Extended smoothing via block convolution to color.
           Implemented auto-gen'd DWA version of hit-miss transform;
           the code for generating these hmt routines is very similar to
           that for DWA auto-gen'd erosion and dilation.

    1.9    28 Feb 03
           Implemented a safe, expandable byte queue.  As an example of
           its use, implemented memory-to-memory compression and decompression
           using zlib.  Generalized PS write to include RGB color.
           Implemented a method to find image skew.

    1.8    31 Jan 03
           Implemented a simple 1-pass color quantization with dithering,
           and improved the 2-pass octree color quantization.
           Documented with an application page, that includes jbig2.
           Added new general sampling operations and made a table
           that summarizes the available scaling operations.

    1.7    31 Dec 02
           Added pixHtmlViewer(), a formatter that allows portable viewing of
           a set of images (like a slide show) in a browser.
           Implemented better octree color quantization, with variable
           number of colors, pruning the octree for good color clusters,
           and fast traversal for pixel assignment to colormap.

    1.6    30 Nov 02
           Generalized shear and shear rotation to arbitrary locations
           about which the operation is performed.  Implemented in-place
           translation using pixRasteropIP().  Implemented arbitrary
           affine transform of image two ways: pointwise and sequential.
           Added binarization by error diffusion.  Added simple color
           quantization by octree.

    1.5    31 Oct 02
           Put jpeglib.h in local directory.  This, along with the jmorecfg.h
           file there prevents compiler warnings about redefined typedefs.
           Compiled everything with g++ to make strictly ansi C compatible.
           Added interface gplotFromFile() for simple file-based plotting with
           gnuplot 3.7.2.   Added functions to convert 2, 4 and 8 bpp
           color-mapped (i.e., palletted) images to 24 bpp color or
           8 bpp grayscale.  Added several jbig2 application cores that
           only require a simple wrapper to make into programs.

    1.4    30 Sep 02
           Added interface to gnuplot 3.7.2 and to x11 display of images.
           Added new functions with arrays of images for use in applications
           such as jbig2 encoders, along with a simple jbig2 implementation
           using either hausdorff or correlation scoring.  Added centroid
           finder for images.  For accessing image arrays from arrays of
           image arrays, added a "new reference" (NEW_REF) flag, with a
           ref count attached to the array.  Added power-of-2 binary
           expansion and reduction.

    1.3    30 Jun 02
           Extended connected components to 8.  Added morphological
           operations tophat and hdome, along with clipped arithmetic
           operators on grayscale images.  Fixed memory error in
           rasteropGeneralLow() that was found using valgrind.
           Tested most operations with valgrind for memory errors.
           Replaced integer arrays with number arrays, to include floats.
           Added arithmetic functions on grayscale images.

    1.2    30 May 02
           Added connected component utility, stack utility, pix arrays,
           line drawing and seed filling.  Binary reconstruction,
           both morphological and raster-oriented, are now supported
           for 4 and 8 connected fills.  Added the distance function
           on binary images, grayscale reconstruction, and grayscale
           morphology using the Gil-Werman method.

    1.1    30 Apr 02
           Added orthogonal rotations, binary scaling, PS output,
           binary reconstruction, integer arrays, structuring element
           input/output.

    1.0    25 Feb 02
           Initial distribution, with rasterops, binary morphology (two
           implementations: rasterops and dwa), affine transforms
           (translation, shear, scaling, rotation), fast convolution,
           and basic i/o (BMP, PNG and JPEG).