Contact the authors Jun.Furuse@inria.fr and
Created the 7th of February 2000.
Last update on Fri Oct 1 2004.
Note: this library is currently(=always) under development.
CamlImages is an image processing library, which provides
freetypeinterface, integrated into the library: you can draw texts into images using any truetype fonts.
In addition, the library can handle huge images that cannot be (or can hardly be) stored into the main memory (the library then automatically creates swap files and escapes them to reduce the memory usage).
Additional example programs are supplied in the
examples directory of the library:
gifencoded series of images.
lscommand to view a set of images. (Also considered as a light version of
xvwith nice slide show capabilities.)
ttfimgalso creates some sample images of true type fonts. Try ttfimg -o sample_micap.jpg ../../test/micap.ttf.
Get the source
tar ball, decompress it,
and read the file
You can also access the read-only CVS repository which contains the latest developing (but not yet released) version.
CamlImages supports the following color models:
Rgb24: 24bit depth full color image.
Index8: 8bit depth indexed image with transparent information.
Index16: 16bit depth indexed image with transparent.
Rgba32: 32bit depth full color image, with the alpha channel.
Cmyk32: 32bit Cyan Magenta Yellow and blacK image. (Unfortunatelly, beautiful conversion between RGB and CMYK is not supported.)
Rgb24if you want to access 24bit depth full color images.
CamlImages supports loading and saving of the following file formats:
For each image format, we provide a separate module. For instance,
Tiff module to load and save images stored in the tiff file
If you do not want to specify the file format, you can use
Image.load: this function automatically analyses the
header of the image file at hand and loads the image into the memory,
if the library supports this format.
CamlImages also provides an interface to the internal image format of O'Caml's Graphics library (this way you can draw your image files into the Graphics window).
You can also draw strings on images using the Freetype library, which is an external library to load and render TrueType fonts.
The modules with names beginning with the letter 'o' contains the object class interface for CamlImages.
When you create/load a huge image, the computer memory may not be
sufficient to contain all the data. (For example, this may happen if
you are working with a scanned image of A4, 720dpi, 24bit fullcolor,
even if you have up to 128Mb of memory!) To work with such huge
images, CamlImages provides image swaps, which can escape part of the
images into files stored on the hard disk. A huge image is thus
partitioned into several blocks and if there is not enough free
memory, the blocks which have not been accessed recently are swapped
to temporary files. If a program requests to access to such a swapped
block, the library silently loads it back into memory.
By default, image swapping is disabled, because it slows down the programs. To activate this function, you have to modify
Bitmap.maximum_liveis the maximum heap live data size of the program (in words)
Bitmap.maximum_block_sizeis the maximum size of swap blocks (in words).
gc.mli, in the standard library for more details (you should change the compaction configuration).
Bitmap.maximum_block_sizeaffects the speed and frequency of image block swapping. If it is larger, each swapping becomes slower. If it is smaller, more swappings will occur. Too large and too small
maximum_block_size, both may make the program slower. I suggest to have maximum_block_size set to
!Bitmap.maximum_live / 10.
/tmpdirectory. If you set the environment variable
"CAMLIMAGESTMPDIR", then its value replaces the default
"/tmp"directory. The temporary files are erased when the program exits successfully. In other situations, for instance in case of spurious exception, you may need to erase temporary files manually.
examplesdirectory including image auto-cropping, resizing and an image viewer with the lablgtk library.
include /usr/local/lib/ocaml/camlimages/Makefile.configThe library directory can be different, if the library is installed somewhere else. The variables
LINKFLAGS_CAMLIMAGESare defined in
Makefile.config; you should add them to the compiler and linker options. A sample Makefile is available as