Grimage

Grimage is a library that enables reading, writing, and drawing images in Caml Light. It handles the BMP and PPM formats. A special extension to the PPM format allows the manipulation of images with transparent areas in them.

It is freely available via FTP and HTTP.

High level interface with the Grimage library uses a generic image format named grimage. Images are converted to and from the grimage format, and then read and written to the file system.

Reading and writing images

Grimage handles the following formats:

• BMP: use
  • grimage__load_bmp_grimage filename to load a BMP image.
  • grimage__save_bmp_grimage filename grim to save a grimage image as a BMP image.
  • grimage__draw_grimage grim x y to draw a BMP image loaded as a grimage value.
  • grimage__image_of_grimage to convert a grimage to an image of the Graphics module.
• PPM (portable pixmaps): files with extension ppm, pgm (portable graymap), or pbm (portable bitmap). As for the BMP format, you may use the corresponding functions from the Grimage module:
  • grimage__load_ppm_grimage filename to load a PPM image.
  • grimage__save_ppm_grimage filename ppm to save a grimage image as a PPM image.
  • grimage__draw_grimage grim x y to draw a PPM image loaded as a grimage value.
  • grimage__image_of_grimage to convert to an image of the Graphics module.

Bitmap and transparency manipulation

Elementary facilities to transform pixmaps (a color image represented as a matrix of R, G, B values) are provided by Grimage:

• pixmap__bitmap_of_pixmap : int -> int -> pixmap -> pixmap maps a pixmap into a bitmap image.
• pixmap__set_background_transp : pixmap -> unit sets to transparent the pixels of a pixmap whose color is the background color.

Low level use of the library is still possible via direct calls to functions from the Bmp and Ppm modules.

For more info about the library, read the interfaces of the modules and have a look to the test directory for working examples.

Enjoy Grimage!

Pierre weis.