AAI image file format
=====================

The "AAI" is the internal format used in Dune devices to represent images
with transparency (alpha channel) support.

File format:
   int32 width;
   int32 height;
   int32[width * height] RGBA_pixel_data; // 0..254, 255 is prohibited

NOTE: the "alpha" component of RGBA pixel data must be in range 0..254; 0
corresponds to fully transparent pixels; 254 corresponds to fully opaque
pixels. 255 is a reserved value and must never be used.

NOTE: All integers in a file are in Little-Endian (PC) byte order.

NOTE: The maximum image size is 2047 x 2047 pixels, the minumum is 1 x 1
pixel.

NOTE: When converting e.g. a BMP file to an AAI file, the recommended way
to convert 0..255 range "alpha" values to 0..254 range supported by Dune is
the following:
   0..254 -> 0..254, 255 -> 254.
E.g.:
   if (source_pixel.A == 255)
      target_pixel.A = 254;
   else
      target_pixel.A = source_pixel.A;

AAImageGen converter application
================================

The "AAImageGen" converter application is used to convert image files of
various formats to the "aai" format. It may work in the automatic mode --
it is enough to drag-and-drop the image file of any supported format (BMP,
PNG, JPG, PSD and many others) onto the icon or a shortcut to the converter
executable file ("AAImageGen.exe"). Then, next to the source image file, a
new file will appear having the same name but the "aai" extension.

If the transparency is not needed, a single-layer image file is enough,
e.g. PNG, BMP, JPG or PSD. However, there is a possibility to use
transparency, moreover, a complete alpha channel support is provided, that
is, for each pixel its transparency level may be specified, and not only
the fact of transparency. If, for example, Adobe Photoshop is used, an
image in RGB mode should be created, the "Alpha" channel should be added in
the "Channels" tab, and the required transparency should be expressed in
that channel. Then it should be checked that the image has only one layer,
and this layer is the "background"; otherwise, the correct behaviour of the
converter is not guaranteed.

To test the conversion result, the "aai" file may be dropped onto the
converter icon, and it will be converted to "bmp".

The converter application may work in manual mode -- if it is simply
launched, it shows a dialog window offering to open the source image file
in one of the supported formats. Before saving the conversion result, the
resulting image is shown on the blue background (honoring the alpha channel
if it exists).

The converter application may work in command line mode -- if it is
launched with a single argument pointing to a source file, it creates the
conversion result in the same directory; if it is launched with two
arguments pointing to a source and a target file, it stores the conversion
result into the specified target file.

ATTENTION: Because of an error in Adobe Photoshop versions up to and
including the CS2 (newer versions were not checked), BMP files with alpha
channel (32 bits per pixel) are saved incorrectly for some image sizes
(e.g. 64x64). Therefore it is recommended to use the native PSD format when
working with Photoshop.