Title:         Icon to Bitmap Converter (ICO2BMP)
Author:        Philip J. Erdelsky, 75746.3411@compuserve.com
Language:      Turbo C/C++ 3.1 for DOS
Platform       DOS
Portability:   Other DOS or UNIX C++ compilers, with slight changes
Restrictions:  Public domain, no restrictions on use
Date:          January 10, 1995
Keywords:      Icon, Bitmap

Abstract:      A simple DOS utility to convert a Windows icon (.ICO)
               file into a Windows bitmap (.BMP) file.

A Windows bitmap is suitable is some situations where a Windows icon is
not. ICO2BMP converts a Windows icon file (with extension .ICO) into a
Windows bitmap file (with extension .BMP), or a Windows bitmap resource
(with extension .RC), retaining as much of the original information as
possible.

If you want to convert an icon file into a bitmap file with the same
name, and you are willing to accept the default values of most
parameters, a command line of the following form will suffice:

     ICO2BMP  MYICON

ICO2BMP will convert the icon file MYICON.ICO (which may contain only
one icon) to the bitmap file MYICO.BMP.

For more complex conversions, ICO2BMP is called up by a command line of
the following form:

  ICO2BMP icon [-i n] [-b bitmap] [-n name] [-a] [-c red green blue] [-v]

     icon    icon file specifications
     n       index number of icon to be converted (first is number 0)
     bitmap  bitmap file specifications
     -a      append bitmap to existing bitmap file
     name    bitmap name
     red     red intensity of background (0-255)
     green   green intensity of background (0-255)
     blue    blue intensity of background (0-255)
     -v      verbose output for diagnostic purposes
      
The icon file specifications must be given. If there is no extension,
.ICO is appended. If there is an extension, it must be .ICO.

The icon file specifications must appear first; the options may appear
in any order.

If the icon file contains more than one icon, you must specify the index
number of the icon to be converted. The index number of the first icon
is zero.

If the bitmap file specifications are omitted, the icon file
specifications are used, with the extension changed to .BMP. If the
bitmap file specifications are given without an extension, .BMP is
appended. If the bitmap file specifications are given with an extension,
it must be either .BMP or .RC.

If the bitmap file extension is .BMP, a bitmap file is generated. If the
bitmap file extension is .RC, a Resource Compiler source file is
generated, in text form.

When the bitmap file extension is .RC, the -a option causes the
generated text to be appended to an existing Resource Compiler source
file.

When the bitmap file extension is .RC, the bitmap must have a name.  If
you specify a name containing an exclamation point (!), the file name of
the icon file is subsituted for the exclamation point. If you do not
specify a name, the name is constructed by appending the icon file name
to BITMAP_.

In some cases, you may wish to specify the red, green and blue
intensities of the background color. An icon may contain transparent
regions where the background shows through, and other regions where the
background is complemented.  If red = green = blue = 0, the background
is black. If red = green = blue = 255, the background is white.
Intermediate intensities give backgrounds of various colors. If you do
not specify a background color, ICO2BMP uses red = green = blue = 192,
which is a light gray color, for most icons. For a two-color (black and
white) icon, however, it uses a white background.

Although they do not appear in icons generated by the Borland Resource
Workshop, the icon file format permits an icon to have regions where the
background is partly complemented. ICO2BMP follows the rules in such
cases, producing partly complemented versions of the background color.

An icon may use 2, 8 or 16 colors. ICO2BMP generates a bitmap which uses
the same colors. If the icon contains transparent or complemented
regions, some parts of the bitmap may contain colors not in the original
icon, especially if the background color is not among the colors used in
the icon. In these cases, ICO2BMP chooses colors from the icon colors
that most closely match the background color or complemented background
color.

For the sake of efficiency, you should not create 8-color icons, since
they occupy the same amount of space as 16-color icons and are converted
into 16-color bitmaps.