Icon for Windows runs on PCs with Windows 3.1 (with Win32s), Windows 95 and above, and Windows NT. Windows machines vary greatly in their hardware capabilities, so this section can't say precisely how things will work in all situations.
Windows does not provide a built-in color naming model, so Icon's standard color names comprise the complete set of recognized names.
Depending on the hardware configuration, Windows may use dithered colors in response to any particular color request. This results in an unattractive appearance in applications where solid colors are expected. Most colors are dithered on 16-color machines, and color-intensive applications are ugly or unusable on those systems.
Color correction is controlled by the gamma attribute. The
default value of the gamma attribute is 1.0.
Windows comes with very few fonts. The set of fonts available on a given machine is a function of the set of applications and fonts that have been installed. As a result, Windows machines vary widely in their interpretation of font requests. The same specification in Icon can produce fonts of different appearance on different machines.
Windows' native font specifications are complex structures that specify
a set of desired characteristics, from which a "nearest match"
is chosen by Windows when a font is requested. Windows has fonts based on
different character sets. The standard Icon font names (fixed,
sans, serif, mono, and typewriter)
return a font that uses the so-called ANSI character set.
In ReadImage(), if an image file is not a valid GIF file,
an attempt is made to read it as a Windows bitmap file.
In WriteImage(), if the file name ends in .bmp or .BMP,
a Windows bitmap file is written. In all other cases a GIF file is written.
Icon uses Windows scan codes as integer event codes for special keys. Symbolic definitions given in Appendix D and located in file keysyms.icn allow applications to refer to these special keys in a system independent way.
The pointer attribute can take any of the values shown in this figure: