PRISM

David Gerrold                           December 11, 1990 (Utilities)


Purpose:      A VGA palette editor/loader that enables text mode display of
              262,144 colors by any of the 16 DOS attribute numbers.

Format:         PRISM [filename]

Remarks:        If the optional filename  (a .PAL file) is supplied when
loading PRISM, the original DOS color values will dissolve into those stored
in the named palette.  Loaded without a filename, PRISM comes up in editing
mode, with the 16 current colors arrayed in two rows of squares in DOS
attribute order (0-7, 8-15).  The color currently selected for editing,
duplicating, or swapping from one attribute position to another is also shown
in a large central rectangle, below which is a frame that separately displays
its component saturation, intensity, red, green, and blue values.  Colors
maybe elected by clicking with a mouse (left button), which can also be used
to drag the sliders that control the color values.  A selected color may be
swapped by clicking the mouse on the central box and then clicking on the
target attribute position.  Duplicating a color is similar except that the
mouse cursor is dragged from the central box to the new position.

        Ctrl-R resets the color palette to its entry condition, and Ctrl-U (or
Esc or the right mouse button) undoes up to 15 color changes successively. 
Ctrl-Left and Ctrl-Right Arrow keys can be used in lieu of a mouse to select
colors, which key be edited with the numeric keypad (Num-Lock ON) arrow keys. 
With Num-Lock OFF, the arrow keys move between items on the menu bar, from
which PRISM commands can also be executed.  Desired palettes can be saved and
loaded while in edit mode from the menu bar.  (The .PAL extension need not be
typed for either operation.)  Default settings for mouse speed, sound effects
on/off, and the dissolve rate between palette shifts can be changed with menu
options.  F1 accesses an extensive on-screen help system.  To prevent
accidental exit, the menu Quit command requires two keystrokes or mouse
clicks.

        PRISM saves and restores the underlying DOS screen even if an expanded
number of rows and columns are being used.  It will also automatically detect
its home subdirectory.  The program is UltraVision-compatible, but will not
operate under Windows and DESQview.  In addition to a VGA, PRISM requires DOS
3.0 or later and 256KB of free RAM.