IRIS 3010, Руководство пользователя

Страница: 121 / 145

2D Window Manager Demonstration Programs
A set of 2D programs is included in the collection of demonstration programs.
These tools include the following programs: bckgrnd , showmap , demomakemap ,
showramp , gamma , cedit , interp , and mag . These tools can be classified into
three categories: backgrounds, color manipulation programs, and pixel access
programs. To start any of these tools, type the name of the tool in the console
window.
Backgrounds
bckgrnd is a non-interactive, textured “wallpaper” with art deco designs. A
particular background fills all available space which is not covered with another
window.
Color Manipulation Programs
showmap is a window filled with up to 1024 little squares. It displays the
current colors in the color map, counting from the color 0 at the lower left
corner up to the largest color index at the top right. (For more information on
color maps, see the IRIS User’s Guide and the makemap (1W) command in the
U
nix
Programmer’s Manual .)
demomakemap makes and remakes the color map for the demonstration
programs. Before other graphics programs are executed, run demomakemap to
build the default color map for the demonstration package. To see the effect of
changing the color map using demomakemap , run showmap in a separate
window. (At any time during the demonstration session, the original color
map can be restored by executing demomakemap .)
demomakemap also works in conjunction with the gamma program. demomakemap
reads the value from the file .gamma in your home directory and uses it to
calculate its shade scales (see below).
showramp is a window with three Gouraud-shaded rectangles. The rectangles
are smoothly colored using physically and chromatically adjacent color indices
that form a color ramp in the color map.
The
gamma program uses a technique called gamma-correction to change the
“smoothness” of the transitions between the color intensities in a color map.
The physical characteristics of the CRT phosphor, the ambient lighting, and the
vision and preference of the viewer affect the perception of the color map. A
strictly linear color ramp often appears too dark, especially towards the middle
of the ramp. gamma allows the increments from color to color to be
exponential, and thus, the middle of the color ramp can be brighter or darker
than in a linear color ramp.
Version 1.1 SERIES 3000
IRIS OWNER’S GUIDE 9-3 Demonstration Programs and Gifts