Basic computer language commands

Basic computer programming language

COLOR Statement

Purpose:

To select display colors

Syntax:

COLOR [foreground][,[background][,border]]
COLOR [background][,[palette]]
COLOR [foreground][,[background]]

Comments:

In general, COLOR allows you to select the foreground and background colors for the display. In SCREEN 0 a border color can also be selected. In SCREEN 1 no foreground color can be selected, but one of two four-color palettes can be selected for use with graphics statements. The different syntaxes and effects that apply to the various screen modes are described below:

ModeEffect
SCREEN 0

Modifies the current default text foreground and background colors, and the screen border. The foreground color must be an integer expression in the range 0-31. It is used to determine the "foreground" color in text mode, which is the default color of text. Sixteen colors can be selected with the integers 0-15. A blinking version of each color can be selected by adding 16 to the color number; for example, a blinking color 7 is equal to 7 + 16, or 23. Thus, the legal integer range for foreground is 0-31.

The background color must be an integer expression in the range 0-7, and is the color of the background for each text character. Blinking colors are not permitted.

The border color is an integer expression in the range 0-15, and is the color used when drawing the screen border. Blinking colors are not permitted.

If no arguments are provided to COLOR, then the default color for background and border is black (COLOR 0), and for foreground, is as described in the SCREEN statement reference pages.

SCREEN 1

In mode 1, the COLOR statement has a unique syntax that includes a palette argument, which is an odd or even integer expression. This argument determines the set of display colors to use when displaying particular color numbers.

For hardware configurations that do not have an IBM® Enhanced Graphics Adapter (EGA), the default color settings for the palette parameter are equivalent to the following:

COLOR ,0  'Same as the next three PALETTE statements
          '1 = green, 2 = red, 3 = yellow

COLOR ,1  'Same as the next three PALETTE statements
          '1 = cyan, 2 = magenta, 3 = white

With the EGA, the default color settings for the palette parameter are equivalent to the following:

COLOR ,0     'Same as the next three PALETTE statements
PALETTE 1,2  'Attribute 1 = color 3 (green)
PALETTE 2,4  'Attribute 2 = color 5 (red)
PALETTE 3,6  'Attribute 3 = color 6 (brown)

COLOR ,1     'Same as the next three PALETTE statements
PALETTE 1,3  'Attribute 1 = color 3 (cyan)
PALETTE 2,5  'Attribute 2 = color 5 (magenta)
PALETTE 3,7  'Attribute 3 = color 15 (white)

Note that a COLOR statement will override previous PALETTE statements.

SCREEN 2No effect. An "Illegal function call" error message occurs if COLOR is used in this mode.
SCREEN 7- SCREEN 10In these modes, no border color can be specified. The graphics background is given by the background color number, which must be in the valid range of color numbers appropriate to the screen mode. See the SCREEN statement reference pages for more details. The foreground color argument is the default line drawing color.

Arguments outside valid numeric ranges result in "Illegal function call" errors.

The foreground color may be the same as the background color, making displayed characters invisible. The default background color is black, or color number 0, for all display hardware configurations and all screen modes.

With the Enhanced Graphics Adapter (EGA) installed, the PALETTE statement gives you flexibility in assigning different display colors to the actual color-number ranges for the foreground, background, and border colors discussed above. See the PALETTE statement reference pages for more details.

For more information, see CIRCLE, DRAW, LINE, PAINT, PALETTE, PRESET, PSET, and SCREEN

Examples:

The following series of examples show COLOR statements and their effects in the various screen modes:

SCREEN 0
COLOR 1, 2, 3  'foreground=1, background=2, border=3 

SCREEN 1
COLOR 1, 0     'foreground=1, even palette number
COLOR 2, 1     'foreground=2, odd palette number

SCREEN 7
COLOR 3, 5     'foreground=3, background=5

SCREEN 8
COLOR 6, 7     'foreground=6, background=7

SCREEN 9
COLOR 1, 2     'foreground=1, background=2

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