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Q50461: COLOR Statement in SCREEN 11 Gives "Illegal Function Call"

Article: Q50461
Product(s): See article
Version(s): 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | SR# S891027-16 B_BasicCom docerr | mspl13_basic
Last Modified: 15-JAN-1990

The COLOR statement correctly returns an "Illegal Function Call" if
used in SCREEN 11. The only way to change the color in SCREEN 11 is to
use the PALETTE statement. However, note that the PALETTE statement
may not work with a video card that is not 100-percent compatible with
the IBM standard VGA or MCGA. (SCREEN 11 requires VGA or MCGA.)

The following resources incorrectly state that the COLOR statement is
valid in SCREEN modes 11-13; they should instead say SCREEN modes
12-13:

1. Two occurrences, on Page 109 of the "Microsoft QuickBASIC 4.0: BASIC
   Language Reference" manual for QuickBASIC Versions 4.00 and 4.00b

2. Two occurrences, on Page 109 of the "Microsoft BASIC Compiler 6.0:
   BASIC Language Reference" manual for Versions 6.00 and 6.00b

3. One occurrence, under the COLOR statement in the QB Advisor online
   Help system for QuickBASIC Version 4.50

This documentation error was corrected in the "Microsoft QuickBASIC
4.5: BASIC Language Reference" manual for QuickBASIC Version 4.50, in
the Microsoft BASIC Professional Development System (PDS) 7.00 "BASIC
Language Reference," and in the Microsoft Advisor online Help system
in the QuickBASIC Extended editor (QBX.EXE) shipped with BASIC PDS
Version 7.00.

The PALETTE statement can be used instead of the COLOR statement in
SCREEN 11 to set the foreground and background colors. Note that the
foreground color can only be set for graphics statements; text will
always be blue.

To change the foreground color in SCREEN 11, the following PALETTE
statement must be used:

   PALETTE 1, color

To change the background color in SCREEN 11, the following PALETTE
statement must be used:

   PALETTE 0, color

Below is another code example demonstrating how to set the foreground
and background colors in SCREEN 11 using the PALETTE statement:

' VGA color equation: COLOR number = 65536 * blue + 256 * green + red
'   where red, blue, and green are numbers between 0 and 63
CLS
SCREEN 11
background& = 256 * 63   'bright green
foreground& = 63         'bright red
PALETTE 0, background&
PALETTE 1, foreground&
LINE (10, 240)-(630, 240)
WHILE INKEY$ = "": WEND

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