Q34917: PRINT to Viewport Has Screen’s Background Color Not Viewport’s

Article: Q34917
Product(s): See article
Version(s): 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | B_BasicCom | mspl13_basic
Last Modified: 16-DEC-1989

When PRINTing text to a viewport that has a different color than the
main screen, the background color of the text will be the same as the
background color of the screen, not the viewport. This is expected
behavior.

This information applies to Microsoft QuickBASIC Versions 4.00 4.00b
and 4.50, to Microsoft BASIC Compiler Versions 6.00 and 6.00b for
MS-DOS and MS OS/2, and to Microsoft BASIC PDS Version 7.00 for MS-DOS
and MS OS/2.

If you have one window on the screen, you can use the following
method:

1.  Switch to graphics mode.

2.  Change the background color to be the color of the window.

3.  Paint the screen the actual background color.

4.  Draw the window.

5.  Print the text.

Note that steps 2 and 3 will cause a flash on the screen. This cannot
be avoided. The following is a code sample:

SCREEN 9
COLOR 7, 1
VIEW (0, 0)-(639, 349), 2
VIEW (100, 100)-(300, 300), 1
LOCATE 20, 20: PRINT "This is a test"
WHILE INKEY$ = "": WEND

The following is a code example of the undesired result:

REM  This is a sample program that demonstrates printing
REM  text to a viewport. The background color of the text
REM  printed to the viewport is the same as that of the
REM  screens.
  CLS
  SCREEN 9
REM Screen has green foreground and light blue background:
  COLOR 10, 11
REM Set up first viewport with red background:
  VIEW (10, 10)-(600, 200), 12, 11
REM Print is green with light blue background:
  LOCATE 1, 11: PRINT "Outer viewport"
REM Set up second viewport with purple background:
  VIEW SCREEN (50, 50)-(350, 150), 5, 7
REM Print is green with light blue background:
  LOCATE 9, 9: PRINT "Inner viewport"
  END