VIEW PRINT: Difference between revisions

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* [https://qb64phoenix.com/forum/showthread.php?tid=1308 Featured in our "Keyword of the Day" series]
* [[CLS]]
* [[CLS]]
* [[WINDOW]]
* [[WINDOW]]
* [[VIEW]] {{text|(graphics view port)}}
* [[VIEW]]
* [[LOCATE]], [[PRINT]]
* [[LOCATE]], [[PRINT]]




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Latest revision as of 18:18, 25 May 2024

The VIEW PRINT statement defines the boundaries of a text viewport PRINT area.


Syntax

VIEW PRINT [topRow% TO bottomRow%]


Parameters

  • topRow% and bottomRow% specify the upper and lower rows of the text viewport.
  • If topRow% and bottomRow% are not specified when first used, the text viewport is defined to be the entire screen.


Description

  • A second VIEW PRINT statement without parameters can also disable a viewport when no longer needed.
  • CLS or CLS 2 statement will clear the active text viewport area only, and reset the cursor location to topRow%.
  • A SCREEN mode change or RUN statement can also clear and disable viewports.
  • After active viewport is disabled, normal screen printing and clearing can begin.
  • Row coordinates may vary when a WIDTH statement has been used.
  • Note: QB64 RUN statements will not close VIEW PRINT, VIEW or WINDOW view ports presently!


Example: Demonstrates how text scrolls within the text viewport.

' clear the entire screen and show the boundaries of the new text viewport
CLS
PRINT "Start at top..."
LOCATE 9, 1: PRINT "<- row 9 ->"
LOCATE 21, 1: PRINT "<- row 21 ->"

' define new text viewport boundaries
VIEW PRINT 10 TO 20

' print some text that will scroll the text viewport
FOR i = 1 TO 15
  PRINT "This is viewport line:"; i
  SLEEP 1
NEXT i

' clear only the active text viewport with CLS or CLS 2
CLS
PRINT "After clearing, the cursor location is reset to the top of the text viewport."

' disable the viewport
VIEW PRINT
_DELAY 4
LOCATE 20, 20: PRINT "Print anywhere after view port is disabled"
_DELAY 4
CLS
PRINT "Back to top left after CLS!"
Note: The bottom row of the VIEW PRINT port can be used only when located or prints end with semicolons.


See also



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