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64 lines
1.9 KiB
Markdown
64 lines
1.9 KiB
Markdown
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The [VIEW PRINT](VIEW-PRINT) statement defines the boundaries of a text viewport PRINT area.
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## Syntax
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> **VIEW PRINT** [topRow% **TO** bottomRow%]
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## Parameter(s)
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* topRow% and bottomRow% specify the upper and lower rows of the text viewport.
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* If topRow% and bottomRow% are not specified when first used, the text viewport is defined to be the entire screen.
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## Description
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* A second [VIEW PRINT](VIEW-PRINT) statement without parameters can also disable a viewport when no longer needed.
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* [CLS](CLS) or [CLS](CLS) statement will clear the active text viewport area only, and reset the cursor location to topRow%.
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* A [SCREEN](SCREEN) mode change or [RUN](RUN) statement can also clear and disable viewports.
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* After active viewport is disabled, normal screen printing and clearing can begin.
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* Row coordinates may vary when a [WIDTH](WIDTH) statement has been used.
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* **Note: QB64 [RUN](RUN) statements will not close [VIEW PRINT](VIEW-PRINT), [VIEW](VIEW) or [WINDOW](WINDOW) view ports presently!**
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## Example(s)
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Demonstrates how text scrolls within the text viewport.
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```vb
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' clear the entire screen and show the boundaries of the new text viewport
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CLS
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PRINT "Start at top..."
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LOCATE 9, 1: PRINT "<- row 9 ->"
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LOCATE 21, 1: PRINT "<- row 21 ->"
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' define new text viewport boundaries
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VIEW PRINT 10 TO 20
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' print some text that will scroll the text viewport
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FOR i = 1 TO 15
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PRINT "This is viewport line:"; i
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SLEEP 1
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NEXT i
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' clear only the active text viewport with CLS or CLS 2
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CLS
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PRINT "After clearing, the cursor location is reset to the top of the text viewport."
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' disable the viewport
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VIEW PRINT
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_DELAY 4
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LOCATE 20, 20: PRINT "Print anywhere after view port is disabled"
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_DELAY 4
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CLS
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PRINT "Back to top left after CLS!"
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```
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> *Note:* The bottom row of the VIEW PRINT port can be used only when located or prints end with semicolons.
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## See Also
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* [CLS](CLS)
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* [WINDOW](WINDOW)
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* [VIEW](VIEW) (graphics view port)
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* [LOCATE](LOCATE), [PRINT](PRINT)
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