mirror of
https://github.com/QB64Official/qb64.git
synced 2024-09-28 11:17:47 +00:00
64 lines
1.9 KiB
Markdown
64 lines
1.9 KiB
Markdown
|
The [VIEW PRINT](VIEW-PRINT) statement defines the boundaries of a text viewport PRINT area.
|
||
|
|
||
|
## Syntax
|
||
|
|
||
|
> **VIEW PRINT** [topRow% **TO** bottomRow%]
|
||
|
|
||
|
## Parameter(s)
|
||
|
|
||
|
* 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](VIEW-PRINT) statement without parameters can also disable a viewport when no longer needed.
|
||
|
* [CLS](CLS) or [CLS](CLS) statement will clear the active text viewport area only, and reset the cursor location to topRow%.
|
||
|
* A [SCREEN](SCREEN) mode change or [RUN](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](WIDTH) statement has been used.
|
||
|
* **Note: QB64 [RUN](RUN) statements will not close [VIEW PRINT](VIEW-PRINT), [VIEW](VIEW) or [WINDOW](WINDOW) view ports presently!**
|
||
|
|
||
|
## Example(s)
|
||
|
|
||
|
Demonstrates how text scrolls within the text viewport.
|
||
|
|
||
|
```vb
|
||
|
|
||
|
' 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
|
||
|
|
||
|
* [CLS](CLS)
|
||
|
* [WINDOW](WINDOW)
|
||
|
* [VIEW](VIEW) (graphics view port)
|
||
|
* [LOCATE](LOCATE), [PRINT](PRINT)
|