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60 lines
2.2 KiB
Text
60 lines
2.2 KiB
Text
The [[VIEW PRINT]] statement defines the boundaries of a text viewport {{KW|PRINT}} area.
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{{PageSyntax}}
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: '''VIEW PRINT''' [{{Parameter|topRow%}} '''TO''' {{Parameter|bottomRow%}}]
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{{Parameters}}
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* {{Parameter|topRow%}} and {{Parameter|bottomRow%}} specify the upper and lower rows of the text viewport.
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* If {{Parameter|topRow%}} and {{Parameter|bottomRow%}} are not specified when first used, the text viewport is defined to be the entire screen.
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{{PageDescription}}
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* A second [[VIEW PRINT]] statement without parameters can also disable a viewport when no longer needed.
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* [[CLS]] or [[CLS|CLS 2]] statement will clear the active text viewport area only, and reset the cursor location to {{Parameter|topRow%}}.
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* A {{KW|SCREEN}} mode change or {{KW|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]] statement has been used.
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* '''Note: QB64 [[RUN]] statements will not close [[VIEW PRINT]], [[VIEW]] or [[WINDOW]] view ports presently!'''
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''Example:'' Demonstrates how text scrolls within the text viewport.
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{{CodeStart}}' clear the entire screen and show the boundaries of the new text viewport
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{{Cl|CLS}}
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{{Cl|PRINT}} "Start at top..."
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{{Cl|LOCATE}} 9, 1: {{Cl|PRINT}} "<- row 9 ->"
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{{Cl|LOCATE}} 21, 1: {{Cl|PRINT}} "<- row 21 ->"
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' define new text viewport boundaries
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{{Cl|VIEW PRINT}} 10 {{Cl|TO}} 20
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' print some text that will scroll the text viewport
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{{Cl|FOR...NEXT|FOR}} i = 1 {{Cl|TO}} 15
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{{Cl|PRINT}} "This is viewport line:"; i
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{{Cl|SLEEP}} 1
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{{Cl|NEXT}} i
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' clear only the active text viewport with CLS or CLS 2
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{{Cl|CLS}}
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{{Cl|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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{{Cl|VIEW PRINT}}
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{{Cl|_DELAY}} 4
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{{Cl|LOCATE}} 20, 20: {{Cl|PRINT}} "Print anywhere after view port is disabled"
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{{Cl|_DELAY}} 4
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{{Cl|CLS}}
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{{Cl|PRINT}} "Back to top left after CLS!" '' ''
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{{CodeEnd}}
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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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{{PageSeeAlso}}
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* [[CLS]]
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* [[WINDOW]]
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* [[VIEW]] {{text|(graphics view port)}}
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* [[LOCATE]], [[PRINT]]
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{{PageNavigation}}
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