The PRINTER widget maintains a total number of lines of text at any one time. The total number is equal to the number of ROWS plus the number of HIDDEN LINES. Since the PRINTER-widget size is adjustable both programmatically and by the operator, the number of visible ROWS can change. If you adjust the size of the PRINTER widget, there are three cases of interest :
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If you have a widget with 3 visible ROWS and 3 HIDDEN LINES (for a total of 6 lines) and you resize it such that only 2 ROWS are visible, HIDDEN LINES is set to 4.
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If you have a widget with 3 visible ROWS and 3 HIDDEN LINES (for a total of 6 lines) and you resize it such that 5 ROWS are visible, HIDDEN LINES is set to 1.
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If you have a widget with 3 visible ROWS and 3 HIDDEN LINES (for a total of 6 lines) and you resize it such that 8 ROWS are visible, HIDDEN LINES is set to 0 and the total number of lines is increased to 8. Now if you resize the widget such that 3 ROWS are visible, HIDDEN LINES is set to 5.
If HIDDEN LINES is set to a value that is less than the value of VALID LINES - ROWS, the oldest lines are lost. Whenever there is off-screen text in the PRINTER widget, a vertical scrollbar appears so that the operator can scroll the window to read the text.
