Dynapro Technologies Dynapro ET TCS, Application Developer'S Manual

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An area within each screen is defined to be a scrolling region. This is so characters can continue
to be displayed without running off the bottom of the screen. When new characters are to be
displayed and the cursor has advanced to the bottom line within the scrolling region, the area of
the screen known as the scrolling region “scrolls.” In the case just described, the top line of the
scrolling region disappears from the screen, each line within the scrolling region moves up one
line in position in the screen, and a new blank line is placed at the bottom of the scrolling region.
Although scrolling usually occurs in the upward direction just described, it can also occur in a
downward direction during certain situations when the cursor is moving upward in the screen.
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Some of the control codes reserved by ANSI affect the format of displayed characters. These
control codes do not cause the display of any characters, but they affect the placement of the
printable characters that follow by moving the cursor.
Remember the following points when interspersing format effectors and graphic codes.
•
If the cursor is on the bottom line of the scrolling region and the format effector causes the
cursor to move downward, the screen scrolls upward, and the cursor remains on the same
line.
•
If the cursor is on the top line of the scrolling region and the format effector causes the
cursor to move upward, the screen scrolls downward, and the cursor remains on the same
line.
•
If the cursor is outside the scrolling region and the format effector attempts to move the
cursor above the top of the screen or below the bottom of the screen, the screen does not
scroll, and the cursor remains on the same line.