Dynapro Technologies Dynapro ET TCS, Руководство разработчика приложений

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The interaction between the setting of the Origin Mode and a Scrolling Region can produce
unexpected results. Note the following points:
•
Setting Origin Mode repositions the cursor to row l, column 1 of the current scrolling region.
Resetting Origin Mode repositions the cursor to row 1, column of the entire screen.
•
When Origin Mode is set, the scrolling region acts like an independent smaller display.
When Origin Mode is reset, the scrolling region merely specifies which portion of the entire
screen is to scroll.
•
Relative cursor movements (such as indexing and line feeds) do not move the cursor out of a
scrolling region, regardless of the setting of the Origin Mode. Absolute cursor positioning
(such as Move Cursor to Absolute Position and Move Cursor to Touchkey) can move the
cursor out of scrolling region, but only when Origin Mode is reset.
The following examples demonstrate some implications:
1. In the simplest case, assume that no scrolling region has been established. In effect, the entire
display area is one large scrolling region. Regardless of the setting of Origin Mode, the
cursor can be moved anywhere in the display.
2. For a slightly more complex case, assume a scrolling region smaller than the entire screen is
set while Origin Mode is reset. The origin remains the upper left corner of the entire screen.
The cursor can be moved anywhere on the entire screen by absolute cursor positioning
commands.
Once the cursor enters the scrolling region, relative cursor movement commands that attempt
to leave the scrolling region stop at the edge of the region. After an absolute cursor
movement command has moved the cursor out of the scrolling region, then relative cursor
commands can move the cursor while it remains outside the region. However, once it crosses
back inside the scrolling region, relative movement commands are once again limited to the
region.
3. Finally, suppose Origin Mode is set while there is no scrolling region. The cursor moves to
the upper left corner (home) of the entire screen. Now create a scrolling region in the middle
of the screen; the cursor repositions to the upper left corner of the scrolling region. It can be
moved at will around the scrolling region, but can never leave, even by an absolute cursor
movement command. While Origin Mode remains set, the scrolling region acts as if it were a
miniature display all its own. All displayed data is restricted to within the region, and line
numbers are relative to the scrolling region.
Commands that specify line 1 now affect the first line of the scrolling region, and the edges
of the region act just like the edges of the screen because display data and cursor movements
are limited to the area within the region. Thus, host programs can treat the scrolling region as
if it were the entire screen without overwriting screen data outside the region.
This last case illustrates the most useful (yet potentially the most troublesome) interaction
between these two TCS functions, the ability to create a scrolling region and the ability to choose
the top of the scrolling region as the origin for absolute cursor movements. To avoid difficulty,
remember: