Screen Manipulation
This chapter describes screen manipulation tips. You can reorganize a standard logical screen equivalent to the physical screen and produce a smaller or larger logical screen.
1. Logical Screen Data Area (LSDA)
When you are using IPFOPN or IPFOVS, you can specify the logical screen data area (LSDA) parameter, which defines the logical screen attributes. When the parameter is omitted, the standard logical screen appears.
The following is possible with LSDA.
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Setting a logical screen larger than the physical screen
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Using screen split for flexible organization of the screen layout
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Fixing a portion of a logical screen where scrolling is available
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Determining the distance traveled when you move information in the screen
When setting these attributes, you need to be careful because the attributes cannot be changed after IPFOPN or IPFOVS is called. The following is a list of twelve attributes that can be set by LSDA and each item is two byte long.
| SIZE1 | Number of rows on the logical screen. |
|---|---|
SIZE2 |
Number of columns on the logical screen. |
HARD1A |
Hardware display area (start row). |
HARD1B |
Hardware display area (end row). |
HARD2A |
Hardware display area (start column). |
HARD2B |
Hardware display area (end column). |
SCR1 |
Scroll distance to be traveled in rows (vertical). |
SCR2 |
Scroll distance to be traveled in columns (horizontal). |
NOT1 |
Fixed screen area (row position). |
NOT2 |
Fixed screen area (column position). |
DISP1 |
Difference from the size of the physical screen (vertical) |
DISP2 |
Difference from the size of the physical screen (horizontal) |
|
When specifying LSDA, you must describe the size of the logical screen and the hardware display area. If you specify 0 for other items, they are set to the values of the standard logical screen. |
2. Screen Split
You can split a screen to produce multiple logical screens on the physical screen. The size of each split logical screen can be specified by LSDA.
2.1. Multiple Logical Screens
You can open more than one logical screen one by one and split the physical screen to display each logical screen. You can open a logical screen first and then open another logical screen that may overlap with a portion of the other one.
When you are splitting the screen, specify the size of each logical screen in the hardware display areas (HARD1A, HARD1B, HARD2A, HARD2B) of LSDA.
2.2. Identifying a Partitioned Screen
A split screen can be identified by a logical screen identification area (LSIA). Because one logical screen requires a LSIA on a one-to-one basis, multiple split screens require multiple LSIAs. If an LSIA is assigned to a logical screen that is open, you cannot use the LSIA to open another logical screen, but you can use an LSIA assigned to a closed logical screen.
3. Scrolling
The standard logical screen size is 80 by 24. If the logical screen is larger than the physical screen, you cannot see all information in the logical screen at once. To see information that falls outside the physical screen, you can scroll by using function keys that move the logical screen.
3.1. Scrolling Function
If the logical screen is larger than the physical screen, the physical screen cannot display all data in the logical screen. To see the data that does not fit into the physical screen, you can use the scrolling function. You can scroll up, down, left, and right to display a large logical screen and enter input for fields that falls outside the physical area.
You can set the vertical scroll distance to be traveled. SCR1 specifies the number of rows to be traveled (vertical distance) and SCR2 specifies the number of columns to be traveled (horizontal distance).
4. Fixing the Screen
If the logical screen is larger than the physical screen, you can move the logical screen by using function keys. When you are moving the screen, you can also fix an area of the screen to be displayed on the physical screen even when scrolling.
The following are some rules for fixing the screen area.
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If you are using the standard logical screen or if you have set the fixed screen area parameters of LSDA to 0, then no screen area is fixed.
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The parameters for the fixed screen area are NOT1, which specifies the number of rows starting from 1, and NOT2, which indicates the number of columns starting from 1.