Designing Interactive Panels (Panel Services) › Process with Light Pens/Cursor Select

Process with Light Pens/Cursor Select

Panel Services lets you use both light pens and the cursor select key. Such fields are termed selector pen detectable, or SPD fields.

Specify an SPD field by the TYPE=SPD operand on the #FLD statement. An SPD field can be regarded as an input field and the processing and formatting options apply accordingly. However, you cannot enter data into an SPD field because it is protected.

An SPD field must nominate a single variable (minus the &). This field can contain data to be displayed when the panel is displayed. It is set to the word SELECTED if you do either of the following:

• Press the light pen against the screen anywhere in the field.
• Press the CURSOR SELECT key when the cursor is positioned anywhere in the field.

In accordance with hardware requirements, a field specified as TYPE=SPD must start with either ampersand (&), question mark (?), or a blank ( ). These characters are termed designator characters and have the following meaning:

• A question mark (?) designates a selection field. If you choose this field, the ? is changed to a greater-than symbol (>) by the hardware to show successful selection (it can be deselected by reselecting it once more).
• An ampersand (&) designates the first format for an attention field-select this field in the normal way. (Selecting this field is also equivalent to pressing the Enter key, which transmits all modified screen data.)
• A blank designates the second format of an attention field. It operates like the & field, but modified data is not transmitted.

The designator character can be followed by one or more blanks and then the name of the variable (without the &) that is to receive notification of the selection. For example:

#NOTE This sample panel definition gives an example of the
#NOTE use of SPD fields.

#FLD / TYPE=SPD

/? SELECTION1

If you use a light pen or the cursor select key to select this field, the variable &SELECTION1 is set to the value SELECTED on return to the NCL procedure.