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Panel Element Conditioning With Truth Tables

IP.com Disclosure Number: IPCOM000037056D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 3 page(s) / 14K

Publishing Venue

IBM

Related People

Allen, PV: AUTHOR [+5]

Abstract

A panel presented on a computer display consists of related text or graphic elements that are placed on that display in a fashion determined by an application programmer. Some of these elements are conditional; that is, they appear on the display only if certain criteria are met. Others are not conditional, and they appear on the panel whenever that panel is displayed. A mechanism is described by which all elements are placed optimally on the display. This mechanism is time efficient in that placement occurs at the time the panel is defined (compile-time) and not at the time the panel is displayed by the application (run-time). An alternative is also described which is space efficient instead, but still provides diagnostic information at compile-time.

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Panel Element Conditioning With Truth Tables

A panel presented on a computer display consists of related text or graphic elements that are placed on that display in a fashion determined by an application programmer. Some of these elements are conditional; that is, they appear on the display only if certain criteria are met. Others are not conditional, and they appear on the panel whenever that panel is displayed. A mechanism is described by which all elements are placed optimally on the display. This mechanism is time efficient in that placement occurs at the time the panel is defined (compile-time) and not at the time the panel is displayed by the application (run-time). An alternative is also described which is space efficient instead, but still provides diagnostic information at compile-time. To avoid the generation of all possible element placements, a truth table mechanism is described which allows a panel designer to specify the exact combinations of conditionable elements which are expected at run-time.

The panel definition proceeds as follows: 1. Define the variable information on the panel. 2. Define the conditions that affect the display of elements on that panel. These conditions are defined in terms of the variable information above. 3. Define the truth tables which show the interrelationships among the conditions.
4. Define the panel itself by defining the contained panel elements, referencing the variable conditions and truth tables previously defined. An example definition follows: variable A integer. variable B integer.

variable C <some other data type>.

condition X is <some boolean expression involving A, B, and/or C>.

condition Y is <some other boolean expression>.

condition Z is <another boolean expression>. /* in the truth table rows, 1 indicates that the condition is true

0 indicates that the condition is false

* indicates that the condition may be either true or false

*/ truth table T for conditions X Y Z is

row 1 1 0

row 1 0 1

row 0 * 1. panel P uses truth table T and consists of

panel element 1.

panel element 2 conditioned by X.

panel element 3 conditioned by Y.

panel element 4 conditioned by Z.

panel element 5. end of panel definition P.

This description of the panel definition shows that panel elements 2, 3, and 4 never all occur on P when P is displayed. Thus, placement information and

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resulting diagnostics are calculated with that assumption. The panel compilation process is:

Create an expanded truth table, replace all rows with "don't care" values with two rows - one with a true value and one with a false value. For each element of the panel do

Format the panel element

For each row of the expanded truth table

referenced by that panel do

Create a new final format

For eac...