You are here: Development Standards > Upgrading OSAS > Converting to 6.xx Graphical > Graphical Terminology

# Graphical Terminology

Before you start converting your application to run in both character and graphical modes, you must understand certain Windows terminology. Below are some common terms.

Form

Any window that is displayed, including the equivalent of character-based screens, error message boxes and other dialogue boxes are known as forms. Open Systems uses the terms screen, window, and form interchangeably.

Control

Every feature on a form—including the pull-down menus, tool buttons, status bar, list buttons, radio buttons, input fields, grids, and so on—are known as controls. Each control carries an ID that is unique to the form on which it resides.

Focus

Unlike in character mode where you must move one field at a time to get from field to field, when you are in graphical mode, several fields are available to you at one time. A user may click on any field to jump to it at any time (when the field is enabled). The act of moving the cursor to a control in response to a mouse click is known as getting focus or gaining focus. Conversely the act of leaving a control in response to a mouse click elsewhere is known as losing focus.

When a form first appears, the first control gets focus, and an edit cursor appears or the field is highlighted in some manner. As you leave that control to go to another, the first control loses focus and the new control gains focus.

Events

The process of gaining and losing focus is just one of many events trapped by Visual PRO/5. Other events include clicking on a check box, selecting an item from a list button, or clicking on a button.

You need not worry about how to trap events. GENINPUT.PUB has a sister program called GENGUINP.PUB that handles most events that can happen within a standard OSAS screen. It then interprets these events and passes the information back in the X$, Y$, and X variables among others, which your program can use much as it would with the character-based GENINPUT.PUB program.

CONTEXT

Visual PRO/5 has a method for tracking multiple graphical screens that are open at the same time. It assigns each graphical form its own CONTEXT number. You can use the CONTEXT mnemonic to assign the context before you open a new form, or to move between open forms. This technique is similar to that of the GOTO mnemonic used to jump between multiple character windows (although you cannot assign a value to a character screen before you open it).

Refer to the Visual PRO/5 manual for more information on CONTEXT.