AMOS Interface

Note that there is no semi-colon after this final set of brackets. if one is included a syntax error will be generated when the program is run. Beware of making this very easy mistake!

Whenever a button is selected by the user, the AMOS Professional Interface performs the following sequence of actions:

• The button setting is incremented by one, and this new setting is compared to the values held in the minimum and maximum parameters.
• The commands held in the button drawing routine are now executed on screen.
• The system waits for the mouse key to be released
• If it has been defined, the "change" routine is now performed. This can change the setting value of any button on the screen, allowing you to link several buttons together. If the "change" commands move one or more buttons to a new setting, they will be updated with an appropriate call to the relevant drawing routine.

Here are some examples of button definitions:

X> BU 1,80,38,50,10,0,0,1; set position and size of button number one
   [PR 1,2,'Button 1',6;][] draw button using a simple print command

   BU 2,10,38,50,10,0,0,1;[PR 1,2,'Button 2',7;][]

ButtonQuit
Interface instruction: trigger an exit button
BQ;

There are special buttons featured in the Editor requesters, such as [Ok] and [Cancel], which are used to leave the dialogue box the moment that they are selected by the user. These "Exit" buttons are created using the Button Quit instruction. This command can be placed inside the "change" brackets in order to trigger a forced exit from the dialogue box after the button has been selected. For example:

X> BU 1,80,38,50,10,0,0,1 ;[PR 1,2,'Button 1',6;][BQ;]

Drawing a button
Buttons can be drawn in a variety of styles, using any of the Interface graphics commands. A full list of all these commands is fully explained in Chapter 9.2. Here are some typical options:

Text buttons can be created by enclosing the required text with a box or a filled bar, as follows:

X> BUtton 1,20,16,50,10,0,0,1;
   [INk 4,0,0;GraphicSquare 0,0,50,10; PRint 1,2,'Button',6;][]

X> BUtton 2,120,16,40,1,0,0,1;
   [INk 1,0,0; GraphicBox 0,0,33,10; PRint 1,2,'Quit',4;][ButtonQuit;]