This Chapter explains how AMOS Professional screens are created and made ready to display the wonders of text, graphics and special effects.
Think of your television set or monitor as a glass window, through which you can view whatever AMOS Professional displays on its own "screen". The screen used to show AMOS Professional images is not the same as your TV display, because an AMOS Professional screen can be changed in many different ways, while the glass window of the TV set remains firmly fixed!
So far in this User Guide, everything has been displayed on a single AMOS Professional screen that appears in the glass window of your TV set. As an aid to understanding the theory of different screens, and to see the theory put into practice, make sure that you use the ready-made HELP programs as you read through this Chapter.
The AMOS Professional screens
The default screen
Whenever an AMOS Professional program is run, a screen area is automatically set up to display
the results of that program. This is known as the "default" screen, and it forms the standard
display area that is used for all normal drawing operations. The default screen is given the
identity number zero. The individual dots on the screen that make up the image are known as
"pixels", and screen zero is 320 pixels wide, 200 pixels high and it can display 16 different
colours.
Additional screens
Apart from the default screen, seven more screens can be set up and used for AMOS
Professional programs, and each of these new screens is given an identity number from 1 to 7.
When a new screen is set up, it has to be "opened", and when this is done, its individual width,
height, number of colours and pixel size is also defined.
Screen resolution
Although the default screen is 320 pixels wide, this "resolution" can be doubled to 640 pixels
across the screen. When the screen is 320 pixels wide it is in low resolution, or "Lowres", for
short. If this is changed to 640 pixels wide, the screen is in high resolution, known as "Hires".
Defining a screen
SCREEN OPEN
instruction: open a new screen
Screen Open number,width,height,colours,pixel mode
To open a new screen give the SCREEN OPEN command, followed by these parameters:
Number is the identification number of the new screen, ranging from 0 to 7. If a screen with this number already exists, it will be completely replaced by this new screen.