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A few variables are made automatically as you load any program in Liberty BASIC. This article will describe the various definitions and helpful applications of them.

Firstly, here is a list of them:

BackgroundColor$    ComboboxColor$      CommandLine$  
DefaultDir$         DisplayHeight       DisplayWidth  
Drives$             ForegroundColor$    ListboxColor$  
Platform$           PrintCollate        PrintCopies  
PrinterName$        TextboxColor$       TexteditorColor$  
Version$            WindowHeight        WindowWidth  
UpperLeftX          UpperLeftY

You probably recognise some of them (if not most of them) and have already used them in your programs. For example, you may have used WindowHeight and WindowWidth whilst making windows in LB, FreeForm or LB Workshop. Hopefully you will be able to make full screen windows with a yellow background and pink textboxes by the end of this article!

Window Colour Variables

These variables control the different colours for the controls in a window (for example, ComboboxColor$ changes the colour of comboboxes). The two variables BackgroundColor$ and ForegroundColor$ control the background and foreground colours of the window (not including the controls). When you define the variables' values, you must only fill them with these colour names: black, blue, brown, buttonface, cyan, darkblue, darkcyan, darkgray, darkgreen, darkpink, darkred, green, lightgray, palegray, pink, red, white and yellow.

Here is an example of all of these colour controls in a window!

ForegroundColor$ = "Brown"
BackgroundColor$ = "Yellow"
TexteditorColor$ = "Blue"
TextboxColor$ = "Pink"
ComboboxColor$ = "Green"
ListboxColor$ = "Red"

textbox #main.textbox1, 15, 15, 137, 24
texteditor #main.texteditor1, 15, 55, 135, 115
listbox #main.list1, nothing$(), [nowhere], 165, 15, 105, 120
combobox #main.combo1, nothing$(), [nowhere], 165, 150, 105, 300

open "Colours Galore!" for window as #main

print #main, "trapclose [quit]"

wait

[quit]
close #main
end

WindowWidth, WindowHeight, DisplayWidth and DisplayHeight

The four variables above are very useful. Below are their definitions:

So, for example, if I wanted to have a 200 x 100 pixel window, I would type into LB:

WindowWidth = 200
WindowHeight = 100
Open "My Program" for window as #program
Wait

This would open a 200 x 100 pixel window.

If you need a full screen game, you would need the window being used to be the same size as your screen. A lot of people have their screen resolution as 800 x 600, so to make a full screen window on that computer you would write:

WindowWidth = 800
WindowHeight = 600
Open "My Program" for window as #program
Wait

The problem comes when your screen resolution is 1024 x 768! To fix this, the variables DisplayWidth and DisplayHeight can be used. On a 800 x 600 computer, DisplayWidth = 800 and DisplayHeight = 600 and on a 1024 x 768 computer, DisplayWidth = 1024 and DisplayHeight = 768. Try this program - it should be full screen!

WindowWidth = DisplayWidth
WindowHeight = DisplayHeight
Open "My Program" for window as #program
Wait

Printer Information

After "printerdialog" has been used, the three global printer variables are set.

PrinterName$ contains the name of the selected printer e.g. "EPSON Stylus C40 Series" and PrintCollate refers to your options set in printerdialog.

If your printer driver is new enough to handle multiple copies, PrintCopies will be "1" and your program can just print once (lprint). On the other hand, if the printer driver cannot do that, PrintCopies is the number of copies chosen in printerdialog. You need to make a loop to print you text if this is the case.

For i = 1 to PrintCopies
Lprint "Hello"
Next i

N.B. In LB2, this works differently. See the helpfile for more details.

File and System Variables

CommandLine$ contains any parameters passed into LB or run.exe. For example, if you went to Start -> Run and typed "run.exe hello", the program...

print CommandLine$
wait