Charlie'sBasic Programming Language Reference

(Colour schemes for the screen modes further below.)

Mode	Screen Width	Screen Height	Columns	Rows	Screen Aspect	Font Height	Colour Scheme	Bits Per Pixel
0	640	200	80	25	2.4	8	rgba	4
1	320	200		25	1.2	8	screen1	2
2	640	200	80	25	2.4	8	monochrome	1
7	320	200		25	1.2	8	rgba	4
8	640	200	80	25	2.4	8	rgba	4
9	640	350	80	25	480/350	14	rgba	4
11	640	480	80	30	1	16	monochrome	2
12	640	480	80	30	1	16	rgba	4
13	320	200		25	1.2	8	undefined	24
14	320	240		15	1	16	undefined	24
15	400	300		18	1	16	undefined	24
16	512	384		24	1	16	undefined	24
17	640	400	80	25	1.2	16	undefined	24
18	640	480	80	30	1	16	undefined	24
19	800	600	100	37	1	16	undefined	24
20	1024	768	128	48	1	16	undefined	24
21	1280	1024	160	64	1	16	undefined	24

Colour Schemes

monochrome colours

0	Black
1	White

screen1 colours

ID	RGB Colour Value
0	███RGB(0, 0, 0) ███RGB(0, 0, 0)
1	███RGB(0, 170, 170) ███RGB(0, 170, 170)
2	███RGB(170, 0, 170) ███RGB(170, 0, 170)
3	███RGB(170, 170, 170) ███RGB(170, 170, 170)

rgba colours

ID	RGB Colour Value
0	███RGB(0, 0, 0) ███RGB(0, 0, 0)
1	███RGB(0, 0, 170) ███RGB(0, 0, 170)
2	███RGB(0, 170, 0) ███RGB(0, 170, 0)
3	███RGB(0, 170, 170) ███RGB(0, 170, 170)
4	███RGB(170, 0, 0) ███RGB(170, 0, 0)
5	███RGB(170, 0, 170) ███RGB(170, 0, 170)
6	███RGB(170, 85, 0) ███RGB(170, 85, 0)
7	███RGB(170, 170, 170) ███RGB(170, 170, 170)
8	███RGB(85, 85, 85) ███RGB(85, 85, 85)
9	███RGB(85, 85, 255) ███RGB(85, 85, 255)
10	███RGB(85, 255, 85) ███RGB(85, 255, 85)
11	███RGB(85, 255, 255) ███RGB(85, 255, 255)
12	███RGB(255, 85, 85) ███RGB(255, 85, 85)
13	███RGB(255, 85, 255) ███RGB(255, 85, 255)
14	███RGB(255, 255, 85) ███RGB(255, 255, 85)
15	███RGB(255, 255, 255) ███RGB(255, 255, 255)

"undefined" colours

Well, maybe this should be called "Full RGB Range", as in the 16,777,216 colours that span the RGB colour model.

To specify a colour when in a screen mode that has the "undefined" colour scheme, this requires specifying the colour number with math related to RGB.

Each of the R, G, and B, values range from 0 to 255.

color = R * (256 ^ 2) + G * (256 ^ 1) + B * (256 ^ 0)
or: color = R * (256 ^ 2) + G * (256 ^ 1) + B * (256 ^ 0)

Say we have some hex colour we want to use in our program. For example, the colour "BurlyWood" (hex #DEB887).

First, we need to break that out into the individual RGB hex values:

R = "DE"
G = "B8"
B = "87"

Next, we need to convert those to decimal values into decimal values:

R = D * 16 ^ 1 + E * 16 ^ 0 = 13 * 16 + 14 * 1 = 208 + 14 = 222
G = B * 16 ^ 1 + 8 * 16 ^ 0 = 11 * 16 + 8 * 1 = 176 + 8 = 184
B = 8 * 16 ^ 1 + 7 * 16 ^ 0 = 8 * 16 * 7 * 1 = 128 + 7 = 135

color = 222 * (256 ^ 2) + 184 ^ 256 + 135 = 14548992 + 47104 + 135 = 14596231

screen 21
circle (260,260), 113, 14596231, , , ,F

will result in a filled in circle that has a colour matching:

SCREEN modes