4-color Characters#
The color of each pixel (4 in a line instead of the usual 8) depends on the bit combination of the byte in the character definition.| Bit Pair | Color | Address dec | Address hex | comment |
|---|---|---|---|---|
| 00 | COLOR4 BAK | 712 | $02C8 | |
| 01 | COLOR0 PF0 | 708 | $02C4 | |
| 10 | COLOR1 PF1 | 709 | $02C5 | |
| 11 | COLOR2 PF2 | 710 | $02C6 | if bit 7 of character code = 0 |
| 11 | COLOR3 PF3 | 711 | $02C7 | if bit 7 of character code = 1 |
Example#
character "A" (code=65) would be displayed as00000000 BAK BAK BAK BAK 00011000 BAK PF0 PF1 BAK 00111100 BAK PF2 PF2 BAK compare with line 3 below 01100110 PF0 PF1 PF0 PF1 01100110 PF0 PF1 PF0 PF1 01111110 PF0 PF2 PF2 PF1 compare with line 6 below 01100110 PF0 PF1 PF0 PF1 00000000 BAK BAK BAK BAK
character "inverse A" (code=193 Bit 7 set!) would be displayed as
00000000 BAK BAK BAK BAK 00011000 BAK PF0 PF1 BAK 00111100 BAK PF3 PF3 BAK compare with line 3 above 01100110 PF0 PF1 PF0 PF1 01100110 PF0 PF1 PF0 PF1 01111110 PF0 PF3 PF3 PF0 compare with line 6 above 01100110 PF0 PF1 PF0 PF1 00000000 BAK BAK BAK BAK
To try this type on an ATARI XL or XE:
GRAPHICS 13:? #6;"A A A":? #6;"A A A":REM the second 3 "A"s are inverse video!
see also: Color topics
