Pim Blokland wrote: > > Jonathan Schattke wrote: > > > > Well, technically, Hi-res can display all 16 colors of lo-res. > > I'd like to see you do that! My record is 12, and I haven't been able > to produce more, unless it was with dithering (i.e. displaying > different colors on odd and even lines). > > > Half-pixels could be made on byte boundaries by changing the hi bit of the > > adjacent bytes, allowing the display of > > Dk Green > > Dk Purple > > Brown > > Dk Blue > > This for instance, is not possible: there are only two positions in > which you can put a half pixel (odd and even), so that you cannot get > dark green and dark red (purple). Only brouwn and dark blue are possible. > Unless you know something I don't. Show me! HCOLOR=3 HPLOT 0,0 TO 0,10 HPLOT 1,11 TO 1,20 HPLOT 6,11 TO 6,20 HPLOT 13,0 TO 13,10 HCOLOR=4 HPLOT 13,11 TO 13,20 HPLOT 20,0 TO 20,10 Shows that what you say is indeed the case, you cannot display the dim purple and dark green. Here's why: Every pixel is passed through the same colorburst circuit, which does not care about what type of mode the system is in (if it is on). This circuit has 4 base states, oscillating between mgnta, blue, green, and orange. When a pixel is sent in, it will get the color of whatever the circuit is currently ready to display. Each of the 4 states has 8 colors, depending on what bit pattern is being sent through: 0000 Black 1000 Dim color 1100 Normal color - hi-res mode colors 1010 Tinted grey 1110 Bright Color 1011 Mix of Dim Color & Color +2 1101 Bright Mix of Color & Color +3 1111 White So, for Magenta, the first color, the resulting colors would be: 0000 Black 1000 Magenta 1100 Purple 1010 Purple tinted grey 1110 Bright Purple 1011 Magenta + Green = Yellow 1101 Purple + Orange = Pink 1111 White The Low-Res generator stuffs the bit buffer with the nybble being displayed: those possibilities are: 0000 Black 1000 Magenta (Base) 0100 Dark Blue (Base) 1100 Purple 0010 Dark Green (Base) 1010 Grey 1 - purpleish/Green fringes 0110 Blue 1110 Light Blue (Blue mixed with some magenta) 0001 Dark Orange 1001 Orange 0101 Grey 2 - orangish/blue fringes 1101 Pink (Purple with some Orange Added) 0011 Green 1011 Yellow (Green with some purple) 0111 Aqua (Green with some blue) 1111 White Some colors are missing from this table, but the patterns normalize to these 16 colors. The Color finges on the lo-res screen are artifacts of the colors turning on in sequence and/or nor being off yet. In the original Hi-Res mode, a pixel made 2 bits come on, so the typical possibilities were: 0000 Black 1100 Purple 0110 Blue 0011 Green 00011=1001 Orange 1111 White However, when a shifted bit is on a byte boundry, if the next byte did not match, things would be odd: 0100 Dark Blue 0111 Aqua 0001 Dark Orange 000111=1101 Pink Also, certain effects happen when you have a normal byte followed by a shifted byte: the last normal pixel stretches another 1/2 pixel: 1110 Lt. Blue 00111=1011 Yellow So, the colors which can be displayed staticly on the Hi-res screen are: 0000 Black 0100 Dk. Blue 1100 Purple 0110 Blue 1110 Lt. Blue 0001 Brown 1001 Orange 0011 Green 1011 Yellow 1101 Pink 0111 Aqua 1111 White Dim Purple, Dark Green and both Greys are not availiable. And that is 12, as you note. -- \ /\ / If you aren't happy, VVizVVom - Wandering Kernel of Happiness it's not my fault. ~~~> homepage at http://pages.ripco.net/~wizwom/ <~~~