Although the cyanish in between colours looked good on an old CRT television, I thought they looked horrible on a monitor. That's why I wrote the greyscale ditherer - see http://www.worldofsam.org/node/40 - it only uses the real greys and dithers the in between a.
Op 19 dec. 2012 om 22:54 heeft Simon Owen <simon.o...@simcoupe.org> het volgende geschreven: > Hi Marcos, > > The SAM palette is make up using 2-bit RGB plus intensity, which bitwise > is: xGRBigrb. For pure greys you'd use: > > 00000000 = 00 = 0 > 00000111 = 07 = 7 > 00001000 = 08 = 8 > 00001111 = 0f = 15 > 01110000 = 70 = 112 > 01110111 = 77 = 119 > 01111000 = 78 = 120 > 01111111 = 7f = 127 > > The SAM demo tape astronaut image uses cyan to fill some of the gaps, > which duplicates black and white on the ends: > > 0, 0, 8, 5, 7, 13, 15, 82, 112, 90, 120, 117, 119, 125, 127, 127 > > That's maybe as good as you'll get for a 16-colour palette. > > Si > > On 19/12/2012 20:43, Marcos Cruz wrote: >> Hi all, >> >> In order to automate and simplify as much as possible the process of >> importing images into the SAM and avoid the palette conversion problems, >> I'm tinkering with the Netpbm raster formats >> (<http://en.wikipedia.org/wiki/Netpbm_format>). BMP and others could be >> used too, but Netpbm files have two encoding variants (ASCII and binary) >> for every type (PBM, PGM and PPM), what makes them very versatile in >> this case. >> >> The Netpbm images are created with Linux tools and the SAM does the >> final conversion, PLOTing the image pixels with the desired equivalent >> colors and GRABbing it. >> >> The first tries with a grayscale image look promising, but I need to >> choose 16 grays from the SAM palette (0, 7, 8, 15, 112, 120, 127...?) >> I'm afraid there are less than 16 gray tones, and blue must be used to >> complete the set. Am I right? Does anyboy know which are the best 16 SAM >> original colors for a grayscale? >> >> Thank you. >> >> Marcos >
