On Mon, 27 Feb 1995 16:42:19 -0500, Gene Fender said: > 2) What is the common > SAM bitmap format & its specs (so that I might write > my own conversion utility)?
There isn't really any. Though I suppose there is the SCREEN$ format that the Sam saves. It is a simple image of the screen memory, as described several times before, followed by the following. - the 16 entries in the colour look-up table - the first four entries again (don't know precisely what these are for, but it might be the four colours for mode 3) - the same 20 bytes repeated (if these bytes are different then the screen will flash between the two sets of colours) - a 255 byte. > For further debate, I know that one of the SAM > resolutions is 256x192, however I have read in > this forum that SAM pixels aren't square in > this mode. The picture seems to be horizontally stretched. The border areas at the sides are much narrower than the ones at the top and bottom (and also narrower than the border areas on a Spectrum). The pixels seem to be 1.25 times as wide as they are high. I'm sure this must have been designed so that the time taken by the TV scan to draw one pixel is exactly the length of one clock cycle on the Sam. It's a shame the pixels are not square, however. If they had designed a 7MHz clock (twice that of a Spectrum) it would have been better. Hmmm, my generally accepted figure of 1.25 implies that a 7.5MHz clock would be required. Does that mean the Spectrum's pixels are not quite square either, or have I just measured it incorrectly?... imc
