On Tue, Mar 02, 1999 at 02:17:37PM +0000, Dave Hooper wrote: > but doesn't the sam rom make the 'assumption' that the pixels are square, > eg, when drawing circles?
I'm pretty sure it does. > Plus my Tv controls were set so that the apparent ratio WAS 4:3 ... does > this mean I was always distorting the shape of the picture, or does it > mean everyone /else's/ Tvs were distorting the shape of the picture? (bit > of a philosophical one there, rather than a genuine question, i suspect) The Sam screen is a bit of an odd beast. It has narrower borders at the sides and a wider screen than the Spectrum. On the speccy, two pixels are sent to the TV every clock cycle, which makes each pixel last about 140 nanoseconds. Most TVs seem to display this as a square pixel (well, more like an amorphous dot really). On the Sam, one pixel is sent to the TV every clock cycle, which makes each pixel last about 165 nanoseconds, which is longer by a factor of 7/6. Thus Sam's display is slightly stretched horizontally with respect to the Spectrum's (and the border is narrower). I have tended to use a horizontal zoom of 1.25 when viewing Sam screens, which means either I got my calculation slightly wrong or the Spectrum's pixels are just slightly wider than they are high. But if you had a ratio of 4:3 then everything else you looked at must have looked squashed. :-) imc
