Sorry for the run around, I found it. I had those chars on my "what do I do with these list" and render a "?". I'll fix that, and I think you can consider prestel terminal emulation complete and awesome :)
Yup, I've just redownloaded the engineer page I sent you - if you show reveal codes on the website, you'll see that start/end box codes are used there, and when exported they export as 0x0a/0x0b. Now to figure out why I'm sending them as ? :)
Hmm.. I have definitely seen start/end box as 0x0a/0x0b - and it does overlap of active user keystrokes (where those are up/down as you described). I've never seen frames store movement chars (I think that idea was before its time).
Hmm.. I must be doing that somewhere (assuming sync doesnt) - I'll need to look. Normally with with zdnet, I export saved pages as "bin 1", and when I did that, a hexdump shows 0x0a and 0x0b where the ?s are rendered. 000003a0 6c 08 46 6c 61 73 68 03 2a 0b 0b 42 6f 78 09 53 |l.Flash.*..Box.S| 000003b0 74 65 61 64 79 18 47 6f 6e 65 0a 0a 3f 16 5e 7f |teady.Gone..?.^.| I dont think I messed things up, but I'll double check.
I did discover somewhere "versions" of the videotex spec, that covered when mosiac black (as well as double width) where used. In prestel (and viatel which was in Aus), the spec at the time didnt have them. I think those were used on teletext as the spec evolved and videotex died?
Yeah, I've seen references to them being used to overlay a TV image as well (and I guess not obstructing the TV picture - ala subtitles). So it probably does make sense on a terminal they are ignored. Its just odd they are referenced start/end box on some videotex specs, but not described.
Howdy, nice work - its great, looks like it's all fixed. A question, when I got a copy of the engineering test page, the bottom line has start box 0x0b and end box 0x0a codes. When I render that page from my BBS, it results in a "?" being rendered - but with telstar its a space. I dont remember what those codes were used for, and I've been trying to figure it out - I find a lot of specs referencing start/end box, but no functional description of what it does. Have you come across it? How do you handle...
Rendering of test page - some inconsistencies.