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rawles / edit.tf

An in-browser editor for teletext frames.
http://edit.tf/
GNU General Public License v3.0
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fix rendering issue with concealed attributes in hold mosaics mode #78

Open ZXGuesser opened 5 years ago

ZXGuesser commented 5 years ago

Yup, the 'un-concealing' happens 'set-after' like the colour change. Once again the spec doesn't really explain how anything with hold mosaics should work, it just says:

up to the end of the row, or until a Colour Code attribute (codes 0/0 to 0/7 or 1/0 to 1/7) is encountered

rawles commented 5 years ago

Yeah, that's the trouble with this spec - 'until' could mean either set-at or set-after. Have you observed it to work like that on televisions then?

ZXGuesser commented 5 years ago

The combination of concealed and held mosaics is pretty unusual as they're both rarely used codes to start with. I've made a test hashstring: #0:QIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIEBH-e_mHLly5cuSX8mUKli_9AgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECBAgQIECA

The patch also ensures that the conceal has priority over the hold mosaic, i.e. the control code is replaced by space rather than the held mosaic.

I've attached photos of my old CRT and new LCD TVs rendering the test page. Both conceal the conceal code itself (set-at). However the new TV interprets the end of the concealed portion at the mosaic green code as my patch does (set-after) while the CRT interprets it as the current code (set-at)

old-conceal old-reveal new-conceal new-reveal