"Invalid triplets" are triplets that have failed Hamming 24/18 decoding.
Previously, invalid triplets were converted at load time to either all zero
bits or, in the case of X/26 enhancement triplets, to "dummy" triplets of
reserved mode 11110 with a row address group that hopefully have no effect.
Now the X/26 enhancement triplet list can explicitly store invalid triplets
and will show them as "error decoding triplet".
Invalid triplets in other packets such as X/28/0 will still be zeroed out at
load time.
Since the TTI format has no provision for storing invalid triplets, saving a
page will convert the invalid triplets to reserved mode 11110 as described
above.
The actual bits of invalid triplets are not stored on the assumption that
they are not recoverable. Thus exporting to t42 format will write an invalid
triplet as a Hamming coded result of all zero bits which will still cause a
Hamming decoding failure.
Attempts to fix a bug where the central page editing widget was sometimes
squashed to a tiny size in the corner.
Also introduces a schema for settings storage. There are no changes in this
schema; this is (mis)used to forget the geometry and state when version
0.8.1 is started for the first time to make sure the central widget is
usuable again.
External pages with DRCS definitions can be loaded using the options in the
"DRCS pages" submenu within the "View" menu. Two DRCS pages can be loaded,
one for Global DRCS definitions and the other for Normal DRCS definitions.
Level 2.5 mode 0 PTUs are fully supported.
Partial support for Level 3.5 mode 1, 2 and 3 PTUs. DCLUTs defined in X/28/1
on the main page are not yet implemented; the characters currently appear in
the default DCLUTs described in D.1.6 and D.2.2 of the ETSI spec.
A document is first loaded as a generic PageBase before being converted to
level one pages afterwards.
This is preparation for loading pages of other types such as DRCS and Public
Object Pages. The latter will need further work as the non-TTI file loaders
blindly assume X/1 to X/25 are 7-bit odd parity coded.
This also reverts 0a1c018 putting back the copy constructor that allows
a PageBase to be converted to a LevelOnePage.
"Metadata" is data which is stored in a teletext file format but is not part
of the page itself, such as DE description and CT cycle time in the TTI file
format.
The saving code has been refactored into one class per format with common
methods for each part of the saving process. This should make it easier to
add further formats, and inheriting a format class can allow implementing a
different format that is largely based on an existing format.
The loading code is also in one class per format but is largely the same as
what it was before.
Both classes have the ability to warn the user if any issues or errors are
or will be encountered when loading or saving.
TTI files are now written with CR/LF line endings on all platforms as a
result of using binary file writing for all formats, previously Linux builds
would save TTI files with just LF line endings. TTI files are still loaded
with readLine() and trimmed() which can cope with either type of line ending.
Experimental support for loading and exporting EP1 and HMS SD-Teletext htt
formats has been added. The htt format inherits from the t42 format as the
format appears to be largely the same except for the bits being reversed
within each byte and the clock run-in and framing code added before each
packet.
This removes the character array from the LevelOnePage class and stores the
characters in packets 0 to 24 natively, adding a packet when a character is
first added to a row and removing a packet when a row becomes space
characters.
"y": packet number
"d": designation code
"t": triplet number
"packet" renamed to "pkt" in method parameters to avoid ambiguity with
the "packet" method.
Actually this is a workaround: it does not attempt to copy construct
unhandled packets, to avoid a bug in the base class where pointers were
copy constructed without copying the contents.
A proper fix will need refactoring of the packet storage code.
These modes can be used to see the inner workings of colourful artworks that
frequently use "foreground colour, new background, foreground colour",
particularly to show exactly which colours are represented by set or clear
sixels.
One mode renders all characters in white on a black background and the other
mode renders black characters on a white background. The latter could be used
to save ink if the resulting image is printed.
Flash is suppressed in these mono modes, this may or may not change.
Qt 5 has had to be dropped as CMakeLists.txt uses qt_* specific commands
which are implemented in Qt 6 onwards.
cmake --install is only working on Linux at the moment; it installs the
executable and the bundled example tti files into /usr/local/share/doc
The teletext decoder with its document storage has been moved to a
subdirectory with the intention of making it possible to use in other
projects, but some further separation of editing stuff will be needed.
When a selection box is dragged, holding Ctrl while pressing the arrow
keys will shift the mosaics one sixel at a time.
If a shifting sixel encounters a non-mosaic cell it will pass through to
the other side of it.
For cut and copy sixels are converted to a monochrome image; unset sixels
are black and set sixels are white. Alphanumerics and control codes are
ignored. Held mosaics are not considered.
For paste a clipboard with only an image is converted to black and white
for unset and set sixels. This only works reliably with fully-black and
fully-white pixels.
This reverts commit 7cd632b4e2.
The commit would cause the font icons to be inverted sometimes. This
reversion is altered to return the font bitmaps as a QPixmap instead of a
QBitmap to be compatible with Qt6.
Gavin MacGregor