There is an insidious problem when the Transformer takes references to internal state
within upstream iterators or state core. This problem only manifests when
a invariant based filtering or grouping operation is added after the Transformer,
because such an operation (notably Filter) will typically attempt to establish
the invariant from the constructor (to avoid dangling state). Unfortunately
doing so involves pulling data ''before the overall pipeline is moved into final location''
A workaround is to make the Transformer ''disengage'' on copy, so to provoke
a refresh and new pull in the new location after the copy / move / swap.
This only works if the transformer function as such is idempotent.
I changed the rendering of unsigned types in diagnostic output
to use the short notation, e.g. `uint` instead of `unsigned int`.
This dramatically improves the legibility of verification strings.
Moreover, I took the opportunigy to look through the existing page
with codeing style guides to explicitly write down some conventions
formed over years of usage.
I did not just »make up« those light heartedly, rather these conventions
are the result of a craftsman's ''attentive observation and self-reflection.''
The drawing code extracts style information from some "virtual"
widgets, which serve as logical placeholder for the actual nested
structure of tracks.
For sake of demonstration, I used rather obvious colours and
also all kinds of margin and padding; a screenshot was added
with annotations to indicate where some specific style settings
are utilised from the drawing code
As we continue with building the backbone of the UI,
and abundance of detail information regaring Layout and styling
will be encountered -- it is tantamount to have a place to
write those findings down....
bottom line is to do most autmatically, and to establish a slave-relation
navigation-area -> timeline-ruler
header-pane-content -> corresponding track-body
this can be accomplished mostly by connecting the aproprieate signals,
thus these widgets will live within the Layout-Manager, which consequently
is renamed into TimelineLayout
This switches the Lumiera UI from GTK-2 to GTK-3
Unfortunately, this move breaks two crucial features, which have been
disabled for now: the display of video and our custom timeline widget.
Since both of these require some reworking, which in fact has already
started, we prefer to do the library and framework switch right away.
This too was a long-standing issue. While these practices
basically can be considered "common knowledge", experience
showed those topics are frequently unknown even to practised
programmers.
So now we have a single page dealing with all those issues of
code bloat, dependency poliferation, binary dependency resolution
and issues of transitive and circular library dependencies
Uniform sequence at start of source files
- copyright claim
- license
- file comment
- header guard
- lumiera includes
- library / system includes
Lumiera uses Brittish spelling. Add an according note to the styleguide.
