Editing has been simplified by breaking down each edit into a
combination of three basic single-element edits: MOVE, TRIM_START, and
TRIM_END.
Each edit follows these steps:
+ Determine which elements are to be edited and under which basic mode
+ Determine which track elements will move as a result
+ Snap the edit position to one of the edges of the main edited element,
(or the edge of one of its descendants, in the case of MOVE), avoiding
moving elements.
NOTE: in particular, we can *not* snap to the edge of a neighbouring
element in a roll edit. This was previously possible, even though the
neighbour was moving!
+ Determine the edit positions for clips (or track elements with no
parent) using the snapped value. In addition, we replace any edits of
a group with an edit of its descendant clips. If any value would be
out of bounds (e.g. negative start) we do not edit.
NOTE: this is now done *after* checking the snapping. This allows the
edit to succeed if snapping would cause it to go from being invalid to
valid!
+ Determine whether the collection of edits would result in a valid
timeline-configuration which does not break the rules for sources
overlapping.
+ If all this succeeds, we emit snapping-started on the timeline.
+ We then perform all the edits. At this point they should all succeed.
The simplification/unification should make it easier to make other
changes.
Fixes https://gitlab.freedesktop.org/gstreamer/gst-editing-services/-/issues/97
Fixes https://gitlab.freedesktop.org/gstreamer/gst-editing-services/-/issues/98
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-editing-services/-/merge_requests/169>
We need different export decorators for the different libs.
For now no actual change though, just rename before the release,
and add prelude headers to define the new decorator to GST_EXPORT.
With two exceptions:
* ges_clip_create_track_elements_func
* ges_uri_clip_set_uri
which were never declared in headers and should always have been static.
+ timeline: Add a snapping-distance property
+ Bump the GLib dependency to 2.28 in the mean time as we need some functions from GSequence that only landed
+ Update the testsuite accordingly
API: GESTimeline:snapping-distance property
API: ges_timeline_object_edit
API: ges_timeline_object_ripple
API: ges_timeline_object_ripple_end
API: ges_timeline_object_roll_start
API: ges_timeline_object_roll_end
API: ges_timeline_object_trim_start
API: ges_track_object_edit
API: GESEdge enum
API: GESEditMode enum
