Make click & drag in the left-hand half of a region with the Timestretch
tool stretch the region on its left, leaving the end position of the new
time-stretched region in the same place as the end of the original.
Editor::motion_handler() only updates the snap-cursor
when no drags are active. While dragging, Drag::motion is
responsible to set the cursor accordingly.
In many cases the snap-cursor simply remained stuck at
the most recent position. Since in many cases
(e.g. RubberbandSelectDrag) it makes no sense to show the
cursor, so Drag::start_grab now hides the cursor by default.
This also fixes cases where the cursor is shown, but
was displayed in the wrong location.
* correctly handle clicks on the immediate right or left of a beat line
* prefer Mid-Twist and End-Stretch terminology over Twist and Linear
* static-tempo vs ramped-tempo is orthogonal to mid- and end- drags (TODO)
This is mostly a simple lexical search+replace but the absence of operator< for
std::weak_ptr<T> leads to some complications, particularly with Evoral::Sequence
and ExportPortChannel.
The old code could not snap to the grid, because it had a lot of confusion about pixels vs. time,
and between line-origin-relative time and absolute time
a drag on a segment without adjacent points would crash because we never
set the _grab_button for the Drag, so the LineDrag object never gets deleted
on mouse-up. This leaves a dangling reversible command, which will then
cause an assert(false) crash in the next Editor::begin_reversible_command()
Confusion caused during nutempo development when a boolean related to nick_m's old
"for music" concept ended up becoming the "auto_partition" argument instead
This used to be a distinct kind of drag, but ended up being refactored into
something that happens during a regular drag. Has not been used in quite some time.
* in the case where there are no existing automation points, then
initiating an automation range drag (select range, switch to Draw)
should initialize the line at the current knob position
