The drawing itself should be unchanged but much of the rest of the
implementation has changed. The WaveViewThreads and WaveViewDrawingThread
classes were added and allow multiple drawing threads.
The Item::prepare_for_render interface is implemented by WaveView to enable
queuing draw requests for the drawing threads to process as soon as the state
change occurs during Editor::visual_changer, which often means the images will
be finished by the time they are needed in WaveView::render. This can
significantly reduce total render time and also flickering caused by images not
being ready for display.
If the drawing thread/s cannot finish the request by the time it is required in
WaveView::render then cancel it and draw the WaveViewImage in the GUI thread if
it is likely it can be completed in the current render pass/frame. This change
also helps reduce the flickering caused by images not being ready with threaded
rendering, but with several drawing threads, drawing in the GUI thread may not
often occur (unless explicitly requested).
Allow unfinished images to be returned from the cache in
WaveView::prepare_for_render so that new draw requests aren't queued for
duplicate images. This reduces the amount of drawing for instance in
compositions where there are many instances of the same sample/waveform
displayed on the canvas as only a single image should be drawn.
Use a random width within a certain range for
WaveView::optimal_image_width_samples so that image drawing is less likely to
occur at the same time (which will cause a spike in render/draw time and
increase the chance of flickering waveforms).
Move implementations of the private WaveView classes into wave_view_private.h
and wave_view_private.cc source files.
Incorporate a fix for limiting the waveview image size to the cairo image size
limit.
Should hopefully Resolve: #6478
This is necessary to allow calculation of correct intersection of visible
canvas area and items for the new Item::prepare_for_render() API.
samples_per_pixel must be set first to calculate the new horizontal canvas
position in Editor::set_horizontal_position and then
WaveView::set_samples_per_pixel will eventually call
WaveView::prepare_for_render for those items that are visible on the new canvas
position at the new position.
Or if there is not a change to zoom state then call Canvas::prepare_for_render
explicitly.
Also changes so that each method is only called once during
Editor::visual_changer
Called when an item has requested a redraw and intersects with visible
canvas area.
Also add Canvas::prepare_for_render that will call Item::prepare_for_render for
items visible on the canvas.
First visual change will be processed as normal and then blocked until the
canvas renders the change. If further visual changes need processing then
Editor::pre_render callback will schedule another expose/redraw/render.
This prevents an issue where idle_visual_changer is called many times in
response to events(keys/motion/etc) but the canvas does not get a chance to
render any but the last one which results in a big pause/jump.
This results in a more responsive canvas and in particular a smoother and more
predictable zooming experience.
This multiplier really should be based on the "responsiveness" of the
canvas..or something. I think this is an improvement for more complex sessions
with many regions.
This may need some small tweaks for MB channelstrip to set
print-format (like LV2 plugins would) for cases where the default
value_as_string() differs.
Do not use AutomationType to identify parameters, use complete
Evoral::Parameter and Automatable.
For "batch connections", a Slavables needs to implement an API to return
the relevant controls.
This is only a first step towards a more generic Master/Slave framework.
Let the plugin implementation of Plugin::add_state use a LocaleGuard if it is
necessary (VST/LV2). This puts the LocaleGuards where they are required but the
LocaleGuards in Session::set/get_state will mean these LocaleGuards are a noop.
They are still useful for documentation purposes and in case the code is called
from a non-Session context at some point.
