Commit ddfc7715cb changed the
airbrush periodic stamp behavior, so that instead of using the main
brush, it issued a full MOTION event, potentially using a different
brush when using a GIH brush.
Fix this, by renaming the "timeout" signal of GimpAirbrush to
"stamp", and by adding a new gimp_airbrush_stamp() function, which
should be used for painting the periodic airbrush dab in response,
instead of calling gimp_paint_core_paint() directly, and which
calls gimp_airbrush_paint() instead, as the old code did.
In order to call this function from the paint thread, we replace
the various gimp_paint_tool_paint_core_foo() functions, introduced
in the above commit, with a generic gimp_paint_tool_paint_push()
function, which takes a callback (and a data pointer) to run on the
paint thread, and queues it for execution (when not using the paint
thread, the function is called directly from the calling thread.)
We'd like subclasses of GimpPaintTool to be able to issue paint
commands to the tool's paint-core (in particular, see the next
commit.) Since paint commands should be executed on the paint
thread, the subclasses must not call the paint-core functions
directly, but should rather let gimppainttool-paint issue the
commands on their behalf.
Reorgainze gimppainttool-paint to make it usable for this purpose
by subclasses. In particular, add
gimp_paint_tool_paint_core_paint() and
gimp_paint_tool_paint_core_interpolate(), which call the
corresponding paint-core functions on the paint thread.
Additionally, rename the {start,end,flush}_paint() virtual
functions of GimpPaintTool to paint_{start,end,flush}(), and rename
gimp_paint_tool_is_painting() to gimp_paint_tool_paint_is_active(),
so that all the gimppainttool-paint-related stuff are grouped under
the same namespace.
Reorganize/clean up gimppainttool-paint. In particular, move all
paint-core interaction during painting to gimppainttool-paint.c, so
that we can have more control over what's going on; specifically,
enter the drawable into paint mode *before* starting the paint
core, so that it picks up the correct buffer. This fixes painting
with the paint thread using GimpApplicator, and enables us to use
the paint thread with GimpMybrushTool.
Add gimppainttool-paint.[ch], which takes care of painting during
motion events in GimpPaintTool. Perform the actual painting in a
separate thread, so that display updates, which can have a
significant synchronization overhead, don't stall painting.
Allow specific paint tools to opt-out of a separate paint thread,
and avoid it in GimpMybrushTool, since it doesn't seem to work.
The separate paint thread can be explicitly disabled by setting the
GIMP_NO_PAINT_THREAD environment variable.
