display: move thread operations to new file

src/display/CMakeLists.txt

@@ -39,6 +39,7 @@ set(display_SRC
     nr-light.cpp
     nr-style.cpp
     nr-svgfonts.cpp
+    threading.cpp
     translucency-group.cpp
 
     control/canvas-temporary-item-list.cpp
@@ -111,6 +112,7 @@ set(display_SRC
     nr-svgfonts.h
     rendermode.h
     tags.h
+    threading.h
     translucency-group.h
 
     control/canvas-temporary-item-list.h

src/display/cairo-templates.h

@@ -15,16 +15,17 @@
 
 #include <glib.h>
 
-#include "dispatch-pool.h"
-
 // single-threaded operation if the number of pixels is below this threshold
 static const int POOL_THRESHOLD = 2048;
 
-#include <cmath>
 #include <algorithm>
 #include <cairo.h>
-#include "display/nr-3dutils.h"
+#include <cmath>
+
 #include "display/cairo-utils.h"
+#include "display/dispatch-pool.h"
+#include "display/nr-3dutils.h"
+#include "display/threading.h"
 
 template <typename T>
 struct surface_accessor {

src/display/cairo-utils.cpp

@@ -19,7 +19,6 @@
 #include <2geom/point.h>
 #include <2geom/sbasis-to-bezier.h>
 #include <2geom/transforms.h>
-#include <atomic>
 #include <boost/algorithm/string.hpp>
 #include <boost/operators.hpp>
 #include <boost/optional/optional.hpp>
@@ -33,7 +32,6 @@
 #include <gdk-pixbuf/gdk-pixbuf.h>
 #include <glib/gstdio.h>
 #include <glibmm/fileutils.h>
-#include <stdexcept>
 
 #include "cairo-templates.h"
 #include "colors/manager.h"
@@ -969,18 +967,6 @@ std::optional<Geom::PathVector> extract_pathvector_from_cairo(cairo_t *ct)
     return res.peek();
 }
 
-static std::atomic<int> num_filter_threads = 4;
-
-int get_num_filter_threads()
-{
-    return num_filter_threads.load(std::memory_order_relaxed);
-}
-
-void set_num_filter_threads(int n)
-{
-    num_filter_threads.store(n, std::memory_order_relaxed);
-}
-
 SPColorInterpolation
 get_cairo_surface_ci(cairo_surface_t *surface) {
     void* data = cairo_surface_get_user_data( surface, &ink_color_interpolation_key );

src/display/cairo-utils.h

@@ -91,10 +91,6 @@ class Pixbuf {
 
 } // namespace Inkscape
 
-// Atomic accessors to global variable governing number of filter threads.
-int  get_num_filter_threads();
-void set_num_filter_threads(int);
-
 SPColorInterpolation get_cairo_surface_ci(cairo_surface_t *surface);
 void set_cairo_surface_ci(cairo_surface_t *surface, SPColorInterpolation cif);
 void copy_cairo_surface_ci(cairo_surface_t *in, cairo_surface_t *out);

src/display/dispatch-pool.cpp

@@ -7,8 +7,6 @@
 
 #include "dispatch-pool.h"
 
-#include "cairo-utils.h"
-
 namespace Inkscape {
 
 dispatch_pool::dispatch_pool(int size)
@@ -114,30 +112,6 @@ void dispatch_pool::execute_batch(std::unique_lock<std::mutex> &lk, local_id id,
     }
 }
 
-namespace {
-
-std::mutex g_dispatch_lock;
-std::shared_ptr<dispatch_pool> g_dispatch_pool;
-int g_dispatch_threads;
-
-} // namespace
-
-std::shared_ptr<dispatch_pool> get_global_dispatch_pool()
-{
-    int const num_threads = get_num_filter_threads();
-
-    std::scoped_lock lk(g_dispatch_lock);
-
-    if (g_dispatch_pool && num_threads == g_dispatch_threads) {
-        return g_dispatch_pool;
-    }
-
-    g_dispatch_pool = std::make_shared<dispatch_pool>(num_threads);
-    g_dispatch_threads = num_threads;
-
-    return g_dispatch_pool;
-}
-
 } // namespace Inkscape
 
 /*

src/display/dispatch-pool.h

@@ -10,7 +10,6 @@
 
 #include <condition_variable>
 #include <functional>
-#include <memory>
 #include <mutex>
 #include <thread>
 #include <vector>
@@ -110,8 +109,6 @@ class dispatch_pool
     std::vector<std::thread> _threads;
 };
 
-std::shared_ptr<dispatch_pool> get_global_dispatch_pool();
-
 } // namespace Inkscape
 
 #endif // INKSCAPE_DISPLAY_DISPATCH_POOL_H

src/display/drawing.cpp

@@ -17,10 +17,11 @@
 #include <thread>
 
 #include "cairo-utils.h"
-#include "drawing-context.h"
 #include "control/canvas-item-drawing.h"
+#include "drawing-context.h"
 #include "nr-filter-gaussian.h"
 #include "nr-filter-types.h"
+#include "threading.h"
 
 namespace Inkscape {
 
@@ -336,8 +337,9 @@ void Drawing::_loadPrefs()
         _cache_budget = 0;
     }
 
-    // Set the global variable governing the number of filter threads, and track it too. (This is ugly, but hopefully transitional.)
-    set_num_filter_threads(prefs->getIntLimited("/options/threading/numthreads", default_numthreads(), 1, 256));
+    // Set the global variable governing the number of threads, and track it too. (This is ugly, but hopefully
+    // transitional.)
+    set_num_dispatch_threads(prefs->getIntLimited("/options/threading/numthreads", default_numthreads(), 1, 256));
 
     // Similarly, enable preference tracking only for the Canvas's drawing.
     if (_canvas_item_drawing) {
@@ -354,7 +356,9 @@ void Drawing::_loadPrefs()
         actions.emplace("/options/cursortolerance/value",        [this] (auto &entry) { setCursorTolerance(entry.getDouble(1.0)); });
         actions.emplace("/options/selection/zeroopacity",        [this] (auto &entry) { setSelectZeroOpacity(entry.getBool(false)); });
         actions.emplace("/options/renderingcache/size",          [this] (auto &entry) { setCacheBudget((1 << 20) * entry.getIntLimited(64, 0, 4096)); });
-        actions.emplace("/options/threading/numthreads",         [this] (auto &entry) { set_num_filter_threads(entry.getIntLimited(default_numthreads(), 1, 256)); });
+        actions.emplace("/options/threading/numthreads", [this](auto &entry) {
+            set_num_dispatch_threads(entry.getIntLimited(default_numthreads(), 1, 256));
+        });
 
         _pref_tracker = Inkscape::Preferences::PreferencesObserver::create("/options", [actions = std::move(actions)] (auto &entry) {
             auto it = actions.find(entry.getPath());

src/display/nr-filter-gaussian.cpp

@@ -12,6 +12,7 @@
  * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
+#include <2geom/affine.h>
 #include <algorithm>
 #include <cmath>
 #include <complex>
@@ -21,18 +22,13 @@
 
 #include "display/cairo-utils.h"
 #include "display/dispatch-pool.h"
-#include "display/nr-filter-primitive.h"
 #include "display/nr-filter-gaussian.h"
-#include "display/nr-filter-types.h"
-#include "display/nr-filter-units.h"
+#include "display/nr-filter-primitive.h"
 #include "display/nr-filter-slot.h"
-#include <2geom/affine.h>
+#include "display/nr-filter-units.h"
+#include "display/threading.h"
 #include "util/fixed_point.h"
 
-#ifndef INK_UNUSED
-#define INK_UNUSED(x) ((void)(x))
-#endif
-
 // IIR filtering method based on:
 // L.J. van Vliet, I.T. Young, and P.W. Verbeek, Recursive Gaussian Derivative Filters,
 // in: A.K. Jain, S. Venkatesh, B.C. Lovell (eds.),

src/display/nr-filter-morphology.cpp

@@ -10,10 +10,6 @@
  * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
-#ifdef HAVE_CONFIG_H
-# include "config.h"  // only include where actually required!
-#endif
-
 #include <cmath>
 #include <algorithm>
 #include <deque>

src/display/threading.cpp

@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Author: Liam White
+ * Copyright (C) 2024 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include "threading.h"
+
+#include <atomic>
+#include <mutex>
+
+#include "dispatch-pool.h"
+
+namespace Inkscape {
+
+namespace {
+
+std::mutex g_dispatch_lock;
+
+std::shared_ptr<dispatch_pool> g_dispatch_pool;
+std::atomic<int> g_num_dispatch_threads = 4;
+
+} // namespace
+
+void set_num_dispatch_threads(int num_dispatch_threads)
+{
+    g_num_dispatch_threads.store(num_dispatch_threads, std::memory_order_relaxed);
+}
+
+std::shared_ptr<dispatch_pool> get_global_dispatch_pool()
+{
+    int const num_threads = g_num_dispatch_threads.load(std::memory_order_relaxed);
+
+    std::scoped_lock lk(g_dispatch_lock);
+
+    if (g_dispatch_pool && num_threads == g_dispatch_pool->size()) {
+        return g_dispatch_pool;
+    }
+
+    g_dispatch_pool = std::make_shared<dispatch_pool>(num_threads);
+    return g_dispatch_pool;
+}
+
+} // namespace Inkscape
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :

src/display/threading.h

@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Author: Liam White
+ * Copyright (C) 2024 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#ifndef INKSCAPE_DISPLAY_THREADING_H
+#define INKSCAPE_DISPLAY_THREADING_H
+
+#include <memory>
+
+namespace Inkscape {
+
+class dispatch_pool;
+
+// Atomic accessor to global variable governing number of dispatch_pool threads.
+void set_num_dispatch_threads(int num_dispatch_threads);
+
+std::shared_ptr<dispatch_pool> get_global_dispatch_pool();
+
+} // namespace Inkscape
+
+#endif // INKSCAPE_DISPLAY_THREADING_H
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :