sysprof: generate flamegraph rectangles off thread

Then cache the render tree so that we can have highlight nodes without
having to use children widgets.

src/sysprof/sysprof-flame-graph.c

@@ -30,11 +30,25 @@
 
 #define ROW_HEIGHT 14
 
+typedef struct
+{
+  SysprofCallgraphNode *node;
+  guint16 x;
+  guint16 y;
+  guint16 w;
+  guint16 h;
+} FlameRectangle;
+
 struct _SysprofFlameGraph
 {
   GtkWidget         parent_instance;
 
   SysprofCallgraph *callgraph;
+  GskRenderNode    *rendered;
+  GArray           *nodes;
+
+  double            motion_x;
+  double            motion_y;
 };
 
 enum {
@@ -47,87 +61,55 @@ G_DEFINE_FINAL_TYPE (SysprofFlameGraph, sysprof_flame_graph, GTK_TYPE_WIDGET)
 
 static GParamSpec *properties [N_PROPS];
 
-static void
-sysprof_flame_graph_snapshot_node (GtkSnapshot           *snapshot,
-                                   SysprofCallgraphNode  *node,
-                                   const graphene_rect_t *area,
-                                   double                 min_width,
-                                   const GdkRGBA         *default_color,
-                                   PangoLayout           *layout,
-                                   int                    depth)
+typedef struct
 {
-  SysprofCallgraphCategory category;
-  const GdkRGBA *color;
-  GdkRGBA fallback;
+  graphene_point_t point;
+  int width;
+} FlameSearch;
 
-  g_assert (GTK_IS_SNAPSHOT (snapshot));
-  g_assert (node != NULL);
-  g_assert (area != NULL);
+static int
+search_compare (gconstpointer key,
+                gconstpointer item)
+{
+  const FlameSearch *search = key;
+  const FlameRectangle *rect = item;
+  graphene_rect_t area;
 
-  category = SYSPROF_CALLGRAPH_CATEGORY_UNMASK (node->category);
+  area = GRAPHENE_RECT_INIT (rect->x / (double)G_MAXUINT16 * search->width,
+                             rect->y,
+                             rect->w / (double)G_MAXUINT16 * search->width,
+                             rect->h);
 
-  if (!(color = sysprof_callgraph_category_get_color (category)) || color->alpha == 0)
-    {
-      fallback = *default_color;
-      fallback.alpha -= depth * .005,
-      color = &fallback;
-    }
+  if (search->point.y < area.origin.y)
+    return -1;
 
-  gtk_snapshot_append_color (snapshot,
-                             color,
-                             &GRAPHENE_RECT_INIT (area->origin.x,
-                                                  area->origin.y + area->size.height - ROW_HEIGHT - 1,
-                                                  area->size.width,
-                                                  ROW_HEIGHT));
+  if (search->point.y > area.origin.y + area.size.height)
+    return 1;
 
-  if (area->size.width > ROW_HEIGHT)
-    {
-      pango_layout_set_text (layout, node->summary->symbol->name, -1);
-      pango_layout_set_width (layout, PANGO_SCALE * area->size.width - 4);
+  if (search->point.x < area.origin.x)
+    return -1;
 
-      gtk_snapshot_save (snapshot);
-      gtk_snapshot_translate (snapshot,
-                              &GRAPHENE_POINT_INIT (round (area->origin.x) + 2,
-                                                    area->origin.y + area->size.height - ROW_HEIGHT));
-      gtk_snapshot_append_layout (snapshot, layout, &(GdkRGBA) {1,1,1,1});
-      gtk_snapshot_restore (snapshot);
-    }
+  if (search->point.x > area.origin.x + area.size.width)
+    return 1;
 
-  if (node->children != NULL)
-    {
-      graphene_rect_t child_area;
-      guint64 weight = 0;
+  return 0;
+}
 
-      child_area.origin.x = area->origin.x;
-      child_area.origin.y = area->origin.y;
-      child_area.size.height = area->size.height - ROW_HEIGHT - 1;
+static FlameRectangle *
+find_node_at_coord (SysprofFlameGraph *self,
+                    double             x,
+                    double             y)
+{
+  FlameSearch search;
 
-      for (SysprofCallgraphNode *child = node->children; child; child = child->next)
-        weight += child->count;
+  if (self->nodes == NULL)
+    return NULL;
 
-      for (SysprofCallgraphNode *child = node->children; child; child = child->next)
-        {
-          double ratio = child->count / (double)weight;
-          double width;
+  search.point.x = x;
+  search.point.y = y;
+  search.width = gtk_widget_get_width (GTK_WIDGET (self));
 
-          width = ratio * area->size.width;
-
-          if (width < min_width)
-            child_area.size.width = min_width;
-          else
-            child_area.size.width = width;
-
-          sysprof_flame_graph_snapshot_node (snapshot,
-                                             child,
-                                             &child_area,
-                                             min_width,
-                                             default_color,
-                                             layout,
-                                             depth + 1);
-
-          child_area.origin.x += width;
-        }
-    }
+  return bsearch (&search, self->nodes->data, self->nodes->len, sizeof (FlameRectangle), search_compare);
 }
 
 static void
@@ -135,28 +117,90 @@ sysprof_flame_graph_snapshot (GtkWidget   *widget,
                               GtkSnapshot *snapshot)
 {
   SysprofFlameGraph *self = (SysprofFlameGraph *)widget;
-  SysprofColorIter iter;
-  PangoLayout *layout;
+  FlameRectangle *highlight = NULL;
+  graphene_point_t point;
+  int width;
 
   g_assert (SYSPROF_IS_FLAME_GRAPH (self));
   g_assert (GTK_IS_SNAPSHOT (snapshot));
 
-  if (self->callgraph == NULL)
+  if (self->nodes == NULL || self->nodes->len == 0)
     return;
 
-  sysprof_color_iter_init (&iter);
-  layout = gtk_widget_create_pango_layout (widget, NULL);
-  pango_layout_set_ellipsize (layout, PANGO_ELLIPSIZE_END);
-  sysprof_flame_graph_snapshot_node (snapshot,
-                                     &self->callgraph->root,
-                                     &GRAPHENE_RECT_INIT (0, 0,
-                                                          gtk_widget_get_width (widget),
-                                                          gtk_widget_get_height (widget)),
-                                     1. / (double)gtk_widget_get_scale_factor (widget),
-                                     sysprof_color_iter_next (&iter),
-                                     layout,
-                                     0);
-  g_object_unref (layout);
+  point = GRAPHENE_POINT_INIT (self->motion_x, self->motion_y);
+  width = gtk_widget_get_width (widget);
+
+  if (self->rendered == NULL)
+    {
+      GtkSnapshot *child_snapshot = gtk_snapshot_new ();
+      const GdkRGBA *default_color;
+      PangoLayout *layout;
+      SysprofColorIter iter;
+
+      sysprof_color_iter_init (&iter);
+      default_color = sysprof_color_iter_next (&iter);
+
+      layout = gtk_widget_create_pango_layout (widget, NULL);
+      pango_layout_set_ellipsize (layout, PANGO_ELLIPSIZE_END);
+
+      for (guint i = 0; i < self->nodes->len; i++)
+        {
+          FlameRectangle *rect = &g_array_index (self->nodes, FlameRectangle, i);
+          SysprofCallgraphCategory category = SYSPROF_CALLGRAPH_CATEGORY_UNMASK (rect->node->category);
+          const GdkRGBA *color = sysprof_callgraph_category_get_color (category);
+          graphene_rect_t area;
+
+          if (color == NULL)
+            color = default_color;
+
+          area = GRAPHENE_RECT_INIT (rect->x / (double)G_MAXUINT16 * width,
+                                     rect->y,
+                                     rect->w / (double)G_MAXUINT16 * width,
+                                     rect->h);
+
+          if (!highlight && graphene_rect_contains_point (&area, &point))
+            highlight = rect;
+
+          gtk_snapshot_append_color (child_snapshot, color, &area);
+
+          if (area.size.width > ROW_HEIGHT)
+            {
+              pango_layout_set_text (layout, rect->node->summary->symbol->name, -1);
+              pango_layout_set_width (layout, PANGO_SCALE * area.size.width - 4);
+
+              gtk_snapshot_save (child_snapshot);
+              gtk_snapshot_translate (child_snapshot,
+                                      &GRAPHENE_POINT_INIT (round (area.origin.x) + 2,
+                                                            area.origin.y + area.size.height - ROW_HEIGHT));
+              gtk_snapshot_append_layout (child_snapshot, layout, &(GdkRGBA) {1,1,1,1});
+              gtk_snapshot_restore (child_snapshot);
+            }
+        }
+
+      self->rendered = gtk_snapshot_free_to_node (child_snapshot);
+
+      g_object_unref (layout);
+    }
+
+  if (self->motion_x || self->motion_y)
+    {
+      if (highlight == NULL)
+        highlight = find_node_at_coord (self, self->motion_x, self->motion_y);
+    }
+
+  gtk_snapshot_append_node (snapshot, self->rendered);
+
+  if (highlight)
+    {
+      graphene_rect_t area;
+
+      area = GRAPHENE_RECT_INIT (highlight->x / (double)G_MAXUINT16 * width,
+                                 highlight->y,
+                                 highlight->w / (double)G_MAXUINT16 * width,
+                                 highlight->h);
+
+      gtk_snapshot_append_color (snapshot, &(GdkRGBA) {1,1,1,.25}, &area);
+    }
 }
 
 static void
@@ -189,11 +233,69 @@ sysprof_flame_graph_measure (GtkWidget      *widget,
     }
 }
 
+static void
+sysprof_flame_graph_motion_enter_cb (SysprofFlameGraph        *self,
+                                     double                    x,
+                                     double                    y,
+                                     GtkEventControllerMotion *motion)
+{
+  g_assert (SYSPROF_IS_FLAME_GRAPH (self));
+  g_assert (GTK_IS_EVENT_CONTROLLER_MOTION (motion));
+
+  self->motion_x = x;
+  self->motion_y = y;
+
+  gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+static void
+sysprof_flame_graph_motion_motion_cb (SysprofFlameGraph        *self,
+                                      double                    x,
+                                      double                    y,
+                                      GtkEventControllerMotion *motion)
+{
+  g_assert (SYSPROF_IS_FLAME_GRAPH (self));
+  g_assert (GTK_IS_EVENT_CONTROLLER_MOTION (motion));
+
+  self->motion_x = x;
+  self->motion_y = y;
+
+  gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+static void
+sysprof_flame_graph_motion_leave_cb (SysprofFlameGraph        *self,
+                                     GtkEventControllerMotion *motion)
+{
+  g_assert (SYSPROF_IS_FLAME_GRAPH (self));
+  g_assert (GTK_IS_EVENT_CONTROLLER_MOTION (motion));
+
+  self->motion_x = 0;
+  self->motion_y = 0;
+
+  gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+static void
+sysprof_flame_graph_size_allocate (GtkWidget *widget,
+                                   int        width,
+                                   int        height,
+                                   int        baseline)
+{
+  SysprofFlameGraph *self = (SysprofFlameGraph *)widget;
+
+  g_assert (SYSPROF_IS_FLAME_GRAPH (self));
+
+  g_clear_pointer (&self->rendered, gsk_render_node_unref);
+}
+
 static void
 sysprof_flame_graph_dispose (GObject *object)
 {
   SysprofFlameGraph *self = (SysprofFlameGraph *)object;
 
+  g_clear_pointer (&self->rendered, gsk_render_node_unref);
+  g_clear_pointer (&self->nodes, g_array_unref);
   g_clear_object (&self->callgraph);
 
   G_OBJECT_CLASS (sysprof_flame_graph_parent_class)->dispose (object);
@@ -249,6 +351,7 @@ sysprof_flame_graph_class_init (SysprofFlameGraphClass *klass)
 
   widget_class->snapshot = sysprof_flame_graph_snapshot;
   widget_class->measure = sysprof_flame_graph_measure;
+  widget_class->size_allocate = sysprof_flame_graph_size_allocate;
 
   properties[PROP_CALLGRAPH] =
     g_param_spec_object ("callgraph", NULL, NULL,
@@ -263,7 +366,27 @@ sysprof_flame_graph_class_init (SysprofFlameGraphClass *klass)
 static void
 sysprof_flame_graph_init (SysprofFlameGraph *self)
 {
+  GtkEventController *motion;
+
   gtk_widget_add_css_class (GTK_WIDGET (self), "view");
+
+  motion = gtk_event_controller_motion_new ();
+  g_signal_connect_object (motion,
+                           "enter",
+                           G_CALLBACK (sysprof_flame_graph_motion_enter_cb),
+                           self,
+                           G_CONNECT_SWAPPED);
+  g_signal_connect_object (motion,
+                           "leave",
+                           G_CALLBACK (sysprof_flame_graph_motion_leave_cb),
+                           self,
+                           G_CONNECT_SWAPPED);
+  g_signal_connect_object (motion,
+                           "motion",
+                           G_CALLBACK (sysprof_flame_graph_motion_motion_cb),
+                           self,
+                           G_CONNECT_SWAPPED);
+  gtk_widget_add_controller (GTK_WIDGET (self), motion);
 }
 
 GtkWidget *
@@ -280,6 +403,119 @@ sysprof_flame_graph_get_callgraph (SysprofFlameGraph *self)
   return self->callgraph;
 }
 
+static void
+sysprof_flame_graph_generate_cb (GObject      *object,
+                                 GAsyncResult *result,
+                                 gpointer      user_data)
+{
+  g_autoptr(SysprofFlameGraph) self = user_data;
+  g_autoptr(GArray) nodes = NULL;
+  GTask *task = (GTask *)result;
+
+  g_assert (SYSPROF_IS_FLAME_GRAPH (self));
+  g_assert (G_IS_TASK (task));
+
+  if ((nodes = g_task_propagate_pointer (task, NULL)))
+    {
+      g_clear_pointer (&self->nodes, g_array_unref);
+      self->nodes = g_steal_pointer (&nodes);
+      gtk_widget_queue_draw (GTK_WIDGET (self));
+    }
+}
+
+static void
+generate (GArray                *array,
+          SysprofCallgraphNode  *node,
+          const graphene_rect_t *area)
+{
+  FlameRectangle rect;
+
+  g_assert (array != NULL);
+  g_assert (node != NULL);
+  g_assert (area != NULL);
+
+  rect.x = area->origin.x;
+  rect.y = area->origin.y + area->size.height - ROW_HEIGHT - 1;
+  rect.w = area->size.width;
+  rect.h = ROW_HEIGHT;
+  rect.node = node;
+
+  g_array_append_val (array, rect);
+
+  if (node->children != NULL)
+    {
+      graphene_rect_t child_area;
+      guint64 weight = 0;
+
+      child_area.origin.x = area->origin.x;
+      child_area.origin.y = area->origin.y;
+      child_area.size.height = area->size.height - ROW_HEIGHT - 1;
+
+      for (SysprofCallgraphNode *child = node->children; child; child = child->next)
+        weight += child->count;
+
+      for (SysprofCallgraphNode *child = node->children; child; child = child->next)
+        {
+          double ratio = child->count / (double)weight;
+          double width;
+
+          width = ratio * area->size.width;
+
+          child_area.size.width = width;
+
+          generate (array, child, &child_area);
+
+          child_area.origin.x += width;
+        }
+    }
+}
+
+static int
+sort_by_coord (gconstpointer a,
+               gconstpointer b)
+{
+  const FlameRectangle *rect_a = a;
+  const FlameRectangle *rect_b = b;
+
+  if (rect_a->y < rect_b->y)
+    return -1;
+
+  if (rect_a->y > rect_b->y)
+    return 1;
+
+  if (rect_a->x < rect_b->x)
+    return -1;
+
+  if (rect_a->x > rect_b->x)
+    return 1;
+
+  return 0;
+}
+
+static void
+sysprof_flame_graph_generate_worker (GTask        *task,
+                                     gpointer      source_object,
+                                     gpointer      task_data,
+                                     GCancellable *cancellable)
+{
+  SysprofCallgraph *callgraph = task_data;
+  g_autoptr(GArray) array = NULL;
+  int height;
+
+  g_assert (SYSPROF_IS_CALLGRAPH (callgraph));
+
+  array = g_array_sized_new (FALSE, FALSE, sizeof (FlameRectangle), callgraph->root.count);
+  height = callgraph->height * ROW_HEIGHT + callgraph->height + 1;
+
+  generate (array,
+            &callgraph->root,
+            &GRAPHENE_RECT_INIT (0, 0, G_MAXUINT16, height));
+
+  g_array_sort (array, sort_by_coord);
+
+  g_task_return_pointer (task, g_steal_pointer (&array), (GDestroyNotify)g_array_unref);
+}
+
 void
 sysprof_flame_graph_set_callgraph (SysprofFlameGraph *self,
                                    SysprofCallgraph  *callgraph)
@@ -289,7 +525,20 @@ sysprof_flame_graph_set_callgraph (SysprofFlameGraph *self,
 
   if (g_set_object (&self->callgraph, callgraph))
     {
+      g_clear_pointer (&self->rendered, gsk_render_node_unref);
+      g_clear_pointer (&self->nodes, g_array_unref);
+
+      if (callgraph != NULL)
+        {
+          g_autoptr(GTask) task = NULL;
+
+          task = g_task_new (NULL, NULL, sysprof_flame_graph_generate_cb, g_object_ref (self));
+          g_task_set_task_data (task, g_object_ref (callgraph), g_object_unref);
+          g_task_run_in_thread (task, sysprof_flame_graph_generate_worker);
+        }
+
       g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_CALLGRAPH]);
+
       gtk_widget_queue_resize (GTK_WIDGET (self));
     }
 }