libsysprof-gtk: add label expression for time span

So we can show labels on things if zoomed in enough. We should also make
this available for hover/query-tooltip/etc.

src/libsysprof-gtk/sysprof-mark-chart-item.c

@@ -159,7 +159,8 @@ sysprof_mark_chart_item_init (SysprofMarkChartItem *self)
   self->series = sysprof_time_series_new (NULL,
                                           g_object_ref (G_LIST_MODEL (self->filtered)),
                                           gtk_property_expression_new (SYSPROF_TYPE_DOCUMENT_MARK, NULL, "time"),
-                                          gtk_property_expression_new (SYSPROF_TYPE_DOCUMENT_MARK, NULL, "duration"));
+                                          gtk_property_expression_new (SYSPROF_TYPE_DOCUMENT_MARK, NULL, "duration"),
+                                          gtk_property_expression_new (SYSPROF_TYPE_DOCUMENT_MARK, NULL, "message"));
 }
 
 SysprofMarkChartItem *

src/libsysprof-gtk/sysprof-session-discover.c

@@ -387,7 +387,8 @@ create_chart_for_marks (SysprofTrack           *track,
   time_series = sysprof_time_series_new (sysprof_track_get_title (track),
                                          g_object_ref (G_LIST_MODEL (info->model)),
                                          gtk_property_expression_new (SYSPROF_TYPE_DOCUMENT_MARK, NULL, "time"),
-                                         gtk_property_expression_new (SYSPROF_TYPE_DOCUMENT_MARK, NULL, "duration"));
+                                         gtk_property_expression_new (SYSPROF_TYPE_DOCUMENT_MARK, NULL, "duration"),
+                                         gtk_property_expression_new (SYSPROF_TYPE_DOCUMENT_MARK, NULL, "message"));
 
   chart = g_object_new (SYSPROF_TYPE_CHART, NULL);
   layer = g_object_new (SYSPROF_TYPE_TIME_SPAN_LAYER,

src/libsysprof-gtk/sysprof-time-series.c

@@ -29,6 +29,7 @@ struct _SysprofTimeSeries
   SysprofSeries  parent_instance;
   GtkExpression *time_expression;
   GtkExpression *duration_expression;
+  GtkExpression *label_expression;
 };
 
 struct _SysprofTimeSeriesClass
@@ -38,8 +39,9 @@ struct _SysprofTimeSeriesClass
 
 enum {
   PROP_0,
-  PROP_TIME_EXPRESSION,
   PROP_DURATION_EXPRESSION,
+  PROP_LABEL_EXPRESSION,
+  PROP_TIME_EXPRESSION,
   N_PROPS
 };
 
@@ -64,8 +66,9 @@ sysprof_time_series_finalize (GObject *object)
 {
   SysprofTimeSeries *self = (SysprofTimeSeries *)object;
 
-  g_clear_pointer (&self->time_expression, gtk_expression_unref);
   g_clear_pointer (&self->duration_expression, gtk_expression_unref);
+  g_clear_pointer (&self->label_expression, gtk_expression_unref);
+  g_clear_pointer (&self->time_expression, gtk_expression_unref);
 
   G_OBJECT_CLASS (sysprof_time_series_parent_class)->finalize (object);
 }
@@ -88,6 +91,10 @@ sysprof_time_series_get_property (GObject    *object,
       gtk_value_set_expression (value, self->duration_expression);
       break;
 
+    case PROP_LABEL_EXPRESSION:
+      gtk_value_set_expression (value, self->label_expression);
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
     }
@@ -111,6 +118,10 @@ sysprof_time_series_set_property (GObject      *object,
       sysprof_time_series_set_duration_expression (self, gtk_value_get_expression (value));
       break;
 
+    case PROP_LABEL_EXPRESSION:
+      sysprof_time_series_set_label_expression (self, gtk_value_get_expression (value));
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
     }
@@ -137,6 +148,10 @@ sysprof_time_series_class_init (SysprofTimeSeriesClass *klass)
     gtk_param_spec_expression ("y-expression", NULL, NULL,
                                (G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS));
 
+  properties [PROP_LABEL_EXPRESSION] =
+    gtk_param_spec_expression ("label-expression", NULL, NULL,
+                               (G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS));
+
   g_object_class_install_properties (object_class, N_PROPS, properties);
 }
 
@@ -153,6 +168,8 @@ sysprof_time_series_init (SysprofTimeSeries *self)
  *   extracting the time value from @model items.
  * @duration_expression: (transfer full) (nullable): a #GtkExpression for
  *   extracting the duration value from @model items.
+ * @label_expression: (transfer full) (nullable): a #GtkExpression for
+ *   extracting the label from @model items.
  *
  * A #SysprofSeries which contains Time,Duration pairs.
  *
@@ -162,7 +179,8 @@ SysprofSeries *
 sysprof_time_series_new (const char    *title,
                          GListModel    *model,
                          GtkExpression *time_expression,
-                         GtkExpression *duration_expression)
+                         GtkExpression *duration_expression,
+                         GtkExpression *label_expression)
 {
   SysprofTimeSeries *xy;
 
@@ -171,10 +189,12 @@ sysprof_time_series_new (const char    *title,
                      "model", model,
                      "x-expression", time_expression,
                      "y-expression", duration_expression,
+                     "label-expression", label_expression,
                      NULL);
 
   g_clear_pointer (&time_expression, gtk_expression_unref);
   g_clear_pointer (&duration_expression, gtk_expression_unref);
+  g_clear_pointer (&label_expression, gtk_expression_unref);
   g_clear_object (&model);
 
   return SYSPROF_SERIES (xy);
@@ -253,3 +273,64 @@ sysprof_time_series_set_duration_expression (SysprofTimeSeries *self,
 
   g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_DURATION_EXPRESSION]);
 }
+
+/**
+ * sysprof_time_series_get_label_expression:
+ * @self: a #SysprofTimeSeries
+ *
+ * Gets the #SysprofTimeSeries:y-expression property.
+ *
+ * This is used to extract the Y coordinate from items in the #GListModel.
+ *
+ * Returns: (transfer none) (nullable): a #GtkExpression or %NULL
+ */
+GtkExpression *
+sysprof_time_series_get_label_expression (SysprofTimeSeries *self)
+{
+  g_return_val_if_fail (SYSPROF_IS_TIME_SERIES (self), NULL);
+
+  return self->label_expression;
+}
+
+void
+sysprof_time_series_set_label_expression (SysprofTimeSeries *self,
+                                          GtkExpression     *label_expression)
+{
+  g_return_if_fail (SYSPROF_IS_TIME_SERIES (self));
+
+  if (self->label_expression == label_expression)
+    return;
+
+  if (label_expression)
+    gtk_expression_ref (label_expression);
+
+  g_clear_pointer (&self->label_expression, gtk_expression_unref);
+
+  self->label_expression = label_expression;
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_LABEL_EXPRESSION]);
+}
+
+char *
+sysprof_time_series_dup_label (SysprofTimeSeries *self,
+                               guint              position)
+{
+  g_autoptr(GObject) item = NULL;
+  g_auto(GValue) value = G_VALUE_INIT;
+  GListModel *model;
+
+  g_return_val_if_fail (SYSPROF_IS_TIME_SERIES (self), NULL);
+
+  if (self->label_expression == NULL)
+    return NULL;
+
+  if (!(model = sysprof_series_get_model (SYSPROF_SERIES (self))))
+    return NULL;
+
+  if (!(item = g_list_model_get_item (model, position)))
+    return NULL;
+
+  g_value_init (&value, G_TYPE_STRING);
+  gtk_expression_evaluate (self->label_expression, item, &value);
+  return g_value_dup_string (&value);
+}

src/libsysprof-gtk/sysprof-time-series.h

@@ -40,7 +40,8 @@ SYSPROF_AVAILABLE_IN_ALL
 SysprofSeries *sysprof_time_series_new                     (const char      *title,
                                                             GListModel      *model,
                                                             GtkExpression   *time_expression,
-                                                            GtkExpression   *duration_expression);
+                                                            GtkExpression   *duration_expression,
+                                                            GtkExpression   *label_expression);
 SYSPROF_AVAILABLE_IN_ALL
 GtkExpression *sysprof_time_series_get_time_expression     (SysprofTimeSeries *self);
 SYSPROF_AVAILABLE_IN_ALL
@@ -51,6 +52,14 @@ GtkExpression *sysprof_time_series_get_duration_expression (SysprofTimeSeries *s
 SYSPROF_AVAILABLE_IN_ALL
 void           sysprof_time_series_set_duration_expression (SysprofTimeSeries *self,
                                                             GtkExpression     *duration_expression);
+SYSPROF_AVAILABLE_IN_ALL
+GtkExpression *sysprof_time_series_get_label_expression    (SysprofTimeSeries *self);
+SYSPROF_AVAILABLE_IN_ALL
+void           sysprof_time_series_set_label_expression    (SysprofTimeSeries *self,
+                                                            GtkExpression     *label_expression);
+SYSPROF_AVAILABLE_IN_ALL
+char          *sysprof_time_series_dup_label               (SysprofTimeSeries *self,
+                                                            guint              position);
 
 G_DEFINE_AUTOPTR_CLEANUP_FUNC (SysprofTimeSeries, g_object_unref)
 

src/libsysprof-gtk/sysprof-time-span-layer.c

@@ -138,6 +138,18 @@ sysprof_time_span_layer_snapshot (GtkWidget   *widget,
 
   if (color->alpha > 0)
     {
+      const GdkRGBA *label_color = _sysprof_chart_layer_get_accent_fg_color ();
+      PangoLayout *layout = gtk_widget_create_pango_layout (GTK_WIDGET (self), NULL);
+      int layout_y;
+      int layout_h;
+
+      pango_layout_set_single_paragraph_mode (layout, TRUE);
+      pango_layout_set_ellipsize (layout, PANGO_ELLIPSIZE_END);
+      pango_layout_set_text (layout, "XM0", -1);
+      pango_layout_get_pixel_size (layout, NULL, &layout_h);
+
+      layout_y = (height - layout_h) / 2;
+
       /* First pass, draw our rectangles for duration which we
        * always want in the background compared to "points" which
        * are marks w/o a duration.
@@ -147,6 +159,12 @@ sysprof_time_span_layer_snapshot (GtkWidget   *widget,
           float begin = x_values[i];
           float end = x2_values[i];
 
+          if (end < .0)
+            continue;
+
+          if (begin > 1.)
+            break;
+
           if (begin != end)
             {
               graphene_rect_t rect;
@@ -157,7 +175,7 @@ sysprof_time_span_layer_snapshot (GtkWidget   *widget,
                                          ceilf ((end - begin) * width),
                                          height);
 
-              /* Ignore empty sized draws */
+              /* Ignore empty draws */
               if (rect.size.width == 0)
                 continue;
 
@@ -169,8 +187,26 @@ sysprof_time_span_layer_snapshot (GtkWidget   *widget,
                 last_end_x = end_x;
 
               gtk_snapshot_append_color (snapshot, color, &rect);
+
+              if (rect.size.width > 20)
+                {
+                  g_autofree char *label = sysprof_time_series_dup_label (self->series, i);
+
+                  if (label != NULL)
+                    {
+                      pango_layout_set_text (layout, label, -1);
+                      pango_layout_set_width (layout, (rect.size.width - 6) * PANGO_SCALE);
+
+                      gtk_snapshot_save (snapshot);
+                      gtk_snapshot_translate (snapshot, &GRAPHENE_POINT_INIT (rect.origin.x + 3, layout_y));
+                      gtk_snapshot_append_layout (snapshot, layout, label_color);
+                      gtk_snapshot_restore (snapshot);
+                    }
+                }
             }
         }
+
+      g_object_unref (layout);
     }
 
   if (event_color->alpha > 0)