libsysprof-gtk: tweak rendering to use CSS named colors

We still don't want to fully rely on the CSS machinery because that would
require widgets, which is far too heavy for the number of render nodes we
need to regularly draw.

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

@@ -27,9 +27,15 @@
 struct _SysprofMarkChartRow
 {
   GtkWidget             parent_instance;
+
   GCancellable         *cancellable;
   SysprofTimeSeries    *series;
   SysprofMarkChartItem *item;
+
+  GdkRGBA               accent_fg_color;
+  GdkRGBA               accent_bg_color;
+  GdkRGBA               success_bg_color;
+
   guint                 update_source;
 };
 
@@ -62,18 +68,38 @@ sysprof_mark_chart_row_set_series (SysprofMarkChartRow *self,
   gtk_widget_queue_draw (GTK_WIDGET (self));
 }
 
+static void
+sysprof_mark_chart_row_css_changed (GtkWidget         *widget,
+                                    GtkCssStyleChange *change)
+{
+  SysprofMarkChartRow *self = (SysprofMarkChartRow *)widget;
+
+  g_assert (SYSPROF_MARK_CHART_ROW (self));
+
+  GTK_WIDGET_CLASS (sysprof_mark_chart_row_parent_class)->css_changed (widget, change);
+
+G_GNUC_BEGIN_IGNORE_DEPRECATIONS
+  {
+    GtkStyleContext *style_context;
+
+    style_context = gtk_widget_get_style_context (widget);
+    gtk_style_context_lookup_color (style_context, "accent_bg_color", &self->accent_bg_color);
+    gtk_style_context_lookup_color (style_context, "accent_fg_color", &self->accent_fg_color);
+    gtk_style_context_lookup_color (style_context, "success_bg_color", &self->success_bg_color);
+  }
+G_GNUC_END_IGNORE_DEPRECATIONS
+}
+
 static void
 sysprof_mark_chart_row_snapshot (GtkWidget   *widget,
                                  GtkSnapshot *snapshot)
 {
   SysprofMarkChartRow *self = (SysprofMarkChartRow *)widget;
-  static const GdkRGBA blue = {0,0,1,1};
-  static const GdkRGBA red = {1,0,0,1};
-  static const GdkRGBA white = {1,1,1,1};
   const SysprofTimeSeriesValue *values;
-  GListModel *model;
   PangoLayout *layout;
+  GListModel *model;
   guint n_values;
+  float last_end_x;
   int width;
   int height;
 
@@ -83,17 +109,21 @@ sysprof_mark_chart_row_snapshot (GtkWidget   *widget,
   if (self->series == NULL)
     return;
 
-  width = gtk_widget_get_width (widget);
-  height = gtk_widget_get_height (widget);
-
   model = sysprof_time_series_get_model (self->series);
   values = sysprof_time_series_get_values (self->series, &n_values);
+  if (model == NULL || n_values == 0)
+    return;
+
+  width = gtk_widget_get_width (widget);
+  height = gtk_widget_get_height (widget);
 
   layout = gtk_widget_create_pango_layout (widget, NULL);
   pango_layout_set_single_paragraph_mode (layout, TRUE);
   pango_layout_set_height (layout, height * PANGO_SCALE);
   pango_layout_set_ellipsize (layout, PANGO_ELLIPSIZE_END);
 
+  last_end_x = 0;
+
   /* First pass, draw our rectangles for duration which we
    * always want in the background compared to "points" which
    * are marks w/o a duration.
@@ -104,15 +134,26 @@ sysprof_mark_chart_row_snapshot (GtkWidget   *widget,
 
       if (v->begin != v->end)
         {
-          graphene_rect_t rect = GRAPHENE_RECT_INIT (floorf (v->begin * width),
+          graphene_rect_t rect;
-                                                     0,
+          float end_x;
-                                                     ceilf ((v->end - v->begin) * width),
-                                                     height);
 
+          rect = GRAPHENE_RECT_INIT (floorf (v->begin * width),
+                                     0,
+                                     ceilf ((v->end - v->begin) * width),
+                                     height);
+
+          /* Ignore empty sized draws */
           if (rect.size.width == 0)
             continue;
 
-          gtk_snapshot_append_color (snapshot, &blue, &rect);
+          /* Cull draw unless it will extend past last rect */
+          end_x = rect.origin.x + rect.size.width;
+          if (end_x <= last_end_x)
+            continue;
+          else
+            last_end_x = end_x;
+
+          gtk_snapshot_append_color (snapshot, &self->accent_bg_color, &rect);
 
           /* Only show the message text if the next item does
            * not overlap and there are at least 20 pixels
@@ -138,7 +179,7 @@ sysprof_mark_chart_row_snapshot (GtkWidget   *widget,
                                                                height));
                   gtk_snapshot_translate (snapshot,
                                           &GRAPHENE_POINT_INIT (v->begin * width, 0));
-                  gtk_snapshot_append_layout (snapshot, layout, &white);
+                  gtk_snapshot_append_layout (snapshot, layout, &self->accent_fg_color);
                   gtk_snapshot_pop (snapshot);
                   gtk_snapshot_restore (snapshot);
                 }
@@ -157,13 +198,13 @@ sysprof_mark_chart_row_snapshot (GtkWidget   *widget,
                                   &GRAPHENE_POINT_INIT (v->begin * width, height / 2));
           gtk_snapshot_rotate (snapshot, 45.f);
           gtk_snapshot_append_color (snapshot,
-                                     &red,
+                                     &self->success_bg_color,
                                      &GRAPHENE_RECT_INIT (-4, -4, 8, 8));
           gtk_snapshot_restore (snapshot);
         }
     }
 
-  g_object_unref (layout);
+  g_clear_object (&layout);
 }
 
 static void
@@ -286,6 +327,7 @@ sysprof_mark_chart_row_class_init (SysprofMarkChartRowClass *klass)
   object_class->get_property = sysprof_mark_chart_row_get_property;
   object_class->set_property = sysprof_mark_chart_row_set_property;
 
+  widget_class->css_changed = sysprof_mark_chart_row_css_changed;
   widget_class->snapshot = sysprof_mark_chart_row_snapshot;
 
   properties [PROP_ITEM] =
@@ -294,6 +336,8 @@ sysprof_mark_chart_row_class_init (SysprofMarkChartRowClass *klass)
                          (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
 
   g_object_class_install_properties (object_class, N_PROPS, properties);
+
+  gtk_widget_class_set_css_name (widget_class, "markchartrow");
 }
 
 static void