sparkline: Add num_sets property so a sparkline graph can have multiple lines (Guido Gunther)

all data is still stored in a 1D array so we can still use g_param_spec_double
for type checking. This removes the support for non cairo builds.

src/graphWidgets/sparkline.c

@@ -44,6 +44,7 @@ enum {
   PROP_DATAARRAY,
   PROP_FILLED,
   PROP_REVERSED,
+  PROP_NUMSETS,
 };
 
 static gpointer parent_class;
@@ -55,6 +56,8 @@ struct _GtkSparklinePrivate
 {
   gboolean filled;
   gboolean reversed;
+  gint num_sets;
+  gint points_per_set;
   GValueArray *data_array;
 };
 
@@ -93,6 +96,8 @@ static void gtk_sparkline_init (GtkSparkline *sparkline)
   priv->filled = TRUE;
   priv->reversed = FALSE;
   priv->data_array = g_value_array_new(0);
+  priv->num_sets = 1;
+  priv->points_per_set = 0;
 
   g_signal_connect (G_OBJECT (sparkline), "expose_event",
                     G_CALLBACK (gtk_sparkline_expose), NULL);
@@ -103,6 +108,7 @@ static void gtk_sparkline_class_init (GtkSparklineClass *class)
 {
   GObjectClass *object_class = G_OBJECT_CLASS (class);
   GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (class);
+  GParamSpec *data_array_spec;
 
   parent_class = g_type_class_peek_parent (class);
 
@@ -114,19 +120,28 @@ static void gtk_sparkline_class_init (GtkSparklineClass *class)
   widget_class->size_request = gtk_sparkline_size_request;
   //widget_class->expose_event = gtk_sparkline_expose;
 
+  data_array_spec = g_param_spec_double("data_array_value",
+		     		        "Data array value",
+				        "GValueArray element",
+					0.0,
+					100.0,
+					0,
+					G_PARAM_READABLE | G_PARAM_WRITABLE);
+
   g_object_class_install_property (object_class,
 				   PROP_DATAARRAY,
 				   g_param_spec_value_array ("data_array",
 							     "Data array",
 							     "GValueArray of data",
-							     g_param_spec_double("data_array_value",
+							     data_array_spec,
-										 "Data array value",
-										 "GValueArray element",
-										 0.0,
-										 100.0,
-										 0,
-										 G_PARAM_READABLE | G_PARAM_WRITABLE),
 							     G_PARAM_READABLE | G_PARAM_WRITABLE));
+  g_object_class_install_property (object_class,
+				   PROP_NUMSETS,
+				   g_param_spec_int ("num_sets",
+						     "Num Sets",
+						     "Number of data sets in data",
+						     1, 2, 1,
+						     G_PARAM_READABLE | G_PARAM_WRITABLE));
   g_object_class_install_property (object_class,
 				   PROP_FILLED,
 				   g_param_spec_boolean ("filled",
@@ -168,6 +183,10 @@ static void gtk_sparkline_get_property (GObject *object,
       g_value_set_boxed(value, priv->data_array);
       break;
 
+    case PROP_NUMSETS:
+      g_value_set_int(value, priv->num_sets);
+      break;
+
     case PROP_FILLED:
       g_value_set_boolean(value, priv->filled);
       break;
@@ -197,6 +216,7 @@ gtk_sparkline_set_property (GObject      *object,
     case PROP_DATAARRAY:
       g_value_array_free(priv->data_array);
       priv->data_array = g_value_array_copy(g_value_get_boxed(value));
+      priv->points_per_set = priv->data_array->n_values / priv->num_sets;
       gtk_widget_queue_draw(GTK_WIDGET(object));
       break;
 
@@ -208,6 +228,10 @@ gtk_sparkline_set_property (GObject      *object,
       priv->reversed = g_value_get_boolean(value);
       break;
 
+    case PROP_NUMSETS:
+      priv->num_sets = g_value_get_int(value);
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, param_id, pspec);
       break;
@@ -225,22 +249,22 @@ static void gtk_sparkline_size_request(GtkWidget *widget,
   data = priv->data_array;
 
   if (area) {
-    area->width = data->n_values;
+    area->width = data->n_values / priv->num_sets;
     area->height = 20;
   }
 }
 
-static double get_y (GtkAllocation *cell_area,
+static double get_y (GtkSparklinePrivate *priv, GtkAllocation *cell_area,
-		     GValueArray *data,
+		     GValueArray *data, int set, int index)
-		     int index, int reversed)
 {
   double baseline_y = cell_area->height;
   int n;
 
-  if (reversed) 
+  n = set * priv->points_per_set;
-    n = data->n_values - 1 - index;
+  if (priv->reversed) 
+    n += priv->points_per_set - 1 - index;
   else
-    n = index;
+    n += index;
 
   GValue *val = g_value_array_get_nth(data, n);
   return baseline_y - ((cell_area->height-1) * g_value_get_double(val));
@@ -253,27 +277,15 @@ gtk_sparkline_expose (GtkWidget *widget,
 {
   GtkSparklinePrivate *priv;
   GValueArray *data;
-  GdkPoint *points;
+  int index, set;
-  int index;
   double pixels_per_point;
   GtkAllocation *cell_area = &widget->allocation;
-#if USE_CAIRO
   cairo_t *cr;
-#endif
 
   priv = GTK_SPARKLINE_GET_PRIVATE (widget);
 
   data = priv->data_array;
-
+  pixels_per_point = (double)cell_area->width / ((double)priv->points_per_set-1);
-  pixels_per_point = (double)cell_area->width / ((double)data->n_values-1);
-
-  points = g_new(GdkPoint, data->n_values);
-  for (index=0;index<data->n_values;index++) {
-    double cx = ((double)index * pixels_per_point);
-    double cy = get_y (cell_area, data, index, priv->reversed);
-    points[index].x = cx;
-    points[index].y = cy;
-  }
 
   gdk_draw_rectangle(widget->window,
 		     widget->style->mid_gc[GTK_WIDGET_STATE (widget)],
@@ -300,7 +312,6 @@ gtk_sparkline_expose (GtkWidget *widget,
 		  cell_area->height/NTICKS*index);
   }
 
-#if USE_CAIRO
   cr = gdk_cairo_create (widget->window);
 
   /* Clip to the cell: */
@@ -308,26 +319,33 @@ gtk_sparkline_expose (GtkWidget *widget,
   cairo_rectangle (cr, 0, 0, cell_area->width, cell_area->height);
   cairo_clip (cr);
 
-  /* Render the line: */
+  /* Render the lines: */
   cairo_set_line_width (cr, (double)0.5);
 
-  for (index=0;index<data->n_values;index++) {
+  for (set=0; set < priv->num_sets; set++) {
-    double cx = points[index].x;
+    /* FIXME: add property to add line color */
-    double cy = points[index].y;
+    if (set)
-    if (index) {
+    	cairo_set_source_rgb (cr, 0.25, 0.25, 0.25);
-      cairo_line_to (cr, cx, cy);
+    else
-    } else {
+    	cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
-      cairo_move_to (cr, cx, cy);
+    for (index=0; index < priv->points_per_set; index++) {
+      double cx = ((double)index * pixels_per_point);
+      double cy = get_y (priv, cell_area, data, set, index);
+      if (index) {
+        cairo_line_to (cr, cx, cy);
+      } else {
+        cairo_move_to (cr, cx, cy);
+      }
     }
-  }
+    if (priv->points_per_set) {
-  if (data->n_values) {
+        if (priv->filled) {
-    if (priv->filled) {
+          double baseline_y = cell_area->height + cell_area->y;
-      double baseline_y = cell_area->height + cell_area->y;
+          cairo_line_to (cr, cell_area->x + cell_area->width, baseline_y);
-      cairo_line_to (cr, cell_area->x + cell_area->width, baseline_y);
+          cairo_line_to (cr, 0, baseline_y);
-      cairo_line_to (cr, 0, baseline_y);
+          cairo_fill (cr);
-      cairo_fill (cr);
+        } else {
-    } else {
+          cairo_stroke (cr);
-      cairo_stroke (cr);
+      }
     }
   }
 
@@ -336,14 +354,6 @@ gtk_sparkline_expose (GtkWidget *widget,
 
   cairo_destroy (cr);
 
-#else
-  gdk_draw_lines(widget->window,
-		 widget->style->fg_gc[GTK_WIDGET_STATE(widget)],
-		 points, data->n_values);
-#endif
-
-  g_free(points);
-
   return TRUE;
 }