added comments

diff --git a/src/graph.c b/src/graph.c
index a69b65a..f26e9cf 100644 (file)
--- a/src/graph.c
+++ b/src/graph.c
@@ -170,8 +170,11 @@ static void draw_background_lines(cairo_t *cr,
        cairo_set_dash(cr, 0, 0, 0);
 }
 
-/* contains the time_t of the measures which have been draw ie not the
- * bezier control points for each sensor. */
+/* Keys: sensor identifier.
+ *
+ * Values: array of time_t. Each time_t is corresponding to a sensor
+ * measure which has been used as the start point of a Bezier curve.
+ */
 static GHashTable *times;
 
 static void draw_sensor_smooth_curve(struct psensor *s,
@@ -202,6 +205,10 @@ static void draw_sensor_smooth_curve(struct psensor *s,
                             s->color->green,
                             s->color->blue);
 
+       /* search the index of the first measure used as a start point
+        * of a Bezier curve. The start and end points of the Bezier
+        * curves must be preserved to ensure the same overall shape
+        * of the graph. */
        i = 0;
        if (stimes) {
                while (i < s->values_max_length) {
@@ -253,7 +260,6 @@ static void draw_sensor_smooth_curve(struct psensor *s,
                        x[0 + j] = ((double)vdt * g_width) / dt + g_xoff;
                        y[0 + j] = compute_y(v, min, max, g_height, g_yoff);
 
-
                        if (j == 0)
                                t0 = t;