gfio: add extra space to the graphs at the edges

This is to make it easier to read and also keeps the lines from
going beyond the edges of the graph.

Signed-off-by: Stephen M. Cameron <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

gfio.c

@@ -200,6 +200,7 @@ static struct graph *setup_iops_graph(void)
 	graph_set_color(g, "Write IOPS", 1.0, 0.0, 0.0);
 	line_graph_set_data_count_limit(g, gfio_graph_limit);
 	graph_y_axis_unit_change_notify(g, iops_graph_y_axis_unit_change);
+	graph_add_extra_space(g, 0.005, 0.005, 0.03, 0.03);
 	return g;
 }
 
@@ -232,6 +233,8 @@ static struct graph *setup_bandwidth_graph(void)
 	graph_set_color(g, "Write Bandwidth", 1.0, 0.0, 0.0);
 	line_graph_set_data_count_limit(g, 100);
 	graph_y_axis_unit_change_notify(g, bandwidth_graph_y_axis_unit_change);
+	graph_add_extra_space(g, 0.005, 0.005, 0.03, 0.03);
+
 	return g;
 }
 

graph.c

@@ -62,6 +62,10 @@ struct graph {
 	const char *font;
 	graph_axis_unit_change_callback x_axis_unit_change_callback;
 	graph_axis_unit_change_callback y_axis_unit_change_callback;
+	double left_extra;	
+	double right_extra;	
+	double top_extra;	
+	double bottom_extra;	
 };
 
 void graph_set_size(struct graph *g, unsigned int xdim, unsigned int ydim)
@@ -474,8 +478,8 @@ static double find_xy_value(struct graph *g, xy_value_extractor getvalue, double
 void line_graph_draw(struct graph *g, cairo_t *cr)
 {
 	double x1, y1, x2, y2;
-	double minx, miny, maxx, maxy;
-	double tx, ty;
+	double minx, miny, maxx, maxy, gminx, gminy, gmaxx, gmaxy;
+	double tx, ty, top_extra, bottom_extra, left_extra, right_extra;
 	struct graph_label *i;
 	struct graph_value *j;
 	int good_data = 1, first = 1;
@@ -497,8 +501,27 @@ void line_graph_draw(struct graph *g, cairo_t *cr)
 		maxy = 100.0;
 	}
 
-	graph_draw_x_ticks(g, cr, x1, y1, x2, y2, minx, maxx, 10);
-	graph_draw_y_ticks(g, cr, x1, y1, x2, y2, miny, maxy, 10);
+	top_extra = 0.0;
+	bottom_extra = 0.0;
+	left_extra = 0.0;
+	right_extra = 0.0;
+
+	if (g->top_extra > 0.001)
+		top_extra = fabs(maxy - miny) * g->top_extra;
+	if (g->bottom_extra > 0.001)
+		bottom_extra = fabs(maxy - miny) * g->bottom_extra;
+	if (g->left_extra > 0.001)
+		left_extra = fabs(maxx - minx) * g->left_extra;
+	if (g->right_extra > 0.001)
+		right_extra = fabs(maxx - minx) * g->right_extra;
+
+	gminx = minx - left_extra;
+	gmaxx = maxx + right_extra;
+	gminy = miny - bottom_extra;
+	gmaxy = maxy + top_extra;
+
+	graph_draw_x_ticks(g, cr, x1, y1, x2, y2, gminx, gmaxx, 10);
+	graph_draw_y_ticks(g, cr, x1, y1, x2, y2, gminy, gmaxy, 10);
 
 	if (!good_data)
 		goto skip_data;
@@ -510,8 +533,8 @@ void line_graph_draw(struct graph *g, cairo_t *cr)
 			continue;
 		cairo_set_source_rgb(cr, i->r, i->g, i->b);
 		for (j = i->values; j; j = j->next) {
-			tx = ((getx(j) - minx) / (maxx - minx)) * (x2 - x1) + x1;
-			ty = y2 - ((gety(j) - miny) / (maxy - miny)) * (y2 - y1);
+			tx = ((getx(j) - gminx) / (gmaxx - gminx)) * (x2 - x1) + x1;
+			ty = y2 - ((gety(j) - gminy) / (gmaxy - gminy)) * (y2 - y1);
 			if (first) {
 				cairo_move_to(cr, tx, ty);
 				first = 0;
@@ -724,3 +747,13 @@ void line_graph_set_data_count_limit(struct graph *g, int per_label_limit)
 	g->per_label_limit = per_label_limit;
 }
 
+void graph_add_extra_space(struct graph *g, double left_percent, double right_percent,
+                                double top_percent, double bottom_percent)
+{
+	g->left_extra = left_percent;	
+	g->right_extra = right_percent;	
+	g->top_extra = top_percent;	
+	g->bottom_extra = bottom_percent;	
+}
+
+

graph.h

@@ -75,5 +75,11 @@ void graph_y_axis_unit_change_notify(struct graph *g, graph_axis_unit_change_cal
  * millions, thousands and ones. 
  */ 
 
+void graph_add_extra_space(struct graph *g, double left_percent, double right_percent,
+				double top_percent, double bottom_percent);
+/* graph_add_extra_space() adds extra space to edges of the the graph
+ * so that the data doesn't go to the very edges.
+ */
+
 #endif