kernelshark: Prevent potential divide by zero in Shape::center()

Signed-off-by: Benjamin ROBIN <dev@benjarobin.fr>
Signed-off-by: Yordan Karadzhov <y.karadz@gmail.com>

src/KsPlotTools.cpp

diff --git a/src/KsPlotTools.cpp b/src/KsPlotTools.cpp
index 1d63a9b..f362eaa 100644
--- a/src/KsPlotTools.cpp
+++ b/src/KsPlotTools.cpp
@@ -318,6 +318,9 @@
 {
 	ksplot_point c = {0, 0};
 
+	if (_nPoints == 0)
+		return c;
+
 	for (size_t i = 0; i < _nPoints; ++i) {
 		c.x += _points[i].x;
 		c.y += _points[i].y;