2 files changed, 13 insertions, 3 deletions
diff --git a/spline-widget/qfunctionconfigurator.cpp b/spline-widget/qfunctionconfigurator.cpp
index 5d910826..112b5457 100644
--- a/spline-widget/qfunctionconfigurator.cpp
+++ b/spline-widget/qfunctionconfigurator.cpp
@@ -21,7 +21,9 @@ QFunctionConfigurator::QFunctionConfigurator(QWidget *parent) :
     QWidget(parent),
     _config(nullptr),
     moving_control_point_idx(-1),
-    _draw_function(true)
+    _draw_function(true),
+    snap_x(0),
+    snap_y(0)
 {
     update_range();
     setMouseTracking(true);
@@ -412,8 +414,13 @@ QPointF QFunctionConfigurator::pixel_coord_to_point(const QPointF& point)
     if (!_config)
         return QPointF(-1, -1);
 
-    double x = (point.x() - pixel_bounds.x()) / c.x();
-    double y = (pixel_bounds.height() - point.y() + pixel_bounds.y()) / c.y();
+    int x = (point.x() - pixel_bounds.x()) / c.x();
+    int y = (pixel_bounds.height() - point.y() + pixel_bounds.y()) / c.y();
+    
+    if (snap_x > 0)
+        x -= x % snap_x;
+    if (snap_y > 0)
+        y -= y % snap_y;
 
     if (x < 0)
         x = 0;
diff --git a/spline-widget/qfunctionconfigurator.h b/spline-widget/qfunctionconfigurator.h
index 4a9cb5f1..d4ba904a 100644
--- a/spline-widget/qfunctionconfigurator.h
+++ b/spline-widget/qfunctionconfigurator.h
@@ -39,6 +39,8 @@ public:
         _background = QPixmap();
         update();
     }
+    void set_snap(int x, int y) { snap_x = x; snap_y = y; }
+    void get_snap(int& x, int& y) const { x = snap_x; y = snap_y; }
 protected slots:
     void paintEvent(QPaintEvent *e) override;
     void mousePressEvent(QMouseEvent *e) override;
@@ -72,4 +74,5 @@ private:
     QPixmap _background;
     QPixmap _function;
     bool _draw_function;
+    int snap_x, snap_y;
 };