Ruler: Add "Set as zero point" context menu entry

[pulseview.git] / pv / views / trace / view.cpp

diff --git a/pv/views/trace/view.cpp b/pv/views/trace/view.cpp
index fa911f0b5ad92ae8a27c0f96b3d69de2de984aab..79277b4e17074708b0f1e3718ef6eeb4996d2c93 100644 (file)
--- a/pv/views/trace/view.cpp
+++ b/pv/views/trace/view.cpp
@@ -495,9 +495,12 @@ const Timestamp& View::ruler_offset() const
        return ruler_offset_;
 }
 
-void View::set_zero_position(pv::util::Timestamp& position)
+void View::set_zero_position(const pv::util::Timestamp& position)
 {
-       ruler_shift_ = -position;
+       // ruler shift is a negative offset and the new zero position is relative
+       // to the current offset. Hence, we adjust the ruler shift only by the
+       // difference.
+       ruler_shift_ = -(position + (-ruler_shift_));
 
        // Force an immediate update of the offsets
        set_offset(offset_, true);