DecodeTrace: Prevent trace height from jumping

[pulseview.git] / pv / view / decodetrace.cpp

diff --git a/pv/view/decodetrace.cpp b/pv/view/decodetrace.cpp
index 2e16ff96ce76f54995742c92a8a0ddcb86fe7f63..f2aadd1b18ff3c7e4b8904a53aeef1b8f7c8d0a9 100644 (file)
--- a/pv/view/decodetrace.cpp
+++ b/pv/view/decodetrace.cpp
@@ -133,6 +133,7 @@ DecodeTrace::DecodeTrace(pv::Session &session,
        session_(session),
        decoder_stack_(decoder_stack),
        row_height_(0),
+       max_visible_rows_(0),
        delete_mapper_(this),
        show_hide_mapper_(this)
 {
@@ -161,9 +162,8 @@ const std::shared_ptr<pv::data::DecoderStack>& DecodeTrace::decoder() const
 pair<int, int> DecodeTrace::v_extents() const
 {
        const int row_height = (ViewItemPaintParams::text_height() * 6) / 4;
-       const int rows = visible_rows_.size();
 
-       return make_pair(-row_height, row_height * rows);
+       return make_pair(-row_height, row_height * max_visible_rows_);
 }
 
 void DecodeTrace::paint_back(QPainter &p, const ViewItemPaintParams &pp)
@@ -222,6 +222,9 @@ void DecodeTrace::paint_mid(QPainter &p, const ViewItemPaintParams &pp)
 
        // Draw the hatching
        draw_unresolved_period(p, annotation_height, pp.left(), pp.right());
+
+       // Update the maximum row count if needed
+       max_visible_rows_ = std::max(max_visible_rows_, (int)visible_rows_.size());
 }
 
 void DecodeTrace::paint_fore(QPainter &p, const ViewItemPaintParams &pp)