AnalogSignal: Prevent threshold bg from spilling beyond extents

diff --git a/pv/views/trace/analogsignal.cpp b/pv/views/trace/analogsignal.cpp
index 2c5c82a9d1d18c5609d9d7965d2a10f35a6e2149..07fc7cf72add70fda687d3bc9b304bcfdf1d72fc 100644 (file)
--- a/pv/views/trace/analogsignal.cpp
+++ b/pv/views/trace/analogsignal.cpp
@@ -225,8 +225,10 @@ void AnalogSignal::paint_back(QPainter &p, ViewItemPaintParams &pp)
 
                // Draw high/neutral/low areas
                if (thresholds.size() == 2) {
-                       const double thr_lo = visual_y - thresholds[0] * scale_;
-                       const double thr_hi = visual_y - thresholds[1] * scale_;
+                       int thr_lo = visual_y - thresholds[0] * scale_;
+                       int thr_hi = visual_y - thresholds[1] * scale_;
+                       thr_lo = min(max(thr_lo, top), btm);
+                       thr_hi = min(max(thr_hi, top), btm);
 
                        p.fillRect(QRectF(pp.left(), top, pp.width(), thr_hi - top),
                                QBrush(ThresholdColorHi));
@@ -235,7 +237,8 @@ void AnalogSignal::paint_back(QPainter &p, ViewItemPaintParams &pp)
                        p.fillRect(QRectF(pp.left(), thr_lo, pp.width(), btm - thr_lo),
                                QBrush(ThresholdColorLo));
                } else {
-                       const double thr = visual_y - thresholds[0] * scale_;
+                       int thr = visual_y - thresholds[0] * scale_;
+                       thr = min(max(thr, top), btm);
 
                        p.fillRect(QRectF(pp.left(), top, pp.width(), thr - top),
                                QBrush(ThresholdColorHi));