+ using pv::data::AnalogSnapshot;
+
+ AnalogSnapshot::EnvelopeSection e;
+ snapshot->get_envelope_section(e, start, end, samples_per_pixel);
+
+ if (e.length < 2)
+ return;
+
+ p.setPen(QPen(Qt::NoPen));
+ p.setBrush(_colour);
+
+ QRectF *const rects = new QRectF[e.length];
+ QRectF *rect = rects;
+
+ for(uint64_t sample = 0; sample < e.length-1; sample++) {
+ const float x = ((e.scale * sample + e.start) /
+ samples_per_pixel - pixels_offset) + left;
+ const AnalogSnapshot::EnvelopeSample *const s =
+ e.samples + sample;
+
+ // We overlap this sample with the next so that vertical
+ // gaps do not appear during steep rising or falling edges
+ const float b = y - max(s->max, (s+1)->min) * _scale;
+ const float t = y - min(s->min, (s+1)->max) * _scale;
+
+ float h = b - t;
+ if(h >= 0.0f && h <= 1.0f)
+ h = 1.0f;
+ if(h <= 0.0f && h >= -1.0f)
+ h = -1.0f;
+
+ *rect++ = QRectF(x, t, 1.0f, h);
+ }
+
+ p.drawRects(rects, e.length);
+
+ delete[] rects;
+ delete[] e.samples;