fix: break chart line on timestamp gaps caused by packet loss#388
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fix: break chart line on timestamp gaps caused by packet loss#388
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During WiFi streaming, packet loss produces missing timestamps that the chart previously bridged with a straight line, giving a misleading linear slope. This change detects those gaps in PlotLogger and inserts a DataPoint.Undefined marker so OxyPlot renders a visible break instead of connecting the points. Detection uses an exponential moving average (EMA, alpha=0.1) of per-channel timestamp deltas. Any delta that exceeds 2× the running average is treated as a gap. The EMA adapts automatically to the current sample rate, so no fixed threshold configuration is needed. Closes #291 Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Extracts the EMA-based gap detection logic from PlotLogger into a standalone TimestampGapDetector class (internal, no WPF dependencies), then adds 11 unit tests covering: - First and second sample never flagged as gaps (EMA bootstrap) - Consistent cadence produces no false positives - Delta exactly at threshold (2×) is not flagged - Delta clearly above threshold is detected - Delta just above threshold is detected - Gap on one channel does not affect another (state isolation) - EMA adapts to a gradually slowing sample rate without false positives - After a detected gap the stream resumes cleanly - Clear() resets all per-channel state PlotLogger now delegates to TimestampGapDetector, keeping the gap logic testable in isolation from WPF rendering infrastructure. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
📊 Code Coverage ReportSummarySummary
CoverageDAQiFi - 19.9%
Daqifi.Desktop.Common - 39.3%
Daqifi.Desktop.IO - 100%
Coverage report generated by ReportGenerator • View full report in build artifacts |
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Summary
DataPoint.Undefinedmarkers in OxyPlot so the chart renders a visible line break instead of a misleading linear connection across the missing dataClearPlot()to keep channels clean between sessionsHow it works
PlotLoggernow maintains two dictionaries keyed by(deviceSerial, channelName):_lastTimestampMs— thedeltaTimeof the previously logged point_avgDeltaMs— the EMA of observed inter-sample deltasOn each
Log(DataSample)call,InsertGapIfNeededcomputes the current delta, compares it toGapThresholdMultiplier * avgDelta(2×), and if exceeded insertsDataPoint.Undefinedbefore the new real point. OxyPlot treats undefined points as line breaks, leaving a visible gap in the chart.Test plan
ClearPlotfully resets the logger and the next session starts freshCloses #291
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