Fix -Werror=type-limits

src/ui/designer/QGCXYPlot.cc

@@ -362,7 +362,14 @@ void QGCXYPlot::appendData(int uasId, const QString& curve, const QString& unit,
     } else
         return;
 
-    if(x_valid && y_valid && (int)qAbs(y_timestamp_us - x_timestamp_us) <= max_timestamp_diff_us) {
+    if(x_valid && y_valid) {
+        quint64 difference;
+        if (y_timestamp_us < x_timestamp_us) {
+            difference = x_timestamp_us - y_timestamp_us;
+        } else {
+            difference = y_timestamp_us - x_timestamp_us;
+        }
+        if (difference <= max_timestamp_diff_us) {
             int removed = xycurve->appendData( QPointF(x,y) );
             x_valid = false;
             y_valid = false;
@@ -377,6 +384,7 @@ void QGCXYPlot::appendData(int uasId, const QString& curve, const QString& unit,
                 xycurve->setStartIndex(value);
             }
         }
+    }
 }
 
 void QGCXYPlot::styleChanged(MainWindow::QGC_MAINWINDOW_STYLE style)

src/ui/designer/QGCXYPlot.h

@@ -48,7 +48,7 @@ private:
     double y; /**< Last unused value for the x-coordinate */
     quint64 y_timestamp_us; /**< Timestamp that we last recieved a value for x */
     bool y_valid; /**< Whether we have recieved an x value but so far no corresponding y value */
-    int max_timestamp_diff_us; /**< Only combine x and y to a data point if the timestamp for both doesn't differ by more than this */
+    quint64 max_timestamp_diff_us; /**< Only combine x and y to a data point if the timestamp for both doesn't differ by more than this */
 };
 
 #endif // QGCXYPLOT_H