Add round sensor filter (esphome#5532)

esphome/components/sensor/__init__.py

@@ -242,6 +242,7 @@ def sensor_entity_category(value):
 CalibratePolynomialFilter = sensor_ns.class_("CalibratePolynomialFilter", Filter)
 SensorInRangeCondition = sensor_ns.class_("SensorInRangeCondition", Filter)
 ClampFilter = sensor_ns.class_("ClampFilter", Filter)
+RoundFilter = sensor_ns.class_("RoundFilter", Filter)
 
 validate_unit_of_measurement = cv.string_strict
 validate_accuracy_decimals = cv.int_
@@ -702,6 +703,23 @@ async def clamp_filter_to_code(config, filter_id):
     )
 
 
+@FILTER_REGISTRY.register(
+    "round",
+    RoundFilter,
+    cv.maybe_simple_value(
+        {
+            cv.Required(CONF_ACCURACY_DECIMALS): cv.uint8_t,
+        },
+        key=CONF_ACCURACY_DECIMALS,
+    ),
+)
+async def round_filter_to_code(config, filter_id):
+    return cg.new_Pvariable(
+        filter_id,
+        config[CONF_ACCURACY_DECIMALS],
+    )
+
+
 async def build_filters(config):
     return await cg.build_registry_list(FILTER_REGISTRY, config)
 

esphome/components/sensor/filter.cpp

@@ -445,5 +445,14 @@ optional<float> ClampFilter::new_value(float value) {
   return value;
 }
 
+RoundFilter::RoundFilter(uint8_t precision) : precision_(precision) {}
+optional<float> RoundFilter::new_value(float value) {
+  if (std::isfinite(value)) {
+    float accuracy_mult = powf(10.0f, this->precision_);
+    return roundf(accuracy_mult * value) / accuracy_mult;
+  }
+  return value;
+}
+
 }  // namespace sensor
 }  // namespace esphome

esphome/components/sensor/filter.h

@@ -419,5 +419,14 @@ class ClampFilter : public Filter {
   float max_{NAN};
 };
 
+class RoundFilter : public Filter {
+ public:
+  explicit RoundFilter(uint8_t precision);
+  optional<float> new_value(float value) override;
+
+ protected:
+  uint8_t precision_;
+};
+
 }  // namespace sensor
 }  // namespace esphome