Add display precision to log_diagnostics_plugin

crates/bevy_asset/src/diagnostic/asset_count_diagnostics_plugin.rs

@@ -1,6 +1,8 @@
 use crate::{Asset, Assets};
 use bevy_app::prelude::*;
-use bevy_diagnostic::{Diagnostic, DiagnosticId, Diagnostics, MAX_DIAGNOSTIC_NAME_WIDTH};
+use bevy_diagnostic::{
+    Diagnostic, DiagnosticId, Diagnostics, DisplayPrecision, MAX_DIAGNOSTIC_NAME_WIDTH,
+};
 use bevy_ecs::system::{Res, ResMut};
 
 /// Adds an asset count diagnostic to an [`App`] for assets of type `T`.
@@ -48,6 +50,7 @@ impl<T: Asset> AssetCountDiagnosticsPlugin<T> {
                 }
             ),
             20,
+            DisplayPrecision::IntegerValue,
         ));
     }
 

crates/bevy_diagnostic/src/diagnostic.rs

@@ -28,6 +28,32 @@ pub struct DiagnosticMeasurement {
     pub value: f64,
 }
 
+/// The number of digits that should be displayed for a diagnostic.
+///
+/// Choose `IntegerValue` for discrete values and `DecimalValue(num_of_decimals)` to specify the number of decimals.
+#[derive(Debug)]
+pub enum DisplayPrecision {
+    IntegerValue,
+    DecimalValue(usize),
+}
+
+impl DisplayPrecision {
+    pub fn num_decimals(&self) -> usize {
+        match self {
+            DisplayPrecision::IntegerValue => 0,
+            DisplayPrecision::DecimalValue(x) => *x,
+        }
+    }
+}
+
+// trait DiagnosticDisplayPercision {
+//     type DisplayPercision;
+// }
+
+// impl DiagnosticDisplayPercision for Diagnostic {
+//     type DisplayPercision = DisplayPercision;
+// }
+
 /// A timeline of [`DiagnosticMeasurement`]s of a specific type.
 /// Diagnostic examples: frames per second, CPU usage, network latency
 #[derive(Debug)]
@@ -41,6 +67,7 @@ pub struct Diagnostic {
     ema_smoothing_factor: f64,
     max_history_length: usize,
     pub is_enabled: bool,
+    pub precision: DisplayPrecision,
 }
 
 impl Diagnostic {
@@ -73,11 +100,12 @@ impl Diagnostic {
             .push_back(DiagnosticMeasurement { time, value });
     }
 
-    /// Create a new diagnostic with the given ID, name and maximum history.
+    /// Create a new diagnostic with the given ID, name, maximum history and decimal precision.
     pub fn new(
         id: DiagnosticId,
         name: impl Into<Cow<'static, str>>,
         max_history_length: usize,
+        precision: DisplayPrecision, // Choose number of decimals for display precision.
     ) -> Diagnostic {
         let name = name.into();
         if name.chars().count() > MAX_DIAGNOSTIC_NAME_WIDTH {
@@ -98,6 +126,7 @@ impl Diagnostic {
             ema: 0.0,
             ema_smoothing_factor: 2.0 / 21.0,
             is_enabled: true,
+            precision,
         }
     }
 
@@ -195,6 +224,11 @@ impl Diagnostic {
     pub fn clear_history(&mut self) {
         self.history.clear();
     }
+
+    /// Get the number of decimals to display for this diagnostic.
+    pub fn num_decimals(&self) -> usize {
+        self.precision.num_decimals()
+    }
 }
 
 /// A collection of [Diagnostic]s

crates/bevy_diagnostic/src/entity_count_diagnostics_plugin.rs

@@ -1,7 +1,7 @@
 use bevy_app::{App, Plugin};
 use bevy_ecs::{entity::Entities, system::ResMut};
 
-use crate::{Diagnostic, DiagnosticId, Diagnostics};
+use crate::{Diagnostic, DiagnosticId, Diagnostics, DisplayPrecision};
 
 /// Adds "entity count" diagnostic to an App
 #[derive(Default)]
@@ -19,7 +19,12 @@ impl EntityCountDiagnosticsPlugin {
         DiagnosticId::from_u128(187513512115068938494459732780662867798);
 
     pub fn setup_system(mut diagnostics: ResMut<Diagnostics>) {
-        diagnostics.add(Diagnostic::new(Self::ENTITY_COUNT, "entity_count", 20));
+        diagnostics.add(Diagnostic::new(
+            Self::ENTITY_COUNT,
+            "entity_count",
+            20,
+            DisplayPrecision::IntegerValue,
+        ));
     }
 
     pub fn diagnostic_system(mut diagnostics: ResMut<Diagnostics>, entities: &Entities) {

crates/bevy_diagnostic/src/frame_time_diagnostics_plugin.rs

@@ -1,4 +1,4 @@
-use crate::{Diagnostic, DiagnosticId, Diagnostics};
+use crate::{Diagnostic, DiagnosticId, Diagnostics, DisplayPrecision};
 use bevy_app::prelude::*;
 use bevy_core::FrameCount;
 use bevy_ecs::system::{Res, ResMut};
@@ -23,10 +23,27 @@ impl FrameTimeDiagnosticsPlugin {
         DiagnosticId::from_u128(73441630925388532774622109383099159699);
 
     pub fn setup_system(mut diagnostics: ResMut<Diagnostics>) {
-        diagnostics.add(Diagnostic::new(Self::FRAME_TIME, "frame_time", 20).with_suffix("ms"));
-        diagnostics.add(Diagnostic::new(Self::FPS, "fps", 20));
-        diagnostics
-            .add(Diagnostic::new(Self::FRAME_COUNT, "frame_count", 1).with_smoothing_factor(0.0));
+        diagnostics.add(
+            Diagnostic::new(
+                Self::FRAME_TIME,
+                "frame_time",
+                20,
+                DisplayPrecision::DecimalValue(6),
+            )
+            .with_suffix("ms"),
+        );
+        diagnostics.add(Diagnostic::new(
+            Self::FPS,
+            "fps",
+            20,
+            DisplayPrecision::DecimalValue(6),
+        ));
+        diagnostics.add(Diagnostic::new(
+            Self::FRAME_COUNT,
+            "frame_count",
+            1,
+            DisplayPrecision::IntegerValue,
+        ));
     }
 
     pub fn diagnostic_system(

crates/bevy_diagnostic/src/log_diagnostics_plugin.rs

@@ -62,20 +62,22 @@ impl LogDiagnosticsPlugin {
                         // so we reserve two columns for it; however,
                         // Do not reserve columns for the suffix in the average
                         // The ) hugging the value is more aesthetically pleasing
-                        "{name:<name_width$}: {value:>11.6}{suffix:2} (avg {average:>.6}{suffix:})",
+                        "{name:<name_width$}: {value:>11.num_of_decimals$}{suffix:2} (avg {average:>.num_of_decimals$}{suffix:})",
                         name = diagnostic.name,
                         suffix = diagnostic.suffix,
                         name_width = crate::MAX_DIAGNOSTIC_NAME_WIDTH,
+                        num_of_decimals = diagnostic.num_decimals(),
                     );
                     return;
                 }
             }
             info!(
                 target: "bevy diagnostic",
-                "{name:<name_width$}: {value:>.6}{suffix:}",
+                "{name:<name_width$}: {value:>.num_of_decimals$}{suffix:}",
                 name = diagnostic.name,
                 suffix = diagnostic.suffix,
                 name_width = crate::MAX_DIAGNOSTIC_NAME_WIDTH,
+                num_of_decimals = diagnostic.num_decimals(),
             );
         }
     }

examples/diagnostics/custom_diagnostic.rs

@@ -1,7 +1,7 @@
 //! This example illustrates how to create a custom diagnostic.
 
 use bevy::{
-    diagnostic::{Diagnostic, DiagnosticId, Diagnostics, LogDiagnosticsPlugin},
+    diagnostic::{Diagnostic, DiagnosticId, Diagnostics, DisplayPrecision, LogDiagnosticsPlugin},
     prelude::*,
 };
 
@@ -28,6 +28,7 @@ fn setup_diagnostic_system(mut diagnostics: ResMut<Diagnostics>) {
         SYSTEM_ITERATION_COUNT,
         "system_iteration_count",
         10,
+        DisplayPrecision::IntegerValue,
     ));
 }