further performance improvements

examples/simple_producer/src/main.rs

@@ -190,8 +190,8 @@ async fn main() -> Result<(), Box<dyn Error>> {
     let mut next_time = Instant::now();
     let mut index = 0;
     while !cancellation_token.is_cancelled() {
-        next_time += Duration::from_millis(100);
-        index += 10;
+        next_time += Duration::from_millis(10);
+        index += 1;
         tokio::time::sleep_until(next_time).await;
         sin_tlm_handle
             .publish(

frontend/src/components/SvgGraph.vue

@@ -79,6 +79,7 @@ provide<GraphData>(GRAPH_DATA, {
     height: () => height.value - 2 * border_top_bottom.value,
     x_map: x_map,
     lines: telemetry_lines,
+    max_update_rate: 1000 / 10
 });
 
 const duration = computed(() => {

frontend/src/components/TelemetryLine.vue

@@ -19,6 +19,7 @@ import {
 import { GRAPH_DATA, type GraphData } from '@/graph/graph';
 import { AXIS_DATA, type AxisData } from '@/graph/axis';
 import ValueLabel from '@/components/ValueLabel.vue';
+import type { Point } from '@/graph/line';
 
 const props = defineProps<{
     data: string;
@@ -39,6 +40,17 @@ const axis_data = inject<AxisData>(AXIS_DATA)!;
 const min = ref(Infinity);
 const max = ref(-Infinity);
 
+const recompute_points = shallowRef(0);
+
+function trigger_recompute() {
+    recompute_points.value = Date.now();
+}
+function debounced_recompute() {
+    if (recompute_points.value + toValue(graph_data.max_update_rate) < Date.now()) {
+        trigger_recompute();
+    }
+}
+
 const line = ref(Symbol());
 const index = computed(() => {
     return graph_data.lines.value.indexOf(line.value);
@@ -52,15 +64,18 @@ onUnmounted(() => {
     );
 });
 
-const memo = shallowRef<TelemetryDataItem[]>([]);
+const memo = shallowRef<Point[]>([]);
 watch([value], ([val]) => {
     const min_x = toValue(graph_data.min_x);
     if (val) {
         const val_t = Date.parse(val.timestamp);
         if (val_t >= min_x) {
             // TODO: Insert this in the right spot in memo
-            const new_memo = [val].concat(memo.value);
             const item_val = val.value[data.value!.data_type] as number;
+            const new_memo = [{
+                x: val_t,
+                y: item_val,
+            }].concat(memo.value);
             if (item_val < min.value) {
                 min.value = item_val;
             }
@@ -68,16 +83,17 @@ watch([value], ([val]) => {
                 max.value = item_val;
             }
             memo.value = new_memo;
+            debounced_recompute();
         }
     }
 });
 watch([graph_data.min_x, graph_data.max_x], ([min_x, max_x]) => {
     let memo_changed = false;
-    const new_memo = ([] as TelemetryDataItem[]).concat(memo.value);
+    const new_memo = ([] as Point[]).concat(memo.value);
     if (min_x) {
         while (
             new_memo.length > 2 &&
-            Date.parse(new_memo[new_memo.length - 2].timestamp) < toValue(min_x)
+            new_memo[new_memo.length - 2].x < toValue(min_x)
         ) {
             new_memo.pop();
             memo_changed = true;
@@ -86,7 +102,7 @@ watch([graph_data.min_x, graph_data.max_x], ([min_x, max_x]) => {
     if (max_x) {
         while (
             new_memo.length > 2 &&
-            Date.parse(new_memo[1].timestamp) > toValue(max_x)
+            new_memo[1].x > toValue(max_x)
         ) {
             new_memo.shift();
             memo_changed = true;
@@ -96,11 +112,12 @@ watch([graph_data.min_x, graph_data.max_x], ([min_x, max_x]) => {
         let min_val = Infinity;
         let max_val = -Infinity;
         for (const item of new_memo) {
-            const item_val = item.value[data.value!.data_type] as number;
+            const item_val = item.y;
             min_val = Math.min(min_val, item_val);
             max_val = Math.max(max_val, item_val);
         }
         memo.value = new_memo;
+        debounced_recompute();
         max.value = max_val;
         min.value = min_val;
     }
@@ -109,6 +126,7 @@ watch([graph_data.min_x, graph_data.max_x], ([min_x, max_x]) => {
 watch(
     [min, axis_data.axis_update_watch],
     ([min_val]) => {
+        trigger_recompute();
         axis_data.min_y_callback(min_val);
     },
     {
@@ -119,6 +137,7 @@ watch(
 watch(
     [max, axis_data.axis_update_watch],
     ([max_val]) => {
+        trigger_recompute()
         axis_data.max_y_callback(max_val);
     },
     {
@@ -126,35 +145,50 @@ watch(
     },
 );
 
-// This function is somewhat slow
-const points = computed(() => {
-    let points = '';
-    if (memo.value.length == 0 || data.value == null) {
-        return '';
-    }
+const points = ref("");
 
-    let last_x = graph_data.x_map(toValue(graph_data.max_x));
-    let last_t = toValue(graph_data.max_x) + smoothing_distance;
+const old_max = ref(0);
 
-    for (const data_item of memo.value) {
-        const t = Date.parse(data_item.timestamp);
-        const v = data_item.value[data.value.data_type];
-        const x = graph_data.x_map(t);
-        const y = axis_data.y_map(v);
+const group_transform = computed(() => {
+    const new_max = toValue(graph_data.max_x);
+    const offset = graph_data.x_map(old_max.value) - graph_data.x_map(new_max);
+    return `translate(${offset} 0)`;
+})
 
-        if (last_t - t < smoothing_distance) {
-            points += ` ${x},${y}`;
-        } else {
-            points += ` ${last_x},${y} ${x},${y}`;
+watch(
+    [recompute_points],
+    () => {
+        let new_points = '';
+        if (memo.value.length == 0 || data.value == null) {
+            return '';
         }
-        last_x = x;
-        last_t = t;
-        if (last_x <= 0.0) {
-            break;
+
+        const future_number = toValue(graph_data.max_x) + 9999999999;
+
+        let last_x = graph_data.x_map(future_number);
+        old_max.value = toValue(graph_data.max_x);
+        let last_t = future_number + smoothing_distance;
+
+        for (const data_item of memo.value) {
+            const t = data_item.x;
+            const v = data_item.y;
+            const x = graph_data.x_map(t);
+            const y = axis_data.y_map(v);
+
+            if (last_t - t < smoothing_distance) {
+                new_points += ` ${x},${y}`;
+            } else {
+                new_points += ` ${last_x},${y} ${x},${y}`;
+            }
+            last_x = x;
+            last_t = t;
+            if (last_x <= 0.0) {
+                break;
+            }
         }
+        points.value = new_points;
     }
-    return points;
-});
+)
 
 const current_value = computed(() => {
     const val = value.value;
@@ -167,11 +201,15 @@ const current_value = computed(() => {
 
 <template>
     <g :class="`indexed-color color-${index}`">
-        <polyline
-            fill="none"
+        <g
             clip-path="url(#content)"
-            :points="points"
-        ></polyline>
+        >
+            <polyline
+                fill="none"
+                :transform="group_transform"
+                :points="points"
+            ></polyline>
+        </g>
         <ValueLabel
             v-if="current_value"
             :x="graph_data.x_map(toValue(graph_data.max_x)) + text_offset"

frontend/src/graph/graph.ts

@@ -10,4 +10,5 @@ export interface GraphData {
     height: MaybeRefOrGetter<number>;
     x_map: (x: number) => number;
     lines: Ref<symbol[]>;
+    max_update_rate: MaybeRefOrGetter<number>,
 }

frontend/src/graph/line.ts

@@ -0,0 +1,5 @@
+
+export interface Point {
+    x: number,
+    y: number,
+}