fix axis scaling of stale data

frontend/src/components/TelemetryLine.vue

@@ -57,14 +57,43 @@ const memo = shallowRef<TelemetryDataItem[]>([]);
 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);
-        while (
-            new_memo.length > 2 &&
-            Date.parse(new_memo[new_memo.length - 2].timestamp) < min_x
-        ) {
-            new_memo.pop();
+            const item_val = val.value[data.value!.data_type] as number;
+            if (item_val < min.value) {
+                min.value = item_val;
+            }
+            if (item_val > max.value) {
+                max.value = item_val;
             }
             memo.value = new_memo;
+        }
+    }
+});
+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);
+    if (min_x) {
+        while (
+            new_memo.length > 2 &&
+            Date.parse(new_memo[new_memo.length - 2].timestamp) < toValue(min_x)
+        ) {
+            new_memo.pop();
+            memo_changed = true;
+        }
+    }
+    if (max_x) {
+        while (
+            new_memo.length > 2 &&
+            Date.parse(new_memo[1].timestamp) > toValue(max_x)
+        ) {
+            new_memo.shift();
+            memo_changed = true;
+        }
+    }
+    if (memo_changed) {
         let min_val = Infinity;
         let max_val = -Infinity;
         for (const item of new_memo) {
@@ -72,6 +101,7 @@ watch([value], ([val]) => {
             min_val = Math.min(min_val, item_val);
             max_val = Math.max(max_val, item_val);
         }
+        memo.value = new_memo;
         max.value = max_val;
         min.value = min_val;
     }
@@ -160,7 +190,8 @@ const current_value = computed(() => {
                 :x="graph_data.x_map(toValue(graph_data.max_x)) + text_offset"
                 :y="axis_data.y_map(current_value)"
             >
-                {{ current_value.toFixed(2) }}
+                {{ max.toFixed(2) }}
+                {{ min.toFixed(2) }}
             </text>
         </template>
     </g>