From a8fbabe695a82f2f1826f8d2aeeb3f42ddfe5ebe Mon Sep 17 00:00:00 2001
From: David Tsay <3614296+davetsay@users.noreply.github.com>
Date: Fri, 27 Sep 2024 14:32:14 -0700
Subject: [PATCH 1/3] fix(#7825): imagery pause (#7842)

* more readable

* unpause explicitly

* fix jsdoc

* e2e testing multiple image removal

* prettier

* fix to remove multiple images from history

* move tests that use playwright clock api into own file

* fix playwright clock tests

* add aria-label to element

* prevent straggler debounced function call on unmount

* clean up and fix tests

* update paths

* lint fix

* lint fix

---------

Co-authored-by: John Hill <john.c.hill@nasa.gov>
---
 e2e/helper/imageryUtils.js                    |  33 ++
 .../imagery/exampleImagery.e2e.spec.js        | 211 +++-----
 .../exampleImageryControlledClock.e2e.spec.js | 489 ++++++++++++++++++
 src/api/telemetry/TelemetryCollection.js      |   3 +-
 .../imagery/components/ImageryTimeView.vue    |   1 +
 .../imagery/components/ImageryView.vue        |   4 +-
 src/plugins/imagery/mixins/imageryData.js     |  17 +-
 src/plugins/timeline/TimelineViewLayout.vue   |   1 +
 8 files changed, 613 insertions(+), 146 deletions(-)
 create mode 100644 e2e/helper/imageryUtils.js
 create mode 100644 e2e/tests/functional/plugins/imagery/exampleImageryControlledClock.e2e.spec.js

diff --git a/e2e/helper/imageryUtils.js b/e2e/helper/imageryUtils.js
new file mode 100644
index 0000000000..880964076c
--- /dev/null
+++ b/e2e/helper/imageryUtils.js
@@ -0,0 +1,33 @@
+import { createDomainObjectWithDefaults } from '../appActions.js';
+import { expect } from '../pluginFixtures.js';
+
+const IMAGE_LOAD_DELAY = 5 * 1000;
+const FIVE_MINUTES = 1000 * 60 * 5;
+const THIRTY_SECONDS = 1000 * 30;
+const MOUSE_WHEEL_DELTA_Y = 120;
+
+/**
+ * @param {import('@playwright/test').Page} page
+ */
+async function createImageryViewWithShortDelay(page, { name, parent }) {
+  await createDomainObjectWithDefaults(page, {
+    name,
+    type: 'Example Imagery',
+    parent
+  });
+
+  await expect(page.locator('.l-browse-bar__object-name')).toContainText('Unnamed Example Imagery');
+  await page.getByLabel('More actions').click();
+  await page.getByLabel('Edit Properties').click();
+  // Clear and set Image load delay to minimum value
+  await page.locator('input[type="number"]').fill(`${IMAGE_LOAD_DELAY}`);
+  await page.getByLabel('Save').click();
+}
+
+export {
+  createImageryViewWithShortDelay,
+  FIVE_MINUTES,
+  IMAGE_LOAD_DELAY,
+  MOUSE_WHEEL_DELTA_Y,
+  THIRTY_SECONDS
+};
diff --git a/e2e/tests/functional/plugins/imagery/exampleImagery.e2e.spec.js b/e2e/tests/functional/plugins/imagery/exampleImagery.e2e.spec.js
index d75e104e0d..d5d218bc05 100644
--- a/e2e/tests/functional/plugins/imagery/exampleImagery.e2e.spec.js
+++ b/e2e/tests/functional/plugins/imagery/exampleImagery.e2e.spec.js
@@ -30,16 +30,19 @@ import {
   navigateToObjectWithRealTime,
   setRealTimeMode
 } from '../../../../appActions.js';
-import { MISSION_TIME } from '../../../../constants.js';
+import {
+  createImageryViewWithShortDelay,
+  FIVE_MINUTES,
+  IMAGE_LOAD_DELAY,
+  MOUSE_WHEEL_DELTA_Y,
+  THIRTY_SECONDS
+} from '../../../../helper/imageryUtils.js';
 import { expect, test } from '../../../../pluginFixtures.js';
+
 const panHotkey = process.platform === 'linux' ? ['Shift', 'Alt'] : ['Alt'];
 const tagHotkey = ['Shift', 'Alt'];
 const expectedAltText = process.platform === 'linux' ? 'Shift+Alt drag to pan' : 'Alt drag to pan';
 const thumbnailUrlParamsRegexp = /\?w=100&h=100/;
-const IMAGE_LOAD_DELAY = 5 * 1000;
-const MOUSE_WHEEL_DELTA_Y = 120;
-const FIVE_MINUTES = 1000 * 60 * 5;
-const THIRTY_SECONDS = 1000 * 30;
 
 //The following block of tests verifies the basic functionality of example imagery and serves as a template for Imagery objects embedded in other objects.
 test.describe('Example Imagery Object', () => {
@@ -357,15 +360,10 @@ test.describe('Example Imagery Object', () => {
   });
 });
 
-test.describe('Example Imagery in Display Layout @clock', () => {
+test.describe('Example Imagery in Display Layout', () => {
   let displayLayout;
 
   test.beforeEach(async ({ page }) => {
-    // We mock the clock so that we don't need to wait for time driven events
-    // to verify functionality.
-    await page.clock.install({ time: MISSION_TIME });
-    await page.clock.resume();
-
     // Go to baseURL
     await page.goto('./', { waitUntil: 'domcontentloaded' });
 
@@ -428,12 +426,7 @@ test.describe('Example Imagery in Display Layout @clock', () => {
     await expect.soft(pausePlayButton).toHaveClass(/is-paused/);
   });
 
-  test('Imagery View operations @clock', async ({ page }) => {
-    test.info().annotations.push({
-      type: 'issue',
-      description: 'https://github.com/nasa/openmct/issues/5265'
-    });
-
+  test('Imagery View operations', async ({ page }) => {
     // Edit mode
     await page.getByLabel('Edit Object').click();
 
@@ -526,14 +519,9 @@ test.describe('Example Imagery in Display Layout @clock', () => {
   });
 });
 
-test.describe('Example Imagery in Flexible layout @clock', () => {
+test.describe('Example Imagery in Flexible layout', () => {
   let flexibleLayout;
   test.beforeEach(async ({ page }) => {
-    // We mock the clock so that we don't need to wait for time driven events
-    // to verify functionality.
-    await page.clock.install({ time: MISSION_TIME });
-    await page.clock.resume();
-
     await page.goto('./', { waitUntil: 'domcontentloaded' });
 
     flexibleLayout = await createDomainObjectWithDefaults(page, { type: 'Flexible Layout' });
@@ -562,7 +550,7 @@ test.describe('Example Imagery in Flexible layout @clock', () => {
     await page.getByRole('button', { name: 'Close' }).click();
   });
 
-  test('Imagery View operations @clock', async ({ page, browserName }) => {
+  test('Imagery View operations', async ({ page, browserName }) => {
     test.fixme(browserName === 'firefox', 'This test needs to be updated to work with firefox');
     test.info().annotations.push({
       type: 'issue',
@@ -573,14 +561,10 @@ test.describe('Example Imagery in Flexible layout @clock', () => {
   });
 });
 
-test.describe('Example Imagery in Tabs View @clock', () => {
+test.describe('Example Imagery in Tabs View', () => {
   let tabsView;
-  test.beforeEach(async ({ page }) => {
-    // We mock the clock so that we don't need to wait for time driven events
-    // to verify functionality.
-    await page.clock.install({ time: MISSION_TIME });
-    await page.clock.resume();
 
+  test.beforeEach(async ({ page }) => {
     await page.goto('./', { waitUntil: 'domcontentloaded' });
 
     tabsView = await createDomainObjectWithDefaults(page, { type: 'Tabs View' });
@@ -607,7 +591,8 @@ test.describe('Example Imagery in Tabs View @clock', () => {
     // Wait for image thumbnail auto-scroll to complete
     await expect(page.getByLabel('Image Thumbnail from').last()).toBeInViewport();
   });
-  test('Imagery View operations @clock', async ({ page }) => {
+
+  test('Imagery View operations', async ({ page }) => {
     await performImageryViewOperationsAndAssert(page, tabsView);
   });
 });
@@ -668,16 +653,19 @@ test.describe('Example Imagery in Time Strip', () => {
  * 3. Can pan the image using the pan hotkey + mouse drag
  * 4. Clicking on the left arrow button pauses imagery and moves to the previous image
  * 5. Imagery is updated as new images stream in, regardless of pause status
- * 6. Old images are discarded when new images stream in
- * 7. Image brightness/contrast can be adjusted by dragging the sliders
+ * 6. Old images are discarded when their timestamps fall out of bounds
+ * 7. Multiple images can be discarded when their timestamps fall out of bounds
+ * 8. Image brightness/contrast can be adjusted by dragging the sliders
  * @param {import('@playwright/test').Page} page
  */
 async function performImageryViewOperationsAndAssert(page, layoutObject) {
-  // Verify that imagery thumbnails use a thumbnail url
-  const thumbnailImages = page.getByLabel('Image thumbnail from').locator('.c-thumb__image');
-  const mainImage = page.locator('.c-imagery__main-image__image');
-  await expect(thumbnailImages.first()).toHaveAttribute('src', thumbnailUrlParamsRegexp);
-  await expect(mainImage).not.toHaveAttribute('src', thumbnailUrlParamsRegexp);
+  await test.step('Verify that imagery thumbnails use a thumbnail url', async () => {
+    const thumbnailImages = page.getByLabel('Image thumbnail from').locator('.c-thumb__image');
+    const mainImage = page.locator('.c-imagery__main-image__image');
+    await expect(thumbnailImages.first()).toHaveAttribute('src', thumbnailUrlParamsRegexp);
+    await expect(mainImage).not.toHaveAttribute('src', thumbnailUrlParamsRegexp);
+  });
+
   // Click previous image button
   const previousImageButton = page.getByLabel('Previous image');
   await expect(previousImageButton).toBeVisible();
@@ -736,19 +724,6 @@ async function performImageryViewOperationsAndAssert(page, layoutObject) {
   // Unpause imagery
   await page.locator('.pause-play').click();
 
-  // verify that old images are discarded
-  const lastImageInBounds = page.getByLabel('Image thumbnail from').first();
-  const lastImageTimestamp = await lastImageInBounds.getAttribute('title');
-  expect(lastImageTimestamp).not.toBeNull();
-
-  // go forward in time to ensure old images are discarded
-  await page.clock.fastForward(IMAGE_LOAD_DELAY);
-  await page.clock.resume();
-  await expect(page.getByLabel(lastImageTimestamp)).toBeHidden();
-
-  //Get background-image url from background-image css prop
-  await assertBackgroundImageUrlFromBackgroundCss(page);
-
   // Open the image filter menu
   await page.locator('[role=toolbar] button[title="Brightness and contrast"]').click();
 
@@ -815,24 +790,6 @@ async function assertBackgroundImageBrightness(page, expected) {
   expect(actual).toBe(expected);
 }
 
-/**
- * @param {import('@playwright/test').Page} page
- */
-async function assertBackgroundImageUrlFromBackgroundCss(page) {
-  const backgroundImage = page.getByLabel('Focused Image Element');
-  const backgroundImageUrl = await backgroundImage.evaluate((el) => {
-    return window
-      .getComputedStyle(el)
-      .getPropertyValue('background-image')
-      .match(/url\(([^)]+)\)/)[1];
-  });
-
-  // go forward in time to ensure old images are discarded
-  await page.clock.fastForward(IMAGE_LOAD_DELAY);
-  await page.clock.resume();
-  await expect(backgroundImage).not.toHaveJSProperty('background-image', backgroundImageUrl);
-}
-
 /**
  * @param {import('@playwright/test').Page} page
  */
@@ -918,62 +875,66 @@ async function mouseZoomOnImageAndAssert(page, factor = 2) {
  * @param {import('@playwright/test').Page} page
  */
 async function buttonZoomOnImageAndAssert(page) {
-  // Lock the zoom and pan so it doesn't reset if a new image comes in
-  await page.getByLabel('Focused Image Element').hover({ trial: true });
-  const lockButton = page.getByRole('button', {
-    name: 'Lock current zoom and pan across all images'
-  });
-  if (!(await lockButton.isVisible())) {
+  await test.step('Can zoom using buttons', async () => {
+    // Lock the zoom and pan so it doesn't reset if a new image comes in
     await page.getByLabel('Focused Image Element').hover({ trial: true });
-  }
-  await lockButton.click();
+    const lockButton = page.getByRole('button', {
+      name: 'Lock current zoom and pan across all images'
+    });
 
-  await expect(page.getByLabel('Focused Image Element')).toHaveJSProperty(
-    'style.transform',
-    'scale(1) translate(0px, 0px)'
-  );
+    await lockButton.isVisible();
+    // if (!(await lockButton.isVisible())) {
+    //   await page.getByLabel('Focused Image Element').hover({ trial: true });
+    // }
+    await lockButton.click();
 
-  // Get initial image dimensions
-  const initialBoundingBox = await page.getByLabel('Focused Image Element').boundingBox();
+    await expect(page.getByLabel('Focused Image Element')).toHaveJSProperty(
+      'style.transform',
+      'scale(1) translate(0px, 0px)'
+    );
 
-  // Zoom in twice via button
-  await zoomIntoImageryByButton(page);
-  await expect(page.getByLabel('Focused Image Element')).toHaveJSProperty(
-    'style.transform',
-    'scale(2) translate(0px, 0px)'
-  );
-  await zoomIntoImageryByButton(page);
-  await expect(page.getByLabel('Focused Image Element')).toHaveJSProperty(
-    'style.transform',
-    'scale(3) translate(0px, 0px)'
-  );
+    // Get initial image dimensions
+    const initialBoundingBox = await page.getByLabel('Focused Image Element').boundingBox();
 
-  // Get and assert zoomed in image dimensions
-  const zoomedInBoundingBox = await page.getByLabel('Focused Image Element').boundingBox();
-  expect(zoomedInBoundingBox.height).toBeGreaterThan(initialBoundingBox.height);
-  expect(zoomedInBoundingBox.width).toBeGreaterThan(initialBoundingBox.width);
+    // Zoom in twice via button
+    await zoomIntoImageryByButton(page);
+    await expect(page.getByLabel('Focused Image Element')).toHaveJSProperty(
+      'style.transform',
+      'scale(2) translate(0px, 0px)'
+    );
+    await zoomIntoImageryByButton(page);
+    await expect(page.getByLabel('Focused Image Element')).toHaveJSProperty(
+      'style.transform',
+      'scale(3) translate(0px, 0px)'
+    );
 
-  // Zoom out once via button
-  await zoomOutOfImageryByButton(page);
-  await expect(page.getByLabel('Focused Image Element')).toHaveJSProperty(
-    'style.transform',
-    'scale(2) translate(0px, 0px)'
-  );
+    // Get and assert zoomed in image dimensions
+    const zoomedInBoundingBox = await page.getByLabel('Focused Image Element').boundingBox();
+    expect(zoomedInBoundingBox.height).toBeGreaterThan(initialBoundingBox.height);
+    expect(zoomedInBoundingBox.width).toBeGreaterThan(initialBoundingBox.width);
 
-  // Get and assert zoomed out image dimensions
-  const zoomedOutBoundingBox = await page.getByLabel('Focused Image Element').boundingBox();
-  expect(zoomedOutBoundingBox.height).toBeLessThan(zoomedInBoundingBox.height);
-  expect(zoomedOutBoundingBox.width).toBeLessThan(zoomedInBoundingBox.width);
+    // Zoom out once via button
+    await zoomOutOfImageryByButton(page);
+    await expect(page.getByLabel('Focused Image Element')).toHaveJSProperty(
+      'style.transform',
+      'scale(2) translate(0px, 0px)'
+    );
 
-  // Zoom out again via button, assert against the initial image dimensions
-  await zoomOutOfImageryByButton(page);
-  await expect(page.getByLabel('Focused Image Element')).toHaveJSProperty(
-    'style.transform',
-    'scale(1) translate(0px, 0px)'
-  );
+    // Get and assert zoomed out image dimensions
+    const zoomedOutBoundingBox = await page.getByLabel('Focused Image Element').boundingBox();
+    expect(zoomedOutBoundingBox.height).toBeLessThan(zoomedInBoundingBox.height);
+    expect(zoomedOutBoundingBox.width).toBeLessThan(zoomedInBoundingBox.width);
 
-  const finalBoundingBox = await page.getByLabel('Focused Image Element').boundingBox();
-  expect(finalBoundingBox).toEqual(initialBoundingBox);
+    // Zoom out again via button, assert against the initial image dimensions
+    await zoomOutOfImageryByButton(page);
+    await expect(page.getByLabel('Focused Image Element')).toHaveJSProperty(
+      'style.transform',
+      'scale(1) translate(0px, 0px)'
+    );
+
+    const finalBoundingBox = await page.getByLabel('Focused Image Element').boundingBox();
+    expect(finalBoundingBox).toEqual(initialBoundingBox);
+  });
 }
 
 /**
@@ -1035,24 +996,6 @@ async function resetImageryPanAndZoom(page) {
   await expect(page.locator('.c-thumb__viewable-area')).toBeHidden();
 }
 
-/**
- * @param {import('@playwright/test').Page} page
- */
-async function createImageryViewWithShortDelay(page, { name, parent }) {
-  await createDomainObjectWithDefaults(page, {
-    name,
-    type: 'Example Imagery',
-    parent
-  });
-
-  await expect(page.locator('.l-browse-bar__object-name')).toContainText('Unnamed Example Imagery');
-  await page.getByLabel('More actions').click();
-  await page.getByLabel('Edit Properties').click();
-  // Clear and set Image load delay to minimum value
-  await page.locator('input[type="number"]').fill(`${IMAGE_LOAD_DELAY}`);
-  await page.getByLabel('Save').click();
-}
-
 /**
  * @param {import('@playwright/test').Page} page
  */
diff --git a/e2e/tests/functional/plugins/imagery/exampleImageryControlledClock.e2e.spec.js b/e2e/tests/functional/plugins/imagery/exampleImageryControlledClock.e2e.spec.js
new file mode 100644
index 0000000000..97c45acbd7
--- /dev/null
+++ b/e2e/tests/functional/plugins/imagery/exampleImageryControlledClock.e2e.spec.js
@@ -0,0 +1,489 @@
+/*****************************************************************************
+ * Open MCT, Copyright (c) 2014-2024, United States Government
+ * as represented by the Administrator of the National Aeronautics and Space
+ * Administration. All rights reserved.
+ *
+ * Open MCT is licensed under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ * Open MCT includes source code licensed under additional open source
+ * licenses. See the Open Source Licenses file (LICENSES.md) included with
+ * this source code distribution or the Licensing information page available
+ * at runtime from the About dialog for additional information.
+ *****************************************************************************/
+
+/*
+This test suite is dedicated to testing how imagery functions over time.
+It only assumes that example imagery is present.
+It uses https://playwright.dev/docs/clock to have control over time
+*/
+
+import {
+  createDomainObjectWithDefaults,
+  navigateToObjectWithRealTime,
+  setRealTimeMode,
+  setStartOffset
+} from '../../../../appActions.js';
+import { MISSION_TIME } from '../../../../constants.js';
+import {
+  createImageryViewWithShortDelay,
+  FIVE_MINUTES,
+  IMAGE_LOAD_DELAY,
+  THIRTY_SECONDS
+} from '../../../../helper/imageryUtils.js';
+import { expect, test } from '../../../../pluginFixtures.js';
+
+test.describe('Example Imagery Object with Controlled Clock @clock', () => {
+  test.beforeEach(async ({ page }) => {
+    // We mock the clock so that we don't need to wait for time driven events
+    // to verify functionality.
+    await page.clock.install({ time: MISSION_TIME });
+    await page.clock.resume();
+
+    //Go to baseURL
+    await page.goto('./', { waitUntil: 'domcontentloaded' });
+
+    // Create a default 'Example Imagery' object
+    // Click the Create button
+    await page.getByRole('button', { name: 'Create' }).click();
+
+    // Click text=Example Imagery
+    await page.getByRole('menuitem', { name: 'Example Imagery' }).click();
+
+    // Clear and set Image load delay to minimum value
+    await page.locator('input[type="number"]').clear();
+    await page.locator('input[type="number"]').fill(`${IMAGE_LOAD_DELAY}`);
+
+    await page.getByLabel('Save').click();
+
+    // Verify that the created object is focused
+    await expect(page.locator('.l-browse-bar__object-name')).toContainText(
+      'Unnamed Example Imagery'
+    );
+    await page.getByLabel('Focused Image Element').hover({ trial: true });
+
+    // set realtime mode
+    await setRealTimeMode(page);
+    await setStartOffset(page, { startMins: '05' });
+  });
+
+  test('Imagery Time Bounding', async ({ page }) => {
+    test.info().annotations.push({
+      type: 'issue',
+      description: 'https://github.com/nasa/openmct/issues/5265'
+    });
+    test.info().annotations.push({
+      type: 'issue',
+      description: 'https://github.com/nasa/openmct/issues/7825'
+    });
+
+    // verify that old images are discarded
+    const lastImageInBounds = page.getByLabel('Image thumbnail from').first();
+    const lastImageTimestamp = await lastImageInBounds.getAttribute('title');
+    expect(lastImageTimestamp).not.toBeNull();
+
+    // go forward in time to ensure old images are discarded
+    await page.clock.fastForward(IMAGE_LOAD_DELAY);
+    await page.clock.resume();
+    await expect(page.getByLabel(lastImageTimestamp)).toBeHidden();
+
+    // go way forward in time to ensure multiple images are discarded
+    const IMAGES_TO_DISCARD_COUNT = 5;
+
+    const lastImageToDiscard = page
+      .getByLabel('Image thumbnail from')
+      .nth(IMAGES_TO_DISCARD_COUNT - 1);
+    const lastImageToDiscardTimestamp = await lastImageToDiscard.getAttribute('title');
+    expect(lastImageToDiscardTimestamp).not.toBeNull();
+
+    const imageAfterLastImageToDiscard = page
+      .getByLabel('Image thumbnail from')
+      .nth(IMAGES_TO_DISCARD_COUNT);
+    const imageAfterLastImageToDiscardTimestamp =
+      await imageAfterLastImageToDiscard.getAttribute('title');
+    expect(imageAfterLastImageToDiscardTimestamp).not.toBeNull();
+
+    await page.clock.fastForward(IMAGE_LOAD_DELAY * IMAGES_TO_DISCARD_COUNT);
+    await page.clock.resume();
+
+    await expect(page.getByLabel(lastImageToDiscardTimestamp)).toBeHidden();
+    await expect(page.getByLabel(imageAfterLastImageToDiscardTimestamp)).toBeVisible();
+  });
+
+  test('Get background-image url from background-image css prop', async ({ page }) => {
+    await assertBackgroundImageUrlFromBackgroundCss(page);
+  });
+});
+
+test.describe('Example Imagery in Display Layout with Controlled Clock @clock', () => {
+  let displayLayout;
+
+  test.beforeEach(async ({ page }) => {
+    // We mock the clock so that we don't need to wait for time driven events
+    // to verify functionality.
+    await page.clock.install({ time: MISSION_TIME });
+    await page.clock.resume();
+
+    // Go to baseURL
+    await page.goto('./', { waitUntil: 'domcontentloaded' });
+
+    displayLayout = await createDomainObjectWithDefaults(page, { type: 'Display Layout' });
+
+    // Create Example Imagery inside Display Layout
+    await createImageryViewWithShortDelay(page, {
+      name: 'Unnamed Example Imagery',
+      parent: displayLayout.uuid
+    });
+
+    // set realtime mode
+    await navigateToObjectWithRealTime(
+      page,
+      displayLayout.url,
+      `${FIVE_MINUTES}`,
+      `${THIRTY_SECONDS}`
+    );
+  });
+
+  test('Imagery Time Bounding', async ({ page }) => {
+    test.info().annotations.push({
+      type: 'issue',
+      description: 'https://github.com/nasa/openmct/issues/5265'
+    });
+    test.info().annotations.push({
+      type: 'issue',
+      description: 'https://github.com/nasa/openmct/issues/7825'
+    });
+
+    // Edit mode
+    await page.getByLabel('Edit Object').click();
+
+    // Click on example imagery to expose toolbar
+    await page.locator('.c-so-view__header').click();
+
+    // Adjust object height
+    await page.locator('div[title="Resize object height"] > input').click();
+    await page.locator('div[title="Resize object height"] > input').fill('50');
+
+    // Adjust object width
+    await page.locator('div[title="Resize object width"] > input').click();
+    await page.locator('div[title="Resize object width"] > input').fill('50');
+
+    await expect(page.getByLabel('Image Thumbnail from').last()).toBeInViewport();
+
+    // verify that old images are discarded
+    const lastImageInBounds = page.getByLabel('Image thumbnail from').first();
+    const lastImageTimestamp = await lastImageInBounds.getAttribute('title');
+    expect(lastImageTimestamp).not.toBeNull();
+
+    // go forward in time to ensure old images are discarded
+    await page.clock.fastForward(IMAGE_LOAD_DELAY);
+    await page.clock.resume();
+    await expect(page.getByLabel(lastImageTimestamp)).toBeHidden();
+
+    // go way forward in time to ensure multiple images are discarded
+    const IMAGES_TO_DISCARD_COUNT = 5;
+
+    const lastImageToDiscard = page
+      .getByLabel('Image thumbnail from')
+      .nth(IMAGES_TO_DISCARD_COUNT - 1);
+    const lastImageToDiscardTimestamp = await lastImageToDiscard.getAttribute('title');
+    expect(lastImageToDiscardTimestamp).not.toBeNull();
+
+    const imageAfterLastImageToDiscard = page
+      .getByLabel('Image thumbnail from')
+      .nth(IMAGES_TO_DISCARD_COUNT);
+    const imageAfterLastImageToDiscardTimestamp =
+      await imageAfterLastImageToDiscard.getAttribute('title');
+    expect(imageAfterLastImageToDiscardTimestamp).not.toBeNull();
+
+    await page.clock.fastForward(IMAGE_LOAD_DELAY * IMAGES_TO_DISCARD_COUNT);
+    await page.clock.resume();
+
+    await expect(page.getByLabel(lastImageToDiscardTimestamp)).toBeHidden();
+    await expect(page.getByLabel(imageAfterLastImageToDiscardTimestamp)).toBeVisible();
+  });
+
+  test('Get background-image url from background-image css prop @clock', async ({ page }) => {
+    await assertBackgroundImageUrlFromBackgroundCss(page);
+  });
+});
+
+test.describe('Example Imagery in Flexible layout with Controlled Clock @clock', () => {
+  let flexibleLayout;
+
+  test.beforeEach(async ({ page }) => {
+    // We mock the clock so that we don't need to wait for time driven events
+    // to verify functionality.
+    await page.clock.install({ time: MISSION_TIME });
+    await page.clock.resume();
+
+    await page.goto('./', { waitUntil: 'domcontentloaded' });
+
+    flexibleLayout = await createDomainObjectWithDefaults(page, { type: 'Flexible Layout' });
+
+    // Create Example Imagery inside the Flexible Layout
+    await createImageryViewWithShortDelay(page, {
+      name: 'Unnamed Example Imagery',
+      parent: flexibleLayout.uuid
+    });
+
+    // set realtime mode
+    await navigateToObjectWithRealTime(
+      page,
+      flexibleLayout.url,
+      `${FIVE_MINUTES}`,
+      `${THIRTY_SECONDS}`
+    );
+
+    // Wait for image thumbnail auto-scroll to complete
+    await expect(page.getByLabel('Image Thumbnail from').last()).toBeInViewport();
+  });
+
+  test('Imagery Time Bounding @clock', async ({ page, browserName }) => {
+    test.fixme(browserName === 'firefox', 'This test needs to be updated to work with firefox');
+    test.info().annotations.push({
+      type: 'issue',
+      description: 'https://github.com/nasa/openmct/issues/5326'
+    });
+    test.info().annotations.push({
+      type: 'issue',
+      description: 'https://github.com/nasa/openmct/issues/7825'
+    });
+
+    // verify that old images are discarded
+    const lastImageInBounds = page.getByLabel('Image thumbnail from').first();
+    const lastImageTimestamp = await lastImageInBounds.getAttribute('title');
+    expect(lastImageTimestamp).not.toBeNull();
+
+    // go forward in time to ensure old images are discarded
+    await page.clock.fastForward(IMAGE_LOAD_DELAY);
+    await page.clock.resume();
+    await expect(page.getByLabel(lastImageTimestamp)).toBeHidden();
+
+    // go way forward in time to ensure multiple images are discarded
+    const IMAGES_TO_DISCARD_COUNT = 5;
+
+    const lastImageToDiscard = page
+      .getByLabel('Image thumbnail from')
+      .nth(IMAGES_TO_DISCARD_COUNT - 1);
+    const lastImageToDiscardTimestamp = await lastImageToDiscard.getAttribute('title');
+    expect(lastImageToDiscardTimestamp).not.toBeNull();
+
+    const imageAfterLastImageToDiscard = page
+      .getByLabel('Image thumbnail from')
+      .nth(IMAGES_TO_DISCARD_COUNT);
+    const imageAfterLastImageToDiscardTimestamp =
+      await imageAfterLastImageToDiscard.getAttribute('title');
+    expect(imageAfterLastImageToDiscardTimestamp).not.toBeNull();
+
+    await page.clock.fastForward(IMAGE_LOAD_DELAY * IMAGES_TO_DISCARD_COUNT);
+    await page.clock.resume();
+
+    await expect(page.getByLabel(lastImageToDiscardTimestamp)).toBeHidden();
+    await expect(page.getByLabel(imageAfterLastImageToDiscardTimestamp)).toBeVisible();
+  });
+
+  test('Get background-image url from background-image css prop @clock', async ({ page }) => {
+    await assertBackgroundImageUrlFromBackgroundCss(page);
+  });
+});
+
+test.describe('Example Imagery in Tabs View with Controlled Clock @clock', () => {
+  let timeStripObject;
+
+  test.beforeEach(async ({ page }) => {
+    // We mock the clock so that we don't need to wait for time driven events
+    // to verify functionality.
+    await page.clock.install({ time: MISSION_TIME });
+    await page.clock.resume();
+
+    await page.goto('./', { waitUntil: 'domcontentloaded' });
+
+    timeStripObject = await createDomainObjectWithDefaults(page, { type: 'Tabs View' });
+    await page.goto(timeStripObject.url);
+
+    /* Create Example Imagery with minimum Image Load Delay */
+    // Click the Create button
+    await page.getByRole('button', { name: 'Create' }).click();
+
+    // Click text=Example Imagery
+    await page.getByRole('menuitem', { name: 'Example Imagery' }).click();
+
+    // Clear and set Image load delay to minimum value
+    await page.locator('input[type="number"]').clear();
+    await page.locator('input[type="number"]').fill(`${IMAGE_LOAD_DELAY}`);
+
+    await page.getByLabel('Save').click();
+
+    await expect(page.locator('.l-browse-bar__object-name')).toContainText(
+      'Unnamed Example Imagery'
+    );
+
+    // set realtime mode
+    await navigateToObjectWithRealTime(
+      page,
+      timeStripObject.url,
+      `${FIVE_MINUTES}`,
+      `${THIRTY_SECONDS}`
+    );
+
+    // Wait for image thumbnail auto-scroll to complete
+    await expect(page.getByLabel('Image Thumbnail from').last()).toBeInViewport();
+  });
+
+  test('Imagery Time Bounding @clock', async ({ page }) => {
+    test.info().annotations.push({
+      type: 'issue',
+      description: 'https://github.com/nasa/openmct/issues/5265'
+    });
+    test.info().annotations.push({
+      type: 'issue',
+      description: 'https://github.com/nasa/openmct/issues/7825'
+    });
+
+    // verify that old images are discarded
+    const lastImageInBounds = page.getByLabel('Image thumbnail from').first();
+    const lastImageTimestamp = await lastImageInBounds.getAttribute('title');
+    expect(lastImageTimestamp).not.toBeNull();
+
+    // go forward in time to ensure old images are discarded
+    await page.clock.fastForward(IMAGE_LOAD_DELAY);
+    await page.clock.resume();
+    await expect(page.getByLabel(lastImageTimestamp)).toBeHidden();
+
+    // go way forward in time to ensure multiple images are discarded
+    const IMAGES_TO_DISCARD_COUNT = 5;
+
+    const lastImageToDiscard = page
+      .getByLabel('Image thumbnail from')
+      .nth(IMAGES_TO_DISCARD_COUNT - 1);
+    const lastImageToDiscardTimestamp = await lastImageToDiscard.getAttribute('title');
+    expect(lastImageToDiscardTimestamp).not.toBeNull();
+
+    const imageAfterLastImageToDiscard = page
+      .getByLabel('Image thumbnail from')
+      .nth(IMAGES_TO_DISCARD_COUNT);
+    const imageAfterLastImageToDiscardTimestamp =
+      await imageAfterLastImageToDiscard.getAttribute('title');
+    expect(imageAfterLastImageToDiscardTimestamp).not.toBeNull();
+
+    await page.clock.fastForward(IMAGE_LOAD_DELAY * IMAGES_TO_DISCARD_COUNT);
+    await page.clock.resume();
+
+    await expect(page.getByLabel(lastImageToDiscardTimestamp)).toBeHidden();
+    await expect(page.getByLabel(imageAfterLastImageToDiscardTimestamp)).toBeVisible();
+  });
+
+  test('Get background-image url from background-image css prop @clock', async ({ page }) => {
+    await assertBackgroundImageUrlFromBackgroundCss(page);
+  });
+});
+
+test.describe('Example Imagery in Time Strip with Controlled Clock @clock', () => {
+  let timeStripObject;
+
+  test.beforeEach(async ({ page }) => {
+    // We mock the clock so that we don't need to wait for time driven events
+    // to verify functionality.
+    await page.clock.install({ time: MISSION_TIME });
+    await page.clock.resume();
+
+    await page.goto('./', { waitUntil: 'domcontentloaded' });
+
+    timeStripObject = await createDomainObjectWithDefaults(page, { type: 'Time Strip' });
+    await page.goto(timeStripObject.url);
+
+    /* Create Example Imagery with minimum Image Load Delay */
+    // Click the Create button
+    await page.getByRole('button', { name: 'Create' }).click();
+
+    // Click text=Example Imagery
+    await page.getByRole('menuitem', { name: 'Example Imagery' }).click();
+
+    // Clear and set Image load delay to minimum value
+    await page.locator('input[type="number"]').clear();
+    await page.locator('input[type="number"]').fill(`${IMAGE_LOAD_DELAY}`);
+
+    await page.getByLabel('Save').click();
+
+    await expect(page.locator('.l-browse-bar__object-name')).toContainText(
+      'Unnamed Example Imagery'
+    );
+
+    // set realtime mode
+    await navigateToObjectWithRealTime(
+      page,
+      timeStripObject.url,
+      `${FIVE_MINUTES}`,
+      `${THIRTY_SECONDS}`
+    );
+
+    // Wait for image thumbnail auto-scroll to complete
+    await expect(page.getByLabel('wrapper-').last()).toBeInViewport();
+  });
+
+  test('Imagery Time Bounding @clock', async ({ page }) => {
+    test.info().annotations.push({
+      type: 'issue',
+      description: 'https://github.com/nasa/openmct/issues/5265'
+    });
+    test.info().annotations.push({
+      type: 'issue',
+      description: 'https://github.com/nasa/openmct/issues/7825'
+    });
+
+    // verify that old images are discarded
+    const lastImageInBounds = page.getByLabel('wrapper-').first();
+    const lastImageTimestamp = await lastImageInBounds.getAttribute('aria-label');
+    expect(lastImageTimestamp).not.toBeNull();
+
+    // go forward in time to ensure old images are discarded
+    await page.clock.fastForward(IMAGE_LOAD_DELAY);
+    await page.clock.resume();
+    await expect(page.getByLabel(lastImageTimestamp)).toBeHidden();
+
+    // go way forward in time to ensure multiple images are discarded
+    const IMAGES_TO_DISCARD_COUNT = 5;
+
+    const lastImageToDiscard = page.getByLabel('wrapper-').nth(IMAGES_TO_DISCARD_COUNT - 1);
+    const lastImageToDiscardTimestamp = await lastImageToDiscard.getAttribute('aria-label');
+    expect(lastImageToDiscardTimestamp).not.toBeNull();
+
+    const imageAfterLastImageToDiscard = page.getByLabel('wrapper-').nth(IMAGES_TO_DISCARD_COUNT);
+    const imageAfterLastImageToDiscardTimestamp =
+      await imageAfterLastImageToDiscard.getAttribute('aria-label');
+    expect(imageAfterLastImageToDiscardTimestamp).not.toBeNull();
+
+    await page.clock.fastForward(IMAGE_LOAD_DELAY * IMAGES_TO_DISCARD_COUNT);
+    await page.clock.resume();
+
+    await expect(page.getByLabel(lastImageToDiscardTimestamp)).toBeHidden();
+    await expect(page.getByLabel(imageAfterLastImageToDiscardTimestamp)).toBeVisible();
+  });
+});
+
+/**
+ * @param {import('@playwright/test').Page} page
+ */
+async function assertBackgroundImageUrlFromBackgroundCss(page) {
+  const backgroundImage = page.getByLabel('Focused Image Element');
+  const backgroundImageUrl = await backgroundImage.evaluate((el) => {
+    return window
+      .getComputedStyle(el)
+      .getPropertyValue('background-image')
+      .match(/url\(([^)]+)\)/)[1];
+  });
+
+  // go forward in time to ensure old images are discarded
+  await page.clock.fastForward(IMAGE_LOAD_DELAY);
+  await page.clock.resume();
+  await expect(backgroundImage).not.toHaveJSProperty('background-image', backgroundImageUrl);
+}
diff --git a/src/api/telemetry/TelemetryCollection.js b/src/api/telemetry/TelemetryCollection.js
index 78e48dc89b..d6f53816b9 100644
--- a/src/api/telemetry/TelemetryCollection.js
+++ b/src/api/telemetry/TelemetryCollection.js
@@ -116,8 +116,7 @@ export default class TelemetryCollection extends EventEmitter {
   }
 
   /**
-   * This will start the requests for historical and realtime data,
-   * as well as setting up initial values and watchers
+   * @returns {Array} All bounded telemetry
    */
   getAll() {
     return this.boundedTelemetry;
diff --git a/src/plugins/imagery/components/ImageryTimeView.vue b/src/plugins/imagery/components/ImageryTimeView.vue
index dfb796b5b6..9c65939e65 100644
--- a/src/plugins/imagery/components/ImageryTimeView.vue
+++ b/src/plugins/imagery/components/ImageryTimeView.vue
@@ -370,6 +370,7 @@ export default {
     createImageWrapper(index, image, showImagePlaceholders) {
       const id = `${ID_PREFIX}${image.time}`;
       let imageWrapper = document.createElement('div');
+      imageWrapper.ariaLabel = id;
       imageWrapper.classList.add(IMAGE_WRAPPER_CLASS);
       imageWrapper.style.left = `${this.xScale(image.time)}px`;
       this.setNSAttributesForElement(imageWrapper, {
diff --git a/src/plugins/imagery/components/ImageryView.vue b/src/plugins/imagery/components/ImageryView.vue
index 5f868b9eb8..db0541f029 100644
--- a/src/plugins/imagery/components/ImageryView.vue
+++ b/src/plugins/imagery/components/ImageryView.vue
@@ -620,7 +620,7 @@ export default {
           if (matchIndex > -1) {
             this.setFocusedImage(matchIndex);
           } else {
-            this.paused();
+            this.paused(false);
           }
         }
 
@@ -1082,7 +1082,7 @@ export default {
     paused(state) {
       this.isPaused = Boolean(state);
 
-      if (!state) {
+      if (!this.isPaused) {
         this.previousFocusedImage = null;
         this.setFocusedImage(this.nextImageIndex);
         this.autoScroll = true;
diff --git a/src/plugins/imagery/mixins/imageryData.js b/src/plugins/imagery/mixins/imageryData.js
index 804d06f4e3..04914b30a0 100644
--- a/src/plugins/imagery/mixins/imageryData.js
+++ b/src/plugins/imagery/mixins/imageryData.js
@@ -90,16 +90,17 @@ export default {
     dataCleared() {
       this.imageHistory = [];
     },
-    dataRemoved(dataToRemove) {
-      this.imageHistory = this.imageHistory.filter((existingDatum) => {
-        const shouldKeep = dataToRemove.some((datumToRemove) => {
-          const existingDatumTimestamp = this.parseTime(existingDatum);
-          const datumToRemoveTimestamp = this.parseTime(datumToRemove);
+    dataRemoved(removed) {
+      const removedTimestamps = {};
+      removed.forEach((_removed) => {
+        const removedTimestamp = this.parseTime(_removed);
+        removedTimestamps[removedTimestamp] = true;
+      });
 
-          return existingDatumTimestamp !== datumToRemoveTimestamp;
-        });
+      this.imageHistory = this.imageHistory.filter((image) => {
+        const imageTimestamp = this.parseTime(image);
 
-        return shouldKeep;
+        return !removedTimestamps[imageTimestamp];
       });
     },
     setDataTimeContext() {
diff --git a/src/plugins/timeline/TimelineViewLayout.vue b/src/plugins/timeline/TimelineViewLayout.vue
index 4a85a9a04d..b1652599d4 100644
--- a/src/plugins/timeline/TimelineViewLayout.vue
+++ b/src/plugins/timeline/TimelineViewLayout.vue
@@ -99,6 +99,7 @@ export default {
     this.composition.off('remove', this.removeItem);
     this.composition.off('reorder', this.reorder);
     this.stopFollowingTimeContext();
+    this.handleContentResize.cancel();
     this.contentResizeObserver.disconnect();
   },
   mounted() {

From c498f7d20c449a899e83e3a3446cb75b44ad6157 Mon Sep 17 00:00:00 2001
From: Charles Hacskaylo <charlesh88@gmail.com>
Date: Sat, 28 Sep 2024 09:17:32 -0700
Subject: [PATCH 2/3] Fix bad color value for Gauge 'Needle' type (#7821)

* Closes #7820
- Fix 0 opacity fill in theme constants files for Gauge type needle.

* move gauge plugin to its own suite

* add two more snapshots

* driveby: fix some flake

* bug: update linting rule

---------

Co-authored-by: John Hill <john.c.hill@nasa.gov>
Co-authored-by: Andrew Henry <akhenry@gmail.com>
---
 e2e/.eslintrc.cjs                             |  6 ++
 e2e/README.md                                 |  1 +
 .../visual-a11y/defaultPlugins.visual.spec.js | 10 ---
 e2e/tests/visual-a11y/gauge.visual.spec.js    | 81 +++++++++++++++++++
 e2e/tests/visual-a11y/notebook.visual.spec.js |  2 +-
 e2e/tests/visual-a11y/search.visual.spec.js   |  2 +-
 src/styles/_constants-espresso.scss           |  2 +-
 src/styles/_constants-maelstrom.scss          |  2 +-
 src/styles/_constants-snow.scss               |  2 +-
 9 files changed, 93 insertions(+), 15 deletions(-)
 create mode 100644 e2e/tests/visual-a11y/gauge.visual.spec.js

diff --git a/e2e/.eslintrc.cjs b/e2e/.eslintrc.cjs
index e044757b41..a8fefcb27e 100644
--- a/e2e/.eslintrc.cjs
+++ b/e2e/.eslintrc.cjs
@@ -27,6 +27,12 @@ module.exports = {
       rules: {
         'playwright/no-raw-locators': 'off'
       }
+    },
+    {
+      files: ['**/*.visual.spec.js'],
+      rules: {
+        'playwright/no-networkidle': 'off' //https://github.com/nasa/openmct/issues/7549
+      }
     }
   ]
 };
diff --git a/e2e/README.md b/e2e/README.md
index b10956ba44..881d8d2327 100644
--- a/e2e/README.md
+++ b/e2e/README.md
@@ -469,6 +469,7 @@ By adhering to this principle, we can create tests that are both robust and refl
     //Select from object
     await percySnapshot(page, `object selected (theme: ${theme})`)
     ```
+8. **Use `networkidle` to wait for network requests to complete**: This is necessary to ensure that all network requests have completed before taking a snapshot. This ensures that icons are loaded and other assets are available. https://github.com/nasa/openmct/issues/7549
 
 #### How to write a great network test
 
diff --git a/e2e/tests/visual-a11y/defaultPlugins.visual.spec.js b/e2e/tests/visual-a11y/defaultPlugins.visual.spec.js
index d7d022d39d..4246141203 100644
--- a/e2e/tests/visual-a11y/defaultPlugins.visual.spec.js
+++ b/e2e/tests/visual-a11y/defaultPlugins.visual.spec.js
@@ -85,16 +85,6 @@ test.describe('Visual - Default @a11y', () => {
     await percySnapshot(page, `Display Layout Create Menu (theme: '${theme}')`);
   });
 
-  test('Visual - Default Gauge', async ({ page, theme }) => {
-    await createDomainObjectWithDefaults(page, {
-      type: 'Gauge',
-      name: 'Default Gauge'
-    });
-
-    // Take a snapshot of the newly created Gauge object
-    await percySnapshot(page, `Default Gauge (theme: '${theme}')`);
-  });
-
   test.afterEach(async ({ page }, testInfo) => {
     await scanForA11yViolations(page, testInfo.title);
   });
diff --git a/e2e/tests/visual-a11y/gauge.visual.spec.js b/e2e/tests/visual-a11y/gauge.visual.spec.js
new file mode 100644
index 0000000000..15d1d5f08d
--- /dev/null
+++ b/e2e/tests/visual-a11y/gauge.visual.spec.js
@@ -0,0 +1,81 @@
+/*****************************************************************************
+ * Open MCT, Copyright (c) 2014-2024, United States Government
+ * as represented by the Administrator of the National Aeronautics and Space
+ * Administration. All rights reserved.
+ *
+ * Open MCT is licensed under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ * Open MCT includes source code licensed under additional open source
+ * licenses. See the Open Source Licenses file (LICENSES.md) included with
+ * this source code distribution or the Licensing information page available
+ * at runtime from the About dialog for additional information.
+ *****************************************************************************/
+import percySnapshot from '@percy/playwright';
+
+import { createDomainObjectWithDefaults } from '../../appActions.js';
+import { scanForA11yViolations, test } from '../../avpFixtures.js';
+import { VISUAL_FIXED_URL } from '../../constants.js';
+
+test.describe('Visual - Gauges', () => {
+  test.beforeEach(async ({ page }) => {
+    await page.goto(VISUAL_FIXED_URL, { waitUntil: 'domcontentloaded' });
+  });
+
+  test('Visual - Default Gauge', async ({ page, theme }) => {
+    await createDomainObjectWithDefaults(page, {
+      type: 'Gauge',
+      name: 'Default Gauge'
+    });
+
+    // Take a snapshot of the newly created Gauge object
+    await percySnapshot(page, `Default Gauge (theme: '${theme}')`);
+  });
+
+  test('Visual - Needle Gauge with State Generator', async ({ page, theme }) => {
+    const needleGauge = await createDomainObjectWithDefaults(page, {
+      type: 'Gauge',
+      name: 'Needle Gauge'
+    });
+
+    //Modify the Gauge to be a Needle Gauge
+    await page.getByLabel('More actions').click();
+    await page.getByLabel('Edit Properties...').click();
+    await page.getByLabel('Gauge type', { exact: true }).selectOption('dial-needle');
+    await page.getByText('Ok').click();
+
+    //Add a State Generator to the Gauge
+    await page.goto(needleGauge.url + '?hideTree=true&hideInspector=true', {
+      waitUntil: 'domcontentloaded'
+    });
+
+    // Take a snapshot of the newly created Gauge object
+    await percySnapshot(page, `Needle Gauge with no telemetry source (theme: '${theme}')`);
+
+    //Add a State Generator to the Gauge. Note this requires that snapshots are taken within 5 seconds
+    await page.getByLabel('Create', { exact: true }).click();
+    await page.getByLabel('State Generator').click();
+    await page.getByLabel('Modal Overlay').getByLabel('Navigate to Needle Gauge').click();
+    await page.getByLabel('Save').click();
+
+    //Add a State Generator to the Gauge
+    await page.goto(needleGauge.url + '?hideTree=true&hideInspector=true', {
+      waitUntil: 'domcontentloaded'
+    });
+
+    // Take a snapshot of the newly created Gauge object
+    await percySnapshot(page, `Needle Gauge with State Generator (theme: '${theme}')`);
+  });
+
+  test.afterEach(async ({ page }, testInfo) => {
+    await scanForA11yViolations(page, testInfo.title);
+  });
+});
diff --git a/e2e/tests/visual-a11y/notebook.visual.spec.js b/e2e/tests/visual-a11y/notebook.visual.spec.js
index 3532953fbf..ca3f801fc2 100644
--- a/e2e/tests/visual-a11y/notebook.visual.spec.js
+++ b/e2e/tests/visual-a11y/notebook.visual.spec.js
@@ -98,7 +98,7 @@ test.describe('Visual - Notebook @a11y', () => {
 
     await page.getByLabel('Expand My Items folder').click();
 
-    await page.goto(notebook.url);
+    await page.goto(notebook.url, { waitUntil: 'networkidle' });
 
     await page
       .getByLabel('Navigate to Dropped Overlay Plot')
diff --git a/e2e/tests/visual-a11y/search.visual.spec.js b/e2e/tests/visual-a11y/search.visual.spec.js
index b6a4966e45..b399556913 100644
--- a/e2e/tests/visual-a11y/search.visual.spec.js
+++ b/e2e/tests/visual-a11y/search.visual.spec.js
@@ -53,7 +53,7 @@ test.describe('Grand Search @a11y', () => {
     theme
   }) => {
     // Navigate to display layout
-    await page.goto(displayLayout.url);
+    await page.goto(displayLayout.url, { waitUntil: 'networkidle' });
 
     // Search for the object
     await page.getByRole('searchbox', { name: 'Search Input' }).click();
diff --git a/src/styles/_constants-espresso.scss b/src/styles/_constants-espresso.scss
index 3abae3f1dc..36702317a5 100644
--- a/src/styles/_constants-espresso.scss
+++ b/src/styles/_constants-espresso.scss
@@ -461,7 +461,7 @@ $colorGaugeMeterTextValue: $colorGaugeTextValue; // Meter text value, overlaid o
 $colorGaugeRange: $colorBodyFg; // Range text color
 $colorGaugeLimitHigh: rgba($colorLimitRedBg, 0.4);
 $colorGaugeLimitLow: $colorGaugeLimitHigh;
-$colorGaugeNeedle: rgba(#fff, 0);
+$colorGaugeNeedle: $colorGaugeValue; // Color of needle in a needle gauge.
 $transitionTimeGauge: 150ms; // CSS transition time used to smooth needle gauge and meter value transitions
 $marginGaugeMeterValue: 10%; // Margin between meter value bar and bounds edges
 $gaugeMeterValueShadow: rgba(255, 255, 255, 0);
diff --git a/src/styles/_constants-maelstrom.scss b/src/styles/_constants-maelstrom.scss
index 8935dfb65b..b0f2999174 100644
--- a/src/styles/_constants-maelstrom.scss
+++ b/src/styles/_constants-maelstrom.scss
@@ -477,7 +477,7 @@ $colorGaugeMeterTextValue: $colorGaugeTextValue; // Meter text value, overlaid o
 $colorGaugeRange: $colorBodyFg; // Range text color
 $colorGaugeLimitHigh: rgba($colorLimitRedBg, 0.4);
 $colorGaugeLimitLow: $colorGaugeLimitHigh;
-$colorGaugeNeedle: rgba(#fff, 0);
+$colorGaugeNeedle: $colorGaugeValue; // Color of needle in a needle gauge.
 $transitionTimeGauge: 150ms; // CSS transition time used to smooth needle gauge and meter value transitions
 $marginGaugeMeterValue: 10%; // Margin between meter value bar and bounds edges
 $gaugeMeterValueShadow: rgba(255, 255, 255, 0);
diff --git a/src/styles/_constants-snow.scss b/src/styles/_constants-snow.scss
index 3bc73d0184..4b4efdb52b 100644
--- a/src/styles/_constants-snow.scss
+++ b/src/styles/_constants-snow.scss
@@ -460,7 +460,7 @@ $colorGaugeMeterTextValue: $colorGaugeTextValue; // Meter text value, overlaid o
 $colorGaugeRange: $colorBodyFg; // Range text color
 $colorGaugeLimitHigh: rgba($colorLimitRedBg, 0.2);
 $colorGaugeLimitLow: $colorGaugeLimitHigh;
-$colorGaugeNeedle: rgba(#fff, 0);
+$colorGaugeNeedle: $colorGaugeValue; // Color of needle in a needle gauge.
 $transitionTimeGauge: 150ms; // CSS transition time used to smooth needle gauge and meter value transitions
 $marginGaugeMeterValue: 10%; // Margin between meter value bar and bounds edges
 $gaugeMeterValueShadow: rgba(255, 255, 255, 0);

From 29f1956d1ab2749b3a753e8267a0ae9f051d2d0f Mon Sep 17 00:00:00 2001
From: Andrew Henry <akhenry@gmail.com>
Date: Mon, 30 Sep 2024 14:36:40 -0700
Subject: [PATCH 3/3] Improve telemetry buffering implementation (#7837)

* Simplifies the implementation of telemetry buffering in Open MCT.
* Switches from per-parameter buffering to a shared queue. Per-parameter buffering is too easily overwhelmed by bursts of telemetry from high-frequency parameters. A single shared buffer has more overhead to grow when a burst arrives without overflowing, because the buffer is shared across all parameters.
* Removes the need for plugins to pass serialized code to a worker.
* Switched to a "one-size-fits-all" batching strategy removing the need for plugins to define a batching strategy at all.
* Captures buffering statistics for display in the PerformanceIndicator.
---
 .../performanceIndicator.e2e.spec.js          |  72 +++++++
 src/api/telemetry/BatchingWebSocket.js        | 195 ++++++++++--------
 src/api/telemetry/WebSocketWorker.js          | 178 ++++++----------
 src/plugins/performanceIndicator/plugin.js    |  64 +++++-
 4 files changed, 309 insertions(+), 200 deletions(-)
 create mode 100644 e2e/tests/functional/plugins/performanceIndicator/performanceIndicator.e2e.spec.js

diff --git a/e2e/tests/functional/plugins/performanceIndicator/performanceIndicator.e2e.spec.js b/e2e/tests/functional/plugins/performanceIndicator/performanceIndicator.e2e.spec.js
new file mode 100644
index 0000000000..ef1709fb99
--- /dev/null
+++ b/e2e/tests/functional/plugins/performanceIndicator/performanceIndicator.e2e.spec.js
@@ -0,0 +1,72 @@
+/*****************************************************************************
+ * Open MCT, Copyright (c) 2014-2023, United States Government
+ * as represented by the Administrator of the National Aeronautics and Space
+ * Administration. All rights reserved.
+ *
+ * Open MCT is licensed under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ * Open MCT includes source code licensed under additional open source
+ * licenses. See the Open Source Licenses file (LICENSES.md) included with
+ * this source code distribution or the Licensing information page available
+ * at runtime from the About dialog for additional information.
+ *****************************************************************************/
+import { expect, test } from '../../../../pluginFixtures.js';
+
+test.describe('The performance indicator', () => {
+  test.beforeEach(async ({ page }) => {
+    await page.goto('./', { waitUntil: 'domcontentloaded' });
+    await page.evaluate(() => {
+      const openmct = window.openmct;
+      openmct.install(openmct.plugins.PerformanceIndicator());
+    });
+  });
+
+  test('can be installed', ({ page }) => {
+    const performanceIndicator = page.getByTitle('Performance Indicator');
+    expect(performanceIndicator).toBeDefined();
+  });
+
+  test('Shows a numerical FPS value', async ({ page }) => {
+    // Frames Per Second. We need to wait at least 1 second to get a value.
+    // eslint-disable-next-line playwright/no-wait-for-timeout
+    await page.waitForTimeout(1000);
+    await expect(page.getByTitle('Performance Indicator')).toHaveText(/\d\d? fps/);
+  });
+
+  test('Supports showing optional extended performance information in an overlay for debugging', async ({
+    page
+  }) => {
+    const performanceMeasurementLabel = 'Some measurement';
+    const performanceMeasurementValue = 'Some value';
+
+    await page.evaluate(
+      ({ performanceMeasurementLabel: label, performanceMeasurementValue: value }) => {
+        const openmct = window.openmct;
+        openmct.performance.measurements.set(label, value);
+      },
+      { performanceMeasurementLabel, performanceMeasurementValue }
+    );
+    const performanceIndicator = page.getByTitle('Performance Indicator');
+    await performanceIndicator.click();
+    //Performance overlay is a crude debugging tool, it's evaluated once per second.
+    // eslint-disable-next-line playwright/no-wait-for-timeout
+    await page.waitForTimeout(1000);
+    const performanceOverlay = page.getByTitle('Performance Overlay');
+    await expect(performanceOverlay).toBeVisible();
+    await expect(performanceOverlay).toHaveText(new RegExp(`${performanceMeasurementLabel}.*`));
+    await expect(performanceOverlay).toHaveText(new RegExp(`.*${performanceMeasurementValue}`));
+
+    //Confirm that it disappears if we click on it again.
+    await performanceIndicator.click();
+    await expect(performanceOverlay).toBeHidden();
+  });
+});
diff --git a/src/api/telemetry/BatchingWebSocket.js b/src/api/telemetry/BatchingWebSocket.js
index a0687751b4..9c5596d0d6 100644
--- a/src/api/telemetry/BatchingWebSocket.js
+++ b/src/api/telemetry/BatchingWebSocket.js
@@ -20,25 +20,46 @@
  * at runtime from the About dialog for additional information.
  *****************************************************************************/
 import installWorker from './WebSocketWorker.js';
+
 /**
- * Describes the strategy to be used when batching WebSocket messages
- *
- * @typedef BatchingStrategy
- * @property {Function} shouldBatchMessage a function that accepts a single
- * argument - the raw message received from the websocket. Every message
- * received will be evaluated against this function so it should be performant.
- * Note also that this function is executed in a worker, so it must be
- * completely self-contained with no external dependencies. The function
- * should return `true` if the message should be batched, and `false` if not.
- * @property {Function} getBatchIdFromMessage a function that accepts a
- * single argument - the raw message received from the websocket. Only messages
- * where `shouldBatchMessage` has evaluated to true will be passed into this
- * function. The function should return a unique value on which to batch the
- * messages. For example a telemetry, channel, or parameter identifier.
+ * @typedef RequestIdleCallbackOptions
+ * @prop {Number} timeout If the number of milliseconds represented by this
+ * parameter has elapsed and the callback has not already been called, invoke
+ *  the callback.
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/Window/requestIdleCallback
  */
+
 /**
- * Provides a reliable and convenient WebSocket abstraction layer that handles
- * a lot of boilerplate common to managing WebSocket connections such as:
+ * Mocks requestIdleCallback for Safari using setTimeout. Functionality will be
+ * identical to setTimeout in Safari, which is to fire the callback function
+ * after the provided timeout period.
+ *
+ * In browsers that support requestIdleCallback, this const is just a
+ * pointer to the native function.
+ *
+ * @param {Function} callback a callback to be invoked during the next idle period, or
+ * after the specified timeout
+ * @param {RequestIdleCallbackOptions} options
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/Window/requestIdleCallback
+ *
+ */
+function requestIdleCallbackPolyfill(callback, options) {
+  return (
+    // eslint-disable-next-line compat/compat
+    window.requestIdleCallback ??
+    ((fn, { timeout }) =>
+      setTimeout(() => {
+        fn({ didTimeout: false });
+      }, timeout))
+  );
+}
+const requestIdleCallback = requestIdleCallbackPolyfill();
+
+const ONE_SECOND = 1000;
+
+/**
+ * Provides a WebSocket abstraction layer that handles a lot of boilerplate common
+ * to managing WebSocket connections such as:
  * - Establishing a WebSocket connection to a server
  * - Reconnecting on error, with a fallback strategy
  * - Queuing messages so that clients can send messages without concern for the current
@@ -49,22 +70,19 @@ import installWorker from './WebSocketWorker.js';
  * and batching of messages without blocking either the UI or server.
  *
  */
-// Shim for Internet Explorer, I mean Safari. It doesn't support requestIdleCallback, but it's in a tech preview, so it will be dropping soon.
-const requestIdleCallback =
-  // eslint-disable-next-line compat/compat
-  window.requestIdleCallback ?? ((fn, { timeout }) => setTimeout(fn, timeout));
-const ONE_SECOND = 1000;
-const FIVE_SECONDS = 5 * ONE_SECOND;
-
 class BatchingWebSocket extends EventTarget {
   #worker;
   #openmct;
   #showingRateLimitNotification;
-  #maxBatchSize;
-  #applicationIsInitializing;
-  #maxBatchWait;
+  #maxBufferSize;
+  #throttleRate;
   #firstBatchReceived;
+  #lastBatchReceived;
+  #peakBufferSize = Number.NEGATIVE_INFINITY;
 
+  /**
+   * @param {import('openmct.js').OpenMCT} openmct
+   */
   constructor(openmct) {
     super();
     // Install worker, register listeners etc.
@@ -74,9 +92,8 @@ class BatchingWebSocket extends EventTarget {
     this.#worker = new Worker(workerUrl);
     this.#openmct = openmct;
     this.#showingRateLimitNotification = false;
-    this.#maxBatchSize = Number.POSITIVE_INFINITY;
-    this.#maxBatchWait = ONE_SECOND;
-    this.#applicationIsInitializing = true;
+    this.#maxBufferSize = Number.POSITIVE_INFINITY;
+    this.#throttleRate = ONE_SECOND;
     this.#firstBatchReceived = false;
 
     const routeMessageToHandler = this.#routeMessageToHandler.bind(this);
@@ -89,20 +106,6 @@ class BatchingWebSocket extends EventTarget {
       },
       { once: true }
     );
-
-    openmct.once('start', () => {
-      // An idle callback is a pretty good indication that a complex display is done loading. At that point set the batch size more conservatively.
-      // Force it after 5 seconds if it hasn't happened yet.
-      requestIdleCallback(
-        () => {
-          this.#applicationIsInitializing = false;
-          this.setMaxBatchSize(this.#maxBatchSize);
-        },
-        {
-          timeout: FIVE_SECONDS
-        }
-      );
-    });
   }
 
   /**
@@ -137,57 +140,48 @@ class BatchingWebSocket extends EventTarget {
   }
 
   /**
-   * Set the strategy used to both decide which raw messages to batch, and how to group
-   * them.
-   * @param {BatchingStrategy} strategy The batching strategy to use when evaluating
-   * raw messages from the WebSocket.
-   */
-  setBatchingStrategy(strategy) {
-    const serializedStrategy = {
-      shouldBatchMessage: strategy.shouldBatchMessage.toString(),
-      getBatchIdFromMessage: strategy.getBatchIdFromMessage.toString()
-    };
-
-    this.#worker.postMessage({
-      type: 'setBatchingStrategy',
-      serializedStrategy
-    });
-  }
-
-  /**
-   * @param {number} maxBatchSize the maximum length of a batch of messages. For example,
-   * the maximum number of telemetry values to batch before dropping them
+   * @param {number} maxBufferSize the maximum length of the receive buffer in characters.
    * Note that this is a fail-safe that is only invoked if performance drops to the
    * point where Open MCT cannot keep up with the amount of telemetry it is receiving.
    * In this event it will sacrifice the oldest telemetry in the batch in favor of the
    * most recent telemetry. The user will be informed that telemetry has been dropped.
    *
-   * This should be set appropriately for the expected data rate. eg. If telemetry
-   * is received at 10Hz for each telemetry point, then a minimal combination of batch
-   * size and rate is 10 and 1000 respectively. Ideally you would add some margin, so
-   * 15 would probably be a better batch size.
+   * This should be set appropriately for the expected data rate. eg. If typical usage
+   * sees 2000 messages arriving at a client per second, with an average message size
+   * of 500 bytes, then 2000 * 500 = 1000000 characters will be right on the limit.
+   * In this scenario, a buffer size of 1500000 character might be more appropriate
+   * to allow some overhead for bursty telemetry, and temporary UI load during page
+   * load.
+   *
+   * The PerformanceIndicator plugin (openmct.plugins.PerformanceIndicator) gives
+   * statistics on buffer utilization. It can be used to scale the buffer appropriately.
    */
-  setMaxBatchSize(maxBatchSize) {
-    this.#maxBatchSize = maxBatchSize;
-    if (!this.#applicationIsInitializing) {
-      this.#sendMaxBatchSizeToWorker(this.#maxBatchSize);
-    }
+  setMaxBufferSize(maxBatchSize) {
+    this.#maxBufferSize = maxBatchSize;
+    this.#sendMaxBufferSizeToWorker(this.#maxBufferSize);
   }
-  setMaxBatchWait(wait) {
-    this.#maxBatchWait = wait;
-    this.#sendBatchWaitToWorker(this.#maxBatchWait);
+  setThrottleRate(throttleRate) {
+    this.#throttleRate = throttleRate;
+    this.#sendThrottleRateToWorker(this.#throttleRate);
   }
-  #sendMaxBatchSizeToWorker(maxBatchSize) {
+  setThrottleMessagePattern(throttleMessagePattern) {
     this.#worker.postMessage({
-      type: 'setMaxBatchSize',
-      maxBatchSize
+      type: 'setThrottleMessagePattern',
+      throttleMessagePattern
     });
   }
 
-  #sendBatchWaitToWorker(maxBatchWait) {
+  #sendMaxBufferSizeToWorker(maxBufferSize) {
     this.#worker.postMessage({
-      type: 'setMaxBatchWait',
-      maxBatchWait
+      type: 'setMaxBufferSize',
+      maxBufferSize
+    });
+  }
+
+  #sendThrottleRateToWorker(throttleRate) {
+    this.#worker.postMessage({
+      type: 'setThrottleRate',
+      throttleRate
     });
   }
 
@@ -203,9 +197,38 @@ class BatchingWebSocket extends EventTarget {
 
   #routeMessageToHandler(message) {
     if (message.data.type === 'batch') {
-      this.start = Date.now();
       const batch = message.data.batch;
-      if (batch.dropped === true && !this.#showingRateLimitNotification) {
+      const now = performance.now();
+
+      let currentBufferLength = message.data.currentBufferLength;
+      let maxBufferSize = message.data.maxBufferSize;
+      let parameterCount = batch.length;
+      if (this.#peakBufferSize < currentBufferLength) {
+        this.#peakBufferSize = currentBufferLength;
+      }
+
+      if (this.#openmct.performance !== undefined) {
+        if (!isNaN(this.#lastBatchReceived)) {
+          const elapsed = (now - this.#lastBatchReceived) / 1000;
+          this.#lastBatchReceived = now;
+          this.#openmct.performance.measurements.set(
+            'Parameters/s',
+            Math.floor(parameterCount / elapsed)
+          );
+        }
+        this.#openmct.performance.measurements.set(
+          'Buff. Util. (bytes)',
+          `${currentBufferLength} / ${maxBufferSize}`
+        );
+        this.#openmct.performance.measurements.set(
+          'Peak Buff. Util. (bytes)',
+          `${this.#peakBufferSize} / ${maxBufferSize}`
+        );
+      }
+
+      this.start = Date.now();
+      const dropped = message.data.dropped;
+      if (dropped === true && !this.#showingRateLimitNotification) {
         const notification = this.#openmct.notifications.alert(
           'Telemetry dropped due to client rate limiting.',
           { hint: 'Refresh individual telemetry views to retrieve dropped telemetry if needed.' }
@@ -240,18 +263,16 @@ class BatchingWebSocket extends EventTarget {
             console.warn(`Event loop is too busy to process batch.`);
             this.#waitUntilIdleAndRequestNextBatch(batch);
           } else {
-            // After ingesting a telemetry batch, wait until the event loop is idle again before
-            // informing the worker we are ready for another batch.
             this.#readyForNextBatch();
           }
         } else {
-          if (waitedFor > ONE_SECOND) {
+          if (waitedFor > this.#throttleRate) {
             console.warn(`Warning, batch processing took ${waitedFor}ms`);
           }
           this.#readyForNextBatch();
         }
       },
-      { timeout: ONE_SECOND }
+      { timeout: this.#throttleRate }
     );
   }
 }
diff --git a/src/api/telemetry/WebSocketWorker.js b/src/api/telemetry/WebSocketWorker.js
index a745ff0ceb..f2791577e9 100644
--- a/src/api/telemetry/WebSocketWorker.js
+++ b/src/api/telemetry/WebSocketWorker.js
@@ -24,10 +24,6 @@ export default function installWorker() {
   const ONE_SECOND = 1000;
   const FALLBACK_AND_WAIT_MS = [1000, 5000, 5000, 10000, 10000, 30000];
 
-  /**
-   * @typedef {import('./BatchingWebSocket').BatchingStrategy} BatchingStrategy
-   */
-
   /**
    * Provides a WebSocket connection that is resilient to errors and dropouts.
    * On an error or dropout, will automatically reconnect.
@@ -215,17 +211,17 @@ export default function installWorker() {
         case 'message':
           this.#websocket.enqueueMessage(message.data.message);
           break;
-        case 'setBatchingStrategy':
-          this.setBatchingStrategy(message);
-          break;
         case 'readyForNextBatch':
           this.#messageBatcher.readyForNextBatch();
           break;
-        case 'setMaxBatchSize':
-          this.#messageBatcher.setMaxBatchSize(message.data.maxBatchSize);
+        case 'setMaxBufferSize':
+          this.#messageBatcher.setMaxBufferSize(message.data.maxBufferSize);
           break;
-        case 'setMaxBatchWait':
-          this.#messageBatcher.setMaxBatchWait(message.data.maxBatchWait);
+        case 'setThrottleRate':
+          this.#messageBatcher.setThrottleRate(message.data.throttleRate);
+          break;
+        case 'setThrottleMessagePattern':
+          this.#messageBatcher.setThrottleMessagePattern(message.data.throttleMessagePattern);
           break;
         default:
           throw new Error(`Unknown message type: ${type}`);
@@ -238,122 +234,69 @@ export default function installWorker() {
     disconnect() {
       this.#websocket.disconnect();
     }
-    setBatchingStrategy(message) {
-      const { serializedStrategy } = message.data;
-      const batchingStrategy = {
-        // eslint-disable-next-line no-new-func
-        shouldBatchMessage: new Function(`return ${serializedStrategy.shouldBatchMessage}`)(),
-        // eslint-disable-next-line no-new-func
-        getBatchIdFromMessage: new Function(`return ${serializedStrategy.getBatchIdFromMessage}`)()
-        // Will also include maximum batch length here
-      };
-      this.#messageBatcher.setBatchingStrategy(batchingStrategy);
-    }
   }
 
   /**
-   * Received messages from the WebSocket, and passes them along to the
-   * Worker interface and back to the main thread.
+   * Responsible for buffering messages
    */
-  class WebSocketToWorkerMessageBroker {
-    #worker;
-    #messageBatcher;
-
-    constructor(messageBatcher, worker) {
-      this.#messageBatcher = messageBatcher;
-      this.#worker = worker;
-    }
-
-    routeMessageToHandler(data) {
-      if (this.#messageBatcher.shouldBatchMessage(data)) {
-        this.#messageBatcher.addMessageToBatch(data);
-      } else {
-        this.#worker.postMessage({
-          type: 'message',
-          message: data
-        });
-      }
-    }
-  }
-
-  /**
-   * Responsible for batching messages according to the defined batching strategy.
-   */
-  class MessageBatcher {
-    #batch;
-    #batchingStrategy;
-    #hasBatch = false;
-    #maxBatchSize;
+  class MessageBuffer {
+    #buffer;
+    #currentBufferLength;
+    #dropped;
+    #maxBufferSize;
     #readyForNextBatch;
     #worker;
     #throttledSendNextBatch;
+    #throttleMessagePattern;
 
     constructor(worker) {
       // No dropping telemetry unless we're explicitly told to.
-      this.#maxBatchSize = Number.POSITIVE_INFINITY;
+      this.#maxBufferSize = Number.POSITIVE_INFINITY;
       this.#readyForNextBatch = false;
       this.#worker = worker;
       this.#resetBatch();
-      this.setMaxBatchWait(ONE_SECOND);
+      this.setThrottleRate(ONE_SECOND);
     }
     #resetBatch() {
-      this.#batch = {};
-      this.#hasBatch = false;
+      //this.#batch = {};
+      this.#buffer = [];
+      this.#currentBufferLength = 0;
+      this.#dropped = false;
     }
-    /**
-     * @param {BatchingStrategy} strategy
-     */
-    setBatchingStrategy(strategy) {
-      this.#batchingStrategy = strategy;
-    }
-    /**
-     * Applies the `shouldBatchMessage` function from the supplied batching strategy
-     * to each message to determine if it should be added to a batch. If not batched,
-     * the message is immediately sent over the worker to the main thread.
-     * @param {any} message the message received from the WebSocket. See the WebSocket
-     * documentation for more details -
-     * https://developer.mozilla.org/en-US/docs/Web/API/MessageEvent/data
-     * @returns
-     */
-    shouldBatchMessage(message) {
-      return (
-        this.#batchingStrategy.shouldBatchMessage &&
-        this.#batchingStrategy.shouldBatchMessage(message)
-      );
-    }
-    /**
-     * Adds the given message to a batch. The batch group that the message is added
-     * to will be determined by the value returned by `getBatchIdFromMessage`.
-     * @param {any} message the message received from the WebSocket. See the WebSocket
-     * documentation for more details -
-     * https://developer.mozilla.org/en-US/docs/Web/API/MessageEvent/data
-     */
-    addMessageToBatch(message) {
-      const batchId = this.#batchingStrategy.getBatchIdFromMessage(message);
-      let batch = this.#batch[batchId];
-      if (batch === undefined) {
-        this.#hasBatch = true;
-        batch = this.#batch[batchId] = [message];
-      } else {
-        batch.push(message);
-      }
-      if (batch.length > this.#maxBatchSize) {
-        console.warn(
-          `Exceeded max batch size of ${this.#maxBatchSize} for ${batchId}. Dropping value.`
-        );
-        batch.shift();
-        this.#batch.dropped = true;
+
+    addMessageToBuffer(message) {
+      this.#buffer.push(message);
+      this.#currentBufferLength += message.length;
+
+      for (
+        let i = 0;
+        this.#currentBufferLength > this.#maxBufferSize && i < this.#buffer.length;
+        i++
+      ) {
+        const messageToConsider = this.#buffer[i];
+        if (this.#shouldThrottle(messageToConsider)) {
+          this.#buffer.splice(i, 1);
+          this.#currentBufferLength -= messageToConsider.length;
+          this.#dropped = true;
+        }
       }
 
       if (this.#readyForNextBatch) {
         this.#throttledSendNextBatch();
       }
     }
-    setMaxBatchSize(maxBatchSize) {
-      this.#maxBatchSize = maxBatchSize;
+
+    #shouldThrottle(message) {
+      return (
+        this.#throttleMessagePattern !== undefined && this.#throttleMessagePattern.test(message)
+      );
     }
-    setMaxBatchWait(maxBatchWait) {
-      this.#throttledSendNextBatch = throttle(this.#sendNextBatch.bind(this), maxBatchWait);
+
+    setMaxBufferSize(maxBufferSize) {
+      this.#maxBufferSize = maxBufferSize;
+    }
+    setThrottleRate(throttleRate) {
+      this.#throttledSendNextBatch = throttle(this.#sendNextBatch.bind(this), throttleRate);
     }
     /**
      * Indicates that client code is ready to receive the next batch of
@@ -362,21 +305,33 @@ export default function installWorker() {
      * any new data is available.
      */
     readyForNextBatch() {
-      if (this.#hasBatch) {
+      if (this.#hasData()) {
         this.#throttledSendNextBatch();
       } else {
         this.#readyForNextBatch = true;
       }
     }
     #sendNextBatch() {
-      const batch = this.#batch;
+      const buffer = this.#buffer;
+      const dropped = this.#dropped;
+      const currentBufferLength = this.#currentBufferLength;
+
       this.#resetBatch();
       this.#worker.postMessage({
         type: 'batch',
-        batch
+        dropped,
+        currentBufferLength: currentBufferLength,
+        maxBufferSize: this.#maxBufferSize,
+        batch: buffer
       });
+
       this.#readyForNextBatch = false;
-      this.#hasBatch = false;
+    }
+    #hasData() {
+      return this.#currentBufferLength > 0;
+    }
+    setThrottleMessagePattern(priorityMessagePattern) {
+      this.#throttleMessagePattern = new RegExp(priorityMessagePattern, 'm');
     }
   }
 
@@ -408,15 +363,14 @@ export default function installWorker() {
   }
 
   const websocket = new ResilientWebSocket(self);
-  const messageBatcher = new MessageBatcher(self);
-  const workerBroker = new WorkerToWebSocketMessageBroker(websocket, messageBatcher);
-  const websocketBroker = new WebSocketToWorkerMessageBroker(messageBatcher, self);
+  const messageBuffer = new MessageBuffer(self);
+  const workerBroker = new WorkerToWebSocketMessageBroker(websocket, messageBuffer);
 
   self.addEventListener('message', (message) => {
     workerBroker.routeMessageToHandler(message);
   });
   websocket.registerMessageCallback((data) => {
-    websocketBroker.routeMessageToHandler(data);
+    messageBuffer.addMessageToBuffer(data);
   });
 
   self.websocketInstance = websocket;
diff --git a/src/plugins/performanceIndicator/plugin.js b/src/plugins/performanceIndicator/plugin.js
index 389cbf6ca1..6fab67a80b 100644
--- a/src/plugins/performanceIndicator/plugin.js
+++ b/src/plugins/performanceIndicator/plugin.js
@@ -19,14 +19,23 @@
  * this source code distribution or the Licensing information page available
  * at runtime from the About dialog for additional information.
  *****************************************************************************/
+const PERFORMANCE_OVERLAY_RENDER_INTERVAL = 1000;
+
 export default function PerformanceIndicator() {
   return function install(openmct) {
     let frames = 0;
     let lastCalculated = performance.now();
-    const indicator = openmct.indicators.simpleIndicator();
+    openmct.performance = {
+      measurements: new Map()
+    };
 
+    const indicator = openmct.indicators.simpleIndicator();
+    indicator.key = 'performance-indicator';
     indicator.text('~ fps');
+    indicator.description('Performance Indicator');
     indicator.statusClass('s-status-info');
+    indicator.on('click', showOverlay);
+
     openmct.indicators.add(indicator);
 
     let rafHandle = requestAnimationFrame(incrementFrames);
@@ -58,5 +67,58 @@ export default function PerformanceIndicator() {
         indicator.statusClass('s-status-error');
       }
     }
+
+    function showOverlay() {
+      const overlayStylesText = `
+          #c-performance-indicator--overlay {
+            background-color:rgba(0,0,0,0.5);
+            position: absolute;
+            width: 300px;
+            left: calc(50% - 300px);
+          }
+      `;
+      const overlayMarkup = `
+        <div id="c-performance-indicator--overlay" title="Performance Overlay">
+          <table id="c-performance-indicator--table">
+            <tr class="c-performance-indicator--row"><td class="c-performance-indicator--measurement-name"></td><td class="c-performance-indicator--measurement-value"></td></tr>
+          </table>
+        </div>
+      `;
+      const overlayTemplate = document.createElement('div');
+      overlayTemplate.innerHTML = overlayMarkup;
+      const overlay = overlayTemplate.cloneNode(true);
+      overlay.querySelector('.c-performance-indicator--row').remove();
+      const overlayStyles = document.createElement('style');
+      overlayStyles.appendChild(document.createTextNode(overlayStylesText));
+
+      document.head.appendChild(overlayStyles);
+      document.body.appendChild(overlay);
+
+      indicator.off('click', showOverlay);
+
+      const interval = setInterval(() => {
+        overlay.querySelector('#c-performance-indicator--table').innerHTML = '';
+
+        for (const [name, value] of openmct.performance.measurements.entries()) {
+          const newRow = overlayTemplate
+            .querySelector('.c-performance-indicator--row')
+            .cloneNode(true);
+          newRow.querySelector('.c-performance-indicator--measurement-name').innerText = name;
+          newRow.querySelector('.c-performance-indicator--measurement-value').innerText = value;
+          overlay.querySelector('#c-performance-indicator--table').appendChild(newRow);
+        }
+      }, PERFORMANCE_OVERLAY_RENDER_INTERVAL);
+
+      indicator.on(
+        'click',
+        () => {
+          overlayStyles.remove();
+          overlay.remove();
+          indicator.on('click', showOverlay);
+          clearInterval(interval);
+        },
+        { once: true, capture: true }
+      );
+    }
   };
 }