front: animate new intermediate op in stdcm

front/src/applications/stdcm/components/StdcmForm/StdcmVias.tsx

@@ -1,4 +1,4 @@
-import { useMemo } from 'react';
+import { useLayoutEffect, useMemo, useState } from 'react';
 
 import { Location } from '@osrd-project/ui-icons';
 import { useTranslation } from 'react-i18next';
@@ -27,6 +27,8 @@ const StdcmVias = ({ disabled = false }: StdcmConfigCardProps) => {
     useOsrdConfActions() as StdcmConfSliceActions;
   const pathSteps = useSelector(getStdcmPathSteps);
 
+  const [newIntermediateOpIndex, setNewIntermediateOpIndex] = useState<number>();
+
   const intermediatePoints = useMemo(() => pathSteps.slice(1, -1), [pathSteps]);
 
   const updateStopType = (newStopType: StdcmStopTypes, pathStep: StdcmPathStep) => {
@@ -44,6 +46,44 @@ const StdcmVias = ({ disabled = false }: StdcmConfigCardProps) => {
     );
   };
 
+  /**
+   * As the new intermediateOp block animates, we want to scroll to keep the box in the viewport.
+   * To do so, we install an animation frame listener (requestAnimationFrame) which updates the scroll position
+   * each time an animation frame is triggered.
+   * An animation end listener is also installed to cancel the animation frame listener.
+   * To properly clean up when the component is unmounted, we return a cleanup function that removes both listeners.
+   */
+  useLayoutEffect(() => {
+    if (!newIntermediateOpIndex) return undefined;
+
+    const newElement = document.querySelector(
+      `.stdcm-vias-bundle:nth-child(${newIntermediateOpIndex}) > :last-child`
+    );
+
+    if (!newElement) return undefined;
+
+    let requestId: number;
+
+    const scrollWithAnimation = () => {
+      newElement.scrollIntoView({
+        block: 'nearest',
+        behavior: 'auto',
+      });
+
+      requestId = requestAnimationFrame(scrollWithAnimation);
+    };
+
+    requestId = requestAnimationFrame(scrollWithAnimation);
+
+    const cancelListener = () => cancelAnimationFrame(requestId);
+
+    newElement.addEventListener('animationend', cancelListener);
+    return () => {
+      newElement.removeEventListener('animationend', cancelListener);
+      cancelListener();
+    };
+  }, [newIntermediateOpIndex]);
+
   const updateStopDuration = (stopTime: string, pathStep: StdcmPathStep) => {
     const stopFor = stopTime ? Number(stopTime) : undefined;
     dispatch(
@@ -60,6 +100,7 @@ const StdcmVias = ({ disabled = false }: StdcmConfigCardProps) => {
 
   const addViaOnClick = (pathStepIndex: number) => {
     dispatch(addStdcmVia(pathStepIndex));
+    setNewIntermediateOpIndex(pathStepIndex);
   };
 
   return (

front/src/styles/scss/applications/stdcm/_home.scss

@@ -106,6 +106,28 @@
           gap: 16px;
         }
 
+        .stdcm-vias-bundle {
+          animation: bouncin-in 0.75s cubic-bezier(0.567, -0.475, 0, 1);
+
+          .stdcm-card {
+            scroll-margin-bottom: 15px;
+          }
+        }
+
+        @keyframes bouncin-in {
+          0% {
+            opacity: 0;
+            height: 0;
+            // To make the new block poping from above the clicked button
+            transform: translateY(-45px);
+            margin-bottom: -30px; // To make the button clicked bounce top
+          }
+          100% {
+            opacity: 1;
+            height: 296px; // height of add OP button + intermedita OP card
+          }
+        }
+
         .stdcm-vias-list {
           margin-block: 16px;
 

front/tests/006-stdcm.spec.ts

@@ -14,6 +14,8 @@ test.use({
 test.describe('Verify train schedule elements and filters', () => {
   test.slow(); // Mark test as slow due to multiple steps
 
+  test.use({ viewport: { width: 1920, height: 1080 } });
+
   let infra: Infra;
   let OSRDLanguage: string;
 

front/tests/pages/stdcm-page-model.ts

@@ -390,6 +390,7 @@ class STDCMPage {
     const fillVia = async (selectedSuggestion: Locator) => {
       await this.addViaButton.nth(viaNumber - 1).click();
       expect(await this.addViaButton.count()).toBe(viaNumber + 1);
+      await expect(this.getViaCi(viaNumber)).toBeVisible();
       await this.getViaCi(viaNumber).fill(viaSearch);
       await selectedSuggestion.click();
       await expect(this.getViaCh(viaNumber)).toHaveValue('BV');
@@ -496,7 +497,7 @@ class STDCMPage {
     // Wait for the download event
     await this.page.waitForTimeout(500);
     const downloadPromise = this.page.waitForEvent('download', { timeout: 120000 });
-    await this.downloadSimulationButton.click({ force: true });
+    await this.downloadSimulationButton.dispatchEvent('click');
     const download = await downloadPromise.catch(() => {
       throw new Error('Download event was not triggered.');
     });
@@ -510,7 +511,7 @@ class STDCMPage {
   }
 
   async clickOnStartNewQueryButton() {
-    await this.startNewQueryButton.click();
+    await this.startNewQueryButton.dispatchEvent('click');
   }
 
   async mapMarkerVisibility() {