From 8873b452303a471f4cb0ad3abbddaacadde46147 Mon Sep 17 00:00:00 2001
From: Tanner Linsley <tannerlinsley@gmail.com>
Date: Tue, 13 Oct 2026 23:29:23 -0600
Subject: [PATCH] test: cover SVG coordinate changes between pointer samples

---
 benchmarks/conformance/previews/manifest.json |  2 +-
 packages/charts-core/src/svg-surface.test.ts  | 35 +++++++++++++++----
 2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/benchmarks/conformance/previews/manifest.json b/benchmarks/conformance/previews/manifest.json
index d38b3b7c..8e27d4b0 100644
--- a/benchmarks/conformance/previews/manifest.json
+++ b/benchmarks/conformance/previews/manifest.json
@@ -2,7 +2,7 @@
   "schemaVersion": 1,
   "width": 288,
   "height": 192,
-  "sourceHash": "b503388bda59296b32222df9ec499915bd86d0c8d93852609d596973cfd21f71",
+  "sourceHash": "2ce2590f5c943219b694d3c51bb4806ed785ff0a4058c108fc520b0e6087c183",
   "assets": [
     {
       "id": "01-line-gaps",
diff --git a/packages/charts-core/src/svg-surface.test.ts b/packages/charts-core/src/svg-surface.test.ts
index 4f0ba6c5..d078ba09 100644
--- a/packages/charts-core/src/svg-surface.test.ts
+++ b/packages/charts-core/src/svg-surface.test.ts
@@ -327,7 +327,7 @@ describe('SVG surface coordinates', () => {
     surface.destroy()
   })
 
-  it('maps client coordinates through the rendered SVG transform', () => {
+  it('refreshes the rendered SVG transform between coordinate samples', () => {
     const scene = createChartScene(
       defineChart({
         marks: [dot([{ x: 1, y: 1 }], { x: 'x', y: 'y' })],
@@ -352,6 +352,8 @@ describe('SVG surface coordinates', () => {
     const renderedHeight = 480
     const scale = renderedWidth / scene.width
     const verticalInset = (renderedHeight - scene.height * scale) / 2
+    let translationX = 0
+    let translationY = 0
 
     vi.spyOn(svg, 'getBoundingClientRect').mockReturnValue(
       DOMRect.fromRect({
@@ -363,16 +365,17 @@ describe('SVG surface coordinates', () => {
     )
     Object.defineProperty(svg, 'getScreenCTM', {
       configurable: true,
-      value: vi.fn(() => ({
-        inverse: () => ({
+      value: vi.fn(() => {
+        const inverse = {
           a: 1 / scale,
           b: 0,
           c: 0,
           d: 1 / scale,
-          e: -left / scale,
-          f: -(top + verticalInset) / scale,
-        }),
-      })),
+          e: -(left + translationX) / scale,
+          f: -(top + verticalInset + translationY) / scale,
+        }
+        return { inverse: () => inverse }
+      }),
     })
 
     const expected = { x: 603.84, y: 28.76 }
@@ -385,6 +388,24 @@ describe('SVG surface coordinates', () => {
     expect(resolved?.x).toBeCloseTo(expected.x)
     expect(resolved?.y).toBeCloseTo(expected.y)
 
+    // Ancestor transforms, preceding layout and scroll can move the SVG
+    // without resizing it or rendering another chart scene.
+    for (const { x, y } of [
+      { x: 40, y: 30 },
+      { x: 0, y: 75 },
+      { x: 0, y: -50 },
+    ]) {
+      translationX = x
+      translationY = y
+      const moved = surface.clientToScene?.(
+        scene,
+        left + translationX + expected.x * scale,
+        top + verticalInset + translationY + expected.y * scale,
+      )
+      expect(moved?.x).toBeCloseTo(expected.x)
+      expect(moved?.y).toBeCloseTo(expected.y)
+    }
+
     surface.destroy()
   })