From 7d690e2cf7c38c993b77a3a3b2d79044b58be5da Mon Sep 17 00:00:00 2001
From: "Taro.Nonoyama" <n2.freevas@gmail.com>
Date: Tue, 16 Jun 2026 11:30:38 +0900
Subject: [PATCH] fix: prevent false emulation detection inside iframe context

---
 .changeset/fix-iframe-emulation.md            |  5 ++++
 .../getScreenDimensions.test.ts               | 27 +++++++++++++++++++
 .../clientSideScripts/getScreenDimensions.ts  |  2 ++
 3 files changed, 34 insertions(+)
 create mode 100644 .changeset/fix-iframe-emulation.md

diff --git a/.changeset/fix-iframe-emulation.md b/.changeset/fix-iframe-emulation.md
new file mode 100644
index 000000000..1ab5115c7
--- /dev/null
+++ b/.changeset/fix-iframe-emulation.md
@@ -0,0 +1,5 @@
+---
+"@wdio/image-comparison-core": patch
+---
+
+fix: prevent false emulation detection when checkElement is called inside an iframe after switchFrame
diff --git a/packages/image-comparison-core/src/clientSideScripts/getScreenDimensions.test.ts b/packages/image-comparison-core/src/clientSideScripts/getScreenDimensions.test.ts
index a2b8093cc..d101602a2 100644
--- a/packages/image-comparison-core/src/clientSideScripts/getScreenDimensions.test.ts
+++ b/packages/image-comparison-core/src/clientSideScripts/getScreenDimensions.test.ts
@@ -168,6 +168,33 @@ describe('getScreenDimensions', () => {
         expect(dimensions.dimensions.window.screenHeight).toBe(1800)
     })
 
+    it('should not detect emulation when running inside an iframe', () => {
+        const originalSelf = window.self
+        Object.defineProperty(window, 'self', {
+            value: {} as Window,
+            configurable: true,
+            writable: true,
+        })
+
+        Object.defineProperty(window, 'devicePixelRatio', { value: 3, configurable: true })
+        Object.defineProperty(window, 'innerWidth', { value: 50, configurable: true })
+        Object.defineProperty(window, 'innerHeight', { value: 100, configurable: true })
+        Object.defineProperty(window, 'matchMedia', {
+            value: vi.fn().mockImplementation(() => ({ matches: false })),
+            ...CONFIGURABLE,
+        })
+
+        const dimensions = getScreenDimensions(false)
+
+        Object.defineProperty(window, 'self', {
+            value: originalSelf,
+            configurable: true,
+            writable: true,
+        })
+
+        expect(dimensions.dimensions.window.isEmulated).toBe(false)
+    })
+
     it('should handle zero devicePixelRatio', () => {
         Object.defineProperty(window, 'devicePixelRatio', { value: 0, configurable: true })
         Object.defineProperty(window, 'innerWidth', { value: 1920, configurable: true })
diff --git a/packages/image-comparison-core/src/clientSideScripts/getScreenDimensions.ts b/packages/image-comparison-core/src/clientSideScripts/getScreenDimensions.ts
index 73c3f6f17..d1add4582 100644
--- a/packages/image-comparison-core/src/clientSideScripts/getScreenDimensions.ts
+++ b/packages/image-comparison-core/src/clientSideScripts/getScreenDimensions.ts
@@ -10,8 +10,10 @@ export default function getScreenDimensions(isMobile: boolean): ScreenDimensions
     const dpr = window.devicePixelRatio || 1
     const minEdge = Math.min(width, height)
     const maxEdge = Math.max(width, height)
+    const isInIframe = window.self !== window.top
     const isLikelyEmulated =
         !isMobile &&              // Only check for emulated on desktop
+        !isInIframe &&            // Skip emulation detection inside iframes
         dpr >= 2 &&               // High-DPI signal
         minEdge <= 800 &&         // Catch phones/tablets in portrait/landscape
         maxEdge <= 1280 &&        // Conservative max for emulated tablet sizes