From c0d49ffdf7e03953fa20cf9bf0a9515446dadfd9 Mon Sep 17 00:00:00 2001
From: Akshar Patel <aksharcommit@gmail.com>
Date: Tue, 13 Oct 2026 22:26:26 -0400
Subject: [PATCH] perf(desktop): stop decoding snapshots twice for
 accessibility

---
 .../src/snapShot/DesktopSnapShot.test.ts      | 27 ++++++++++++++-----
 apps/desktop/src/snapShot/DesktopSnapShot.ts  |  9 ++++---
 2 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/apps/desktop/src/snapShot/DesktopSnapShot.test.ts b/apps/desktop/src/snapShot/DesktopSnapShot.test.ts
index 39a7dddf5de7..9e1895beb4a0 100644
--- a/apps/desktop/src/snapShot/DesktopSnapShot.test.ts
+++ b/apps/desktop/src/snapShot/DesktopSnapShot.test.ts
@@ -1049,9 +1049,15 @@ it.effect("matches Windows accessibility windows on a scaled display", () => {
   );
 });
 
-it.effect.each(["gnome", "niri", "kde", "hyprland"] as const)(
-  "persists %s text without inventing AT-SPI screen coordinates",
-  (backend) => {
+it.effect.each([
+  { backend: "gnome", screenshot: "PNG" },
+  { backend: "niri", screenshot: "PNG" },
+  { backend: "kde", screenshot: "PNG" },
+  { backend: "hyprland", screenshot: "PNG" },
+  { backend: "gnome", screenshot: "invalid" },
+] as const)(
+  "persists $backend accessibility text with a $screenshot screenshot",
+  ({ backend, screenshot }) => {
     vi.stubEnv("XDG_SESSION_TYPE", "wayland");
     flashWindows.length = 0;
     const window = {
@@ -1068,7 +1074,16 @@ it.effect.each(["gnome", "niri", "kde", "hyprland"] as const)(
       ...(backend === "niri" ? { accessibilityBoundsReliable: false } : {}),
       ...(backend === "kde" ? { clientBounds: { x: 479, y: 371, width: 700, height: 520 } } : {}),
     };
-    linuxCaptureMock.mockResolvedValueOnce({ png: Buffer.from([1, 2, 3]), window });
+    // The captured pixels differ from the compositor's logical window bounds.
+    const imageSize = screenshot === "PNG" ? { width: 1400, height: 1040 } : window.bounds;
+    const png =
+      screenshot === "PNG"
+        ? Buffer.from(
+            "iVBORw0KGgoAAAANSUhEUgAABXgAAAQQAQAAAABwoA4ZAAAAyElEQVR4nO3BMQEAAADCoPVPbQwfoAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAHgYyx4AAepc/c0AAAAASUVORK5CYII=",
+            "base64",
+          )
+        : Buffer.from([1, 2, 3]);
+    linuxCaptureMock.mockResolvedValueOnce({ png, window });
     activeWindowMock.mockClear();
     getSourcesMock.mockClear();
     accessibilityByPidMock.mockReset().mockResolvedValue({
@@ -1108,7 +1123,7 @@ it.effect.each(["gnome", "niri", "kde", "hyprland"] as const)(
         assert.deepInclude(saved.source.accessibility, {
           format: "element-tree",
           coordinateSpace: "captured-image",
-          imageSize: { width: 700, height: window.bounds.height },
+          imageSize: { width: imageSize.width, height: imageSize.height },
           truncated: false,
         });
         assert.deepInclude(
@@ -1118,7 +1133,7 @@ it.effect.each(["gnome", "niri", "kde", "hyprland"] as const)(
           {
             role: "window",
             name: "Editor",
-            bounds: { x: 0, y: 0, width: 700, height: window.bounds.height },
+            bounds: { x: 0, y: 0, width: imageSize.width, height: imageSize.height },
             state: { active: true },
           },
         );
diff --git a/apps/desktop/src/snapShot/DesktopSnapShot.ts b/apps/desktop/src/snapShot/DesktopSnapShot.ts
index 164c97b4f22f..1703666ea828 100644
--- a/apps/desktop/src/snapShot/DesktopSnapShot.ts
+++ b/apps/desktop/src/snapShot/DesktopSnapShot.ts
@@ -90,6 +90,7 @@ import {
   snapShotShortcutSystemConflict,
 } from "./snapShot.ts";
 import * as HostProcess from "@t3tools/shared/HostProcess";
+import { readImageDimensions } from "@t3tools/shared/imageDimensions";
 
 const MAX_CAPTURE_WIDTH = 2_560;
 const MAX_CAPTURE_HEIGHT = 1_600;
@@ -418,10 +419,10 @@ async function requestMacSnapShotPermissions(
 }
 
 function snapShotImageSize(png: Buffer, fallback: Electron.Rectangle): Electron.Size {
-  try {
-    const size = Electron.nativeImage.createFromBuffer(png).getSize();
-    if (size.width > 0 && size.height > 0) return size;
-  } catch {}
+  // Capture backends already validate or encode the PNG. Reading its header
+  // avoids decoding every pixel again just to size accessibility coordinates.
+  const size = readImageDimensions(png);
+  if (size) return size;
   return {
     width: Math.max(1, Math.round(fallback.width)),
     height: Math.max(1, Math.round(fallback.height)),