chore: import upstream snapshot with attribution

2026-07-13 12:58:35 +08:00
commit 85453da49f
4031 changed files with 710987 additions and 0 deletions
@@ -0,0 +1,8 @@
+{
+  "name": "Transparency Regression",
+  "description": "Asserts that webm + png-sequence outputs preserve a real alpha channel end-to-end. Exercised by `tsx src/transparency-test.ts`, NOT by the standard regression harness (which compares against a golden MP4).",
+  "tags": ["transparency", "alpha", "smoke"],
+  "renderConfig": {
+    "fps": 30
+  }
+}
@@ -0,0 +1,50 @@
+<!doctype html>
+<html>
+  <head>
+    <style>
+      /*
+        We DELIBERATELY paint a non-transparent body background here to
+        exercise the regression this PR fixes. The pre-navigation
+        Emulation.setDefaultBackgroundColorOverride that the engine used
+        to set is overridden by any `body { background: ... }` rule, so
+        on the buggy code path the captured PNG's "transparent" pixels
+        decode as opaque #111 (rgba [17, 17, 17, 255]).
+        The fix injects an `[data-composition-id]{background:transparent !important}`
+        stylesheet via initTransparentBackground() AFTER navigation, which
+        force-overrides this body background and produces a real alpha
+        channel — pixels outside the .card decode as rgba [0, 0, 0, 0].
+        If the test passes against this fixture, alpha is genuinely making
+        it through end-to-end.
+      */
+      html,
+      body {
+        margin: 0;
+        padding: 0;
+        background: #111;
+      }
+      .card {
+        position: absolute;
+        left: 50px;
+        top: 50px;
+        width: 100px;
+        height: 100px;
+        background: rgb(255, 0, 0);
+      }
+    </style>
+  </head>
+  <body
+    data-composition-id="transparency-regression"
+    data-duration="1"
+    data-width="200"
+    data-height="200"
+  >
+    <div class="card"></div>
+    <script>
+      // Minimal seek protocol — the composition is static.
+      window.__hf = {
+        duration: 1,
+        seek: () => {},
+      };
+    </script>
+  </body>
+</html>