From 634b74d0c677e153e16f1587849df5e85cfcc34d Mon Sep 17 00:00:00 2001
From: Miguel de Benito Delgado <m.debenito.d@gmail.com>
Date: Sun, 27 Sep 2026 20:55:27 +0200
Subject: [PATCH] :construction: WIP Step 14, Grab correct w/h attrs from
 context

---
 .../test/benches/render_wasm/browser.cljs     | 19 ++++++++++---------
 .../benches/lifecycle_test.cljs               | 14 ++++++++++++--
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/frontend/test/benches/render_wasm/browser.cljs b/frontend/test/benches/render_wasm/browser.cljs
index e503b6d501..e712a1446c 100644
--- a/frontend/test/benches/render_wasm/browser.cljs
+++ b/frontend/test/benches/render_wasm/browser.cljs
@@ -204,8 +204,10 @@
   "Records effective graphics settings: requested CSS size and DPR
   separately from the observed drawing-buffer size and the context's actual
   attributes. Requested defaults live in `webgl/default-context-options`;
-  what the browser granted comes from `getContextAttributes`."
-  [canvas ctx width height dpr renderer]
+  the drawing-buffer size is the context's actual `drawingBufferWidth/Height`,
+  not the canvas attributes. What the browser granted comes from
+  `getContextAttributes`."
+  [ctx width height dpr renderer]
   (let [attrs (try
                 (.getContextAttributes ^js ctx)
                 (catch :default _ nil))
@@ -214,8 +216,8 @@
                   (unchecked-get attrs k)))]
     {"cssWidth" width
      "cssHeight" height
-     "drawingBufferWidth" (.-width ^js canvas)
-     "drawingBufferHeight" (.-height ^js canvas)
+     "drawingBufferWidth" (.-drawingBufferWidth ^js ctx)
+     "drawingBufferHeight" (.-drawingBufferHeight ^js ctx)
      "dpr" dpr
      "webgl2" true
      "antialias" (attr "antialias")
@@ -231,7 +233,7 @@
   for explicit disposal. Every failure path releases the owner when it still
   owns the realm, so budget exhaustion and context loss never leave a live
   canvas behind. Stale results never dispose: a newer owner is live."
-  [epoch module-ms graphics-ms upload-ms alive? poll snapshot seed canvas ctx width height dpr renderer]
+  [epoch module-ms graphics-ms upload-ms alive? poll snapshot seed ctx width height dpr renderer]
   (let [pm (js->clj poll :keywordize-keys true)]
     (cond
       (:stale pm)
@@ -264,7 +266,7 @@
         "renderFrames" (:frames pm)
         "scene" {"shapes" (count (:objects snapshot))
                  "seed" seed}
-        "effectiveGraphics" (read-graphics canvas ctx width height dpr renderer)})
+        "effectiveGraphics" (read-graphics ctx width height dpr renderer)})
 
       :else
       (do
@@ -542,7 +544,6 @@
                                  {:module-ms factory-ms
                                   :graphics-ms (- (now) g0)
                                   :renderer (renderer-string (:context ctx))
-                                  :canvas canvas
                                   :ctx ctx}))))))
                 (.then (fn [g]
                          (guard-current! epoch "scene-build")
@@ -582,13 +583,13 @@
                                                cause)))))))
                 (.then (fn [g]
                          (guard-current! epoch "first-render")
-                         (let [{:keys [module-ms graphics-ms renderer canvas ctx snapshot upload-ms]} g
+                         (let [{:keys [module-ms graphics-ms renderer ctx snapshot upload-ms]} g
                                r0 (now)]
                            (-> (poll-full epoch 0 r0)
                                (.then (fn [poll]
                                         (render-ok epoch module-ms graphics-ms upload-ms
                                                    (live?) poll snapshot seed
-                                                   canvas (:context ctx)
+                                                   (:context ctx)
                                                    width height dpr renderer)))
                                (.catch (fn [cause]
                                          (terminal-failure epoch cause "first-render")))))))
diff --git a/frontend/test/frontend_tests/benches/lifecycle_test.cljs b/frontend/test/frontend_tests/benches/lifecycle_test.cljs
index 715ecd20f8..d0a4dad8fe 100644
--- a/frontend/test/frontend_tests/benches/lifecycle_test.cljs
+++ b/frontend/test/frontend_tests/benches/lifecycle_test.cljs
@@ -182,12 +182,17 @@
 
 (defn- fake-canvas
   "Numbered fake canvas identified by `id`. Removal and context loss are
-  recorded in the shared call log."
+  recorded in the shared call log. The context reports a drawing-buffer size
+  distinct from any canvas size, so tests prove `read-graphics` reads it from
+  the context rather than the canvas attributes."
   [id]
   (let [lose-ext #js {:loseContext (fn [] (record! ["lose" id]) nil)}
         context  #js {:getExtension (fn [name]
                                       (when (= name "WEBGL_lose_context")
-                                        lose-ext))}]
+                                        lose-ext))
+                      :getContextAttributes (fn [] nil)
+                      :drawingBufferWidth 1234
+                      :drawingBufferHeight 5678}]
     #js {:id id
          :width 0
          :height 0
@@ -337,6 +342,11 @@
                        (t/is (= "ok" (:status m)))
                        (t/is (= 1 (:renderFrames m)))
                        (t/is (= 1001 (:shapes (:scene m))) "the canonical scene uploads whole")
+                       (let [graphics (:effectiveGraphics m)]
+                         (t/is (= 1234 (:drawingBufferWidth graphics))
+                               "drawing buffer width comes from the context")
+                         (t/is (= 5678 (:drawingBufferHeight graphics))
+                               "drawing buffer height comes from the context"))
                        (let [calls (read-calls)]
                          (t/is (= 1 (effect-count calls "create")) "one canvas per load")
                          (t/is (zero? (effect-count calls "remove")) "success keeps the owner live"))