Fusion - the Fusion 360 Bridge

@@ -11,6 +11,7 @@ import ctypes import ctypes.wintypes import os import struct+import subprocess import time  # Guard windll so the module imports on non-Windows hosts (the bridge must boot@@ -138,14 +139,74 @@ def _send_input(*inputs):  # --- Window finding --- -def _find_fusion_hwnd() -> int:-    """Find Fusion 360's MAIN window: the LARGEST visible window titled 'Autodesk Fusion'.+def _fusion_window_pids() -> set:+    """PIDs of running Fusion360.exe processes, for title-independent window matching."""+    try:+        out = subprocess.check_output(+            ["tasklist", "/FI", "IMAGENAME eq Fusion360.exe", "/FO", "CSV", "/NH"],+            stdin=subprocess.DEVNULL, stderr=subprocess.DEVNULL, text=True, timeout=5,+            creationflags=(subprocess.CREATE_NO_WINDOW+                           if hasattr(subprocess, "CREATE_NO_WINDOW") else 0))+    except Exception:+        return set()+    pids = set()+    for line in out.splitlines():+        parts = [p.strip('"') for p in line.split('","')]+        if len(parts) > 1:+            try:+                pids.add(int(parts[1]))+            except Exception:+                pass+    return pids -    First-match was wrong (2026-08-15, caught by the demo tour's gallery): Fusion keeps-    tiny helper/ghost windows carrying the same title, and when one enumerates first the-    'screenshot' is a 236px title-bar sliver. The real main window is always the largest-    match by area, so pick that.++def _find_fusion_hwnd() -> int:+    """Find Fusion 360's MAIN window: the LARGEST visible window OWNED BY A FUSION PROCESS.++    Two generations of this bug, both producing a 237x39 title-bar sliver instead of the+    app:+      1. first-match (fixed 2026-08-15) - Fusion keeps tiny helper/ghost windows carrying+         the same title, and one of them enumerated first.+      2. TITLE-match (fixed 2026-08-19) - picking the largest window *titled* "Autodesk+         Fusion" still fails whenever the main window is mid-transition and does not carry+         that title, leaving the sliver as the only match. The 8/8 surfaces pass caught it:+         the library surface returned a 237x39 capture while every other surface returned+         1568x940.+    Ownership by PID is title-independent, so a retitled or transitioning main window can+    no longer be lost. Title matching stays as the fallback for the case where the process+    list is unreadable.     """+    pids = _fusion_window_pids()+    if pids:+        best_pid = [0, 0]++        WNDENUMPROC_P = ctypes.WINFUNCTYPE(+            ctypes.c_bool, ctypes.wintypes.HWND, ctypes.wintypes.LPARAM+        )++        def cb_pid(hwnd, _lparam):+            if user32.IsWindowVisible(hwnd):+                pid = ctypes.wintypes.DWORD()+                user32.GetWindowThreadProcessId(hwnd, ctypes.byref(pid))+                if pid.value in pids:+                    try:+                        l, t, r, b = _get_window_rect(hwnd)+                        area = max(0, r - l) * max(0, b - t)+                    except Exception:+                        area = 0+                    if area > best_pid[1]:+                        best_pid[0], best_pid[1] = hwnd, area+            return True++        cbp = WNDENUMPROC_P(cb_pid)+        _callbacks.append(cbp)+        user32.EnumWindows(cbp, 0)+        _callbacks.remove(cbp)+        # Require something PLAUSIBLY the app, not a toast/sliver: anything under+        # 400x300 is not Fusion's main window, so fall through to the title pass.+        if best_pid[0] and best_pid[1] >= 400 * 300:+            return best_pid[0]+     best = [0, 0]  # hwnd, area     WNDENUMPROC = ctypes.WINFUNCTYPE(         ctypes.c_bool, ctypes.wintypes.HWND, ctypes.wintypes.LPARAM@@ -417,6 +478,19 @@ def screenshot_fusion_window(use_bitblt: bool = False) -> dict:     if width <= 0 or height <= 0:         return {"success": False, "error": f"Invalid window rect: {left},{top},{right},{bottom}"} +    # A SLIVER IS NOT EVIDENCE (2026-08-19). If the only window we could find is+    # smaller than the app could possibly be, the main window is mid-transition -+    # wait briefly and re-resolve rather than returning a 237x39 title-bar strip+    # that a caller will happily render as "the library surface, captured".+    if width < 400 or height < 300:+        time.sleep(2.5)+        hwnd2 = _find_fusion_hwnd()+        if hwnd2:+            l2, t2, r2, b2 = _get_window_rect(hwnd2)+            if (r2 - l2) >= 400 and (b2 - t2) >= 300:+                hwnd, left, top, right, bottom = hwnd2, l2, t2, r2, b2+                width, height = right - left, bottom - top+     if use_bitblt:         # Screen DC capture — needs foreground         SW_RESTORE = 9