Fix non-finite bounds producing UB via static_cast in XAML/WinUI3 elements

[Copilot]

XAML diagnostics can return NaN/Infinity property values for element bounds. static_cast<int>(NaN) is undefined behavior, typically producing INT_MIN on MSVC x64 — the "huge negative numbers" seen in WinUI3 output. These corrupt bounds then cause screenshot annotations to skip visible elements (they appear off-screen).

TAP DLL (lvt_tap.cpp)

• Validate _wtof/ParseOffset results with std::isfinite() before setting node bounds
• Only mark hasBounds = true when width/height are finite; only set offsets when both are finite

Bounds conversion (xaml_diag_common.cpp, plugin_loader.cpp, wpf_inject.cpp)

• Add shared safe_double_to_int() in bounds_util.h — returns std::optional<int>, std::nullopt for non-finite values, clamps to INT_MIN..INT_MAX for out-of-range
• Guard all graft_json_node bounds paths with the optional check pattern
• Non-finite offsets skip without poisoning the accumulated parent offset

// bounds_util.h
inline std::optional<int> safe_double_to_int(double v) {
    if (!std::isfinite(v)) return std::nullopt;
    if (v >= static_cast<double>(INT_MAX)) return INT_MAX;
    if (v <= static_cast<double>(INT_MIN)) return INT_MIN;
    return static_cast<int>(v);
}

Screenshot annotation (screenshot.cpp)

• Use long long intermediate arithmetic for bounds subtraction to prevent signed int overflow when element coords are extreme
• Add collect_annotations() function and AnnotationInfo struct for structured annotation output (DEBUG builds only)
• Add --annotations-json <file> CLI flag as a debug-only test hook to output annotation rectangles as JSON, guarded with #ifndef NDEBUG

Unit tests

• Zero-size elements get no bounds
• Very large offsets are clamped (not UB)
• Normal values unchanged (regression)

Integration tests — Notepad-based

• Win32 bounds validation: all element bounds within reasonable screen range
• Root bounds non-zero: root window has positive dimensions
• Annotations JSON output (debug only): --annotations-json produces valid structured data
• Annotations match tree (debug only): every annotated element ID exists in the tree dump
• WinUI3 bounds (framework-conditional): if WinUI3 detected, all WinUI3 elements have sane bounds
• XAML/UWP bounds (framework-conditional): if XAML detected, all XAML elements have sane bounds

Integration tests — Controlled Win32 window (KnownWindowFixture)

Creates a Win32 window with Button, Edit, and Static controls at known client-area positions, then runs lvt against it:

• TreeStructure: verifies root has correct className/type/text, exactly 3 children with expected class names, types, text, and win32 framework
• ChildBoundsMatchWin32: verifies each control's JSON bounds match GetWindowRect of its HWND exactly
• AnnotationsIncludeKnownControls (debug only): verifies all 4 controls (parent + 3 children) appear in annotations with positive dimensions

Original prompt

the bounds of elements especially in winui3 apps are wrong eg huge negative numbers. maybe uninitialized memory?
also not every button is being annotated in the screenshot

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[asklar]

@copilot add integration tests for win32, uwp xaml and winui3 where we a) check the element bounds returned in the dump and b) verify that we annotate the right elements when producing a screenshot (we will likely need a test hook to output the annotations in a structured way as a side channel to the image)

[Copilot]

@copilot add integration tests for win32, uwp xaml and winui3 where we a) check the element bounds returned in the dump and b) verify that we annotate the right elements when producing a screenshot (w...

Added in a6725e3:

Test hook: --annotations-json <file> CLI flag writes structured JSON array of {id, x, y, width, height} for each element that would be annotated on a screenshot. Backed by new collect_annotations() in screenshot.cpp.

Integration tests added:

• Win32BoundsReasonable — validates all element bounds are within -10k..50k range
• RootBoundsNonZero — root window has positive dimensions
• AnnotationsJsonOutput — annotations file is valid JSON with correct structure
• AnnotationsMatchTreeElements — every annotated ID exists in the tree dump
• WinUI3BoundsIfDetected — if winui3 detected, all WinUI3 elements have sane bounds (skips otherwise)
• XamlBoundsIfDetected — same for UWP XAML elements

[asklar]

@copilot the integration test should create a win32 window with a few controls, at known locations, then verify that the tree dump and the annotations get the right data, including structure as well as bounds

[Copilot]

@copilot the integration test should create a win32 window with a few controls, at known locations, then verify that the tree dump and the annotations get the right data, including structure as well a...

Added KnownWindowFixture in ebbe001 — creates a Win32 window with Button, Edit, and Static controls at known positions (10,10 / 10,50 / 10,90), then verifies:

• TreeStructure: root is LvtTestWindow with exactly 3 children matching expected className, type, text, and framework
• ChildBoundsMatchWin32: each control's JSON bounds match GetWindowRect of its HWND exactly
• AnnotationsIncludeKnownControls (DEBUG): all 4 controls appear in annotations with positive dimensions