sdl_rail_window.cpp

 
#include <algorithm>
#include <string>
#include <utility>
 
#include <freerdp/codec/color.h>
#include <freerdp/log.h>
#include <freerdp/window.h>
 
#include "sdl_rail_platform.hpp"
#include "sdl_rail_window.hpp"
#include "sdl_rail_window_style.hpp"
#include "sdl_utils.hpp"
#include "sdl_window.hpp"
 
#define TAG CLIENT_TAG("sdl.rail.window")
 
/* Timeout bounding stale anchored frame while awaiting server surface update. */
static constexpr uint64_t kAwaitServerFrameMs = 1000;
 
/* Maximum timeout waiting for server restore geometry order. */
static constexpr uint64_t kAwaitRestoreRectMs = 500;
 
/* Reports kept to recognize late echoes. */
static constexpr size_t kMaxReported = 16;
 
/* Unanswered reports are sent again after this. */
static constexpr uint64_t kReportConfirmMs = 1000;
 
static void armDeadline(uint64_t& until, uint64_t ms)
{
  until = SDL_GetTicks() + ms;
  if (!sdl_push_update_after(WINPR_ASSERTING_INT_CAST(Uint32, ms + 1)))
    WLog_WARN(TAG, "SDL_AddTimer failed: %s", SDL_GetError());
}
 
/* A Wayland popup moved again within this time is still being dragged by its app. */
static constexpr uint64_t kMoveActiveMs = 250;
 
/* Longest a Wayland popup frame waits for the configure of its move. */
static constexpr uint64_t kPlaceWaitMs = 50;
 
/* Check for real per-pixel alpha in region. */
static bool regionHasAlpha(const uint8_t* base, uint32_t stride, const SDL_Rect& r)
{
  for (int y = r.y; y < r.y + r.h; y++)
  {
    const uint8_t* row = base + static_cast<size_t>(y) * stride;
    for (int x = r.x; x < r.x + r.w; x++)
      if (row[static_cast<size_t>(x) * 4 + 3] != 0)
        return true;
  }
  return false;
}
 
static bool regionIsBlank(const uint8_t* base, uint32_t stride, const SDL_Rect& r)
{
  for (int y = r.y; y < r.y + r.h; y++)
  {
    const auto* row = reinterpret_cast<const uint32_t*>(base + static_cast<size_t>(y) * stride);
    for (int x = r.x; x < r.x + r.w; x++)
      if (row[x] != 0)
        return false;
  }
  return true;
}
 
SdlRailWindow::SdlRailWindow(uint64_t id, const SDL_Rect& rect) : _id(id), _windowRect(rect)
{
}
 
/* Out of line: SdlWindow is only forward-declared in the header. */
SdlRailWindow::~SdlRailWindow() = default;
 
uint64_t SdlRailWindow::id() const
{
  return _id;
}
 
SDL_WindowID SdlRailWindow::sdlId() const
{
  return _win ? _win->id() : 0;
}
 
SDL_Window* SdlRailWindow::window() const
{
  return _win ? _win->window() : nullptr;
}
 
SDL_Renderer* SdlRailWindow::renderer() const
{
  return _win ? _win->renderer() : nullptr;
}
 
void SdlRailWindow::updateWindowRect(const SDL_Rect& rect)
{
  std::unique_lock lock(_gfxLock);
  /* Minimized, Windows parks the window off screen; keep the rect to restore to. */
  if (_minState.server)
    return;
  _awaitRestoreUntil = 0; /* Server geometry received. */
  if (_localMoveActive)
  {
    /* Adopt server size change during local move. */
    if (!_localMoveIsResize && ((rect.w != _windowRect.w) || (rect.h != _windowRect.h)))
    {
      WLog_DBG(TAG, "size adopted mid-move id=0x%08" PRIx32 " %dx%d -> %dx%d at %d,%d",
               static_cast<uint32_t>(_id), _windowRect.w, _windowRect.h, rect.w, rect.h,
               rect.x, rect.y);
      _windowRect.w = rect.w;
      _windowRect.h = rect.h;
      /* Record server re-anchor position. */
      _localMoveServerPos = { rect.x, rect.y };
      _localMoveSizeChanged = true;
      _painted = false;
    }
    return;
  }
  /* Accept post-move geometry echoes. */
  if (SDL_RectsEqual(&rect, &_windowRect))
  {
    _reported.clear();
    return;
  }
  /* The echo of an older report can arrive after a newer one was sent. */
  const auto echo = std::find_if(_reported.begin(), _reported.end(),
                                 [&](const SDL_Rect& r) { return SDL_RectsEqual(&r, &rect); });
  if (echo != _reported.end())
  {
    WLog_DBG(TAG, "late echo id=0x%08" PRIx32 " %dx%d ignored", static_cast<uint32_t>(_id),
             rect.w, rect.h);
    _reported.erase(_reported.begin(), echo + 1);
    return;
  }
  _reported.clear();
  /* A resize recreates the render target, so the content needs a full re-copy. */
  if ((rect.w != _windowRect.w) || (rect.h != _windowRect.h))
    _painted = false;
  _windowRect = rect;
  /* Mark dirty even if frozen/maximized so pending restore rect applies upon unfreeze. */
  _geometryDirty = true;
}
 
void SdlRailWindow::setLocalMoveActive(bool active)
{
  std::unique_lock lock(_gfxLock);
  _localMoveActive = active;
  if (active)
  {
    _localMoveIsResize = false; /* default to move; setResizeAnchor marks a resize */
    _localMoveSizeChanged = false;
  }
}
 
void SdlRailWindow::setResizeAnchor(bool right, bool bottom)
{
  std::unique_lock lock(_gfxLock);
  _resizeAnchorRight = right;
  _resizeAnchorBottom = bottom;
  _localMoveIsResize = true;
}
 
bool SdlRailWindow::localMoveActive() const
{
  std::unique_lock lock(_gfxLock);
  return _localMoveActive;
}
 
bool SdlRailWindow::localMoveSizeChanged() const
{
  std::unique_lock lock(_gfxLock);
  return _localMoveSizeChanged;
}
 
SDL_Point SdlRailWindow::localMoveServerPos() const
{
  std::unique_lock lock(_gfxLock);
  return _localMoveServerPos;
}
 
void SdlRailWindow::adoptLocalGeometry(const SDL_Rect& rect)
{
  /* Adopt local geometry so the server's echoing WINDOW_ORDER is a no-op (not a size snap). */
  std::unique_lock lock(_gfxLock);
  /* A completed local move settles geometry via the completion path, not the reporter. */
  _geomApplyPending = false;
  /* Translate visible offset by move delta. */
  if (_visOffsetSet)
  {
    _visOffset.x += rect.x - _windowRect.x;
    _visOffset.y += rect.y - _windowRect.y;
  }
  if (!SDL_RectsEqual(&rect, &_windowRect))
  {
    if (_reported.size() >= kMaxReported)
      _reported.erase(_reported.begin());
    _reported.push_back(rect);
    armDeadline(_reportCheckAt, kReportConfirmMs);
  }
  _windowRect = rect;
  _geometryDirty = false;
  /* A resize drag ends here; the server surface still has the pre-drag size. */
  _awaitingFrameUntil =
      (_localMoveActive && _localMoveIsResize) ? (SDL_GetTicks() + kAwaitServerFrameMs) : 0;
  _localMoveActive = false;
  _needsFullBlit = true;
  /* Repaint real content (clear placeholder). */
  if (_hasGfx)
    _gfxDamage.assign(1, SDL_Rect{ 0, 0, static_cast<int>(_gfxW), static_cast<int>(_gfxH) });
}
 
SDL_Rect SdlRailWindow::windowRect() const
{
  std::unique_lock lock(_gfxLock);
  return _windowRect;
}
 
void SdlRailWindow::markDeleted()
{
  std::unique_lock lock(_gfxLock);
  _deleted = true;
}
 
void SdlRailWindow::releaseWindow()
{
  std::unique_lock lock(_gfxLock);
  if (!_win)
    return;
  WLog_DBG(TAG, "release id=0x%08" PRIx32 " %s%s", static_cast<uint32_t>(_id), role(),
           _deleted ? "" : " (SDL parent gone, re-created on next pass)");
  _win.reset();
  /* Back to the "never created" state: create() + first frame + map run again. */
  _mapped = false;
  _painted = false;
  _gfxPresented = false;
  _needsFullBlit = true;
  _geometryDirty = true;
  _parentApplied = false;
  _fullscreen = false;
  _appliedInsets = { 0, 0, 0, 0 };
  _extentsApplied = { 0, 0, 0, 0 };
  _lastWinW = _lastWinH = _lastGfxW = _lastGfxH = 0;
}
 
bool SdlRailWindow::isDeleted() const
{
  std::unique_lock lock(_gfxLock);
  return _deleted;
}
 
bool SdlRailWindow::geomApplyPending() const
{
  std::unique_lock lock(_gfxLock);
  return _geomApplyPending;
}
 
void SdlRailWindow::clearGeomApplyPending()
{
  std::unique_lock lock(_gfxLock);
  _geomApplyPending = false;
}
 
void SdlRailWindow::armLoopEnd()
{
  std::unique_lock lock(_gfxLock);
  _loopEnd.pending = true;
}
 
bool SdlRailWindow::loopEndPending() const
{
  std::unique_lock lock(_gfxLock);
  return _loopEnd.pending;
}
 
void SdlRailWindow::deferMaximize()
{
  std::unique_lock lock(_gfxLock);
  _loopEnd.maximize = true;
}
 
void SdlRailWindow::deferSnap(const SDL_Rect& serverRect)
{
  std::unique_lock lock(_gfxLock);
  _loopEnd.snap = true;
  _loopEnd.snapRect = serverRect;
}
 
void SdlRailWindow::clearLoopEnd()
{
  std::unique_lock lock(_gfxLock);
  _loopEnd = {};
}
 
SdlRailWindow::LoopEndActions SdlRailWindow::takeLoopEnd()
{
  std::unique_lock lock(_gfxLock);
  const LoopEndActions actions{ _loopEnd.maximize, _loopEnd.snap, _loopEnd.snapRect };
  _loopEnd = {};
  return actions;
}
 
bool SdlRailWindow::takeWmOverride(SDL_Rect& outer)
{
  std::unique_lock lock(_gfxLock);
  if (!_wmRefused)
    return false;
  outer = _wmRefusedOuter;
  _wmRefused = false;
  return true;
}
 
void SdlRailWindow::setVisibilityRects(std::vector<SDL_Rect> rects)
{
  std::unique_lock lock(_gfxLock);
  _visRects = std::move(rects);
  _visDirty = true;
}
 
void SdlRailWindow::setVisibleOffset(SDL_Point offset)
{
  std::unique_lock lock(_gfxLock);
  /* Freeze visible offset during local move. */
  if (_localMoveActive)
    return;
  if (_visOffsetSet && (offset.x == _visOffset.x) && (offset.y == _visOffset.y))
    return;
  _visOffset = offset;
  _visOffsetSet = true;
  _visDirty = true;
}
 
void SdlRailWindow::setMinMaxSize(SDL_Point minSize, SDL_Point maxSize)
{
  std::unique_lock lock(_gfxLock);
  _minSize = { std::max(0, minSize.x), std::max(0, minSize.y) };
  _maxSize = { std::max(0, maxSize.x), std::max(0, maxSize.y) };
  _minMaxDirty = true;
  /* Re-apply geometry on min/max change. */
  _geometryDirty = true;
}
 
void SdlRailWindow::setResizeMargins(int left, int top, int right, int bottom)
{
  std::unique_lock lock(_gfxLock);
  const SDL_Rect m = { left, top, right, bottom };
  if (SDL_RectsEqual(&m, &_resizeMargins))
    return;
  _resizeMargins = m;
  /* Margins usually arrive after the first frame; the window must regrow to cover them. */
  if (!railMaximized())
    _geometryDirty = true;
}
 
SDL_Rect SdlRailWindow::resizeMargins() const
{
  std::unique_lock lock(_gfxLock);
  return _resizeMargins;
}
 
void SdlRailWindow::setFrameMargins(const SDL_Rect& m)
{
  std::unique_lock lock(_gfxLock);
  _frameMargins = m;
}
 
SDL_Rect SdlRailWindow::frameMargins() const
{
  std::unique_lock lock(_gfxLock);
  return _frameMargins;
}
 
bool SdlRailWindow::takeUnconfirmedReport(SDL_Rect& rect)
{
  std::unique_lock lock(_gfxLock);
  if ((_reportCheckAt == 0) || (SDL_GetTicks() < _reportCheckAt))
    return false;
  _reportCheckAt = 0;
  if (_reported.empty())
    return false;
  rect = _reported.back();
  _reported.clear();
  return true;
}
 
void SdlRailWindow::setOwner(uint64_t ownerId)
{
  std::unique_lock lock(_gfxLock);
  _ownerId = ownerId;
}
 
uint64_t SdlRailWindow::owner() const
{
  std::unique_lock lock(_gfxLock);
  return _ownerId;
}
 
bool SdlRailWindow::isPopup() const
{
  std::unique_lock lock(_gfxLock);
  return _isPopup;
}
 
bool SdlRailWindow::isFullscreen() const
{
  std::unique_lock lock(_gfxLock);
  return _fullscreen;
}
 
bool SdlRailWindow::activatable() const
{
  std::unique_lock lock(_gfxLock);
  return (!_isPopup || _fullscreen) && ((_exStyle & WS_EX_NOACTIVATE) == 0);
}
 
bool SdlRailWindow::isLayered() const
{
  std::unique_lock lock(_gfxLock);
  return _layered;
}
 
void SdlRailWindow::setShadowAnchored(bool anchored)
{
  std::unique_lock lock(_gfxLock);
  _shadowAnchored = anchored;
}
 
void SdlRailWindow::setFrame(bool frame)
{
  std::unique_lock lock(_gfxLock);
  _frame = frame;
}
 
bool SdlRailWindow::isFrame() const
{
  std::unique_lock lock(_gfxLock);
  return _frame;
}
 
bool SdlRailWindow::styleResizable() const
{
  /* Once resizable, keep band eligibility to avoid oscillation. */
  return _everResizable;
}
 
/* Minimum grabbable width for each outside-band resize edge. */
static constexpr int kMinGrip = 4;
 
SDL_Rect SdlRailWindow::bandMargins() const
{
  if (!_visible || _isPopup || _layered || !styleResizable() || effectivelyMaximized())
    return { 0, 0, 0, 0 };
  /* Enforce minimum grip margins for resizable windows. */
  const SDL_Rect& m = _resizeMargins;
  return { std::max(m.x, kMinGrip), std::max(m.y, kMinGrip), std::max(m.w, kMinGrip),
         std::max(m.h, kMinGrip) };
}
 
SDL_Rect SdlRailWindow::bandInsets() const
{
  /* NativeFrame: the OS adds the band outside the client area, not part of our geometry. */
  const auto band = railPlatformCaps().band;
  if ((band == RailBandMechanism::None) || (band == RailBandMechanism::NativeFrame))
    return { 0, 0, 0, 0 };
  return bandMargins();
}
 
/* Add edge insets (x=L y=T w=R h=B) to a server rect to get its outer (band-inclusive) rect. */
static SDL_Rect addInsets(const SDL_Rect& r, const SDL_Rect& i)
{
  return { r.x - i.x, r.y - i.y, r.w + i.x + i.w, r.h + i.y + i.h };
}
 
/* Inverse of addInsets: strip the insets back off an outer rect to recover the server rect.
 */
static SDL_Rect stripInsets(const SDL_Rect& r, const SDL_Rect& i)
{
  return { r.x + i.x, r.y + i.y, r.w - i.x - i.w, r.h - i.y - i.h };
}
 
/* Caller holds _gfxLock. */
bool SdlRailWindow::isFullDisplaySize() const
{
  SDL_Rect disp{};
  return SDL_GetDisplayBounds(SDL_GetPrimaryDisplay(), &disp) && (_windowRect.w >= disp.w) &&
         (_windowRect.h >= disp.h);
}
 
/* Server rect inflated by the FRESH band insets (the target the window should become); caller
 * holds _gfxLock. Used by reconcile/create to size the window. */
SDL_Rect SdlRailWindow::targetOuterRect() const
{
  SDL_Rect r = addInsets(_windowRect, bandInsets());
  r.x += _localShift.x;
  r.y += _localShift.y;
  return r;
}
 
/* The insets baked into the window ON SCREEN (not the freshly recomputed target). */
SDL_Rect SdlRailWindow::insets() const
{
  std::unique_lock lock(_gfxLock);
  return _appliedInsets;
}
 
/* On-screen outer geometry: _windowRect inflated by the applied insets. */
SDL_Rect SdlRailWindow::outerRect() const
{
  std::unique_lock lock(_gfxLock);
  SDL_Rect r = addInsets(_windowRect, _appliedInsets);
  r.x += _localShift.x;
  r.y += _localShift.y;
  return r;
}
 
SDL_Rect SdlRailWindow::serverRect(const SDL_Rect& outer) const
{
  SDL_Rect r = stripInsets(outer, insets());
  r.x -= _localShift.x;
  r.y -= _localShift.y;
  return r;
}
 
void SdlRailWindow::setLocalShift(const SDL_Point& shift)
{
  std::unique_lock lock(_gfxLock);
  _localShift = shift;
}
 
/* Surface blit offset within the local window (content anchor when maximized). */
SDL_Point SdlRailWindow::blitOffset() const
{
  if (!effectivelyMaximized())
    return { _appliedInsets.x, _appliedInsets.y };
  /* Use frame margins as origin only when surface matches frame-inclusive geometry. */
  const bool frameInSurface =
      ((_frameMargins.x > 0) || (_frameMargins.y > 0)) &&
      (static_cast<int>(_gfxW) == _windowRect.w + _frameMargins.x + _frameMargins.w) &&
      (static_cast<int>(_gfxH) == _windowRect.h + _frameMargins.y + _frameMargins.h);
  SDL_Point content = { 0, 0 };
  if (frameInSurface)
    content = { _frameMargins.x, _frameMargins.y };
  else if (_visOffsetSet)
    content = { _visOffset.x - _windowRect.x, _visOffset.y - _windowRect.y };
  return { -std::clamp(content.x, 0, static_cast<int>(_gfxW)),
         -std::clamp(content.y, 0, static_cast<int>(_gfxH)) };
}
 
/* Shows a held popup frame whose configure never came. */
static Uint32 placeWaitTimer([[maybe_unused]] void* userdata, [[maybe_unused]] SDL_TimerID timerID,
                             [[maybe_unused]] Uint32 interval)
{
  if (!sdl_push_user_event(SDL_EVENT_USER_UPDATE))
    WLog_WARN(TAG, "could not wake the paint loop for a held popup");
  return 0;
}
 
/* Wayland input is relative to where a popup is shown. mutter shows a move at our first commit
 * after its configure, KWin also before it: hold frames until the configure. */
void SdlRailWindow::notePlaced()
{
  std::unique_lock lock(_gfxLock);
  placeRequested();
}
 
/* Caller holds _gfxLock. */
void SdlRailWindow::placeRequested()
{
  _pendingRel = _requestedRel;
  _placeInFlight = false;
}
 
/* Caller holds _gfxLock. True while a move waits for its configure. */
bool SdlRailWindow::holdForPlacement()
{
  if (!_placeInFlight)
    return false;
  if (SDL_GetTicks() - _requestedAt < kPlaceWaitMs)
    return true;
  placeRequested(); /* no configure came */
  return false;
}
 
/* Caller holds _gfxLock. */
void SdlRailWindow::placePopup(const SDL_Rect& vis, const SDL_Rect& parentRect)
{
  const SDL_Point rel = { vis.x - parentRect.x, vis.y - parentRect.y };
  const bool wayland = !railPlatformCaps().supportsWindowPositions;
  const bool moved = (rel.x != _requestedRel.x) || (rel.y != _requestedRel.y);
  if (wayland)
  {
    _requestedRel = rel;
    _requestedAt = SDL_GetTicks();
  }
  if (!SDL_SetWindowPosition(_win->window(), rel.x, rel.y))
  {
    WLog_VRB(TAG, "popup reposition unsupported id=0x%08" PRIx32 ": %s",
             static_cast<uint32_t>(_id), SDL_GetError());
    return;
  }
  if (!wayland)
    return;
  _needsFullBlit = true; /* Wayland applies move on next surface commit */
  if (!moved || !_mapped)
    return;
  _placeInFlight = true;
  if (SDL_AddTimer(static_cast<Uint32>(kPlaceWaitMs + 1), placeWaitTimer, nullptr) == 0)
    WLog_WARN(TAG, "popup placement timer failed: %s", SDL_GetError());
}
 
/* Caller holds _gfxLock. Called after a present. */
void SdlRailWindow::commitPlacement()
{
  if (!_pendingRel)
    return;
  _placedRel = _pendingRel;
  _pendingRel.reset();
}
 
bool SdlRailWindow::placedRel(SDL_Point& rel) const
{
  std::unique_lock lock(_gfxLock);
  /* Only while moving: a resting popup may sit elsewhere (off screen), map it as on X11. */
  if (!_placedRel || (SDL_GetTicks() - _requestedAt >= kMoveActiveMs))
    return false;
  rel = *_placedRel;
  return true;
}
 
SDL_Point SdlRailWindow::serverOrigin() const
{
  std::unique_lock lock(_gfxLock);
  /* Derive server coordinate from blit offset to match on-screen pixels. */
  const SDL_Point dst = blitOffset();
  return { _windowRect.x - dst.x, _windowRect.y - dst.y };
}
 
void SdlRailWindow::setStyle(uint32_t style, uint32_t exStyle)
{
  std::unique_lock lock(_gfxLock);
  const bool wasTopmost = _topmost;
  _style = style;
  _exStyle = exStyle;
  _topmost = (exStyle & WS_EX_TOPMOST) != 0;
  if (_topmost != wasTopmost)
    _topmostDirty = true;
  if (!_everResizable && ((style & (WS_THICKFRAME | WS_MAXIMIZEBOX)) != 0))
  {
    _everResizable = true;
    _styleDirty = true;
  }
  /* Classify popup and layered window types once on creation. */
  if (!_popupClassified)
  {
    const auto classification = classifySdlRailWindowStyle(style, exStyle, _ownerId != 0);
    _isPopup = classification.popup;
    _layered = classification.layered;
    _overlay = classification.overlay;
    _popupClassified = true;
  }
}
 
void SdlRailWindow::setTitle(const std::string& title)
{
  std::unique_lock lock(_gfxLock);
  _title = title;
  _titleDirty = true;
}
 
void SdlRailWindow::setVisible(bool visible)
{
  std::unique_lock lock(_gfxLock);
  _visible = visible;
}
 
void SdlRailWindow::setIcon(const SdlRailIcon& icon)
{
  std::unique_lock lock(_gfxLock);
  _icon = icon;
  _iconDirty = true;
}
/* Caller holds _gfxLock. */
bool SdlRailWindow::create(SDL_Window* parent, const SDL_Rect& parentRect)
{
  if (_win)
    return true;
 
  const RailPlatformCaps& caps = railPlatformCaps();
 
  /* Local window = server rect + band insets (the outside resize band is part of our window). */
  const SDL_Rect vis = targetOuterRect();
  _appliedInsets = bandInsets(); /* the insets baked into the window we are about to create */
  /* Realize full-display popups as fullscreen toplevels on Wayland. */
  const bool fullscreen = _isPopup && !caps.supportsWindowPositions && isFullDisplaySize();
  if (_isPopup && parent && !fullscreen)
  {
    /* SDL popups position parent-relative (works on Wayland too, via xdg_popup). */
    const SDL_Rect rel = { vis.x - parentRect.x, vis.y - parentRect.y, vis.w, vis.h };
    _requestedRel = { rel.x, rel.y };
    _win = std::make_unique<SdlWindow>(
        SdlWindow::createPopup(parent, rel, caps.supportsTransparentWindows, _overlay));
  }
  else if (_isPopup && !caps.supportsWindowPositions && !fullscreen)
  {
    /* No owner yet: a Wayland popup needs a parent; retry once an app window exists. */
    WLog_VRB(TAG, "popup create deferred id=0x%08" PRIx32 ": no parent yet",
             static_cast<uint32_t>(_id));
    return false;
  }
  else
  {
    /* Transparent hides the band ring; a native frame needs a framed window. */
    Uint32 flags = SDL_WINDOW_HIDDEN;
    if (_isPopup || (caps.band != RailBandMechanism::NativeFrame))
      flags |= SDL_WINDOW_BORDERLESS;
    if (caps.supportsTransparentWindows)
      flags |= SDL_WINDOW_TRANSPARENT;
    if ((_exStyle & WS_EX_NOACTIVATE) != 0)
      flags |= SDL_WINDOW_NOT_FOCUSABLE;
    _win = std::make_unique<SdlWindow>(
        SdlWindow::create(SDL_GetPrimaryDisplay(), _title, flags, vis));
  }
  if (!_win || !_win->window() || !_win->renderer())
  {
    _win.reset();
    WLog_WARN(TAG, "create failed id=0x%08" PRIx32 " %s", static_cast<uint32_t>(_id), role());
    return false;
  }
  _win->resizeable(styleResizable());
  if (fullscreen)
  {
    /* Cover the whole output (panel included) - the Wayland-correct way to reach 0,0. */
    _fullscreen = true;
    SDL_SetWindowFullscreen(_win->window(), true);
    WLog_DBG(TAG, "fullscreen id=0x%08" PRIx32 " %dx%d (WS_POPUP spans display)",
             static_cast<uint32_t>(_id), _windowRect.w, _windowRect.h);
  }
 
  /* Backend setup (Wayland seat, Win32 frame), then the server geometry again: dropping the
   * Win32 caption grew the client area. */
  if (!_isPopup)
  {
    railPlatformPrepareWindow(_win->window());
    std::ignore = railPlatformSetWindowRect(_win->window(), vis);
  }
 
  WLog_DBG(TAG,
           "create id=0x%08" PRIx32 " sdl=%" PRIu32 " %s vis=%dx%d+%d+%d margins=L%d,T%d,R%d,B%d "
           "transparent=%d",
           static_cast<uint32_t>(_id), static_cast<uint32_t>(_win->id()), role(), vis.w, vis.h,
           vis.x, vis.y, _resizeMargins.x, _resizeMargins.y, _resizeMargins.w, _resizeMargins.h,
           caps.supportsTransparentWindows ? 1 : 0);
  return true;
}
 
bool SdlRailWindow::reconcile(SDL_Window* parent, const SDL_Rect& parentRect)
{
  std::unique_lock lock(_gfxLock);
 
  /* Hidden windows get no local SDL window. Layered windows (e.g. docks) need GFX content and
   * vis-rects to show; this hides empty DWM snap overlays. */
  const bool popupReady = !_isPopup || _hasGfx;
  /* Suppress server shadow frames and unparented full-display overlays. */
  const bool unplaceable =
      _frame || (_overlay && !railPlatformCaps().supportsWindowPositions && isFullDisplaySize());
  /* Layered window is shown only when anchored to an adjoining visible popup or overlay. */
  const bool drawable =
      _visible && (_windowRect.w > 0) && (_windowRect.h > 0) && popupReady && !unplaceable &&
      (!_layered || (_hasGfx && !_visRects.empty() && (_shadowAnchored || _overlay)));
 
  if (!drawable)
  {
    /* Log standalone layered windows suppressed by popup shadow heuristic. */
    if (_layered && _hasGfx && !_visRects.empty() && !_shadowAnchored && !_overlay &&
        !_shadowSuppressLogged)
    {
      _shadowSuppressLogged = true;
      WLog_DBG(TAG,
               "shadow-rule suppressed id=0x%08" PRIx32 " %dx%d style=0x%08" PRIx32
               " ex=0x%08" PRIx32,
               static_cast<uint32_t>(_id), _windowRect.w, _windowRect.h, _style, _exStyle);
    }
    if (_win)
    {
      if ((SDL_GetWindowFlags(_win->window()) & SDL_WINDOW_HIDDEN) == 0)
      {
        WLog_DBG(TAG, "hide id=0x%08" PRIx32 " %s", static_cast<uint32_t>(_id), role());
        SDL_HideWindow(_win->window());
      }
      _mapped = false;
    }
    if (_isPopup && !_visible)
    {
      _gfxPresented = false;
      _hasGfx = false;
    }
    return false;
  }
 
  if (!_win)
  {
    if (!create(parent, parentRect))
      return false;
    _geometryDirty = false;
    /* Shown + raised in paint() after the first frame (created hidden). */
  }
 
  /* create() returned false on failure, so _win is non-null from here down. */
  if (_topmostDirty)
  {
    _topmostDirty = false;
    /* X11 only; Wayland has no protocol for this, the call still returns true. */
    if (!_isPopup && !_layered)
      std::ignore = SDL_SetWindowAlwaysOnTop(_win->window(), _topmost);
  }
 
  /* Resizability first: SDL refuses to maximize a non-resizable window. */
  if (_styleDirty)
  {
    _win->resizeable(styleResizable());
    _styleDirty = false;
    /* Insets refresh on geometry updates to avoid flicker. */
  }
 
  /* State first: maximized/minimized gates the geometry apply below. */
  /* Hold geometry sync until server sends restored rect to prevent re-maximizing. */
  if (applyServerState(_maxState, "maximize", SDL_MaximizeWindow))
    armDeadline(_awaitRestoreUntil, kAwaitRestoreRectMs);
  /* Still minimized after our SC_RESTORE: ask once more, then follow the server. */
  if ((_localRestoreUntil != 0) && (SDL_GetTicks() >= _localRestoreUntil))
  {
    _localRestoreUntil = 0;
    if (_minState.server && !_minState.rail && !_restoreRetried)
    {
      _restoreRetried = true;
      _restoreRetry = true;
      armDeadline(_localRestoreUntil, kAwaitRestoreRectMs);
    }
    else if (_minState.server != _minState.rail)
      _minState.dirty = true;
  }
  std::ignore = applyServerState(_minState, "minimize", SDL_MinimizeWindow);
  const bool restorePending = restoreRectPending();
 
  /* Update insets across maximize transitions outside active drag grab. */
  const bool maxed = effectivelyMaximized();
  const SDL_Rect band = bandInsets();
  if ((maxed != _wasMaximized) && !_localMoveActive && !restorePending)
  {
    setAppliedInsets(band);
    if (!maxed)
      _geometryDirty = true;
    _wasMaximized = maxed;
  }
 
  /* X11: set frame extents before the resize (KWin needs that), not while restoring. */
  if ((railPlatformCaps().band == RailBandMechanism::FrameExtents) && !restorePending &&
      !SDL_RectsEqual(&band, &_extentsApplied) && railPlatformSetBand(_win->window(), band))
  {
    _extentsApplied = band;
  }
  const bool wmOwnsGeometry =
      _localMoveActive || geometryFrozen() || _fullscreen || restorePending;
  /* Clamp min size hints to target bounds so stale hints do not block programmatic resize.
   * Defer size hints and programmatic resize during active WM move/resize grab. */
  if ((_minMaxDirty || _geometryDirty) && !wmOwnsGeometry)
  {
    const SDL_Rect vis = targetOuterRect();
    const int bandW = band.x + band.w;
    const int bandH = band.y + band.h;
    /* Convert server track size hints (which include server margins) to outer window bounds. */
    const SDL_Rect& m = _resizeMargins;
    const int padW = bandW - m.x - m.w;
    const int padH = bandH - m.y - m.h;
    const auto toOuter = [](int track, int pad)
    { return (track > 0) ? std::max(1, track + pad) : 0; };
    const int minW = toOuter(_minSize.x, padW);
    const int minH = toOuter(_minSize.y, padH);
    SDL_SetWindowMinimumSize(_win->window(), std::clamp(minW, 0, vis.w),
                             std::clamp(minH, 0, vis.h));
    int maxW = toOuter(_maxSize.x, padW);
    int maxH = toOuter(_maxSize.y, padH);
    /* Wayland: cap to the usable area - an oversized window cannot be dragged into reach. */
    SDL_Rect usable{};
    if (!railPlatformCaps().supportsWindowPositions &&
        SDL_GetDisplayUsableBounds(SDL_GetPrimaryDisplay(), &usable))
    {
      const int capW = usable.w + bandW;
      const int capH = usable.h + bandH;
      if ((maxW == 0) || (maxW > capW))
        maxW = capW;
      if ((maxH == 0) || (maxH > capH))
        maxH = capH;
    }
    SDL_SetWindowMaximumSize(_win->window(), maxW, maxH);
    _minMaxDirty = false;
  }
 
  /* Skip geometry apply when maximized, minimized or WM-dragged. */
  if (_geometryDirty && !wmOwnsGeometry)
  {
    const SDL_Rect vis = targetOuterRect();
    /* Record applied insets so server coordinate mapping strips the exact offset. */
    setAppliedInsets(band);
    int cw = 0;
    int ch = 0;
    SDL_GetWindowSize(_win->window(), &cw, &ch);
    bool applied = false;
    bool placed = false; /* railPlatformSetWindowRect set position and size at once */
    /* Apply position and size if changed. */
    if (_isPopup && parent)
    {
      placePopup(vis, parentRect);
      applied = true;
    }
    else if (railPlatformCaps().supportsWindowPositions &&
             !(_isPopup && SDL_GetWindowParent(_win->window())))
    {
      int cx = 0;
      int cy = 0;
      SDL_GetWindowPosition(_win->window(), &cx, &cy);
      if ((cx != vis.x) || (cy != vis.y))
      {
        placed = railPlatformSetWindowRect(_win->window(), vis);
        if (!placed)
          SDL_SetWindowPosition(_win->window(), vis.x, vis.y);
        applied = true;
      }
    }
    if ((cw != vis.w) || (ch != vis.h))
    {
      if (!placed && !railPlatformSetWindowRect(_win->window(), vis))
        std::ignore = _win->resize({ vis.w, vis.h });
      applied = true;
      /* Settle window resize via SDL_SyncWindow before reading back geometry to avoid
       * adopting transient dimensions while configure events are in flight. */
      if (railPlatformCaps().supportsWindowPositions && !_isPopup && !_localMoveActive &&
          !_loopEnd.pending)
      {
        const bool settled = SDL_SyncWindow(_win->window());
        int aw = 0;
        int ah = 0;
        SDL_GetWindowSize(_win->window(), &aw, &ah);
        if (settled && ((aw != vis.w) || (ah != vis.h)))
        {
          /* Adopt WM size while preserving server origin. */
          _wmRefusedOuter = { vis.x, vis.y, aw, ah };
          _wmRefused = true;
          applied = false; /* Geometry refused by WM; do not await echo. */
        }
      }
    }
    _geometryDirty = false;
    /* Echo filtering is only tracked for top-level app windows. */
    _geomApplyPending = applied && !_isPopup;
  }
  /* Make dialog transient for owner. */
  /* Attach only to a shown owner: SDL hides child windows with their parent. */
  if (!_isPopup && parent && !_parentApplied &&
      ((SDL_GetWindowFlags(parent) & SDL_WINDOW_HIDDEN) == 0))
  {
    if (SDL_SetWindowParent(_win->window(), parent))
    {
      _parentApplied = true;
      /* Reattached after the owner was shown again: the owner was mapped on top. */
      if (((SDL_GetWindowFlags(_win->window()) & SDL_WINDOW_HIDDEN) == 0) &&
          !railPlatformRaiseOwned(_win->window()))
        WLog_WARN(TAG, "raising dialog id=0x%08" PRIx32 " failed",
                  static_cast<uint32_t>(_id));
    }
  }
  if (_titleDirty)
  {
    if (!_isPopup)
      SDL_SetWindowTitle(_win->window(), _title.c_str());
    _titleDirty = false;
  }
  if (_iconDirty)
  {
    if (!_isPopup && !_icon.bgra.empty())
    {
      SDL_Surface* s = SDL_CreateSurfaceFrom(
          static_cast<int>(_icon.w), static_cast<int>(_icon.h), SDL_PIXELFORMAT_BGRA32,
          _icon.bgra.data(), static_cast<int>(_icon.w * 4));
      if (s)
      {
        if (!SDL_SetWindowIcon(_win->window(), s))
          WLog_WARN(TAG, "SDL_SetWindowIcon failed for window 0x%08" PRIx32 ": %s",
                    static_cast<uint32_t>(_id), SDL_GetError());
        SDL_DestroySurface(s);
      }
    }
    _iconDirty = false;
  }
 
  /* Defer show until first frame; this runs every reconcile, so skip the call once visible. */
  if (!_minState.rail && _gfxPresented &&
      (SDL_GetWindowFlags(_win->window()) & SDL_WINDOW_HIDDEN))
  {
    /* If transient-for owner was closed or hidden, show dialog standalone. */
    SDL_Window* owner = _isPopup ? nullptr : SDL_GetWindowParent(_win->window());
    if (owner && ((SDL_GetWindowFlags(owner) & SDL_WINDOW_HIDDEN) != 0))
    {
      if (SDL_SetWindowParent(_win->window(), nullptr))
        _parentApplied = false; /* reattach once the owner is shown again */
      else
        WLog_WARN(TAG, "detaching dialog id=0x%08" PRIx32 " failed: %s",
                  static_cast<uint32_t>(_id), SDL_GetError());
    }
    SDL_ShowWindow(_win->window());
  }
  return true;
}
 
bool SdlRailWindow::takeSurfaceChange(uint32_t surfaceId)
{
  std::unique_lock lock(_gfxLock);
  if (_surfaceId == surfaceId)
    return false;
  _surfaceId = surfaceId;
  return true;
}
 
void SdlRailWindow::updateGfxSurface(const void* data, uint32_t stride, uint32_t width,
                                     uint32_t height, const RECTANGLE_16* damage, uint32_t nbDamage,
                                     WINPR_ATTR_UNUSED uint32_t format)
{
  std::unique_lock lock(_gfxLock);
  /* The copies below are byte-for-byte; gdi_CreateSurface yields nothing else. */
  WINPR_ASSERT((format == PIXEL_FORMAT_BGRA32) || (format == PIXEL_FORMAT_BGRX32));
  /* Deep-copy GDI pixels to prevent UAF. */
  const size_t bytes = static_cast<size_t>(stride) * height;
  if (!data || (bytes == 0) || (width == 0) || (height == 0))
  {
    if (_hasGfx)
      WLog_DBG(TAG, "gfx cleared id=0x%08" PRIx32 " (surface unmapped)",
               static_cast<uint32_t>(_id));
    _gfxBuffer.clear();
    _hasGfx = false;
    _gfxDamage.clear();
    _gfxStride = stride;
    _gfxW = width;
    _gfxH = height;
    _gfxVisOrigin = { 0, 0 };
    return;
  }
 
  const auto* src = static_cast<const uint8_t*>(data);
  /* Geometry/stride change, first frame, or no damage rects: full copy + repaint. */
  const bool full = !_hasGfx || (_gfxBuffer.size() != bytes) || (_gfxStride != stride) ||
                    (_gfxW != width) || (_gfxH != height) || (nbDamage == 0);
  if (full)
  {
    const SDL_Rect bounds{ 0, 0, static_cast<int>(width), static_cast<int>(height) };
    /* Check _hasGfx first to avoid redundant full-surface blank checks once content exists. */
    if (!_hasGfx && regionIsBlank(src, stride, bounds))
      return;
    _gfxBuffer.assign(src, src + bytes);
    _gfxDamage.assign(1, SDL_Rect{ 0, 0, static_cast<int>(width), static_cast<int>(height) });
    _needsFullBlit = true;
    /* Blend real alpha, force opaque otherwise. */
    _gfxHasAlpha = honorsAlpha() &&
                   regionHasAlpha(_gfxBuffer.data(), stride,
                                  { 0, 0, static_cast<int>(width), static_cast<int>(height) });
  }
  else
  {
    const SDL_Rect bounds{ 0, 0, static_cast<int>(width), static_cast<int>(height) };
    for (uint32_t i = 0; i < nbDamage; i++)
    {
      const SDL_Rect r{ damage[i].left, damage[i].top, damage[i].right - damage[i].left,
                      damage[i].bottom - damage[i].top };
      SDL_Rect clip{};
      if (!SDL_GetRectIntersection(&r, &bounds, &clip))
        continue;
      std::ignore = freerdp_image_copy_no_overlap(
          _gfxBuffer.data(), PIXEL_FORMAT_BGRA32, stride, static_cast<UINT32>(clip.x),
          static_cast<UINT32>(clip.y), static_cast<UINT32>(clip.w),
          static_cast<UINT32>(clip.h), src, PIXEL_FORMAT_BGRA32, stride,
          static_cast<UINT32>(clip.x), static_cast<UINT32>(clip.y), nullptr,
          FREERDP_FLIP_NONE);
      _gfxDamage.push_back(clip);
      /* Alpha may first appear in a later incremental frame (e.g. a menu fading in). */
      if (honorsAlpha() && !_gfxHasAlpha && regionHasAlpha(_gfxBuffer.data(), stride, clip))
        _gfxHasAlpha = true;
    }
    /* A hidden window accumulates rects without ever painting; collapse to one full repaint. */
    if (_gfxDamage.size() > 32)
      _gfxDamage.assign(1,
                        SDL_Rect{ 0, 0, static_cast<int>(width), static_cast<int>(height) });
  }
  if ((_gfxW != width) || (_gfxH != height))
  {
    _resizeAnchorRight = false;
    _resizeAnchorBottom = false;
    _needsFullBlit = true;
    /* Invalidate surface origin until visibility rect matching new dimensions arrives. */
    _gfxVisOrigin = { 0, 0 };
  }
  _hasGfx = true;
  _gfxStride = stride;
  _gfxW = width;
  _gfxH = height;
  WLog_VRB(TAG, "gfx id=0x%08" PRIx32 " %ux%u full=%d nDamage=%u", static_cast<uint32_t>(_id),
           width, height, full ? 1 : 0, nbDamage);
}
 
void SdlRailWindow::invalidateAll()
{
  std::unique_lock lock(_gfxLock);
  _needsFullBlit = true;
  if (_hasGfx)
    _gfxDamage.assign(1, SDL_Rect{ 0, 0, static_cast<int>(_gfxW), static_cast<int>(_gfxH) });
}
 
void SdlRailWindow::setServerState(StateSync& s, bool m)
{
  std::unique_lock lock(_gfxLock);
  if (m != s.server)
  {
    s.server = m;
    s.dirty = true;
  }
}
 
void SdlRailWindow::setServerMaximized(bool m)
{
  setServerState(_maxState, m);
}
 
void SdlRailWindow::setServerMinimized(bool m)
{
  {
    std::unique_lock lock(_gfxLock);
    /* Late minimize of a window the user already restored. */
    if (m && (_localRestoreUntil != 0) && (SDL_GetTicks() < _localRestoreUntil))
    {
      _minState.server = true;
      return;
    }
    if (!m)
      _localRestoreUntil = 0;
  }
  setServerState(_minState, m);
}
 
void SdlRailWindow::noteLocalRestore()
{
  std::unique_lock lock(_gfxLock);
  _restoreRetried = false;
  armDeadline(_localRestoreUntil, kAwaitRestoreRectMs);
}
 
bool SdlRailWindow::takeRestoreRetry()
{
  std::unique_lock lock(_gfxLock);
  return std::exchange(_restoreRetry, false);
}
 
bool SdlRailWindow::applyServerState(StateSync& s, const char* what, bool (*enter)(SDL_Window*))
{
  if (!s.dirty)
    return false;
  bool restored = false;
  if (s.server && !s.rail)
  {
    /* Apply server maximize/minimize state. */
    s.rail = true;
    WLog_DBG(TAG, "%s id=0x%08" PRIx32 "", what, static_cast<uint32_t>(_id));
    enter(_win->window());
  }
  else if (!s.server && s.rail)
  {
    restored = true;
    s.rail = false;
    WLog_DBG(TAG, "restore id=0x%08" PRIx32 " (%s)", static_cast<uint32_t>(_id), what);
    SDL_RestoreWindow(_win->window());
  }
  else
  {
    s.dirty = false;
    return false;
  }
  /* Settle WM state before reading window properties. */
  (void)SDL_SyncWindow(_win->window());
  s.dirty = false;
  return restored;
}
 
/* Caller holds _gfxLock. */
void SdlRailWindow::setAppliedInsets(const SDL_Rect& insets)
{
  if (SDL_RectsEqual(&insets, &_appliedInsets))
    return;
  _appliedInsets = insets;
  _needsFullBlit = true;
}
 
bool SdlRailWindow::insetsStale() const
{
  std::unique_lock lock(_gfxLock);
  return _wasMaximized != effectivelyMaximized();
}
 
/* Caller holds _gfxLock. */
bool SdlRailWindow::restoreRectPending() const
{
  return (_awaitRestoreUntil != 0) && (SDL_GetTicks() < _awaitRestoreUntil);
}
 
bool SdlRailWindow::effectivelyMaximized() const
{
  return _maxState.rail ||
         (_win && (SDL_GetWindowFlags(_win->window()) & SDL_WINDOW_MAXIMIZED) != 0);
}
 
bool SdlRailWindow::paint(SDL_Surface* primary, SDL_PixelFormat fallbackFormat,
                          const std::vector<SDL_Rect>& damage, SDL_Window* parent,
                          const SDL_Rect& parentRect)
{
  if (!reconcile(parent, parentRect))
    return false;
 
  auto ok = false;
  auto legacy = false;
  {
    std::unique_lock lock(_gfxLock);
    if (_hasGfx)
      ok = paintGfx(fallbackFormat);
    else
      legacy = true;
  }
  if (legacy)
    ok = paintLegacy(primary, damage);
 
  /* Map in the same pass as the first frame, else the window defers a frame (menu lag). */
  if (_gfxPresented && !_mapped && !_minState.rail)
  {
    _mapped = true;
    WLog_DBG(TAG, "map id=0x%08" PRIx32 " %s", static_cast<uint32_t>(_id), role());
    SDL_ShowWindow(_win->window());
    /* Reassert target position after show to override stale events. */
    if (_isPopup && parent)
    {
      std::unique_lock lock(_gfxLock);
      const SDL_Rect vis = targetOuterRect();
      placePopup(vis, parentRect);
    }
    if (((!_isPopup && !_layered) || _fullscreen) && ((_exStyle & WS_EX_NOACTIVATE) == 0))
      _win->raise(); /* Bring app and fullscreen windows to front. */
  }
  return ok;
}
 
/* Caller holds _gfxLock. Blits the window-mapped GFX surface via the shared SdlWindow path. */
bool SdlRailWindow::paintGfx(SDL_PixelFormat format)
{
  if (holdForPlacement())
    return true;
  /* Blit using applied insets to preserve resize borders. */
  const SDL_Rect bi = _appliedInsets;
  int ww = 0;
  int wh = 0;
  SDL_GetWindowSizeInPixels(_win->window(), &ww, &wh);
  const int cw = ww - bi.x - bi.w; /* content area inside the insets */
  const int ch = wh - bi.y - bi.h;
  const int gw =
      static_cast<int>(_gfxW); /* GFX surface size as int (used across the blit paths) */
  const int gh = static_cast<int>(_gfxH);
  /* Only adopt visibility origin rects that match current surface dimensions. */
  if ((_visRects.size() == 1) && (_visRects.at(0).w == gw) && (_visRects.at(0).h == gh))
    _gfxVisOrigin = { _visRects.at(0).x, _visRects.at(0).y };
  /* Server surface caught up with the content area: the drag is fully settled. */
  if (!_localMoveActive && (cw == gw) && (ch == gh))
  {
    _resizeAnchorRight = false;
    _resizeAnchorBottom = false;
    _awaitingFrameUntil = 0;
  }
  /* Timeout safety net for server resize frame anchoring. */
  if ((_awaitingFrameUntil != 0) && (SDL_GetTicks() > _awaitingFrameUntil))
  {
    WLog_DBG(TAG, "resize frame timeout id=0x%08" PRIx32 " win=%dx%d gfx=%dx%d",
             static_cast<uint32_t>(_id), cw, ch, gw, gh);
    _awaitingFrameUntil = 0;
    /* Adopt server surface dimensions if resize was clamped. */
    if ((cw != gw) || (ch != gh))
    {
      if (_resizeAnchorRight)
        _windowRect.x += _windowRect.w - gw;
      if (_resizeAnchorBottom)
        _windowRect.y += _windowRect.h - gh;
      _windowRect.w = gw;
      _windowRect.h = gh;
      _resizeAnchorRight = false;
      _resizeAnchorBottom = false;
      _geometryDirty = true;
      _needsFullBlit = true;
    }
  }
 
  /* Keep stale frame anchored while awaiting server GFX surface. */
  const bool awaitingServerResize = (_awaitingFrameUntil != 0) && ((cw != gw) || (ch != gh));
  const bool localResize = awaitingServerResize ||
                           (_localMoveActive && (_localMoveIsResize || (cw != gw) || (ch != gh)));
 
  /* Window or surface size changed outside a drag: repaint once even without damage. */
  const bool winResized = (ww != _lastWinW) || (wh != _lastWinH);
  const bool gfxResized = (gw != _lastGfxW) || (gh != _lastGfxH);
  const bool serverResize =
      !_localMoveActive && !awaitingServerResize &&
      (winResized || gfxResized || _needsFullBlit || _pendingRel.has_value());
 
  /* Skip undamaged frames. */
  if (!localResize && !serverResize && _gfxDamage.empty() && !(_layered && _visDirty))
  {
    WLog_VRB(TAG, "paintGfx skip id=0x%08" PRIx32 " no-damage no-resize",
             static_cast<uint32_t>(_id));
    return true;
  }
 
  /* Gate popup mapping until initial content is presented to prevent black flash. */
  if (_isPopup && !_gfxPresented && (_gfxW > 0) && (_gfxH > 0))
  {
    const uint32_t first = *reinterpret_cast<const uint32_t*>(_gfxBuffer.data());
    /* BGRA32 as a host word: alpha on top, so mask it off and test the colour alone. */
    bool uniform = (first & 0x00FFFFFFu) == 0;
    for (uint32_t y = 0; uniform && (y < _gfxH); y++)
    {
      const auto* row = reinterpret_cast<const uint32_t*>(
          _gfxBuffer.data() + static_cast<size_t>(y) * _gfxStride);
      for (uint32_t x = 0; x < _gfxW; x++)
        if (row[x] != first)
        {
          uniform = false;
          break;
        }
    }
    if (uniform)
    {
      /* Disarm repaint triggers while popup surface remains blank. */
      _gfxDamage.clear();
      _needsFullBlit = false;
      _lastWinW = ww;
      _lastWinH = wh;
      _lastGfxW = gw;
      _lastGfxH = gh;
      return true;
    }
  }
 
  /* RAIL content is mostly opaque (ignore alpha). Exception: layered app windows. */
  SDL_PixelFormat contentFormat = format;
  if (format == SDL_PIXELFORMAT_BGRA32)
  {
    const bool blend = railPlatformCaps().supportsTransparentWindows;
    if (!blend || (_isPopup && !_layered && !_gfxHasAlpha))
      contentFormat = SDL_PIXELFORMAT_BGRX32;
  }
 
  SDL_Surface* s = SDL_CreateSurfaceFrom(gw, gh, contentFormat, _gfxBuffer.data(),
                                         static_cast<int>(_gfxStride));
  if (!s)
  {
    WLog_WARN(TAG, "paintGfx id=0x%08" PRIx32 " SDL_CreateSurfaceFrom failed: %s",
              static_cast<uint32_t>(_id), SDL_GetError());
    return false;
  }
 
  /* Content blits at the inset offset; the ring outside it is the transparent resize band. */
  if (localResize)
  {
    /* Crop frame rows during mid-drag restore until new surface arrives. */
    const SDL_Point crop = { std::clamp(_gfxVisOrigin.x, 0, gw),
                           std::clamp(_gfxVisOrigin.y, 0, gh) };
    /* Anchor the stale frame to the fixed corner. */
    const SDL_Point off = { (_resizeAnchorRight ? (ww - bi.w - gw) : bi.x) - crop.x,
                          (_resizeAnchorBottom ? (wh - bi.h - gh) : bi.y) - crop.y };
    /* Show dashes only during active drag; on release, keep the clean anchored frame. */
    const bool showDashes = _localMoveActive && _localMoveIsResize;
    /* Only fill revealed area during resize, not move drag. */
    const bool fillRevealed = showDashes || awaitingServerResize;
    std::ignore =
        _win->paintResizeFrame(s, off, !_gfxDamage.empty(), bi, fillRevealed, showDashes);
  }
  else
  {
    /* Render accumulated damage or re-blit full surface on bare resize. */
    const SDL_Rect full = { 0, 0, gw, gh };
    const SDL_Point dst = blitOffset();
    const bool maxed = effectivelyMaximized();
    if (_layered && !_visRects.empty() && !maxed)
    {
      /* Layered shadow cutout: draw only inside visibility rects. */
      const bool logClip = _visDirty;
      /* Consume full-blit request on resize. */
      if (_visDirty || serverResize)
      {
        /* Wipe so newly-excluded regions don't keep stale pixels. */
        std::ignore = _win->fill(static_cast<Uint8>(0), 0, 0, 0);
        _gfxDamage.assign(1, full);
        _visDirty = false;
        _needsFullBlit = false;
      }
      const SDL_Point off = { _visOffsetSet ? (_visOffset.x - _windowRect.x) : 0,
                            _visOffsetSet ? (_visOffset.y - _windowRect.y) : 0 };
      if (logClip)
        WLog_VRB(TAG,
                 "clip id=0x%08" PRIx32 " off=%d,%d nVis=%zu vis0=%dx%d+%d+%d win=%dx%d "
                 "gfx=%ux%u",
                 static_cast<uint32_t>(_id), off.x, off.y, _visRects.size(),
                 _visRects.at(0).w, _visRects.at(0).h, _visRects.at(0).x, _visRects.at(0).y,
                 ww, wh, _gfxW, _gfxH);
      const std::vector<SDL_Rect>& damageRects = _gfxDamage;
      std::vector<SDL_Rect> draw;
      draw.reserve(damageRects.size() * _visRects.size());
      for (const auto& d : damageRects)
      {
        for (auto v : _visRects)
        {
          v.x += off.x;
          v.y += off.y;
          SDL_Rect part{};
          if (SDL_GetRectIntersection(&d, &v, &part))
            draw.push_back(part);
        }
      }
      if (!draw.empty()) /* empty vector would mean "draw everything" to drawRects */
        std::ignore = _win->drawRects(s, dst, draw);
    }
    else if (_gfxDamage.empty() || serverResize)
    {
      /* Clear target and redraw surface on size change. */
      if (serverResize)
      {
        const bool transparentWin =
            (SDL_GetWindowFlags(_win->window()) & SDL_WINDOW_TRANSPARENT) != 0;
        /* Wipe surface to avoid black border artifacts on opaque windows. */
        std::ignore = _win->fill(static_cast<Uint8>(0), 0, 0,
                                 static_cast<Uint8>(transparentWin ? 0x00 : 0xFF));
        _needsFullBlit = false;
      }
      std::ignore = _win->drawRects(s, dst, { full });
    }
    else
    {
      std::ignore = _win->drawRects(s, dst, _gfxDamage);
    }
 
    _win->updateSurface();
    _gfxPresented = true; /* First frame rendered; paint() may map the window. */
    commitPlacement();
  }
  SDL_DestroySurface(s);
  WLog_VRB(TAG, "paintGfx id=0x%08" PRIx32 " mode=%s win=%dx%d dmg=%zu",
           static_cast<uint32_t>(_id),
           localResize ? "resize" : (serverResize ? "server-resize" : "gfx"), ww, wh,
           _gfxDamage.size());
  _gfxDamage.clear();
  /* Preserve size baseline during local resize. */
  if (!localResize)
  {
    _lastWinW = ww;
    _lastWinH = wh;
    _lastGfxW = gw;
    _lastGfxH = gh;
  }
  return true;
}
 
bool SdlRailWindow::paintLegacy(SDL_Surface* primary, const std::vector<SDL_Rect>& damage)
{
  SDL_Rect rect{};
  SDL_Rect bi{};
  std::vector<SDL_Rect> vis;
  bool full = false;
  {
    std::unique_lock lock(_gfxLock);
    /* Layered decorations have no meaningful content in the shared primary. */
    if (!primary || _layered || (_windowRect.w <= 0) || (_windowRect.h <= 0) ||
        holdForPlacement())
      return true;
 
    /* Damage-driven: re-copy only server-updated regions, keep the last frame elsewhere. */
    full = !_painted || _pendingRel.has_value();
    if (!full && damage.empty())
    {
      WLog_VRB(TAG, "paintLegacy skip id=0x%08" PRIx32 " no-damage",
               static_cast<uint32_t>(_id));
      return true;
    }
 
    rect = _windowRect;
    bi = _appliedInsets;
    vis = _visRects;
  }
 
  if (vis.empty())
    vis.push_back({ 0, 0, rect.w, rect.h });
 
  /* Paint only the visible sub-rects (stacked windows don't bleed through), clamped and 1:1. */
  const SDL_Rect bounds = { 0, 0, primary->w, primary->h };
  bool blitted = false;
  for (const auto& v : vis)
  {
    SDL_Rect src = { rect.x + v.x, rect.y + v.y, v.w, v.h };
    SDL_Rect clipped{};
    if (!SDL_GetRectIntersection(&src, &bounds, &clipped))
      continue;
 
    if (full)
    {
      SDL_Rect dst = { clipped.x - rect.x + bi.x, clipped.y - rect.y + bi.y, clipped.w,
                     clipped.h };
      if (_win->blit(primary, clipped, dst))
        blitted = true;
      continue;
    }
    for (const auto& d : damage)
    {
      SDL_Rect part{};
      if (!SDL_GetRectIntersection(&clipped, &d, &part))
        continue;
      SDL_Rect dst = { part.x - rect.x + bi.x, part.y - rect.y + bi.y, part.w, part.h };
      if (_win->blit(primary, part, dst))
        blitted = true;
    }
  }
  if (blitted)
  {
    {
      std::unique_lock lock(_gfxLock);
      _painted = true;
    }
    _win->updateSurface();
    {
      std::unique_lock lock(_gfxLock);
      commitPlacement();
    }
    WLog_VRB(TAG, "paintLegacy id=0x%08" PRIx32 " full=%d visRects=%zu",
             static_cast<uint32_t>(_id), full ? 1 : 0, vis.size());
    /* Defer mapping until GFX frame arrives to avoid desktop flash. */
  }
  return true;
}