sdl_x11.cpp

 
#include "sdl_x11.hpp"
 
#include <utility>
 
#include <winpr/platform.h>
#include "sdl_utils.hpp"
 
#include <cstdio>
 
#if defined(WITH_SDL_X11_NATIVE)
 
#include <X11/Xatom.h>
#include <X11/Xlib.h>
 
bool sdl_x11_has_compositor()
{
  if (!sdl::utils::isX11Driver())
    return true;
  /* Short-lived connection: caps are detected once, and no SDL window may exist yet. */
  Display* dpy = XOpenDisplay(nullptr);
  if (!dpy)
    return true; /* Default to composited if undetected. */
  char sel[32];
  (void)snprintf(sel, sizeof(sel), "_NET_WM_CM_S%d", DefaultScreen(dpy));
  const Atom atom = XInternAtom(dpy, sel, False);
  const bool composited = (XGetSelectionOwner(dpy, atom) != None);
  XCloseDisplay(dpy);
  return composited;
}
 
/* The window's X11 Display + Window, or {nullptr, 0} off the X11 driver. */
static std::pair<Display*, Window> sdl_x11_handles(SDL_Window* window)
{
  if (!window || !sdl::utils::isX11Driver())
    return { nullptr, 0 };
  auto props = SDL_GetWindowProperties(window);
  auto dpy = static_cast<Display*>(
      SDL_GetPointerProperty(props, SDL_PROP_WINDOW_X11_DISPLAY_POINTER, nullptr));
  const auto xwin =
      static_cast<Window>(SDL_GetNumberProperty(props, SDL_PROP_WINDOW_X11_WINDOW_NUMBER, 0));
  return { dpy, xwin };
}
 
bool sdl_x11_begin_move_size(SDL_Window* window, int netDirection)
{
  const auto [dpy, xwin] = sdl_x11_handles(window);
  if (!dpy || (xwin == 0))
    return false;
 
  /* One display per process; resolve the atom once instead of a roundtrip per move. */
  static Atom s_moveResize = None;
  if (s_moveResize == None)
    s_moveResize = XInternAtom(dpy, "_NET_WM_MOVERESIZE", False);
 
  float gx = 0;
  float gy = 0;
  SDL_GetGlobalMouseState(&gx, &gy);
 
  XClientMessageEvent xev = {};
  xev.type = ClientMessage;
  xev.window = xwin;
  xev.message_type = s_moveResize;
  xev.format = 32;
  // NOLINTBEGIN(cppcoreguidelines-pro-type-union-access,google-runtime-int)
  xev.data.l[0] = static_cast<long>(gx);
  xev.data.l[1] = static_cast<long>(gy);
  xev.data.l[2] = netDirection;
  xev.data.l[3] = Button1;
  xev.data.l[4] = 1; /* source: normal application */
  // NOLINTEND(cppcoreguidelines-pro-type-union-access,google-runtime-int)
 
  /* Release the implicit pointer grab of the pressed button, or the WM cannot take over. */
  XUngrabPointer(dpy, CurrentTime);
  XSendEvent(dpy, DefaultRootWindow(dpy), False,
             SubstructureRedirectMask | SubstructureNotifyMask, reinterpret_cast<XEvent*>(&xev));
  XFlush(dpy);
  return true;
}
 
bool sdl_x11_set_frame_extents(SDL_Window* window, int left, int right, int top, int bottom)
{
  const auto [dpy, xwin] = sdl_x11_handles(window);
  if (!dpy || (xwin == 0))
    return false;
 
  static Atom s_extents = None;
  if (s_extents == None)
    s_extents = XInternAtom(dpy, "_GTK_FRAME_EXTENTS", False);
 
  /* Set _GTK_FRAME_EXTENTS for invisible resize bands. */
  const long data[4] = { left, right, top, bottom }; // NOLINT(google-runtime-int)
  XChangeProperty(dpy, xwin, s_extents, XA_CARDINAL, 32, PropModeReplace,
                  reinterpret_cast<const unsigned char*>(data), 4);
  XFlush(dpy);
  return true;
}
 
bool sdl_x11_set_bit_gravity(SDL_Window* window, int gravity)
{
  const auto [dpy, xwin] = sdl_x11_handles(window);
  if (!dpy || (xwin == 0))
    return false;
 
  /* Set bit gravity to prevent frame jumping during async window resize. */
  XSetWindowAttributes attrs{};
  attrs.bit_gravity = gravity;
  XChangeWindowAttributes(dpy, xwin, CWBitGravity, &attrs);
  XFlush(dpy);
  return true;
}
 
bool sdl_x11_send_left_button_release(SDL_Window* window)
{
  const auto [dpy, xwin] = sdl_x11_handles(window);
  if (!dpy || (xwin == 0))
    return false;
 
  /* Empty mask: delivered to this client only, never to the WM. */
  XButtonEvent ev = {};
  ev.type = ButtonRelease;
  ev.display = dpy;
  ev.window = xwin;
  ev.root = DefaultRootWindow(dpy);
  ev.time = CurrentTime; /* SDL ignores X event time. */
  ev.button = Button1;
  ev.same_screen = True;
  if (!XSendEvent(dpy, xwin, False, NoEventMask, reinterpret_cast<XEvent*>(&ev)))
    return false;
  XFlush(dpy);
  return true;
}
 
static Window sdl_x11_xwindow(SDL_Window* window)
{
  return sdl_x11_handles(window).second;
}
 
bool sdl_x11_restack_windows(const std::vector<SDL_Window*>& topToBottom)
{
  if (!sdl::utils::isX11Driver() || (topToBottom.size() < 2))
    return false;
 
  auto props = SDL_GetWindowProperties(topToBottom.front());
  auto dpy = static_cast<Display*>(
      SDL_GetPointerProperty(props, SDL_PROP_WINDOW_X11_DISPLAY_POINTER, nullptr));
  if (!dpy)
    return false;
 
  static Atom s_restack = None;
  if (s_restack == None)
    s_restack = XInternAtom(dpy, "_NET_RESTACK_WINDOW", False);
 
  const Window root = DefaultRootWindow(dpy);
  /* Restack each window below its predecessor to realize the server z-order. */
  for (size_t i = 1; i < topToBottom.size(); i++)
  {
    const Window win = sdl_x11_xwindow(topToBottom.at(i));
    const Window sibling = sdl_x11_xwindow(topToBottom.at(i - 1));
    if ((win == 0) || (sibling == 0))
      continue;
 
    XClientMessageEvent xev = {};
    xev.type = ClientMessage;
    xev.window = win;
    xev.message_type = s_restack;
    xev.format = 32;
    // NOLINTBEGIN(cppcoreguidelines-pro-type-union-access,google-runtime-int)
    xev.data.l[0] = 2; /* source indication: pager/direct (authoritative) */
    xev.data.l[1] = static_cast<long>(sibling);
    xev.data.l[2] = Below;
    // NOLINTEND(cppcoreguidelines-pro-type-union-access,google-runtime-int)
    XSendEvent(dpy, root, False, SubstructureRedirectMask | SubstructureNotifyMask,
               reinterpret_cast<XEvent*>(&xev));
  }
  XFlush(dpy);
  return true;
}
 
#else /* !WITH_SDL_X11_NATIVE */
 
bool sdl_x11_has_compositor()
{
  return true;
}
 
bool sdl_x11_begin_move_size(WINPR_ATTR_UNUSED SDL_Window* window,
                             WINPR_ATTR_UNUSED int netDirection)
{
  return false;
}
 
bool sdl_x11_set_frame_extents(WINPR_ATTR_UNUSED SDL_Window* window, WINPR_ATTR_UNUSED int left,
                               WINPR_ATTR_UNUSED int right, WINPR_ATTR_UNUSED int top,
                               WINPR_ATTR_UNUSED int bottom)
{
  return false;
}
 
bool sdl_x11_set_bit_gravity(WINPR_ATTR_UNUSED SDL_Window* window, WINPR_ATTR_UNUSED int gravity)
{
  return false;
}
 
bool sdl_x11_restack_windows(WINPR_ATTR_UNUSED const std::vector<SDL_Window*>& topToBottom)
{
  return false;
}
 
bool sdl_x11_send_left_button_release(WINPR_ATTR_UNUSED SDL_Window* window)
{
  return false;
}
 
#endif