polybar/src/components/screen.cpp

#include <csignal>
#include <thread>

#include "components/config.hpp"
#include "components/logger.hpp"
#include "components/screen.hpp"
#include "components/types.hpp"
#include "components/signals.hpp"
#include "components/eventloop.hpp"
#include "x11/connection.hpp"
#include "x11/randr.hpp"
#include "x11/winspec.hpp"

POLYBAR_NS

/**
 * Configure injection module
 */
di::injector<unique_ptr<screen>> configure_screen() {
  return di::make_injector(configure_connection(), configure_logger(), configure_config());
}

/**
 * Construct screen instance
 */
screen::screen(connection& conn, const logger& logger, const config& conf)
    : m_connection(conn)
    , m_log(logger)
    , m_conf(conf)
    , m_root(conn.root())
    , m_size({conn.screen()->width_in_pixels, conn.screen()->height_in_pixels}) {
  assert(g_signals::event::enqueue != nullptr);

  // Check if the reloading has been disabled by the user
  if (!m_conf.get<bool>("settings", "screenchange-reload", false)) {
    return;
  }

  // clang-format off
  m_proxy = winspec(m_connection)
    << cw_size(1U, 1U)
    << cw_pos(-1, -1)
    << cw_parent(m_root)
    << cw_params_override_redirect(true)
    << cw_params_event_mask(XCB_EVENT_MASK_PROPERTY_CHANGE)
    << cw_flush(true);
  // clang-format on

  // Receive randr events
  m_connection.randr().select_input(m_proxy, XCB_RANDR_NOTIFY_MASK_SCREEN_CHANGE);
  m_connection.ensure_event_mask(m_root, XCB_EVENT_MASK_SUBSTRUCTURE_NOTIFY);

  // Create window used as event proxy
  m_connection.map_window(m_proxy);
  m_connection.flush();

  // Wait until the proxy window has been mapped
  using evt = xcb_map_notify_event_t;
  m_connection.wait_for_response<evt, XCB_MAP_NOTIFY>([&](const evt& evt) -> bool { return evt.window == m_proxy; });
  m_connection.clear_event_mask(m_root);

  // Finally attach the sink the process randr events
  m_connection.attach_sink(this, SINK_PRIORITY_SCREEN);
}

/**
 * Deconstruct screen instance
 */
screen::~screen() {
  m_connection.detach_sink(this, SINK_PRIORITY_SCREEN);

  if (m_proxy != XCB_NONE) {
    m_connection.destroy_window(m_proxy);
  }
}

/**
 * Handle XCB_RANDR_SCREEN_CHANGE_NOTIFY events
 *
 * If the screen dimensions have changed we raise USR1 to trigger a reload
 */
void screen::handle(const evt::randr_screen_change_notify& evt) {
  if (!m_sigraised && evt->request_window == m_proxy) {
    m_log.warn("randr_screen_change_notify (%ux%u)... reloading", evt->width, evt->height);
    m_sigraised = true;
    quit_event quit{};
    quit.reload = true;
    g_signals::event::enqueue(reinterpret_cast<const eventloop::entry_t&>(quit));
  }
}

POLYBAR_NS_END