conky/src/display-wayland.cc

/*
 *
 * Conky, a system monitor, based on torsmo
 *
 * Please see COPYING for details
 *
 * Copyright (C) 2018-2021 François Revol et al.
 * Copyright (c) 2004, Hannu Saransaari and Lauri Hakkarainen
 * Copyright (c) 2005-2021 Brenden Matthews, Philip Kovacs, et. al.
 *	(see AUTHORS)
 * All rights reserved.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include <config.h>

#ifdef BUILD_WAYLAND
#include <wayland-client.h>
// #include "wayland.h"
#include <cairo.h>
#include <fontconfig/fontconfig.h>
#include <pango/pangocairo.h>
#include <pango/pangofc-fontmap.h>

#include <fcntl.h>
#include <sys/epoll.h>
#include <sys/mman.h>
#include <sys/timerfd.h>
#include <unistd.h>

#include <wayland-client-protocol.h>
#include <wlr-layer-shell-client-protocol.h>
#include <xdg-shell-client-protocol.h>

#endif /* BUILD_WAYLAND */

#include <iostream>
#include <sstream>

#include "conky.h"
#include "display-wayland.hh"
#include "gui.h"
#include "llua.h"
#ifdef BUILD_X11
#include "x11.h"
#endif
#ifdef BUILD_WAYLAND
#include "fonts.h"
#endif

#pragma GCC diagnostic ignored "-Wunused-parameter"

/* TODO: cleanup global namespace */
#ifdef BUILD_WAYLAND

static int set_cloexec_or_close(int fd) {
  long flags;

  if (fd == -1) return -1;

  flags = fcntl(fd, F_GETFD);
  if (flags == -1) goto err;

  if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1) goto err;

  return fd;

err:
  close(fd);
  return -1;
}

static int create_tmpfile_cloexec(char *tmpname) {
  int fd;

#ifdef HAVE_MKOSTEMP
  fd = mkostemp(tmpname, O_CLOEXEC);
  if (fd >= 0) unlink(tmpname);
#else
  fd = mkstemp(tmpname);
  if (fd >= 0) {
    fd = set_cloexec_or_close(fd);
    unlink(tmpname);
  }
#endif

  return fd;
}

/*
 * Create a new, unique, anonymous file of the given size, and
 * return the file descriptor for it. The file descriptor is set
 * CLOEXEC. The file is immediately suitable for mmap()'ing
 * the given size at offset zero.
 *
 * The file should not have a permanent backing store like a disk,
 * but may have if XDG_RUNTIME_DIR is not properly implemented in OS.
 *
 * The file name is deleted from the file system.
 *
 * The file is suitable for buffer sharing between processes by
 * transmitting the file descriptor over Unix sockets using the
 * SCM_RIGHTS methods.
 *
 * If the C library implements posix_fallocate(), it is used to
 * guarantee that disk space is available for the file at the
 * given size. If disk space is insufficent, errno is set to ENOSPC.
 * If posix_fallocate() is not supported, program may receive
 * SIGBUS on accessing mmap()'ed file contents instead.
 */
static int os_create_anonymous_file(off_t size) {
  static const char templ[] = "/weston-shared-XXXXXX";
  const char *path;
  char *name;
  int fd;
  int ret;

  path = getenv("XDG_RUNTIME_DIR");
  if (!path) {
    errno = ENOENT;
    return -1;
  }

  name = static_cast<char *>(malloc(strlen(path) + sizeof(templ)));
  if (!name) return -1;

  strcpy(name, path);
  strcat(name, templ);

  fd = create_tmpfile_cloexec(name);

  free(name);

  if (fd < 0) return -1;
  ret = posix_fallocate(fd, 0, size);
  if (ret != 0) {
    close(fd);
    errno = ret;
    return -1;
  }
  return fd;
}

// TODO: cleanup externs (move to conky.h ?)
#ifdef OWN_WINDOW
extern int fixed_size, fixed_pos;
#endif
extern int text_start_x, text_start_y;   /* text start position in window */
extern int text_offset_x, text_offset_y; /* offset for start position */
extern int text_width,
    text_height; /* initially 1 so no zero-sized window is created */
extern double current_update_time, next_update_time, last_update_time;
void update_text();
extern int need_to_update;
int get_border_total();
extern conky::range_config_setting<int> maximum_width;
extern Colour current_color;

/* for pango_fonts */
struct pango_font {
  PangoFontDescription *desc;

  struct {
    uint32_t ascent;
    uint32_t descent;
  } metrics;
  int font_alpha;

  pango_font() : desc(nullptr), metrics({0, 0}), font_alpha(0xffff) {}
};

static std::vector<pango_font> pango_fonts; /* indexed by selected_font */

namespace {
class textalpha_setting : public conky::simple_config_setting<float> {
  using Base = conky::simple_config_setting<float>;

 protected:
  void lua_setter(lua::state &l, bool init) override {
    lua::stack_sentry s(l, -2);

    Base::lua_setter(l, init);

    if (init) {
      pango_fonts.resize(std::max(1, static_cast<int>(fonts.size())));
      pango_fonts[0].desc = nullptr;
      pango_fonts[0].font_alpha = do_convert(l, -1).first * 0xffff;
    }

    ++s;
  }

 public:
  textalpha_setting() : Base("textalpha", 1.0, false) {}
};

textalpha_setting textalpha;
}  // namespace

static void wayland_create_window();

static void wayland_create_window() {
  setup_fonts();
  load_fonts(utf8_mode.get(*state));
  update_text_area(); /* to position text/window on screen */

#ifdef OWN_WINDOW
  if (own_window.get(*state)) {
    if (fixed_pos == 0) {
      // XMoveWindow(display, window.window, window.x, window.y);
      // TODO
    }

    // set_transparent_background(window.window);
  }
#endif

  selected_font = 0;
  update_text_area(); /* to get initial size of the window */
}

#endif /* BUILD_WAYLAND */

namespace conky {
namespace {

#ifdef BUILD_WAYLAND
conky::display_output_wayland wayland_output;
#else
conky::disabled_display_output wayland_output_disabled("wayland",
                                                       "BUILD_WAYLAND");
#endif

}  // namespace
extern void init_wayland_output() {}

namespace priv {}  // namespace priv

#ifdef BUILD_WAYLAND

display_output_wayland::display_output_wayland()
    : display_output_base("wayland") {
  is_graphical = true;
  priority = 2;
}

bool display_output_wayland::detect() {
  if (out_to_wayland.get(*state)) {
    DBGP2("Wayland display output '%s' enabled in config.", name.c_str());
    return true;
  }
  return false;
}

static int epoll_fd;
static struct epoll_event ep[1];

static struct window *global_window;
static wl_display *global_display;

struct rectangle {
  size_t x, y, width, height;
};

struct window {
  struct rectangle rectangle;
  struct wl_shm *shm;
  struct wl_surface *surface;
  struct zwlr_layer_surface_v1 *layer_surface;
  int scale, pending_scale;
  cairo_surface_t *cairo_surface;
  cairo_t *cr;
  PangoLayout *layout;
  PangoContext *pango_context;
};

struct {
  struct wl_registry *registry;
  struct wl_compositor *compositor;
  struct wl_shm *shm;
  struct wl_surface *surface;
  struct wl_seat *seat;
  /*	struct wl_pointer *pointer;*/
  struct wl_output *output;
  struct xdg_wm_base *shell;
  struct zwlr_layer_shell_v1 *layer_shell;
} wl_globals;

static void xdg_wm_base_ping(void *data, struct xdg_wm_base *shell,
                             uint32_t serial) {
  xdg_wm_base_pong(shell, serial);
}

static const struct xdg_wm_base_listener xdg_wm_base_listener = {
    /*.ping =*/&xdg_wm_base_ping,
};

static void output_geometry(void *data, struct wl_output *wl_output, int32_t x,
                            int32_t y, int32_t physical_width,
                            int32_t physical_height, int32_t subpixel,
                            const char *make, const char *model,
                            int32_t transform) {}

static void output_mode(void *data, struct wl_output *wl_output, uint32_t flags,
                        int32_t width, int32_t height, int32_t refresh) {}

#ifdef WL_OUTPUT_DONE_SINCE_VERSION
static void output_done(void *data, struct wl_output *wl_output) {}
#endif

#ifdef WL_OUTPUT_SCALE_SINCE_VERSION
void output_scale(void *data, struct wl_output *wl_output, int32_t factor) {
  /* For now, assume we have one output and adopt its scale unconditionally. */
  /* We should also re-render immediately when scale changes. */
  global_window->pending_scale = factor;
}
#endif

#ifdef WL_OUTPUT_NAME_SINCE_VERSION
static void output_name(void *data, struct wl_output *wl_output,
                        const char *name) {}
#endif

#ifdef WL_OUTPUT_DESCRIPTION_SINCE_VERSION
static void output_description(void *data, struct wl_output *wl_output,
                               const char *description) {}
#endif

const struct wl_output_listener output_listener = {
    /*.geometry =*/output_geometry,
    /*.mode =*/output_mode,
#ifdef WL_OUTPUT_DONE_SINCE_VERSION
    /*.done =*/output_done,
#endif
#ifdef WL_OUTPUT_SCALE_SINCE_VERSION
    /*.scale =*/&output_scale,
#endif
#ifdef WL_OUTPUT_NAME_SINCE_VERSION
    /*.name =*/&output_name,
#endif
#ifdef WL_OUTPUT_DESCRIPTION_SINCE_VERSION
    /*.description =*/&output_description,
#endif
};

void registry_handle_global(void *data, struct wl_registry *registry,
                            uint32_t name, const char *interface,
                            uint32_t version) {
  if (strcmp(interface, "wl_compositor") == 0) {
    wl_globals.compositor = static_cast<wl_compositor *>(
        wl_registry_bind(registry, name, &wl_compositor_interface, 3));
  } else if (strcmp(interface, "wl_shm") == 0) {
    wl_globals.shm = static_cast<wl_shm *>(
        wl_registry_bind(registry, name, &wl_shm_interface, 1));
  } else if (strcmp(interface, "wl_seat") == 0) {
    wl_globals.seat = static_cast<wl_seat *>(
        wl_registry_bind(registry, name, &wl_seat_interface, 1));
  } else if (strcmp(interface, "wl_output") == 0) {
    wl_globals.output = static_cast<wl_output *>(
        wl_registry_bind(registry, name, &wl_output_interface, 2));
    wl_output_add_listener(wl_globals.output, &output_listener, nullptr);
  } else if (strcmp(interface, "xdg_wm_base") == 0) {
    wl_globals.shell = static_cast<xdg_wm_base *>(
        wl_registry_bind(registry, name, &xdg_wm_base_interface, 1));
    xdg_wm_base_add_listener(wl_globals.shell, &xdg_wm_base_listener, nullptr);
  } else if (strcmp(interface, "zwlr_layer_shell_v1") == 0) {
    wl_globals.layer_shell = static_cast<zwlr_layer_shell_v1 *>(
        wl_registry_bind(registry, name, &zwlr_layer_shell_v1_interface, 1));
  }
}

void registry_handle_global_remove(void *data, struct wl_registry *registry,
                                   uint32_t name) {}

static const struct wl_registry_listener registry_listener = {
    registry_handle_global, registry_handle_global_remove};

static void layer_surface_configure(void *data,
                                    struct zwlr_layer_surface_v1 *layer_surface,
                                    uint32_t serial, uint32_t width,
                                    uint32_t height) {
  zwlr_layer_surface_v1_ack_configure(layer_surface, serial);
}

static void layer_surface_closed(void *data,
                                 struct zwlr_layer_surface_v1 *layer_surface) {}

static const struct zwlr_layer_surface_v1_listener layer_surface_listener = {
    /*.configure =*/&layer_surface_configure,
    /*.closed =*/&layer_surface_closed,
};

struct window *window_create(struct wl_surface *surface, struct wl_shm *shm,
                             int width, int height);

void window_resize(struct window *window, int width, int height);

void window_allocate_buffer(struct window *window);

void window_destroy(struct window *window);

void window_commit_buffer(struct window *window);

void window_get_width_height(struct window *window, int *w, int *h);

void window_layer_surface_set_size(struct window *window) {
  zwlr_layer_surface_v1_set_size(global_window->layer_surface,
                                 global_window->rectangle.width,
                                 global_window->rectangle.height);
}

bool display_output_wayland::initialize() {
  epoll_fd = epoll_create1(0);
  if (epoll_fd < 0) {
    perror("conky: epoll_create");
    return false;
  }
  global_display = wl_display_connect(NULL);
  if (!global_display) {
    perror("conky: wl_display_connect");
    return false;
  }

  wl_globals.registry = wl_display_get_registry(global_display);
  wl_registry_add_listener(wl_globals.registry, &registry_listener, NULL);

  wl_display_roundtrip(global_display);

  struct wl_surface *surface =
      wl_compositor_create_surface(wl_globals.compositor);
  global_window = window_create(surface, wl_globals.shm, 1, 1);
  window_allocate_buffer(global_window);

  global_window->layer_surface = zwlr_layer_shell_v1_get_layer_surface(
      wl_globals.layer_shell, global_window->surface, nullptr,
      ZWLR_LAYER_SHELL_V1_LAYER_BOTTOM, "conky_namespace");
  window_layer_surface_set_size(global_window);
  zwlr_layer_surface_v1_add_listener(global_window->layer_surface,
                                     &layer_surface_listener, nullptr);

  wl_surface_commit(global_window->surface);
  wl_display_roundtrip(global_display);

  wayland_create_window();
  return true;
}

typedef void (*display_global_handler_t)(struct display *display, uint32_t name,
                                         const char *interface,
                                         uint32_t version, void *data);
typedef void (*display_output_handler_t)(struct output *output, void *data);

bool display_output_wayland::shutdown() { return false; }

#define ARRAY_LENGTH(x) (sizeof(x) / sizeof(x[0]))

static bool added = false;

bool display_output_wayland::main_loop_wait(double t) {
  while (wl_display_prepare_read(global_display) != 0)
    wl_display_dispatch_pending(global_display);
  wl_display_flush(global_display);

  if (t < 0.0) { t = 0.0; }
  int ms = t * 1000;

  /* add fd to epoll set the first time around */
  if (!added) {
    ep[0].events = EPOLLIN | EPOLLERR | EPOLLHUP | EPOLLET;
    ep[0].data.ptr = nullptr;
    if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, wl_display_get_fd(global_display),
                  &ep[0]) == -1) {
      perror("conky: epoll_ctl: add");
      return false;
    }
    added = true;
  }

  /* wait for Wayland event or timeout */
  int ep_count = epoll_wait(epoll_fd, ep, ARRAY_LENGTH(ep), ms);
  if (ep_count > 0) {
    if (ep[0].events & (EPOLLERR | EPOLLHUP)) {
      NORM_ERR("output closed");
      exit(1);
      return false;
    }
  }

  wl_display_read_events(global_display);

  wl_display_dispatch_pending(global_display);

  wl_display_flush(global_display);

  /* timeout */
  if (ep_count == 0) { update_text(); }

  if (need_to_update != 0) {
    need_to_update = 0;
    selected_font = 0;
    update_text_area();

    int changed = 0;
    int border_total = get_border_total();

    int width, height;
    window_get_width_height(global_window, &width, &height);

    int fixed_size = 0;

    bool scale_changed = global_window->scale != global_window->pending_scale;

    /* resize window if it isn't right size */
    if ((fixed_size == 0) &&
        (text_width + 2 * border_total != width ||
         text_height + 2 * border_total != height || scale_changed)) {
      /* clamp text_width to configured maximum */
      if (maximum_width.get(*state)) {
        int mw = global_window->scale * maximum_width.get(*state);
        if (text_width > mw && mw > 0) { text_width = mw; }
      }

      /* pending scale will be applied by resizing the window */
      global_window->scale = global_window->pending_scale;

      width = text_width + 2 * border_total;
      height = text_height + 2 * border_total;
      window_resize(global_window, width, height); /* resize window */

      changed++;
      /* update lua window globals */
      llua_update_window_table(text_start_x, text_start_y, text_width,
                               text_height);
    }

/* move window if it isn't in right position */
#ifdef POSITION
    if ((fixed_pos == 0) && (window.x != wx || window.y != wy)) {
      // XMoveWindow(display, window.window, window.x, window.y);
      changed++;
    }
#endif

    /* update struts */
    if (changed != 0) {
      int anchor = -1;

      DBGP("%s", _(PACKAGE_NAME ": defining struts\n"));
      fflush(stderr);

      switch (text_alignment.get(*state)) {
        case TOP_LEFT:
          anchor = ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP |
                   ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT;
          break;
        case TOP_RIGHT:
          anchor = ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP |
                   ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT;
          break;
        case TOP_MIDDLE: {
          anchor = ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP;
          break;
        }
        case BOTTOM_LEFT:
          anchor = ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM |
                   ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT;
          break;
        case BOTTOM_RIGHT:
          anchor = ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM |
                   ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT;
          break;
        case BOTTOM_MIDDLE: {
          anchor = ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM;
          break;
        }
        case MIDDLE_LEFT: {
          anchor = ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT;
          break;
        }
        case MIDDLE_RIGHT: {
          anchor = ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT;
          break;
        }

        case NONE:
        case MIDDLE_MIDDLE: /* XXX What about these? */;
      }

      if (anchor != -1) {
        zwlr_layer_surface_v1_set_anchor(global_window->layer_surface, anchor);
        zwlr_layer_surface_v1_set_margin(global_window->layer_surface,
                                         gap_y.get(*state), gap_x.get(*state),
                                         gap_y.get(*state), gap_x.get(*state));
      }
    }

    clear_text(1);
    draw_stuff();
  }
  wl_display_flush(global_display);

#ifdef INPUT
#ifdef X_EVENT
  case ButtonPress:
    if (own_window.get(*state)) {
      /* if an ordinary window with decorations */
      if ((own_window_type.get(*state) == TYPE_NORMAL &&
           !TEST_HINT(own_window_hints.get(*state), HINT_UNDECORATED)) ||
          own_window_type.get(*state) == TYPE_DESKTOP) {
        /* allow conky to hold input focus. */
        break;
      }
      /* forward the click to the desktop window */
      XUngrabPointer(display, ev.xbutton.time);
      ev.xbutton.window = window.desktop;
      ev.xbutton.x = ev.xbutton.x_root;
      ev.xbutton.y = ev.xbutton.y_root;
      XSendEvent(display, ev.xbutton.window, False, ButtonPressMask, &ev);
      XSetInputFocus(display, ev.xbutton.window, RevertToParent,
                     ev.xbutton.time);
    }
    break;

  case ButtonRelease:
    if (own_window.get(*state)) {
      /* if an ordinary window with decorations */
      if ((own_window_type.get(*state) == TYPE_NORMAL) &&
          !TEST_HINT(own_window_hints.get(*state), HINT_UNDECORATED)) {
        /* allow conky to hold input focus. */
        break;
      }
      /* forward the release to the desktop window */
      ev.xbutton.window = window.desktop;
      ev.xbutton.x = ev.xbutton.x_root;
      ev.xbutton.y = ev.xbutton.y_root;
      XSendEvent(display, ev.xbutton.window, False, ButtonReleaseMask, &ev);
    }
    break;
#endif /*X_EVENT*/
#endif /*INPUT*/

    // handled
    return true;
}

void display_output_wayland::sigterm_cleanup() {}

void display_output_wayland::cleanup() {
  if (global_window != nullptr) {
    window_destroy(global_window);
    global_window = nullptr;
  }
  free_fonts(utf8_mode.get(*state));
}

void display_output_wayland::set_foreground_color(Colour c) {
  current_color = c;
#ifdef BUILD_ARGB
  current_color.alpha = own_window_argb_value.get(*state);
#endif /* BUILD_ARGB */
  if (global_window->cr) {
    cairo_set_source_rgba(global_window->cr, current_color.red / 255.0,
                          current_color.green / 255.0,
                          current_color.blue / 255.0,
                          current_color.alpha / 255.0);
  }
}

int display_output_wayland::calc_text_width(const char *s) {
  struct window *window = global_window;
  size_t slen = strlen(s);
  pango_layout_set_text(window->layout, s, slen);
  PangoRectangle margin_rect;
  pango_layout_set_font_description(window->layout,
                                    pango_fonts[selected_font].desc);
  pango_layout_get_pixel_extents(window->layout, nullptr, &margin_rect);
  return margin_rect.width;
}

static void adjust_coords(int &x, int &y) {
  x -= text_start_x;
  y -= text_start_y;
  int border = get_border_total();
  x += border;
  y += border;
}

void display_output_wayland::draw_string_at(int x, int y, const char *s,
                                            int w) {
  struct window *window = global_window;
  y -= pango_fonts[selected_font].metrics.ascent;
  adjust_coords(x, y);
  pango_layout_set_text(window->layout, s, strlen(s));
  cairo_save(window->cr);
  uint8_t r = current_color.red;
  uint8_t g = current_color.green;
  uint8_t b = current_color.blue;
  unsigned int a = pango_fonts[selected_font].font_alpha;
  cairo_set_source_rgba(global_window->cr, r / 255.0, g / 255.0, b / 255.0,
                        a / 65535.);
  cairo_move_to(window->cr, x, y);
  pango_cairo_show_layout(window->cr, window->layout);
  cairo_restore(window->cr);
}

void display_output_wayland::set_line_style(int w, bool solid) {
  struct window *window = global_window;
  static double dashes[2] = {1.0, 1.0};
  if (solid)
    cairo_set_dash(window->cr, nullptr, 0, 0);
  else
    cairo_set_dash(window->cr, dashes, 2, 0);
  cairo_set_line_width(window->cr, w);
}

void display_output_wayland::set_dashes(char *s) {
  struct window *window = global_window;
  size_t len = strlen(s);
  double *dashes = new double[len];
  for (size_t i = 0; i < len; i++) { dashes[i] = s[i]; }
  cairo_set_dash(window->cr, dashes, len, 0);
  delete[] dashes;
}

void display_output_wayland::draw_line(int x1, int y1, int x2, int y2) {
  struct window *window = global_window;
  adjust_coords(x1, y1);
  adjust_coords(x2, y2);
  cairo_save(window->cr);
  cairo_move_to(window->cr, x1 - 0.5, y1 - 0.5);
  cairo_line_to(window->cr, x2 - 0.5, y2 - 0.5);
  cairo_stroke(window->cr);
  cairo_restore(window->cr);
}

static void do_rect(int x, int y, int w, int h, bool fill) {
  struct window *window = global_window;
  adjust_coords(x, y);

  cairo_save(window->cr);
  if (fill) {
    /* Note that cairo interprets fill and stroke coordinates differently,
    so here we don't add 0.5 to move between centers and corners of pixels. */
    cairo_rectangle(window->cr, x, y, w - 1, h - 1);
    cairo_fill(window->cr);
  } else {
    cairo_rectangle(window->cr, x - 0.5, y - 0.5, w, h);
    cairo_stroke(window->cr);
  }
  cairo_restore(window->cr);
}

void display_output_wayland::draw_rect(int x, int y, int w, int h) {
  do_rect(x, y, w, h, false);
}

void display_output_wayland::fill_rect(int x, int y, int w, int h) {
  do_rect(x, y, w, h, true);
}

void display_output_wayland::draw_arc(int x, int y, int w, int h, int a1,
                                      int a2) {
  struct window *window = global_window;
  adjust_coords(x, y);
  cairo_save(window->cr);
  cairo_translate(window->cr, x + w / 2. - 0.5, y + h / 2. - 0.5);
  cairo_scale(window->cr, w / 2., h / 2.);
  cairo_set_line_width(window->cr, 2. / (w + h));
  double mult = M_PI / (180. * 64.);
  cairo_arc_negative(window->cr, 0., 0., 1., a1 * mult, a2 * mult);
  cairo_stroke(window->cr);
  cairo_restore(window->cr);
}

void display_output_wayland::move_win(int x, int y) {
  // window.x = x;
  // window.y = y;
  // TODO
}

int display_output_wayland::dpi_scale(int value) { return value; }

void display_output_wayland::end_draw_stuff() {
  window_commit_buffer(global_window);
}

void display_output_wayland::clear_text(int exposures) {
  struct window *window = global_window;
  cairo_save(window->cr);
  Colour color;
#ifdef OWN_WINDOW
  color = background_colour.get(*state);
  if (set_transparent.get(*state)) {
    color.alpha = 0;
  } else {
#ifdef BUILD_ARGB
    color.alpha = own_window_argb_value.get(*state);
#else
    color.alpha = 0xff;
#endif
  }
#endif
  cairo_set_source_rgba(window->cr, color.red / 255.0, color.green / 255.0,
                        color.blue / 255.0, color.alpha / 255.0);
  cairo_set_operator(window->cr, CAIRO_OPERATOR_SOURCE);
  cairo_paint(window->cr);
  cairo_restore(window->cr);
}

int display_output_wayland::font_height(unsigned int f) {
  if (pango_fonts.size() == 0) { return 2; }
  assert(f < pango_fonts.size());
  return pango_fonts[f].metrics.ascent + pango_fonts[f].metrics.descent;
}

int display_output_wayland::font_ascent(unsigned int f) {
  if (pango_fonts.size() == 0) { return 1; }
  assert(f < pango_fonts.size());
  return pango_fonts[f].metrics.ascent;
}

int display_output_wayland::font_descent(unsigned int f) {
  if (pango_fonts.size() == 0) { return 1; }
  assert(f < pango_fonts.size());
  return pango_fonts[f].metrics.descent;
}

void display_output_wayland::setup_fonts(void) { /* Nothing to do here */
}

void display_output_wayland::set_font(unsigned int f) {
  assert(f < pango_fonts.size());
  if (pango_fonts.size() > f && pango_fonts[f].desc != nullptr) {
    pango_layout_set_font_description(global_window->layout,
                                      pango_fonts[f].desc);
  }
}

void display_output_wayland::free_fonts(bool utf8) {
  for (auto &font : pango_fonts) {
    if (font.desc != nullptr) {
      pango_font_description_free(font.desc);
      font.desc = nullptr;
    }
  }
  pango_fonts.clear();
}

void display_output_wayland::load_fonts(bool utf8) {
  free_fonts(utf8);
  pango_fonts.resize(fonts.size());
  for (unsigned int i = 0; i < fonts.size(); i++) {
    auto &font = fonts[i];
    auto &pango_font_entry = pango_fonts[i];
    FcPattern *fc_pattern =
        FcNameParse(reinterpret_cast<const unsigned char *>(font.name.c_str()));
    pango_font_entry.desc =
        pango_fc_font_description_from_pattern(fc_pattern, true);

    // Handle pixel size ourselves because
    // pango_fc_font_description_from_pattern does not
    double pixel_size = -1;
    if (FcPatternGetDouble(fc_pattern, FC_PIXEL_SIZE, 0, &pixel_size) ==
        FcResultMatch) {
      pango_font_description_set_absolute_size(pango_font_entry.desc,
                                               pixel_size * PANGO_SCALE);
    }
    FcPatternDestroy(fc_pattern);

    PangoFont *pango_font = pango_context_load_font(
        global_window->pango_context, pango_font_entry.desc);
    PangoFontMetrics *font_metrics =
        pango_font_get_metrics(pango_font, nullptr);
    auto ascent = pango_font_metrics_get_ascent(font_metrics) / PANGO_SCALE;
    auto descent = pango_font_metrics_get_descent(font_metrics) / PANGO_SCALE;
    pango_font_metrics_unref(font_metrics);
    g_object_unref(pango_font);

    pango_font_entry.metrics.ascent = ascent;
    pango_font_entry.metrics.descent = descent;
  }
}

struct shm_pool {
  struct wl_shm_pool *pool;
  size_t size;
  size_t used;
  void *data;
};

struct shm_surface_data {
  struct wl_buffer *buffer;
  struct shm_pool *pool;
};

static const cairo_user_data_key_t shm_surface_data_key = {0};

struct wl_buffer *get_buffer_from_cairo_surface(cairo_surface_t *surface) {
  struct shm_surface_data *data;

  data = static_cast<struct shm_surface_data *>(
      cairo_surface_get_user_data(surface, &shm_surface_data_key));

  return data->buffer;
}

static void shm_pool_destroy(struct shm_pool *pool);

static void shm_surface_data_destroy(void *p) {
  struct shm_surface_data *data = static_cast<struct shm_surface_data *>(p);
  wl_buffer_destroy(data->buffer);
  if (data->pool) shm_pool_destroy(data->pool);

  delete data;
}

static struct wl_shm_pool *make_shm_pool(struct wl_shm *shm, int size,
                                         void **data) {
  struct wl_shm_pool *pool;
  int fd;

  fd = os_create_anonymous_file(size);
  if (fd < 0) {
    fprintf(stderr, "creating a buffer file for %d B failed: %m\n", size);
    return NULL;
  }

  *data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  if (*data == MAP_FAILED) {
    fprintf(stderr, "mmap failed: %m\n");
    close(fd);
    return NULL;
  }

  pool = wl_shm_create_pool(shm, fd, size);

  close(fd);

  return pool;
}

static struct shm_pool *shm_pool_create(struct wl_shm *shm, size_t size) {
  struct shm_pool *pool = new struct shm_pool;

  if (!pool) return NULL;

  pool->pool = make_shm_pool(shm, size, &pool->data);
  if (!pool->pool) {
    delete pool;
    return NULL;
  }

  pool->size = size;
  pool->used = 0;

  return pool;
}

static void *shm_pool_allocate(struct shm_pool *pool, size_t size,
                               int *offset) {
  if (pool->used + size > pool->size) return NULL;

  *offset = pool->used;
  pool->used += size;

  return (char *)pool->data + *offset;
}

/* destroy the pool. this does not unmap the memory though */
static void shm_pool_destroy(struct shm_pool *pool) {
  munmap(pool->data, pool->size);
  wl_shm_pool_destroy(pool->pool);
  delete pool;
}

static int stride_for_shm_surface(struct rectangle *rect, int scale) {
  return cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32,
                                       rect->width * scale);
}

static int data_length_for_shm_surface(struct rectangle *rect, int scale) {
  int stride;

  stride = stride_for_shm_surface(rect, scale);
  return stride * rect->height * scale;
}

static cairo_surface_t *create_shm_surface_from_pool(
    void *none, struct rectangle *rectangle, struct shm_pool *pool, int scale) {
  struct shm_surface_data *data;
  uint32_t format;
  cairo_surface_t *surface;
  cairo_format_t cairo_format;
  int stride, length, offset;
  void *map;

  data = new struct shm_surface_data;
  if (data == NULL) return NULL;

  cairo_format = CAIRO_FORMAT_ARGB32; /*or CAIRO_FORMAT_RGB16_565 who knows??*/

  stride = stride_for_shm_surface(rectangle, scale);
  length = data_length_for_shm_surface(rectangle, scale);
  data->pool = NULL;
  map = shm_pool_allocate(pool, length, &offset);

  if (!map) {
    delete data;
    return NULL;
  }

  surface = cairo_image_surface_create_for_data(
      static_cast<unsigned char *>(map), cairo_format, rectangle->width * scale,
      rectangle->height * scale, stride);

  cairo_surface_set_user_data(surface, &shm_surface_data_key, data,
                              shm_surface_data_destroy);

  format = WL_SHM_FORMAT_ARGB8888; /*or WL_SHM_FORMAT_RGB565*/

  data->buffer =
      wl_shm_pool_create_buffer(pool->pool, offset, rectangle->width * scale,
                                rectangle->height * scale, stride, format);

  return surface;
}

void window_allocate_buffer(struct window *window) {
  assert(window->shm != nullptr);

  int scale = window->pending_scale;
  struct shm_pool *pool;
  pool = shm_pool_create(
      window->shm, data_length_for_shm_surface(&window->rectangle, scale));
  if (!pool) {
    fprintf(stderr, "could not allocate shm pool\n");
    return;
  }

  window->cairo_surface = create_shm_surface_from_pool(
      window->shm, &window->rectangle, pool, scale);
  cairo_surface_set_device_scale(window->cairo_surface, scale, scale);

  if (!window->cairo_surface) {
    shm_pool_destroy(pool);
    return;
  }

  window->cr = cairo_create(window->cairo_surface);
  window->layout = pango_cairo_create_layout(window->cr);
  window->pango_context = pango_cairo_create_context(window->cr);

  /* make sure we destroy the pool when the surface is destroyed */
  struct shm_surface_data *data;
  data = static_cast<struct shm_surface_data *>(cairo_surface_get_user_data(
      window->cairo_surface, &shm_surface_data_key));
  data->pool = pool;
}

struct window *window_create(struct wl_surface *surface, struct wl_shm *shm,
                             int width, int height) {
  struct window *window;
  window = new struct window;

  window->rectangle.x = 0;
  window->rectangle.y = 0;
  window->rectangle.width = width;
  window->rectangle.height = height;
  window->scale = 0;
  window->pending_scale = 1;

  window->surface = surface;
  window->shm = shm;

  window->cairo_surface = nullptr;
  window->cr = nullptr;
  window->layout = nullptr;
  window->pango_context = nullptr;

  return window;
}

void window_free_buffer(struct window *window) {
  cairo_surface_destroy(window->cairo_surface);
  cairo_destroy(window->cr);
  g_object_unref(window->layout);
  g_object_unref(window->pango_context);
  window->cairo_surface = nullptr;
  window->cr = nullptr;
  window->layout = nullptr;
  window->pango_context = nullptr;
}

void window_destroy(struct window *window) {
  window_free_buffer(window);
  zwlr_layer_surface_v1_destroy(window->layer_surface);
  wl_surface_attach(window->surface, nullptr, 0, 0);
  wl_surface_commit(window->surface);
  wl_display_roundtrip(global_display);
  wl_surface_destroy(window->surface);
  wl_shm_destroy(window->shm);
  delete window;
}

void window_resize(struct window *window, int width, int height) {
  window_free_buffer(window);
  window->rectangle.width = width;
  window->rectangle.height = height;
  window_allocate_buffer(window);
  window_layer_surface_set_size(window);
}

void window_commit_buffer(struct window *window) {
  assert(window->cairo_surface != nullptr);
  wl_surface_set_buffer_scale(global_window->surface,
                              global_window->pending_scale);
  wl_surface_attach(window->surface,
                    get_buffer_from_cairo_surface(window->cairo_surface), 0, 0);
  /* repaint all the pixels in the surface, change size to only repaint changed
   * area*/
  wl_surface_damage(window->surface, window->rectangle.x, window->rectangle.y,
                    window->rectangle.width, window->rectangle.height);
  wl_surface_commit(window->surface);
}

void window_get_width_height(struct window *window, int *w, int *h) {
  *w = window->rectangle.width;
  *h = window->rectangle.height;
}

#endif /* BUILD_WAYLAND */

}  // namespace conky