zdwm/src/client.c

#include "client.h"

#include <stdint.h>
#include <string.h>
#include <xcb/xcb.h>
#include <xcb/xcb_aux.h>
#include <xcb/xcb_icccm.h>
#include <xcb/xproto.h>

#include "atoms-extern.h"
#include "base.h"
#include "monitor.h"
#include "rect.h"
#include "types.h"
#include "utils.h"
#include "wm.h"
#include "xwindow.h"

client_t *client_get_by_window(xcb_window_t window) {
  for (client_t *c = wm.client_list; c; c = c->next) {
    if (c->window == window) return c;
  }

  return nullptr;
}

client_t *client_get_next_by_class(client_t *current, const char *class) {
  client_t *start = current ? current->next : wm.client_list;
  for (client_t *c = start; c; c = c->next) {
    if (strcmp(class, c->class) == 0) return c;
  }

  for (client_t *c = wm.client_list; c && c != start; c = c->next) {
    if (strcmp(class, c->class) == 0) return c;
  }

  return nullptr;
}

static void client_attach_list(client_t *client) {
  client->next = wm.client_list;
  wm.client_list = client;
}

static void client_detach_list(client_t *client) {
  client_t **tc = nullptr;
  for (tc = &wm.client_list; *tc && *tc != client; tc = &(*tc)->next);
  *tc = client->next;
}

static void client_attach_stack(client_t *client) {
  client->stack_next = wm.client_stack_list;
  wm.client_stack_list = client;
}

static void client_detach_stack(client_t *client) {
  client_t **tc = &wm.client_stack_list;
  for (; *tc && *tc != client; tc = &(*tc)->stack_next);
  *tc = client->stack_next;

  if (client == wm.client_focused) {
    client_t *t = wm.client_stack_list;
    for (; t && !client_is_visible(t); t = t->stack_next);
    wm.client_focused = t;
  }
}

task_in_tag_t *client_get_task_in_tag(client_t *client, tag_t *tag) {
  for (task_in_tag_t *task = tag->task_list; task; task = task->next) {
    if (task->client == client) return task;
  }
  return nullptr;
}

task_in_tag_t *client_get_next_task_in_tag(client_t *client, tag_t *tag) {
  if (!tag->task_list) return nullptr;

  task_in_tag_t *task = tag->task_list;
  for (; task && task->client != client; task = task->next);
  return task && task->next ? task->next : tag->task_list;
}

task_in_tag_t *client_get_previous_task_in_tag(client_t *client, tag_t *tag) {
  if (!tag->task_list) return nullptr;

  task_in_tag_t *task = tag->task_list;
  for (; task && task->next && task->next->client != client; task = task->next);
  return task ? task : tag->task_list;
}

static void client_add_to_tag(client_t *client, tag_t *tag) {
  if (client_get_task_in_tag(client, tag)) return;

  xwindow_set_wm_desktop(client->window, tag->index);

  task_in_tag_t *task = p_new(task_in_tag_t, 1);
  task->client = client;
  task->next = tag->task_list;
  tag->task_list = task;
  task->geometry = client->geometry;
}

static void client_remove_from_tag(client_t *client, tag_t *tag) {
  task_in_tag_t **task = &tag->task_list;
  while (*task) {
    if ((*task)->client == client) {
      task_in_tag_t *t = *task;
      *task = (*task)->next;
      p_delete(&t);
      continue;
    }

    task = &(*task)->next;
  }
}

static inline void client_wipe(client_t *client) {
  p_delete(&client->class);
  p_delete(&client->instance);
  p_delete(&client->name);
  p_delete(&client->net_name);
  p_delete(&client->role);
  p_delete(&client);
}

static inline void client_tags_apply(client_t *client) {
  for (tag_t *tag = client->monitor->tag_list; tag; tag = tag->next) {
    if (client->tags & tag->mask) {
      client_add_to_tag(client, tag);
    } else {
      client_remove_from_tag(client, tag);
    }
  }

  if (client->tags == 0) client_wipe(client);
}

static inline void client_update_names(client_t *c) {
  xwindow_get_text_property(c->window, WM_NAME, &c->name);
  xwindow_get_text_property(c->window, _NET_WM_NAME, &c->net_name);
}

static inline void client_init_geometry(client_t *c) {
  if (c->maximize || c->fullscreen || c->minimize) return;

  area_t workarea = c->monitor->workarea;
  if (c->geometry.x + client_width(c) > workarea.x + workarea.width) {
    c->geometry.x = workarea.x + workarea.width - client_width(c);
  }
  if (c->geometry.y + client_height(c) > workarea.y + workarea.height) {
    c->geometry.y = workarea.y + workarea.height - client_height(c);
  }
  c->geometry.x = MAX(c->geometry.x, workarea.x);
  c->geometry.y = MAX(c->geometry.y, workarea.y);

  client_move_to(c, c->geometry.x, c->geometry.y);
  client_resize(c, c->geometry.width, c->geometry.height);
  client_change_border_color(c, &wm.color_set.active_border_color);
  client_change_border_width(c, wm.border_width);
}

static void client_init_tag_by_wm_desktop(client_t *client, uint32_t tag_mask) {
  uint32_t tag_index = 0;
  if (!xwindow_get_wm_desktop(client->window, &tag_index)) {
    goto tag_fallback;
  }

  for (monitor_t *m = wm.monitor_list; m; m = m->next) {
    for (tag_t *tag = m->tag_list; tag; tag = tag->next) {
      if (tag->index == tag_index) {
        client->monitor = m;
        client->tags = tag->mask;
        return;
      }
    }
  }

tag_fallback:
  client->tags = tag_mask;
}

static void set_window_event_mask(xcb_window_t window, bool clean) {
  xcb_cw_t change_mask = XCB_CW_EVENT_MASK;
  uint32_t init_event_mask =
    XCB_EVENT_MASK_ENTER_WINDOW | XCB_EVENT_MASK_FOCUS_CHANGE |
    XCB_EVENT_MASK_PROPERTY_CHANGE | XCB_EVENT_MASK_STRUCTURE_NOTIFY |
    XCB_EVENT_MASK_SUBSTRUCTURE_NOTIFY;
  uint32_t event_mask = clean ? XCB_EVENT_MASK_NO_EVENT : init_event_mask;
  xcb_params_cw_t params = {.event_mask = event_mask};
  xcb_aux_change_window_attributes(wm.xcb_conn, window, change_mask, &params);
}

void client_manage(xcb_window_t window,
                   xcb_get_geometry_reply_t *geometry_reply) {
  client_t *c = p_new(client_t, 1);
  c->window = window;
  c->old_geometry.x = geometry_reply->x;
  c->old_geometry.y = geometry_reply->y;
  c->old_geometry.width = geometry_reply->width;
  c->old_geometry.height = geometry_reply->height;
  c->geometry = c->old_geometry;
  c->old_border_width = geometry_reply->border_width;

  c->minimize = xwindow_get_state(window) == XCB_ICCCM_WM_STATE_ICONIC;

  set_window_event_mask(window, false);

  client_update_names(c);
  xwindow_get_text_property(c->window, WM_WINDOW_ROLE, &c->role);
  client_update_wm_hints(c);

  {
    xcb_icccm_get_wm_class_reply_t prop;
    xcb_get_property_cookie_t cookie =
      xcb_icccm_get_wm_class_unchecked(wm.xcb_conn, c->window);
    if (xcb_icccm_get_wm_class_reply(wm.xcb_conn, cookie, &prop, nullptr)) {
      c->class = strdup(prop.class_name);
      c->instance = strdup(prop.instance_name);
      xcb_icccm_get_wm_class_reply_wipe(&prop);
    }
  }

  {
    xcb_get_property_cookie_t cookie =
      xcb_icccm_get_wm_transient_for_unchecked(wm.xcb_conn, window);
    xcb_icccm_get_wm_transient_for_reply(wm.xcb_conn, cookie,
                                         &c->transient_for_window, nullptr);

    client_t *transient_for_client = nullptr;
    if (c->transient_for_window && (transient_for_client = client_get_by_window(
                                      c->transient_for_window))) {
      c->monitor = transient_for_client->monitor;
      client_init_tag_by_wm_desktop(c, transient_for_client->tags);
    } else {
      c->monitor = wm.current_monitor;
      client_init_tag_by_wm_desktop(c, c->monitor->selected_tag->mask);
      client_apply_rules(c, wm.rules, wm.rules_count);
    }

    client_init_geometry(c);
    client_tags_apply(c);
  }

  client_attach_list(c);
  client_attach_stack(c);
  client_update_window_type(c);
  client_update_size_hints(c);

  xcb_change_property(wm.xcb_conn, XCB_PROP_MODE_APPEND, wm.screen->root,
                      _NET_CLIENT_LIST, XCB_ATOM_WINDOW, 32, 1, &window);

  if (c->minimize) {
    xwindow_set_state(window, XCB_ICCCM_WM_STATE_ICONIC);
  } else {
    xwindow_set_state(window, XCB_ICCCM_WM_STATE_NORMAL);
    xcb_map_window(wm.xcb_conn, window);
  }

  monitor_arrange(c->monitor);
  monitor_draw_bar(c->monitor);

  wm_restack_clients();
  if (c->tags & c->monitor->selected_tag->mask) client_focus(c);

  xcb_flush(wm.xcb_conn);
}

char **client_get_task_title(client_t *client) {
  if (client->net_name) return &client->net_name;
  if (client->name) return &client->name;
  if (client->instance) return &client->instance;
  if (client->class) return &client->class;
  return nullptr;
}

bool client_need_layout(client_t *client) {
  if (client->floating || client->fullscreen || client->maximize ||
      client->minimize || client->size_freeze) {
    return false;
  }
  return true;
}

void client_send_to_tag(client_t *client, uint32_t tag_mask) {
  if (client->tags == tag_mask) return;
  client->tags = tag_mask;
  client_tags_apply(client);
  monitor_arrange(client->monitor);
  monitor_draw_bar(client->monitor);
  monitor_deal_focus(client->monitor);
  xcb_flush(wm.xcb_conn);
}

void client_send_to_monitor(client_t *client, monitor_t *monitor) {
  if (client->monitor == monitor) return;

  for (tag_t *tag = client->monitor->tag_list; tag; tag = tag->next) {
    client_remove_from_tag(client, tag);
  }

  monitor_t *m = client->monitor;

  client->monitor = monitor;
  client->tags = monitor->selected_tag->mask;
  client_add_to_tag(client, monitor->selected_tag);

  wm_set_current_monitor(monitor, true);
  monitor_arrange(m);
  monitor_arrange(monitor);
  monitor_draw_bar(m);
  monitor_draw_bar(monitor);

  xcb_flush(wm.xcb_conn);
}

void client_move_to(client_t *client, int16_t x, int16_t y) {
  client->geometry.x = x;
  client->geometry.y = y;
  uint16_t mask = XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y;
  const xcb_params_configure_window_t params = {.x = x, .y = y};
  xcb_aux_configure_window(wm.xcb_conn, client->window, mask, &params);
  logger("== client 0x%x move to x: %d, y: %d\n", client->window, x, y);
}

void client_resize(client_t *client, uint16_t width, uint16_t height) {
  client->geometry.width = width;
  client->geometry.height = height;
  uint16_t mask = XCB_CONFIG_WINDOW_WIDTH | XCB_CONFIG_WINDOW_HEIGHT;
  const xcb_params_configure_window_t params = {
    .width = width,
    .height = height,
  };
  xcb_aux_configure_window(wm.xcb_conn, client->window, mask, &params);
  logger("== client 0x%x resize to width: %d, height: %d\n", client->window,
         width, height);
}

void client_change_border_color(client_t *client, color_t *color) {
  uint16_t mask = XCB_CW_BORDER_PIXEL;
  const xcb_params_cw_t params = {.border_pixel = color->argb};
  xcb_aux_change_window_attributes(wm.xcb_conn, client->window, mask, &params);
  client->border_color = color;
  logger("== client 0x%x border color: RGBA(#%08x), ARGB(#%08x)\n",
         client->window, color->rgba, color->argb);
}

void client_change_border_width(client_t *client, uint16_t border_width) {
  if (client->border_width == border_width) return;
  uint16_t mask = XCB_CONFIG_WINDOW_BORDER_WIDTH;
  const xcb_params_configure_window_t params = {.border_width = border_width};
  xcb_aux_configure_window(wm.xcb_conn, client->window, mask, &params);
  client->border_width = border_width;
  logger("== client 0x%x border width: %u\n", client->window, border_width);
}

void client_update_window_type(client_t *client) {
  xcb_window_t window = client->window;
  xcb_get_property_cookie_t state_cookie = xcb_get_property_unchecked(
    wm.xcb_conn, false, window, _NET_WM_STATE, XCB_ATOM_ATOM, 0, 1);
  xcb_get_property_cookie_t window_type_cookie = xcb_get_property_unchecked(
    wm.xcb_conn, false, window, _NET_WM_WINDOW_TYPE, XCB_ATOM_ATOM, 0, 1);
  xcb_get_property_reply_t *state_reply =
    xcb_get_property_reply(wm.xcb_conn, state_cookie, nullptr);
  xcb_get_property_reply_t *window_type_reply =
    xcb_get_property_reply(wm.xcb_conn, window_type_cookie, nullptr);

  if (state_reply) {
    xcb_atom_t state = *(xcb_atom_t *)xcb_get_property_value(state_reply);
    if (state == _NET_WM_STATE_FULLSCREEN) {
      client_set_fullscreen(client, true);
    }
    p_delete(&state_reply);
  }

  if (window_type_reply) {
    xcb_atom_t window_type =
      *(xcb_atom_t *)xcb_get_property_value(window_type_reply);
    if (window_type == _NET_WM_WINDOW_TYPE_DIALOG) {
      client_set_floating(client, true);
    }
    p_delete(&window_type_reply);
  }
}

void client_update_wm_hints(client_t *client) {
  xcb_get_property_cookie_t cookie =
    xcb_icccm_get_wm_hints(wm.xcb_conn, client->window);
  xcb_icccm_wm_hints_t hints;
  if (xcb_icccm_get_wm_hints_reply(wm.xcb_conn, cookie, &hints, nullptr)) {
    if (client == wm.client_focused &&
        (hints.flags & XCB_ICCCM_WM_HINT_X_URGENCY)) {
      hints.flags &= ~XCB_ICCCM_WM_HINT_X_URGENCY;
      xcb_icccm_set_wm_hints(wm.xcb_conn, client->window, &hints);
    } else {
      client->urgent = hints.flags & XCB_ICCCM_WM_HINT_X_URGENCY;
    }
  }
}

void client_update_size_hints(client_t *client) {
  xcb_connection_t *conn = wm.xcb_conn;
  xcb_size_hints_t hints;
  xcb_get_property_cookie_t cookie =
    xcb_icccm_get_wm_normal_hints_unchecked(conn, client->window);
  if (!xcb_icccm_get_wm_normal_hints_reply(conn, cookie, &hints, nullptr)) {
    return;
  }

  int32_t min_width = 0, min_height = 0, max_width = 0, max_height = 0;
  if (hints.flags & XCB_ICCCM_SIZE_HINT_P_MIN_SIZE) {
    min_width = hints.min_width;
    min_height = hints.min_height;
  }
  if (hints.flags & XCB_ICCCM_SIZE_HINT_P_MAX_SIZE) {
    max_width = hints.max_width;
    max_height = hints.max_height;
  }
  if (min_width == max_width && min_height == max_height) {
    client->size_freeze = true;
    client_set_floating(client, true);
  }
}

void client_set_floating(client_t *client, bool floating) {
  if (client->floating == floating || client->fullscreen) return;

  logger("== client set floating: %s\n", floating ? "true" : "false");
  logger("== old geometry: x -> %d, y -> %d, width -> %u, height -> %u\n",
         client->old_geometry.x, client->old_geometry.y,
         client->old_geometry.width, client->old_geometry.height);
  client->floating = floating;
  if (floating) {
    client_apply_workarea_geometry(client, client->old_geometry);
    client->old_geometry = client->geometry;
  }

  monitor_arrange(client->monitor);
}

void client_set_fullscreen(client_t *client, bool fullscreen) {
  if (client->fullscreen == fullscreen) return;

  client->fullscreen = fullscreen;
  if (fullscreen) {
    xcb_change_property(wm.xcb_conn, XCB_PROP_MODE_REPLACE, client->window,
                        _NET_WM_STATE, XCB_ATOM_ATOM, 32, 1,
                        &_NET_WM_STATE_FULLSCREEN);
    client->old_border_width = client->border_width;
    if (client->floating) client->old_geometry = client->geometry;
    client_change_border_width(client, 0);
    client_apply_geometry(client, client->monitor->geometry);
    client_stack_raise(client);
  } else {
    xcb_change_property(wm.xcb_conn, XCB_PROP_MODE_REPLACE, client->window,
                        _NET_WM_STATE, XCB_ATOM_ATOM, 32, 0, 0);
    client_change_border_width(client, client->old_border_width);
    client_apply_geometry(client, client->old_geometry);
  }
  monitor_arrange(client->monitor);
  client_focus(client);
}

void client_set_maximize(client_t *client, bool maximize) {
  if (client->maximize == maximize) return;

  client->maximize = maximize;
  if (maximize) {
    xcb_atom_t max_atoms[] = {
      _NET_WM_STATE_MAXIMIZED_HORZ,
      _NET_WM_STATE_MAXIMIZED_VERT,
    };
    xcb_change_property(wm.xcb_conn, XCB_PROP_MODE_REPLACE, client->window,
                        _NET_WM_STATE, XCB_ATOM_ATOM, 32, countof(max_atoms),
                        max_atoms);
    client->old_border_width = client->border_width;
    if (client->floating) client->old_geometry = client->geometry;
    client_change_border_width(client, 0);
    client_apply_geometry(client, client->monitor->workarea);
    client_stack_raise(client);
  } else {
    xcb_change_property(wm.xcb_conn, XCB_PROP_MODE_REPLACE, client->window,
                        _NET_WM_STATE, XCB_ATOM_ATOM, 32, 0, 0);
    client_change_border_width(client, client->old_border_width);
    client_apply_geometry(client, client->old_geometry);
  }
  monitor_arrange(client->monitor);
  client_focus(client);
}

void client_set_minimize(client_t *client, bool minimize) {
  if (client->minimize == minimize) return;

  client->minimize = minimize;
  if (minimize) {
    xwindow_set_state(client->window, XCB_ICCCM_WM_STATE_ICONIC);

    xcb_grab_server(wm.xcb_conn);
    set_window_event_mask(client->window, true);
    xcb_unmap_window(wm.xcb_conn, client->window);
    set_window_event_mask(client->window, false);
    xcb_ungrab_server(wm.xcb_conn);
  } else {
    xwindow_set_state(client->window, XCB_ICCCM_WM_STATE_NORMAL);
    xcb_map_window(wm.xcb_conn, client->window);
  }
  monitor_arrange(client->monitor);
  client_focus(client);
}

static void update_client_list(void) {
  xcb_connection_t *conn = wm.xcb_conn;
  xcb_window_t root = wm.screen->root;
  xcb_atom_t atom = _NET_CLIENT_LIST;
  uint8_t mode = XCB_PROP_MODE_PREPEND;
  xcb_atom_t type = XCB_ATOM_WINDOW;

  xcb_delete_property(conn, root, atom);
  for (client_t *c = wm.client_list; c; c = c->next) {
    xcb_change_property(conn, mode, root, atom, type, 32, 1, &c->window);
  }
}

void client_kill(client_t *client) {
  if (!xwindow_send_event(client->window, WM_DELETE_WINDOW)) {
    xwindow_kill_window(client->window);
  }
}

void client_unmanage(client_t *client, bool destroyed) {
  monitor_t *m = client->monitor;

  client_detach_list(client);
  client_detach_stack(client);

  for (tag_t *tag = m->tag_list; tag; tag = tag->next) {
    if (tag->mask & client->tags) client_remove_from_tag(client, tag);
  }

  if (!destroyed) {
    set_window_event_mask(client->window, true);
    client_change_border_width(client, client->old_border_width);
    xwindow_set_state(client->window, XCB_ICCCM_WM_STATE_WITHDRAWN);
    xcb_flush(wm.xcb_conn);
  }

  client_wipe(client);

  update_client_list();

  wm_restack_clients();
  monitor_deal_focus(m);
  monitor_arrange(m);
  monitor_draw_bar(m);
  xcb_flush(wm.xcb_conn);
}

void client_apply_geometry(client_t *client, area_t geometry) {
  uint16_t mask = 0;
  const xcb_params_configure_window_t params = {
    .x = geometry.x,
    .y = geometry.y,
    .width = geometry.width,
    .height = geometry.height,
  };
  if (client->geometry.x != geometry.x) mask |= XCB_CONFIG_WINDOW_X;
  if (client->geometry.y != geometry.y) mask |= XCB_CONFIG_WINDOW_Y;
  if (client->geometry.width != geometry.width) mask |= XCB_CONFIG_WINDOW_WIDTH;
  if (client->geometry.height != geometry.height) {
    mask |= XCB_CONFIG_WINDOW_HEIGHT;
  }

  client->geometry = geometry;
  xcb_aux_configure_window(wm.xcb_conn, client->window, mask, &params);
}

/**
 * @brief 调整 client 的几何信息但需让 client 任在其 monitor 的 workarea 中
 * @param client 要调整几何信息的 client
 * @param geometry 目标几何信息
 */
void client_apply_workarea_geometry(client_t *client, area_t geometry) {
  area_t workarea = client->monitor->workarea;
  uint16_t width = MIN(geometry.width, workarea.width);
  uint16_t height = MIN(geometry.height, workarea.height);
  int16_t x = MAX(geometry.x, workarea.x);
  int16_t y = MAX(geometry.y, workarea.y);
  if (x + width + client->border_width * 2 > workarea.x + workarea.width) {
    x = workarea.x + workarea.width - width - client->border_width * 2;
  }
  if (y + height + client->border_width * 2 > workarea.y + workarea.height) {
    y = workarea.y + workarea.height - height - client->border_width * 2;
  }

  area_t rect = {.x = x, .y = y, .width = width, .height = height};
  client_apply_geometry(client, rect);
}

void client_apply_rules(client_t *client, const rule_t rules[],
                        size_t rules_count) {
  for (size_t i = 0; i < rules_count; i++) {
    const rule_t *r = &rules[i];
    if (!((!r->role || (client->role && strstr(client->role, r->role))) &&
          (!r->class || (client->class && strstr(client->class, r->class))))) {
      continue;
    }

    client->fullscreen = r->fullscreen;
    client->maximize = r->maximize;
    client->floating = r->floating;

    for (monitor_t *m = wm.monitor_list; m; m = m->next) {
      for (tag_t *t = m->tag_list; t; t = t->next) {
        if (t->index != r->tag_index) continue;

        client->monitor = m;
        client->tags = t->mask;

        if (r->switch_to_tag) {
          wm_set_current_monitor(m, true);
          m->selected_tag = t;

          logger("++ switch to tag: %u\n", t->index);
        }
      }
    }
  }

  if (client->fullscreen) {
    xcb_change_property(wm.xcb_conn, XCB_PROP_MODE_REPLACE, client->window,
                        _NET_WM_STATE, XCB_ATOM_ATOM, 32, 1,
                        &_NET_WM_STATE_FULLSCREEN);
  } else if (client->maximize) {
    xcb_atom_t max_atoms[] = {
      _NET_WM_STATE_MAXIMIZED_HORZ,
      _NET_WM_STATE_MAXIMIZED_VERT,
    };
    xcb_change_property(wm.xcb_conn, XCB_PROP_MODE_REPLACE, client->window,
                        _NET_WM_STATE, XCB_ATOM_ATOM, 32, countof(max_atoms),
                        max_atoms);
  }
}

void client_focus(client_t *client) {
  wm.client_focused = client;
  xwindow_focus(client ? client->window : XCB_WINDOW_NONE);
}

void client_stack_raise(client_t *client) {
  if (wm.client_stack_list == client) return;

  client_detach_stack(client);
  client_attach_stack(client);
  wm_restack_clients();
}

bool client_is_visible(client_t *client) {
  return client->tags & client->monitor->selected_tag->mask;
}

static inline rect_t client_to_rect(client_t *client) {
  return (rect_t){
    .x1 = client->geometry.x,
    .y1 = client->geometry.y,
    .x2 = client->geometry.x + (int32_t)client_width(client),
    .y2 = client->geometry.y + (int32_t)client_height(client),
  };
}

obscured_t client_get_obscured_state(client_t *client, client_t *client_stack) {
  if (!client || !client_stack) return obscured_none;

  rect_t source = client_to_rect(client);
  size_t clip_count = 0;
  size_t clip_capacity = 0;
  rect_t *clips = nullptr;

  bool has_overlap = false;
  for (client_t *c = client_stack; c; c = c->stack_next) {
    if (c == client) break;
    if (c->minimize || !client_is_visible(c)) continue;

    rect_t clip = client_to_rect(c);
    if (!rect_intersection(source, clip, nullptr)) continue;

    has_overlap = true;
    if (clip_count == clip_capacity) {
      clip_capacity = clip_capacity ? clip_capacity * 2 : 4;
      p_realloc(&clips, clip_capacity);
    }
    clips[clip_count++] = clip;
  }

  if (!has_overlap) {
    p_delete(&clips);
    return obscured_none;
  }

  rect_t *remaining = nullptr;
  size_t remaining_count =
    rect_subtract_many(source, clips, clip_count, &remaining);

  p_delete(&clips);
  p_delete(&remaining);
  return remaining_count == 0 ? obscured_fully : obscured_partially;
}