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layout restore: create and render placeholder windows
[i3/i3] / src / restore_layout.c
1 #undef I3__FILE__
2 #define I3__FILE__ "restore_layout.c"
3 /*
4  * vim:ts=4:sw=4:expandtab
5  *
6  * i3 - an improved dynamic tiling window manager
7  * © 2009-2013 Michael Stapelberg and contributors (see also: LICENSE)
8  *
9  * restore_layout.c: Everything for restored containers that is not pure state
10  *                   parsing (which can be found in load_layout.c).
11  *
12  *
13  */
14 #include "all.h"
15
16 typedef struct placeholder_state {
17     /** The X11 placeholder window. */
18     xcb_window_t window;
19     /** The container to which this placeholder window belongs. */
20     Con *con;
21
22     /** Current size of the placeholder window (to detect size changes). */
23     Rect rect;
24
25     /** The pixmap to render on (back buffer). */
26     xcb_pixmap_t pixmap;
27     /** The graphics context for “pixmap”. */
28     xcb_gcontext_t gc;
29
30     TAILQ_ENTRY(placeholder_state) state;
31 } placeholder_state;
32
33 static TAILQ_HEAD(state_head, placeholder_state) state_head =
34     TAILQ_HEAD_INITIALIZER(state_head);
35
36 static xcb_connection_t *restore_conn;
37
38 static void restore_handle_event(int type, xcb_generic_event_t *event);
39
40 /* Documentation for these functions can be found in src/main.c, starting at xcb_got_event */
41 static void restore_xcb_got_event(EV_P_ struct ev_io *w, int revents) {
42 }
43
44 static void restore_xcb_prepare_cb(EV_P_ ev_prepare *w, int revents) {
45     xcb_flush(restore_conn);
46 }
47
48 static void restore_xcb_check_cb(EV_P_ ev_check *w, int revents) {
49     xcb_generic_event_t *event;
50
51     if (xcb_connection_has_error(restore_conn)) {
52         // TODO: figure out how to reconnect with libev
53         ELOG("connection has an error\n");
54         return;
55     }
56
57     while ((event = xcb_poll_for_event(restore_conn)) != NULL) {
58         if (event->response_type == 0) {
59             xcb_generic_error_t *error = (xcb_generic_error_t*)event;
60             DLOG("X11 Error received (probably harmless)! sequence 0x%x, error_code = %d\n",
61                  error->sequence, error->error_code);
62             free(event);
63             continue;
64         }
65
66         /* Strip off the highest bit (set if the event is generated) */
67         int type = (event->response_type & 0x7F);
68
69         restore_handle_event(type, event);
70
71         free(event);
72     }
73 }
74
75 /*
76  * Opens a separate connection to X11 for placeholder windows when restoring
77  * layouts. This is done as a safety measure (users can xkill a placeholder
78  * window without killing their window manager) and for better isolation, both
79  * on the wire to X11 and thus also in the code.
80  *
81  */
82 void restore_connect(void) {
83     int screen;
84     restore_conn = xcb_connect(NULL, &screen);
85     if (restore_conn == NULL || xcb_connection_has_error(restore_conn))
86         errx(EXIT_FAILURE, "Cannot open display\n");
87
88     struct ev_io *xcb_watcher = scalloc(sizeof(struct ev_io));
89     struct ev_check *xcb_check = scalloc(sizeof(struct ev_check));
90     struct ev_prepare *xcb_prepare = scalloc(sizeof(struct ev_prepare));
91
92     ev_io_init(xcb_watcher, restore_xcb_got_event, xcb_get_file_descriptor(restore_conn), EV_READ);
93     ev_io_start(main_loop, xcb_watcher);
94
95     ev_check_init(xcb_check, restore_xcb_check_cb);
96     ev_check_start(main_loop, xcb_check);
97
98     ev_prepare_init(xcb_prepare, restore_xcb_prepare_cb);
99     ev_prepare_start(main_loop, xcb_prepare);
100 }
101
102 static void update_placeholder_contents(placeholder_state *state) {
103     // TODO: introduce color configuration for placeholder windows.
104     xcb_change_gc(restore_conn, state->gc, XCB_GC_FOREGROUND, (uint32_t[]) { config.client.background });
105     xcb_poly_fill_rectangle(restore_conn, state->pixmap, state->gc, 1,
106             (xcb_rectangle_t[]) { { 0, 0, state->rect.width, state->rect.height } });
107
108     // TODO: make i3font functions per-connection, at least these two for now…?
109     xcb_flush(restore_conn);
110     xcb_aux_sync(restore_conn);
111
112     // TODO: actually represent the criteria, most likely just line by line from (0, 0)
113     set_font_colors(state->gc, config.client.focused.background, 0);
114     i3String *line = i3string_from_utf8("⌚");
115     int text_width = predict_text_width(line);
116     int x = (state->rect.width / 2) - (text_width / 2);
117     int y = (state->rect.height / 2) - (config.font.height / 2);
118     draw_text(line, state->pixmap, state->gc, x, y, text_width);
119     i3string_free(line);
120     xcb_flush(conn);
121     xcb_aux_sync(conn);
122 }
123
124 static void open_placeholder_window(Con *con) {
125     if (con_is_leaf(con)) {
126         xcb_window_t placeholder = create_window(
127                 restore_conn,
128                 con->rect,
129                 XCB_COPY_FROM_PARENT,
130                 XCB_COPY_FROM_PARENT,
131                 XCB_WINDOW_CLASS_INPUT_OUTPUT,
132                 XCURSOR_CURSOR_POINTER,
133                 true,
134                 XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK,
135                 (uint32_t[]){
136                     // TODO: use the background color as background pixel to avoid flickering
137                     root_screen->white_pixel,
138                     XCB_EVENT_MASK_EXPOSURE | XCB_EVENT_MASK_STRUCTURE_NOTIFY,
139                 });
140         // TODO: set window title from con->name
141         DLOG("Created placeholder window 0x%08x for leaf container %p / %s\n",
142              placeholder, con, con->name);
143
144         placeholder_state *state = scalloc(sizeof(placeholder_state));
145         state->window = placeholder;
146         state->con = con;
147         state->rect = con->rect;
148         state->pixmap = xcb_generate_id(restore_conn);
149         // TODO: get rid of hardcoded 24
150         xcb_create_pixmap(restore_conn, 24, state->pixmap,
151                           state->window, state->rect.width, state->rect.height);
152         state->gc = xcb_generate_id(restore_conn);
153         xcb_create_gc(restore_conn, state->gc, state->pixmap, XCB_GC_GRAPHICS_EXPOSURES, (uint32_t[]){ 0 });
154         update_placeholder_contents(state);
155         TAILQ_INSERT_TAIL(&state_head, state, state);
156
157         /* create temporary id swallow to match the placeholder */
158         Match *temp_id = smalloc(sizeof(Match));
159         match_init(temp_id);
160         temp_id->id = placeholder;
161         TAILQ_INSERT_TAIL(&(con->swallow_head), temp_id, matches);
162     }
163
164     Con *child;
165     TAILQ_FOREACH(child, &(con->nodes_head), nodes) {
166         open_placeholder_window(child);
167     }
168     TAILQ_FOREACH(child, &(con->floating_head), floating_windows) {
169         open_placeholder_window(child);
170     }
171 }
172
173 /*
174  * Open placeholder windows for all children of parent. The placeholder window
175  * will vanish as soon as a real window is swallowed by the container. Until
176  * then, it exposes the criteria that must be fulfilled for a window to be
177  * swallowed by this container.
178  *
179  */
180 void restore_open_placeholder_windows(Con *parent) {
181     Con *child;
182     TAILQ_FOREACH(child, &(parent->nodes_head), nodes) {
183         open_placeholder_window(child);
184     }
185     TAILQ_FOREACH(child, &(parent->floating_head), floating_windows) {
186         open_placeholder_window(child);
187     }
188
189     xcb_flush(restore_conn);
190 }
191
192 static void expose_event(xcb_expose_event_t *event) {
193     placeholder_state *state;
194     TAILQ_FOREACH(state, &state_head, state) {
195         if (state->window != event->window)
196             continue;
197
198         DLOG("refreshing window 0x%08x contents (con %p)\n", state->window, state->con);
199
200         /* Since we render to our pixmap on every change anyways, expose events
201          * only tell us that the X server lost (parts of) the window contents. We
202          * can handle that by copying the appropriate part from our pixmap to the
203          * window. */
204         xcb_copy_area(restore_conn, state->pixmap, state->window, state->gc,
205                       event->x, event->y, event->x, event->y,
206                       event->width, event->height);
207         xcb_flush(restore_conn);
208         return;
209     }
210
211     ELOG("Received ExposeEvent for unknown window 0x%08x\n", event->window);
212 }
213
214 /*
215  * Window size has changed. Update the width/height, then recreate the back
216  * buffer pixmap and the accompanying graphics context and force an immediate
217  * re-rendering.
218  *
219  */
220 static void configure_notify(xcb_configure_notify_event_t *event) {
221     placeholder_state *state;
222     TAILQ_FOREACH(state, &state_head, state) {
223         if (state->window != event->window)
224             continue;
225
226         DLOG("ConfigureNotify: window 0x%08x has now width=%d, height=%d (con %p)\n",
227              state->window, event->width, event->height, state->con);
228
229         state->rect.width = event->width;
230         state->rect.height = event->height;
231
232         xcb_free_pixmap(restore_conn, state->pixmap);
233         xcb_free_gc(restore_conn, state->gc);
234
235         state->pixmap = xcb_generate_id(restore_conn);
236         // TODO: get rid of hardcoded 24
237         xcb_create_pixmap(restore_conn, 24, state->pixmap,
238                           state->window, state->rect.width, state->rect.height);
239         state->gc = xcb_generate_id(restore_conn);
240         xcb_create_gc(restore_conn, state->gc, state->pixmap, XCB_GC_GRAPHICS_EXPOSURES, (uint32_t[]){ 0 });
241
242         update_placeholder_contents(state);
243         xcb_copy_area(restore_conn, state->pixmap, state->window, state->gc,
244                       0, 0, 0, 0, state->rect.width, state->rect.height);
245         xcb_flush(restore_conn);
246         return;
247     }
248
249     ELOG("Received ConfigureNotify for unknown window 0x%08x\n", event->window);
250 }
251
252 // TODO: this event loop is not taken care of in the floating event handler
253 static void restore_handle_event(int type, xcb_generic_event_t *event) {
254     switch (type) {
255         case XCB_EXPOSE:
256             expose_event((xcb_expose_event_t*)event);
257             break;
258         case XCB_CONFIGURE_NOTIFY:
259             configure_notify((xcb_configure_notify_event_t*)event);
260             break;
261         default:
262             DLOG("Received unhandled X11 event of type %d\n", type);
263             break;
264     }
265 }