i3/src/xinerama.c

/*
 * vim:ts=8:expandtab
 *
 * i3 - an improved dynamic tiling window manager
 *
 * © 2009 Michael Stapelberg and contributors
 *
 * See file LICENSE for license information.
 *
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <assert.h>
#include <time.h>

#include <xcb/xcb.h>
#include <xcb/xinerama.h>

#include "queue.h"
#include "i3.h"
#include "data.h"
#include "table.h"
#include "util.h"
#include "xinerama.h"
#include "layout.h"
#include "xcb.h"
#include "config.h"
#include "workspace.h"

/* This TAILQ of i3Screens stores the virtual screens, used for handling overlapping screens
 * (xrandr --same-as) */
struct screens_head *virtual_screens;

static bool xinerama_enabled = true;

/*
 * Returns true if both screen objects describe the same screen (checks their
 * size and position).
 *
 */
bool screens_are_equal(i3Screen *screen1, i3Screen *screen2) {
        /* If one of both objects (or both) are NULL, we cannot compare them */
        if (screen1 == NULL || screen2 == NULL)
                return false;

        /* If the pointers are equal, take the short-circuit */
        if (screen1 == screen2)
                return true;

        /* Compare their size - other properties are not relevant to determine
         * if a screen is equal to another one */
        return (memcmp(&(screen1->rect), &(screen2->rect), sizeof(Rect)) == 0);
}

/*
 * Looks in virtual_screens for the i3Screen whose start coordinates are x, y
 *
 */
i3Screen *get_screen_at(int x, int y, struct screens_head *screenlist) {
        i3Screen *screen;
        TAILQ_FOREACH(screen, screenlist, screens)
                if (screen->rect.x == x && screen->rect.y == y)
                        return screen;

        return NULL;
}

/*
 * Looks in virtual_screens for the i3Screen which contains coordinates x, y
 *
 */
i3Screen *get_screen_containing(int x, int y) {
        i3Screen *screen;
        TAILQ_FOREACH(screen, virtual_screens, screens) {
                LOG("comparing x=%d y=%d with x=%d and y=%d width %d height %d\n",
                                x, y, screen->rect.x, screen->rect.y, screen->rect.width, screen->rect.height);
                if (x >= screen->rect.x && x < (screen->rect.x + screen->rect.width) &&
                    y >= screen->rect.y && y < (screen->rect.y + screen->rect.height))
                        return screen;
        }

        return NULL;
}

/*
 * Gets the screen which is the last one in the given direction, for example the screen
 * on the most bottom when direction == D_DOWN, the screen most right when direction == D_RIGHT
 * and so on.
 *
 * This function always returns a screen.
 *
 */
i3Screen *get_screen_most(direction_t direction, i3Screen *current) {
        i3Screen *screen, *candidate = NULL;
        int position = 0;
        TAILQ_FOREACH(screen, virtual_screens, screens) {
                /* Repeated calls of WIN determine the winner of the comparison */
                #define WIN(variable, condition) \
                        if (variable condition) { \
                                candidate = screen; \
                                position = variable; \
                        } \
                        break;

                if (((direction == D_UP) || (direction == D_DOWN)) &&
                    (current->rect.x != screen->rect.x))
                        continue;

                if (((direction == D_LEFT) || (direction == D_RIGHT)) &&
                    (current->rect.y != screen->rect.y))
                        continue;

                switch (direction) {
                        case D_UP:
                                WIN(screen->rect.y, <= position);
                        case D_DOWN:
                                WIN(screen->rect.y, >= position);
                        case D_LEFT:
                                WIN(screen->rect.x, <= position);
                        case D_RIGHT:
                                WIN(screen->rect.x, >= position);
                }
        }

        assert(candidate != NULL);

        return candidate;
}

static void initialize_screen(xcb_connection_t *conn, i3Screen *screen, Workspace *workspace) {
        i3Font *font = load_font(conn, config.font);

        workspace->screen = screen;
        screen->current_workspace = workspace->num;

        /* Create a bar for each screen */
        Rect bar_rect = {screen->rect.x,
                         screen->rect.height - (font->height + 6),
                         screen->rect.x + screen->rect.width,
                         font->height + 6};
        uint32_t mask = XCB_CW_OVERRIDE_REDIRECT | XCB_CW_EVENT_MASK;
        uint32_t values[] = {1, XCB_EVENT_MASK_EXPOSURE | XCB_EVENT_MASK_BUTTON_PRESS};
        screen->bar = create_window(conn, bar_rect, XCB_WINDOW_CLASS_INPUT_OUTPUT, XCB_CURSOR_LEFT_PTR, true, mask, values);
        screen->bargc = xcb_generate_id(conn);
        xcb_create_gc(conn, screen->bargc, screen->bar, 0, 0);

        SLIST_INIT(&(screen->dock_clients));

        LOG("that is virtual screen at %d x %d with %d x %d\n",
                        screen->rect.x, screen->rect.y, screen->rect.width, screen->rect.height);
}

/*
 * Fills virtual_screens with exactly one screen with width/height of the whole X server.
 *
 */
static void disable_xinerama(xcb_connection_t *conn) {
        xcb_screen_t *root_screen = xcb_setup_roots_iterator(xcb_get_setup(conn)).data;

        i3Screen *s = calloc(sizeof(i3Screen), 1);

        s->rect.x = 0;
        s->rect.y = 0;
        s->rect.width = root_screen->width_in_pixels;
        s->rect.height = root_screen->height_in_pixels;

        num_screens = 1;
        s->num = 0;

        TAILQ_INSERT_TAIL(virtual_screens, s, screens);

        xinerama_enabled = false;
}

/*
 * Gets the Xinerama screens and converts them to virtual i3Screens (only one screen for two
 * Xinerama screen which are configured in clone mode) in the given screenlist
 *
 */
static void query_screens(xcb_connection_t *conn, struct screens_head *screenlist) {
        xcb_xinerama_query_screens_reply_t *reply;
        xcb_xinerama_screen_info_t *screen_info;
        time_t before_trying = time(NULL);

        /* Try repeatedly to find screens (there might be short timeframes in
         * which the X server does not return any screens, such as when rotating
         * screens), but not longer than 5 seconds (strictly speaking, only four
         * seconds of trying are guaranteed due to the 1-second-resolution) */
        while ((time(NULL) - before_trying) < 5) {
                reply = xcb_xinerama_query_screens_reply(conn, xcb_xinerama_query_screens_unchecked(conn), NULL);
                if (!reply) {
                        LOG("Couldn't get Xinerama screens\n");
                        return;
                }
                screen_info = xcb_xinerama_query_screens_screen_info(reply);
                int screens = xcb_xinerama_query_screens_screen_info_length(reply);
                num_screens = 0;

                for (int screen = 0; screen < screens; screen++) {
                        i3Screen *s = get_screen_at(screen_info[screen].x_org, screen_info[screen].y_org, screenlist);
                        if (s != NULL) {
                                /* This screen already exists. We use the littlest screen so that the user
                                   can always see the complete workspace */
                                s->rect.width = min(s->rect.width, screen_info[screen].width);
                                s->rect.height = min(s->rect.height, screen_info[screen].height);
                        } else {
                                s = calloc(sizeof(i3Screen), 1);
                                s->rect.x = screen_info[screen].x_org;
                                s->rect.y = screen_info[screen].y_org;
                                s->rect.width = screen_info[screen].width;
                                s->rect.height = screen_info[screen].height;
                                /* We always treat the screen at 0x0 as the primary screen */
                                if (s->rect.x == 0 && s->rect.y == 0)
                                        TAILQ_INSERT_HEAD(screenlist, s, screens);
                                else TAILQ_INSERT_TAIL(screenlist, s, screens);
                                num_screens++;
                        }

                        LOG("found Xinerama screen: %d x %d at %d x %d\n",
                                        screen_info[screen].width, screen_info[screen].height,
                                        screen_info[screen].x_org, screen_info[screen].y_org);
                }

                free(reply);

                if (num_screens == 0) {
                        LOG("No screens found. This is weird. Trying again...\n");
                        continue;
                }

                break;
        }
}

/*
 * We have just established a connection to the X server and need the initial Xinerama
 * information to setup workspaces for each screen.
 *
 */
void initialize_xinerama(xcb_connection_t *conn) {
        virtual_screens = scalloc(sizeof(struct screens_head));
        TAILQ_INIT(virtual_screens);

        if (!xcb_get_extension_data(conn, &xcb_xinerama_id)->present) {
                LOG("Xinerama extension not found, disabling.\n");
                disable_xinerama(conn);
        } else {
                xcb_xinerama_is_active_reply_t *reply;
                reply = xcb_xinerama_is_active_reply(conn, xcb_xinerama_is_active(conn), NULL);

                if (reply == NULL || !reply->state) {
                        LOG("Xinerama is not active (in your X-Server), disabling.\n");
                        disable_xinerama(conn);
                } else
                        query_screens(conn, virtual_screens);

                FREE(reply);
        }

        i3Screen *screen;
        num_screens = 0;
        /* Just go through each workspace and associate as many screens as we can. */
        TAILQ_FOREACH(screen, virtual_screens, screens) {
                screen->num = num_screens;
                num_screens++;
                Workspace *ws = get_first_workspace_for_screen(virtual_screens, screen);
                initialize_screen(conn, screen, ws);
        }
}

/*
 * This is called when the rootwindow receives a configure_notify event and therefore the
 * number/position of the Xinerama screens could have changed.
 *
 */
void xinerama_requery_screens(xcb_connection_t *conn) {
        i3Font *font = load_font(conn, config.font);

        /* POSSIBLE PROBLEM: Is the order of the Xinerama screens always constant? That is, can
           it change when I move the --right-of video projector to --left-of? */

        if (!xinerama_enabled) {
                LOG("Xinerama is disabled\n");
                return;
        }

        /* We use a separate copy to diff with the previous set of screens */
        struct screens_head *new_screens = scalloc(sizeof(struct screens_head));
        TAILQ_INIT(new_screens);

        query_screens(conn, new_screens);

        i3Screen *first = TAILQ_FIRST(new_screens),
                 *screen,
                 *old_screen;
        int screen_count = 0;
        /* Mark each workspace which currently is assigned to a screen, so we
         * can garbage-collect afterwards */
        for (int c = 0; c < num_workspaces; c++)
                workspaces[c].reassigned = (workspaces[c].screen == NULL);

        TAILQ_FOREACH(screen, new_screens, screens) {
                screen->num = screen_count;
                screen->current_workspace = -1;

                TAILQ_FOREACH(old_screen, virtual_screens, screens) {
                        if (old_screen->num != screen_count)
                                continue;

                        LOG("Found a matching screen\n");
                        /* Use the same workspace */
                        screen->current_workspace = old_screen->current_workspace;

                        /* Re-use the old bar window */
                        screen->bar = old_screen->bar;
                        screen->bargc = old_screen->bargc;
                        LOG("old_screen->bar = %p\n", old_screen->bar);

                        Rect bar_rect = {screen->rect.x,
                                         screen->rect.height - (font->height + 6),
                                         screen->rect.x + screen->rect.width,
                                         font->height + 6};

                        LOG("configuring bar to be at %d x %d with %d x %d\n",
                                        bar_rect.x, bar_rect.y, bar_rect.height, bar_rect.width);
                        xcb_configure_window(conn, screen->bar, XCB_CONFIG_WINDOW_X |
                                                                XCB_CONFIG_WINDOW_Y |
                                                                XCB_CONFIG_WINDOW_WIDTH |
                                                                XCB_CONFIG_WINDOW_HEIGHT, &(bar_rect.x));

                        /* Copy the list head for the dock clients */
                        screen->dock_clients = old_screen->dock_clients;

                        /* Update the dimensions */
                        for (int c = 0; c < num_workspaces; c++) {
                                Workspace *ws = &(workspaces[c]);
                                if (ws->screen != old_screen)
                                        continue;

                                LOG("re-assigning ws %d\n", ws->num);
                                memcpy(&(ws->rect), &(screen->rect), sizeof(Rect));
                                ws->screen = screen;
                                ws->reassigned = true;
                        }

                        break;
                }
                if (screen->current_workspace == -1) {
                        /* Find the first unused workspace, preferring the ones
                         * which are assigned to this screen and initialize
                         * the screen with it. */
                        LOG("getting first ws for screen %p\n", screen);
                        Workspace *ws = get_first_workspace_for_screen(new_screens, screen);
                        initialize_screen(conn, screen, ws);
                        ws->reassigned = true;

                        /* As this workspace just got visible (we got a new screen
                         * without workspace), we need to map its clients */
                        workspace_map_clients(conn, ws);
                }
                screen_count++;
        }

        /* Check for workspaces which are out of bounds */
        for (int c = 0; c < num_workspaces; c++) {
                if (workspaces[c].reassigned)
                        continue;

                /* f_ws is a shortcut to the workspace to fix */
                Workspace *f_ws = &(workspaces[c]);
                Client *client;

                LOG("Closing bar window (%p)\n", f_ws->screen->bar);
                xcb_destroy_window(conn, f_ws->screen->bar);

                LOG("Workspace %d's screen out of bounds, assigning to first screen\n", c+1);
                f_ws->screen = first;
                memcpy(&(f_ws->rect), &(first->rect), sizeof(Rect));

                /* Force reconfiguration for each client on that workspace */
                FOR_TABLE(f_ws)
                        CIRCLEQ_FOREACH(client, &(f_ws->table[cols][rows]->clients), clients)
                                client->force_reconfigure = true;

                /* Render the workspace to reconfigure the clients. However, they will be visible now, so… */
                render_workspace(conn, first, f_ws);

                /* …unless we want to see them at the moment, we should hide that workspace */
                if (workspace_is_visible(f_ws))
                        continue;

                workspace_unmap_clients(conn, f_ws);

                if (c_ws == f_ws) {
                        LOG("Need to adjust c_ws...\n");
                        c_ws = &(workspaces[first->current_workspace]);
                }
        }
        xcb_flush(conn);

        /* Free the old list */
        while (!TAILQ_EMPTY(virtual_screens)) {
                screen = TAILQ_FIRST(virtual_screens);
                TAILQ_REMOVE(virtual_screens, screen, screens);
                free(screen);
        }
        free(virtual_screens);

        virtual_screens = new_screens;

        LOG("Current workspace is now: %d\n", first->current_workspace);

        render_layout(conn);
}