/*
* vim:ts=4:sw=4:expandtab
*
* i3 - an improved dynamic tiling window manager
* © 2009 Michael Stapelberg and contributors (see also: LICENSE)
*
* drag.c: click and drag.
*
*/
#include "all.h"
/* Custom data structure used to track dragging-related events. */
struct drag_x11_cb {
ev_prepare prepare;
/* Whether this modal event loop should be exited and with which result. */
drag_result_t result;
/* The container that is being dragged or resized, or NULL if this is a
* drag of the resize handle. */
Con *con;
/* The original event that initiated the drag. */
const xcb_button_press_event_t *event;
/* The dimensions of con when the loop was started. */
Rect old_rect;
/* The callback to invoke after every pointer movement. */
callback_t callback;
/* Drag distance threshold exceeded. If use_threshold is not set, then
* threshold_exceeded is always true. */
bool threshold_exceeded;
/* Cursor to set after the threshold is exceeded. */
xcb_cursor_t xcursor;
/* User data pointer for callback. */
const void *extra;
};
static bool threshold_exceeded(uint32_t x1, uint32_t y1,
uint32_t x2, uint32_t y2) {
/* The threshold is about the height of one window decoration. */
const uint32_t threshold = logical_px(15);
return (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2) > threshold * threshold;
}
static bool drain_drag_events(EV_P, struct drag_x11_cb *dragloop) {
xcb_motion_notify_event_t *last_motion_notify = NULL;
xcb_generic_event_t *event;
while ((event = xcb_poll_for_event(conn)) != NULL) {
if (event->response_type == 0) {
xcb_generic_error_t *error = (xcb_generic_error_t *)event;
DLOG("X11 Error received (probably harmless)! sequence 0x%x, error_code = %d\n",
error->sequence, error->error_code);
free(event);
continue;
}
/* Strip off the highest bit (set if the event is generated) */
int type = (event->response_type & 0x7F);
switch (type) {
case XCB_BUTTON_RELEASE:
dragloop->result = DRAG_SUCCESS;
break;
case XCB_KEY_PRESS:
DLOG("A key was pressed during drag, reverting changes.\n");
dragloop->result = DRAG_REVERT;
handle_event(type, event);
break;
case XCB_UNMAP_NOTIFY: {
xcb_unmap_notify_event_t *unmap_event = (xcb_unmap_notify_event_t *)event;
Con *con = con_by_window_id(unmap_event->window);
if (con != NULL) {
DLOG("UnmapNotify for window 0x%08x (container %p)\n", unmap_event->window, con);
if (con_get_workspace(con) == con_get_workspace(focused)) {
DLOG("UnmapNotify for a managed window on the current workspace, aborting\n");
dragloop->result = DRAG_ABORT;
}
}
handle_event(type, event);
break;
}
case XCB_MOTION_NOTIFY:
/* motion_notify events are saved for later */
FREE(last_motion_notify);
last_motion_notify = (xcb_motion_notify_event_t *)event;
break;
default:
DLOG("Passing to original handler\n");
handle_event(type, event);
break;
}
if (last_motion_notify != (xcb_motion_notify_event_t *)event)
free(event);
if (dragloop->result != DRAGGING) {
ev_break(EV_A_ EVBREAK_ONE);
if (dragloop->result == DRAG_SUCCESS) {
/* Ensure motion notify events are handled. */
break;
} else {
free(last_motion_notify);
return true;
}
}
}
if (last_motion_notify == NULL) {
return true;
}
if (!dragloop->threshold_exceeded &&
threshold_exceeded(last_motion_notify->root_x, last_motion_notify->root_y,
dragloop->event->root_x, dragloop->event->root_y)) {
if (dragloop->xcursor != XCB_NONE) {
xcb_change_active_pointer_grab(
conn,
dragloop->xcursor,
XCB_CURRENT_TIME,
XCB_EVENT_MASK_BUTTON_RELEASE | XCB_EVENT_MASK_POINTER_MOTION);
}
dragloop->threshold_exceeded = true;
}
/* Ensure that we are either dragging the resize handle (con is NULL) or that the
* container still exists. The latter might not be true, e.g., if the window closed
* for any reason while the user was dragging it. */
if (dragloop->threshold_exceeded && (!dragloop->con || con_exists(dragloop->con))) {
dragloop->callback(
dragloop->con,
&(dragloop->old_rect),
last_motion_notify->root_x,
last_motion_notify->root_y,
dragloop->event,
dragloop->extra);
}
FREE(last_motion_notify);
xcb_flush(conn);
return dragloop->result != DRAGGING;
}
static void xcb_drag_prepare_cb(EV_P_ ev_prepare *w, int revents) {
struct drag_x11_cb *dragloop = (struct drag_x11_cb *)w->data;
while (!drain_drag_events(EV_A, dragloop)) {
/* repeatedly drain events: draining might produce additional ones */
}
}
/*
* This function grabs your pointer and keyboard and lets you drag stuff around
* (borders). Every time you move your mouse, an XCB_MOTION_NOTIFY event will
* be received and the given callback will be called with the parameters
* specified (client, the original event), the original rect of the client,
* and the new coordinates (x, y).
*
* If use_threshold is set, dragging only starts after the user moves the
* pointer past a certain threshold. That is, the cursor will not be set and the
* callback will not be called until then.
*
*/
drag_result_t drag_pointer(Con *con, const xcb_button_press_event_t *event,
xcb_window_t confine_to, int cursor,
bool use_threshold, callback_t callback,
const void *extra) {
xcb_cursor_t xcursor = cursor ? xcursor_get_cursor(cursor) : XCB_NONE;
/* Grab the pointer */
xcb_grab_pointer_cookie_t cookie;
xcb_grab_pointer_reply_t *reply;
xcb_generic_error_t *error;
cookie = xcb_grab_pointer(conn,
false, /* get all pointer events specified by the following mask */
root, /* grab the root window */
XCB_EVENT_MASK_BUTTON_RELEASE | XCB_EVENT_MASK_POINTER_MOTION, /* which events to let through */
XCB_GRAB_MODE_ASYNC, /* pointer events should continue as normal */
XCB_GRAB_MODE_ASYNC, /* keyboard mode */
confine_to, /* confine_to = in which window should the cursor stay */
use_threshold ? XCB_NONE : xcursor, /* possibly display a special cursor */
XCB_CURRENT_TIME);
if ((reply = xcb_grab_pointer_reply(conn, cookie, &error)) == NULL) {
ELOG("Could not grab pointer (error_code = %d)\n", error->error_code);
free(error);
return DRAG_ABORT;
}
free(reply);
/* Grab the keyboard */
xcb_grab_keyboard_cookie_t keyb_cookie;
xcb_grab_keyboard_reply_t *keyb_reply;
keyb_cookie = xcb_grab_keyboard(conn,
false, /* get all keyboard events */
root, /* grab the root window */
XCB_CURRENT_TIME,
XCB_GRAB_MODE_ASYNC, /* continue processing pointer events as normal */
XCB_GRAB_MODE_ASYNC /* keyboard mode */
);
if ((keyb_reply = xcb_grab_keyboard_reply(conn, keyb_cookie, &error)) == NULL) {
ELOG("Could not grab keyboard (error_code = %d)\n", error->error_code);
free(error);
xcb_ungrab_pointer(conn, XCB_CURRENT_TIME);
return DRAG_ABORT;
}
free(keyb_reply);
/* Go into our own event loop */
struct drag_x11_cb loop = {
.result = DRAGGING,
.con = con,
.event = event,
.callback = callback,
.threshold_exceeded = !use_threshold,
.xcursor = xcursor,
.extra = extra,
};
ev_prepare *prepare = &loop.prepare;
if (con)
loop.old_rect = con->rect;
ev_prepare_init(prepare, xcb_drag_prepare_cb);
prepare->data = &loop;
main_set_x11_cb(false);
ev_prepare_start(main_loop, prepare);
ev_loop(main_loop, 0);
ev_prepare_stop(main_loop, prepare);
main_set_x11_cb(true);
xcb_ungrab_keyboard(conn, XCB_CURRENT_TIME);
xcb_ungrab_pointer(conn, XCB_CURRENT_TIME);
xcb_flush(conn);
return loop.result;
}