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| -rw-r--r-- | .gitignore | 4 | ||||
| -rw-r--r-- | LICENSE | 690 | ||||
| -rw-r--r-- | Makefile | 30 | ||||
| -rw-r--r-- | README.md | 50 | ||||
| -rw-r--r-- | config.h | 7 | ||||
| -rw-r--r-- | dwl.c | 950 |
6 files changed, 1731 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..e8ad87c --- /dev/null +++ b/.gitignore @@ -0,0 +1,4 @@ +dwl +*-protocol.c +*-protocol.h +.ccls-cache @@ -0,0 +1,690 @@ +dwl - dwm for Wayland + +Copyright © 2020 Devin J. Pohly + +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. + +---- + + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/> + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. By contrast, +the GNU General Public License is intended to guarantee your freedom to +share and change all versions of a program--to make sure it remains free +software for all its users. We, the Free Software Foundation, use the +GNU General Public License for most of our software; it applies also to +any other work released this way by its authors. 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If not, see <https://www.gnu.org/licenses/>. + +Also add information on how to contact you by electronic and paper mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + <program> Copyright (C) <year> <name of author> + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, your program's commands +might be different; for a GUI interface, you would use an "about box". + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU GPL, see +<https://www.gnu.org/licenses/>. + + The GNU General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +<https://www.gnu.org/licenses/why-not-lgpl.html>. diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..818686c --- /dev/null +++ b/Makefile @@ -0,0 +1,30 @@ +WAYLAND_PROTOCOLS=$(shell pkg-config --variable=pkgdatadir wayland-protocols) +WAYLAND_SCANNER=$(shell pkg-config --variable=wayland_scanner wayland-scanner) +LIBS=\ + $(shell pkg-config --cflags --libs wlroots) \ + $(shell pkg-config --cflags --libs wayland-server) \ + $(shell pkg-config --cflags --libs xkbcommon) + +# wayland-scanner is a tool which generates C headers and rigging for Wayland +# protocols, which are specified in XML. wlroots requires you to rig these up +# to your build system yourself and provide them in the include path. +xdg-shell-protocol.h: + $(WAYLAND_SCANNER) server-header \ + $(WAYLAND_PROTOCOLS)/stable/xdg-shell/xdg-shell.xml $@ + +xdg-shell-protocol.c: xdg-shell-protocol.h + $(WAYLAND_SCANNER) private-code \ + $(WAYLAND_PROTOCOLS)/stable/xdg-shell/xdg-shell.xml $@ + +dwl: dwl.c config.h xdg-shell-protocol.h xdg-shell-protocol.c + $(CC) $(CFLAGS) \ + -g -Werror -I. \ + -DWLR_USE_UNSTABLE \ + -o $@ $< \ + $(LIBS) + +clean: + rm -f dwl xdg-shell-protocol.h xdg-shell-protocol.c + +.DEFAULT_GOAL=dwl +.PHONY: clean diff --git a/README.md b/README.md new file mode 100644 index 0000000..d76211f --- /dev/null +++ b/README.md @@ -0,0 +1,50 @@ +# dwl + +This is the "minimum viable product" Wayland compositor based on wlroots. It +aims to implement a Wayland compositor in the fewest lines of code possible, +while still supporting a reasonable set of features. Reading this code is the +best starting point for anyone looking to build their own Wayland compositor +based on wlroots. + + +## Building dwl + +dwl is disconnected from the main wlroots build system, in order to make it +easier to understand the build requirements for your own Wayland compositors. +Simply install the dependencies: + +- wlroots +- wayland-protocols + +And run `make`. + + +## Running dwl + +You can run dwl with `./dwl`. In an existing Wayland or X11 session, +dwl will open a Wayland or X11 window respectively to act as a virtual +display. You can then open Wayland windows by setting `WAYLAND_DISPLAY` to the +value shown in the logs. You can also run `./dwl` from a TTY. + +In either case, you will likely want to specify `-s [cmd]` to run a command at +startup, such as a terminal emulator. This will be necessary to start any new +programs from within the compositor, as dwl does not support any custom +keybindings. dwl supports the following keybindings: + +- `Alt+Escape`: Terminate the compositor +- `Alt+F1`: Cycle between windows + + +## Limitations + +Notable omissions from dwl: + +- HiDPI support +- Any kind of configuration, e.g. output layout +- Any protocol other than xdg-shell (e.g. layer-shell, for + panels/taskbars/etc; or Xwayland, for proxied X11 windows) +- Optional protocols, e.g. screen capture, primary selection, virtual + keyboard, etc. Most of these are plug-and-play with wlroots, but they're + omitted for brevity. +- Damage tracking, which tracks which parts of the screen are changing and + minimizes redraws accordingly. diff --git a/config.h b/config.h new file mode 100644 index 0000000..ff05992 --- /dev/null +++ b/config.h @@ -0,0 +1,7 @@ +static const struct xkb_rule_names xkb_rules = { + .rules = NULL, + .model = NULL, + .layout = "dvorak", + .variant = NULL, + .options = NULL, +}; @@ -0,0 +1,950 @@ +/* + * See LICENSE file for copyright and license details. + */ +#define _POSIX_C_SOURCE 200112L +#include <getopt.h> +#include <stdbool.h> +#include <stdlib.h> +#include <stdio.h> +#include <time.h> +#include <unistd.h> +#include <wayland-server-core.h> +#include <wlr/backend.h> +#include <wlr/render/wlr_renderer.h> +#include <wlr/types/wlr_cursor.h> +#include <wlr/types/wlr_compositor.h> +#include <wlr/types/wlr_data_device.h> +#include <wlr/types/wlr_input_device.h> +#include <wlr/types/wlr_keyboard.h> +#include <wlr/types/wlr_matrix.h> +#include <wlr/types/wlr_output.h> +#include <wlr/types/wlr_output_layout.h> +#include <wlr/types/wlr_pointer.h> +#include <wlr/types/wlr_seat.h> +#include <wlr/types/wlr_xcursor_manager.h> +#include <wlr/types/wlr_xdg_shell.h> +#include <wlr/util/log.h> +#include <xkbcommon/xkbcommon.h> + +/* For brevity's sake, struct members are annotated where they are used. */ +enum dwl_cursor_mode { + DWL_CURSOR_PASSTHROUGH, + DWL_CURSOR_MOVE, + DWL_CURSOR_RESIZE, +}; + +struct dwl_server { + struct wl_display *wl_display; + struct wlr_backend *backend; + struct wlr_renderer *renderer; + + struct wlr_xdg_shell *xdg_shell; + struct wl_listener new_xdg_surface; + struct wl_list views; + + struct wlr_cursor *cursor; + struct wlr_xcursor_manager *cursor_mgr; + struct wl_listener cursor_motion; + struct wl_listener cursor_motion_absolute; + struct wl_listener cursor_button; + struct wl_listener cursor_axis; + struct wl_listener cursor_frame; + + struct wlr_seat *seat; + struct wl_listener new_input; + struct wl_listener request_cursor; + struct wl_list keyboards; + enum dwl_cursor_mode cursor_mode; + struct dwl_view *grabbed_view; + double grab_x, grab_y; + int grab_width, grab_height; + uint32_t resize_edges; + + struct wlr_output_layout *output_layout; + struct wl_list outputs; + struct wl_listener new_output; +}; + +struct dwl_output { + struct wl_list link; + struct dwl_server *server; + struct wlr_output *wlr_output; + struct wl_listener frame; +}; + +struct dwl_view { + struct wl_list link; + struct dwl_server *server; + struct wlr_xdg_surface *xdg_surface; + struct wl_listener map; + struct wl_listener unmap; + struct wl_listener destroy; + struct wl_listener request_move; + struct wl_listener request_resize; + bool mapped; + int x, y; +}; + +struct dwl_keyboard { + struct wl_list link; + struct dwl_server *server; + struct wlr_input_device *device; + + struct wl_listener modifiers; + struct wl_listener key; +}; + +#include "config.h" + +static void focus_view(struct dwl_view *view, struct wlr_surface *surface) { + /* Note: this function only deals with keyboard focus. */ + if (view == NULL) { + return; + } + struct dwl_server *server = view->server; + struct wlr_seat *seat = server->seat; + struct wlr_surface *prev_surface = seat->keyboard_state.focused_surface; + if (prev_surface == surface) { + /* Don't re-focus an already focused surface. */ + return; + } + if (prev_surface) { + /* + * Deactivate the previously focused surface. This lets the client know + * it no longer has focus and the client will repaint accordingly, e.g. + * stop displaying a caret. + */ + struct wlr_xdg_surface *previous = wlr_xdg_surface_from_wlr_surface( + seat->keyboard_state.focused_surface); + wlr_xdg_toplevel_set_activated(previous, false); + } + struct wlr_keyboard *keyboard = wlr_seat_get_keyboard(seat); + /* Move the view to the front */ + wl_list_remove(&view->link); + wl_list_insert(&server->views, &view->link); + /* Activate the new surface */ + wlr_xdg_toplevel_set_activated(view->xdg_surface, true); + /* + * Tell the seat to have the keyboard enter this surface. wlroots will keep + * track of this and automatically send key events to the appropriate + * clients without additional work on your part. + */ + wlr_seat_keyboard_notify_enter(seat, view->xdg_surface->surface, + keyboard->keycodes, keyboard->num_keycodes, &keyboard->modifiers); +} + +static void keyboard_handle_modifiers( + struct wl_listener *listener, void *data) { + /* This event is raised when a modifier key, such as shift or alt, is + * pressed. We simply communicate this to the client. */ + struct dwl_keyboard *keyboard = + wl_container_of(listener, keyboard, modifiers); + /* + * A seat can only have one keyboard, but this is a limitation of the + * Wayland protocol - not wlroots. We assign all connected keyboards to the + * same seat. You can swap out the underlying wlr_keyboard like this and + * wlr_seat handles this transparently. + */ + wlr_seat_set_keyboard(keyboard->server->seat, keyboard->device); + /* Send modifiers to the client. */ + wlr_seat_keyboard_notify_modifiers(keyboard->server->seat, + &keyboard->device->keyboard->modifiers); +} + +static bool handle_keybinding(struct dwl_server *server, xkb_keysym_t sym) { + /* + * Here we handle compositor keybindings. This is when the compositor is + * processing keys, rather than passing them on to the client for its own + * processing. + * + * This function assumes Alt is held down. + */ + switch (sym) { + case XKB_KEY_Escape: + wl_display_terminate(server->wl_display); + break; + case XKB_KEY_F1: + /* Cycle to the next view */ + if (wl_list_length(&server->views) < 2) { + break; + } + struct dwl_view *current_view = wl_container_of( + server->views.next, current_view, link); + struct dwl_view *next_view = wl_container_of( + current_view->link.next, next_view, link); + focus_view(next_view, next_view->xdg_surface->surface); + /* Move the previous view to the end of the list */ + wl_list_remove(¤t_view->link); + wl_list_insert(server->views.prev, ¤t_view->link); + break; + default: + return false; + } + return true; +} + +static void keyboard_handle_key( + struct wl_listener *listener, void *data) { + /* This event is raised when a key is pressed or released. */ + struct dwl_keyboard *keyboard = + wl_container_of(listener, keyboard, key); + struct dwl_server *server = keyboard->server; + struct wlr_event_keyboard_key *event = data; + struct wlr_seat *seat = server->seat; + + /* Translate libinput keycode -> xkbcommon */ + uint32_t keycode = event->keycode + 8; + /* Get a list of keysyms based on the keymap for this keyboard */ + const xkb_keysym_t *syms; + int nsyms = xkb_state_key_get_syms( + keyboard->device->keyboard->xkb_state, keycode, &syms); + + bool handled = false; + uint32_t modifiers = wlr_keyboard_get_modifiers(keyboard->device->keyboard); + if ((modifiers & WLR_MODIFIER_ALT) && event->state == WLR_KEY_PRESSED) { + /* If alt is held down and this button was _pressed_, we attempt to + * process it as a compositor keybinding. */ + for (int i = 0; i < nsyms; i++) { + handled = handle_keybinding(server, syms[i]); + } + } + + if (!handled) { + /* Otherwise, we pass it along to the client. */ + wlr_seat_set_keyboard(seat, keyboard->device); + wlr_seat_keyboard_notify_key(seat, event->time_msec, + event->keycode, event->state); + } +} + +static void server_new_keyboard(struct dwl_server *server, + struct wlr_input_device *device) { + struct dwl_keyboard *keyboard = + calloc(1, sizeof(struct dwl_keyboard)); + keyboard->server = server; + keyboard->device = device; + + /* We need to prepare an XKB keymap and assign it to the keyboard. This + * assumes the defaults (e.g. layout = "us"). */ + struct xkb_context *context = xkb_context_new(XKB_CONTEXT_NO_FLAGS); + struct xkb_keymap *keymap = xkb_map_new_from_names(context, &xkb_rules, + XKB_KEYMAP_COMPILE_NO_FLAGS); + + wlr_keyboard_set_keymap(device->keyboard, keymap); + xkb_keymap_unref(keymap); + xkb_context_unref(context); + wlr_keyboard_set_repeat_info(device->keyboard, 25, 600); + + /* Here we set up listeners for keyboard events. */ + keyboard->modifiers.notify = keyboard_handle_modifiers; + wl_signal_add(&device->keyboard->events.modifiers, &keyboard->modifiers); + keyboard->key.notify = keyboard_handle_key; + wl_signal_add(&device->keyboard->events.key, &keyboard->key); + + wlr_seat_set_keyboard(server->seat, device); + + /* And add the keyboard to our list of keyboards */ + wl_list_insert(&server->keyboards, &keyboard->link); +} + +static void server_new_pointer(struct dwl_server *server, + struct wlr_input_device *device) { + /* We don't do anything special with pointers. All of our pointer handling + * is proxied through wlr_cursor. On another compositor, you might take this + * opportunity to do libinput configuration on the device to set + * acceleration, etc. */ + wlr_cursor_attach_input_device(server->cursor, device); +} + +static void server_new_input(struct wl_listener *listener, void *data) { + /* This event is raised by the backend when a new input device becomes + * available. */ + struct dwl_server *server = + wl_container_of(listener, server, new_input); + struct wlr_input_device *device = data; + switch (device->type) { + case WLR_INPUT_DEVICE_KEYBOARD: + server_new_keyboard(server, device); + break; + case WLR_INPUT_DEVICE_POINTER: + server_new_pointer(server, device); + break; + default: + break; + } + /* We need to let the wlr_seat know what our capabilities are, which is + * communiciated to the client. In dwl we always have a cursor, even if + * there are no pointer devices, so we always include that capability. */ + uint32_t caps = WL_SEAT_CAPABILITY_POINTER; + if (!wl_list_empty(&server->keyboards)) { + caps |= WL_SEAT_CAPABILITY_KEYBOARD; + } + wlr_seat_set_capabilities(server->seat, caps); +} + +static void seat_request_cursor(struct wl_listener *listener, void *data) { + struct dwl_server *server = wl_container_of( + listener, server, request_cursor); + /* This event is rasied by the seat when a client provides a cursor image */ + struct wlr_seat_pointer_request_set_cursor_event *event = data; + struct wlr_seat_client *focused_client = + server->seat->pointer_state.focused_client; + /* This can be sent by any client, so we check to make sure this one is + * actually has pointer focus first. */ + if (focused_client == event->seat_client) { + /* Once we've vetted the client, we can tell the cursor to use the + * provided surface as the cursor image. It will set the hardware cursor + * on the output that it's currently on and continue to do so as the + * cursor moves between outputs. */ + wlr_cursor_set_surface(server->cursor, event->surface, + event->hotspot_x, event->hotspot_y); + } +} + +static bool view_at(struct dwl_view *view, + double lx, double ly, struct wlr_surface **surface, + double *sx, double *sy) { + /* + * XDG toplevels may have nested surfaces, such as popup windows for context + * menus or tooltips. This function tests if any of those are underneath the + * coordinates lx and ly (in output Layout Coordinates). If so, it sets the + * surface pointer to that wlr_surface and the sx and sy coordinates to the + * coordinates relative to that surface's top-left corner. + */ + double view_sx = lx - view->x; + double view_sy = ly - view->y; + + struct wlr_surface_state *state = &view->xdg_surface->surface->current; + + double _sx, _sy; + struct wlr_surface *_surface = NULL; + _surface = wlr_xdg_surface_surface_at( + view->xdg_surface, view_sx, view_sy, &_sx, &_sy); + + if (_surface != NULL) { + *sx = _sx; + *sy = _sy; + *surface = _surface; + return true; + } + + return false; +} + +static struct dwl_view *desktop_view_at( + struct dwl_server *server, double lx, double ly, + struct wlr_surface **surface, double *sx, double *sy) { + /* This iterates over all of our surfaces and attempts to find one under the + * cursor. This relies on server->views being ordered from top-to-bottom. */ + struct dwl_view *view; + wl_list_for_each(view, &server->views, link) { + if (view_at(view, lx, ly, surface, sx, sy)) { + return view; + } + } + return NULL; +} + +static void process_cursor_move(struct dwl_server *server, uint32_t time) { + /* Move the grabbed view to the new position. */ + server->grabbed_view->x = server->cursor->x - server->grab_x; + server->grabbed_view->y = server->cursor->y - server->grab_y; +} + +static void process_cursor_resize(struct dwl_server *server, uint32_t time) { + /* + * Resizing the grabbed view can be a little bit complicated, because we + * could be resizing from any corner or edge. This not only resizes the view + * on one or two axes, but can also move the view if you resize from the top + * or left edges (or top-left corner). + * + * Note that I took some shortcuts here. In a more fleshed-out compositor, + * you'd wait for the client to prepare a buffer at the new size, then + * commit any movement that was prepared. + */ + struct dwl_view *view = server->grabbed_view; + double dx = server->cursor->x - server->grab_x; + double dy = server->cursor->y - server->grab_y; + double x = view->x; + double y = view->y; + int width = server->grab_width; + int height = server->grab_height; + if (server->resize_edges & WLR_EDGE_TOP) { + y = server->grab_y + dy; + height -= dy; + if (height < 1) { + y += height; + } + } else if (server->resize_edges & WLR_EDGE_BOTTOM) { + height += dy; + } + if (server->resize_edges & WLR_EDGE_LEFT) { + x = server->grab_x + dx; + width -= dx; + if (width < 1) { + x += width; + } + } else if (server->resize_edges & WLR_EDGE_RIGHT) { + width += dx; + } + view->x = x; + view->y = y; + wlr_xdg_toplevel_set_size(view->xdg_surface, width, height); +} + +static void process_cursor_motion(struct dwl_server *server, uint32_t time) { + /* If the mode is non-passthrough, delegate to those functions. */ + if (server->cursor_mode == DWL_CURSOR_MOVE) { + process_cursor_move(server, time); + return; + } else if (server->cursor_mode == DWL_CURSOR_RESIZE) { + process_cursor_resize(server, time); + return; + } + + /* Otherwise, find the view under the pointer and send the event along. */ + double sx, sy; + struct wlr_seat *seat = server->seat; + struct wlr_surface *surface = NULL; + struct dwl_view *view = desktop_view_at(server, + server->cursor->x, server->cursor->y, &surface, &sx, &sy); + if (!view) { + /* If there's no view under the cursor, set the cursor image to a + * default. This is what makes the cursor image appear when you move it + * around the screen, not over any views. */ + wlr_xcursor_manager_set_cursor_image( + server->cursor_mgr, "left_ptr", server->cursor); + } + if (surface) { + bool focus_changed = seat->pointer_state.focused_surface != surface; + /* + * "Enter" the surface if necessary. This lets the client know that the + * cursor has entered one of its surfaces. + * + * Note that this gives the surface "pointer focus", which is distinct + * from keyboard focus. You get pointer focus by moving the pointer over + * a window. + */ + wlr_seat_pointer_notify_enter(seat, surface, sx, sy); + if (!focus_changed) { + /* The enter event contains coordinates, so we only need to notify + * on motion if the focus did not change. */ + wlr_seat_pointer_notify_motion(seat, time, sx, sy); + } + } else { + /* Clear pointer focus so future button events and such are not sent to + * the last client to have the cursor over it. */ + wlr_seat_pointer_clear_focus(seat); + } +} + +static void server_cursor_motion(struct wl_listener *listener, void *data) { + /* This event is forwarded by the cursor when a pointer emits a _relative_ + * pointer motion event (i.e. a delta) */ + struct dwl_server *server = + wl_container_of(listener, server, cursor_motion); + struct wlr_event_pointer_motion *event = data; + /* The cursor doesn't move unless we tell it to. The cursor automatically + * handles constraining the motion to the output layout, as well as any + * special configuration applied for the specific input device which + * generated the event. You can pass NULL for the device if you want to move + * the cursor around without any input. */ + wlr_cursor_move(server->cursor, event->device, + event->delta_x, event->delta_y); + process_cursor_motion(server, event->time_msec); +} + +static void server_cursor_motion_absolute( + struct wl_listener *listener, void *data) { + /* This event is forwarded by the cursor when a pointer emits an _absolute_ + * motion event, from 0..1 on each axis. This happens, for example, when + * wlroots is running under a Wayland window rather than KMS+DRM, and you + * move the mouse over the window. You could enter the window from any edge, + * so we have to warp the mouse there. There is also some hardware which + * emits these events. */ + struct dwl_server *server = + wl_container_of(listener, server, cursor_motion_absolute); + struct wlr_event_pointer_motion_absolute *event = data; + wlr_cursor_warp_absolute(server->cursor, event->device, event->x, event->y); + process_cursor_motion(server, event->time_msec); +} + +static void server_cursor_button(struct wl_listener *listener, void *data) { + /* This event is forwarded by the cursor when a pointer emits a button + * event. */ + struct dwl_server *server = + wl_container_of(listener, server, cursor_button); + struct wlr_event_pointer_button *event = data; + /* Notify the client with pointer focus that a button press has occurred */ + wlr_seat_pointer_notify_button(server->seat, + event->time_msec, event->button, event->state); + double sx, sy; + struct wlr_seat *seat = server->seat; + struct wlr_surface *surface; + struct dwl_view *view = desktop_view_at(server, + server->cursor->x, server->cursor->y, &surface, &sx, &sy); + if (event->state == WLR_BUTTON_RELEASED) { + /* If you released any buttons, we exit interactive move/resize mode. */ + server->cursor_mode = DWL_CURSOR_PASSTHROUGH; + } else { + /* Focus that client if the button was _pressed_ */ + focus_view(view, surface); + } +} + +static void server_cursor_axis(struct wl_listener *listener, void *data) { + /* This event is forwarded by the cursor when a pointer emits an axis event, + * for example when you move the scroll wheel. */ + struct dwl_server *server = + wl_container_of(listener, server, cursor_axis); + struct wlr_event_pointer_axis *event = data; + /* Notify the client with pointer focus of the axis event. */ + wlr_seat_pointer_notify_axis(server->seat, + event->time_msec, event->orientation, event->delta, + event->delta_discrete, event->source); +} + +static void server_cursor_frame(struct wl_listener *listener, void *data) { + /* This event is forwarded by the cursor when a pointer emits an frame + * event. Frame events are sent after regular pointer events to group + * multiple events together. For instance, two axis events may happen at the + * same time, in which case a frame event won't be sent in between. */ + struct dwl_server *server = + wl_container_of(listener, server, cursor_frame); + /* Notify the client with pointer focus of the frame event. */ + wlr_seat_pointer_notify_frame(server->seat); +} + +/* Used to move all of the data necessary to render a surface from the top-level + * frame handler to the per-surface render function. */ +struct render_data { + struct wlr_output *output; + struct wlr_renderer *renderer; + struct dwl_view *view; + struct timespec *when; +}; + +static void render_surface(struct wlr_surface *surface, + int sx, int sy, void *data) { + /* This function is called for every surface that needs to be rendered. */ + struct render_data *rdata = data; + struct dwl_view *view = rdata->view; + struct wlr_output *output = rdata->output; + + /* We first obtain a wlr_texture, which is a GPU resource. wlroots + * automatically handles negotiating these with the client. The underlying + * resource could be an opaque handle passed from the client, or the client + * could have sent a pixel buffer which we copied to the GPU, or a few other + * means. You don't have to worry about this, wlroots takes care of it. */ + struct wlr_texture *texture = wlr_surface_get_texture(surface); + if (texture == NULL) { + return; + } + + /* The view has a position in layout coordinates. If you have two displays, + * one next to the other, both 1080p, a view on the rightmost display might + * have layout coordinates of 2000,100. We need to translate that to + * output-local coordinates, or (2000 - 1920). */ + double ox = 0, oy = 0; + wlr_output_layout_output_coords( + view->server->output_layout, output, &ox, &oy); + ox += view->x + sx, oy += view->y + sy; + + /* We also have to apply the scale factor for HiDPI outputs. This is only + * part of the puzzle, dwl does not fully support HiDPI. */ + struct wlr_box box = { + .x = ox * output->scale, + .y = oy * output->scale, + .width = surface->current.width * output->scale, + .height = surface->current.height * output->scale, + }; + + /* + * Those familiar with OpenGL are also familiar with the role of matricies + * in graphics programming. We need to prepare a matrix to render the view + * with. wlr_matrix_project_box is a helper which takes a box with a desired + * x, y coordinates, width and height, and an output geometry, then + * prepares an orthographic projection and multiplies the necessary + * transforms to produce a model-view-projection matrix. + * + * Naturally you can do this any way you like, for example to make a 3D + * compositor. + */ + float matrix[9]; + enum wl_output_transform transform = + wlr_output_transform_invert(surface->current.transform); + wlr_matrix_project_box(matrix, &box, transform, 0, + output->transform_matrix); + + /* This takes our matrix, the texture, and an alpha, and performs the actual + * rendering on the GPU. */ + wlr_render_texture_with_matrix(rdata->renderer, texture, matrix, 1); + + /* This lets the client know that we've displayed that frame and it can + * prepare another one now if it likes. */ + wlr_surface_send_frame_done(surface, rdata->when); +} + +static void output_frame(struct wl_listener *listener, void *data) { + /* This function is called every time an output is ready to display a frame, + * generally at the output's refresh rate (e.g. 60Hz). */ + struct dwl_output *output = + wl_container_of(listener, output, frame); + struct wlr_renderer *renderer = output->server->renderer; + + struct timespec now; + clock_gettime(CLOCK_MONOTONIC, &now); + + /* wlr_output_attach_render makes the OpenGL context current. */ + if (!wlr_output_attach_render(output->wlr_output, NULL)) { + return; + } + /* The "effective" resolution can change if you rotate your outputs. */ + int width, height; + wlr_output_effective_resolution(output->wlr_output, &width, &height); + /* Begin the renderer (calls glViewport and some other GL sanity checks) */ + wlr_renderer_begin(renderer, width, height); + + float color[4] = {0.3, 0.3, 0.3, 1.0}; + wlr_renderer_clear(renderer, color); + + /* Each subsequent window we render is rendered on top of the last. Because + * our view list is ordered front-to-back, we iterate over it backwards. */ + struct dwl_view *view; + wl_list_for_each_reverse(view, &output->server->views, link) { + if (!view->mapped) { + /* An unmapped view should not be rendered. */ + continue; + } + struct render_data rdata = { + .output = output->wlr_output, + .view = view, + .renderer = renderer, + .when = &now, + }; + /* This calls our render_surface function for each surface among the + * xdg_surface's toplevel and popups. */ + wlr_xdg_surface_for_each_surface(view->xdg_surface, + render_surface, &rdata); + } + + /* Hardware cursors are rendered by the GPU on a separate plane, and can be + * moved around without re-rendering what's beneath them - which is more + * efficient. However, not all hardware supports hardware cursors. For this + * reason, wlroots provides a software fallback, which we ask it to render + * here. wlr_cursor handles configuring hardware vs software cursors for you, + * and this function is a no-op when hardware cursors are in use. */ + wlr_output_render_software_cursors(output->wlr_output, NULL); + + /* Conclude rendering and swap the buffers, showing the final frame + * on-screen. */ + wlr_renderer_end(renderer); + wlr_output_commit(output->wlr_output); +} + +static void server_new_output(struct wl_listener *listener, void *data) { + /* This event is rasied by the backend when a new output (aka a display or + * monitor) becomes available. */ + struct dwl_server *server = + wl_container_of(listener, server, new_output); + struct wlr_output *wlr_output = data; + + /* Some backends don't have modes. DRM+KMS does, and we need to set a mode + * before we can use the output. The mode is a tuple of (width, height, + * refresh rate), and each monitor supports only a specific set of modes. We + * just pick the monitor's preferred mode, a more sophisticated compositor + * would let the user configure it. */ + if (!wl_list_empty(&wlr_output->modes)) { + struct wlr_output_mode *mode = wlr_output_preferred_mode(wlr_output); + wlr_output_set_mode(wlr_output, mode); + wlr_output_enable(wlr_output, true); + if (!wlr_output_commit(wlr_output)) { + return; + } + } + + /* Allocates and configures our state for this output */ + struct dwl_output *output = + calloc(1, sizeof(struct dwl_output)); + output->wlr_output = wlr_output; + output->server = server; + /* Sets up a listener for the frame notify event. */ + output->frame.notify = output_frame; + wl_signal_add(&wlr_output->events.frame, &output->frame); + wl_list_insert(&server->outputs, &output->link); + + /* Adds this to the output layout. The add_auto function arranges outputs + * from left-to-right in the order they appear. A more sophisticated + * compositor would let the user configure the arrangement of outputs in the + * layout. */ + wlr_output_layout_add_auto(server->output_layout, wlr_output); + + /* Creating the global adds a wl_output global to the display, which Wayland + * clients can see to find out information about the output (such as + * DPI, scale factor, manufacturer, etc). */ + wlr_output_create_global(wlr_output); +} + +static void xdg_surface_map(struct wl_listener *listener, void *data) { + /* Called when the surface is mapped, or ready to display on-screen. */ + struct dwl_view *view = wl_container_of(listener, view, map); + view->mapped = true; + focus_view(view, view->xdg_surface->surface); +} + +static void xdg_surface_unmap(struct wl_listener *listener, void *data) { + /* Called when the surface is unmapped, and should no longer be shown. */ + struct dwl_view *view = wl_container_of(listener, view, unmap); + view->mapped = false; +} + +static void xdg_surface_destroy(struct wl_listener *listener, void *data) { + /* Called when the surface is destroyed and should never be shown again. */ + struct dwl_view *view = wl_container_of(listener, view, destroy); + wl_list_remove(&view->link); + free(view); +} + +static void begin_interactive(struct dwl_view *view, + enum dwl_cursor_mode mode, uint32_t edges) { + /* This function sets up an interactive move or resize operation, where the + * compositor stops propegating pointer events to clients and instead + * consumes them itself, to move or resize windows. */ + struct dwl_server *server = view->server; + struct wlr_surface *focused_surface = + server->seat->pointer_state.focused_surface; + if (view->xdg_surface->surface != focused_surface) { + /* Deny move/resize requests from unfocused clients. */ + return; + } + server->grabbed_view = view; + server->cursor_mode = mode; + struct wlr_box geo_box; + wlr_xdg_surface_get_geometry(view->xdg_surface, &geo_box); + if (mode == DWL_CURSOR_MOVE) { + server->grab_x = server->cursor->x - view->x; + server->grab_y = server->cursor->y - view->y; + } else { + server->grab_x = server->cursor->x + geo_box.x; + server->grab_y = server->cursor->y + geo_box.y; + } + server->grab_width = geo_box.width; + server->grab_height = geo_box.height; + server->resize_edges = edges; +} + +static void xdg_toplevel_request_move( + struct wl_listener *listener, void *data) { + /* This event is raised when a client would like to begin an interactive + * move, typically because the user clicked on their client-side + * decorations. Note that a more sophisticated compositor should check the + * provied serial against a list of button press serials sent to this + * client, to prevent the client from requesting this whenever they want. */ + struct dwl_view *view = wl_container_of(listener, view, request_move); + begin_interactive(view, DWL_CURSOR_MOVE, 0); +} + +static void xdg_toplevel_request_resize( + struct wl_listener *listener, void *data) { + /* This event is raised when a client would like to begin an interactive + * resize, typically because the user clicked on their client-side + * decorations. Note that a more sophisticated compositor should check the + * provied serial against a list of button press serials sent to this + * client, to prevent the client from requesting this whenever they want. */ + struct wlr_xdg_toplevel_resize_event *event = data; + struct dwl_view *view = wl_container_of(listener, view, request_resize); + begin_interactive(view, DWL_CURSOR_RESIZE, event->edges); +} + +static void server_new_xdg_surface(struct wl_listener *listener, void *data) { + /* This event is raised when wlr_xdg_shell receives a new xdg surface from a + * client, either a toplevel (application window) or popup. */ + struct dwl_server *server = + wl_container_of(listener, server, new_xdg_surface); + struct wlr_xdg_surface *xdg_surface = data; + if (xdg_surface->role != WLR_XDG_SURFACE_ROLE_TOPLEVEL) { + return; + } + + /* Allocate a dwl_view for this surface */ + struct dwl_view *view = + calloc(1, sizeof(struct dwl_view)); + view->server = server; + view->xdg_surface = xdg_surface; + + /* Listen to the various events it can emit */ + view->map.notify = xdg_surface_map; + wl_signal_add(&xdg_surface->events.map, &view->map); + view->unmap.notify = xdg_surface_unmap; + wl_signal_add(&xdg_surface->events.unmap, &view->unmap); + view->destroy.notify = xdg_surface_destroy; + wl_signal_add(&xdg_surface->events.destroy, &view->destroy); + + /* cotd */ + struct wlr_xdg_toplevel *toplevel = xdg_surface->toplevel; + view->request_move.notify = xdg_toplevel_request_move; + wl_signal_add(&toplevel->events.request_move, &view->request_move); + view->request_resize.notify = xdg_toplevel_request_resize; + wl_signal_add(&toplevel->events.request_resize, &view->request_resize); + + /* Add it to the list of views. */ + wl_list_insert(&server->views, &view->link); +} + +int main(int argc, char *argv[]) { + wlr_log_init(WLR_DEBUG, NULL); + char *startup_cmd = NULL; + + int c; + while ((c = getopt(argc, argv, "s:h")) != -1) { + switch (c) { + case 's': + startup_cmd = optarg; + break; + default: + printf("Usage: %s [-s startup command]\n", argv[0]); + return 0; + } + } + if (optind < argc) { + printf("Usage: %s [-s startup command]\n", argv[0]); + return 0; + } + + struct dwl_server server; + /* The Wayland display is managed by libwayland. It handles accepting + * clients from the Unix socket, manging Wayland globals, and so on. */ + server.wl_display = wl_display_create(); + /* The backend is a wlroots feature which abstracts the underlying input and + * output hardware. The autocreate option will choose the most suitable + * backend based on the current environment, such as opening an X11 window + * if an X11 server is running. The NULL argument here optionally allows you + * to pass in a custom renderer if wlr_renderer doesn't meet your needs. The + * backend uses the renderer, for example, to fall back to software cursors + * if the backend does not support hardware cursors (some older GPUs + * don't). */ + server.backend = wlr_backend_autocreate(server.wl_display, NULL); + + /* If we don't provide a renderer, autocreate makes a GLES2 renderer for us. + * The renderer is responsible for defining the various pixel formats it + * supports for shared memory, this configures that for clients. */ + server.renderer = wlr_backend_get_renderer(server.backend); + wlr_renderer_init_wl_display(server.renderer, server.wl_display); + + /* This creates some hands-off wlroots interfaces. The compositor is + * necessary for clients to allocate surfaces and the data device manager + * handles the clipboard. Each of these wlroots interfaces has room for you + * to dig your fingers in and play with their behavior if you want. */ + wlr_compositor_create(server.wl_display, server.renderer); + wlr_data_device_manager_create(server.wl_display); + + /* Creates an output layout, which a wlroots utility for working with an + * arrangement of screens in a physical layout. */ + server.output_layout = wlr_output_layout_create(); + + /* Configure a listener to be notified when new outputs are available on the + * backend. */ + wl_list_init(&server.outputs); + server.new_output.notify = server_new_output; + wl_signal_add(&server.backend->events.new_output, &server.new_output); + + /* Set up our list of views and the xdg-shell. The xdg-shell is a Wayland + * protocol which is used for application windows. For more detail on + * shells, refer to my article: + * + * https://drewdevault.com/2018/07/29/Wayland-shells.html + */ + wl_list_init(&server.views); + server.xdg_shell = wlr_xdg_shell_create(server.wl_display); + server.new_xdg_surface.notify = server_new_xdg_surface; + wl_signal_add(&server.xdg_shell->events.new_surface, + &server.new_xdg_surface); + + /* + * Creates a cursor, which is a wlroots utility for tracking the cursor + * image shown on screen. + */ + server.cursor = wlr_cursor_create(); + wlr_cursor_attach_output_layout(server.cursor, server.output_layout); + + /* Creates an xcursor manager, another wlroots utility which loads up + * Xcursor themes to source cursor images from and makes sure that cursor + * images are available at all scale factors on the screen (necessary for + * HiDPI support). We add a cursor theme at scale factor 1 to begin with. */ + server.cursor_mgr = wlr_xcursor_manager_create(NULL, 24); + wlr_xcursor_manager_load(server.cursor_mgr, 1); + + /* + * wlr_cursor *only* displays an image on screen. It does not move around + * when the pointer moves. However, we can attach input devices to it, and + * it will generate aggregate events for all of them. In these events, we + * can choose how we want to process them, forwarding them to clients and + * moving the cursor around. More detail on this process is described in my + * input handling blog post: + * + * https://drewdevault.com/2018/07/17/Input-handling-in-wlroots.html + * + * And more comments are sprinkled throughout the notify functions above. + */ + server.cursor_motion.notify = server_cursor_motion; + wl_signal_add(&server.cursor->events.motion, &server.cursor_motion); + server.cursor_motion_absolute.notify = server_cursor_motion_absolute; + wl_signal_add(&server.cursor->events.motion_absolute, + &server.cursor_motion_absolute); + server.cursor_button.notify = server_cursor_button; + wl_signal_add(&server.cursor->events.button, &server.cursor_button); + server.cursor_axis.notify = server_cursor_axis; + wl_signal_add(&server.cursor->events.axis, &server.cursor_axis); + server.cursor_frame.notify = server_cursor_frame; + wl_signal_add(&server.cursor->events.frame, &server.cursor_frame); + + /* + * Configures a seat, which is a single "seat" at which a user sits and + * operates the computer. This conceptually includes up to one keyboard, + * pointer, touch, and drawing tablet device. We also rig up a listener to + * let us know when new input devices are available on the backend. + */ + wl_list_init(&server.keyboards); + server.new_input.notify = server_new_input; + wl_signal_add(&server.backend->events.new_input, &server.new_input); + server.seat = wlr_seat_create(server.wl_display, "seat0"); + server.request_cursor.notify = seat_request_cursor; + wl_signal_add(&server.seat->events.request_set_cursor, + &server.request_cursor); + + /* Add a Unix socket to the Wayland display. */ + const char *socket = wl_display_add_socket_auto(server.wl_display); + if (!socket) { + wlr_backend_destroy(server.backend); + return 1; + } + + /* Start the backend. This will enumerate outputs and inputs, become the DRM + * master, etc */ + if (!wlr_backend_start(server.backend)) { + wlr_backend_destroy(server.backend); + wl_display_destroy(server.wl_display); + return 1; + } + + /* Set the WAYLAND_DISPLAY environment variable to our socket and run the + * startup command if requested. */ + setenv("WAYLAND_DISPLAY", socket, true); + if (startup_cmd) { + if (fork() == 0) { + execl("/bin/sh", "/bin/sh", "-c", startup_cmd, (void *)NULL); + } + } + /* Run the Wayland event loop. This does not return until you exit the + * compositor. Starting the backend rigged up all of the necessary event + * loop configuration to listen to libinput events, DRM events, generate + * frame events at the refresh rate, and so on. */ + wlr_log(WLR_INFO, "Running Wayland compositor on WAYLAND_DISPLAY=%s", + socket); + wl_display_run(server.wl_display); + + /* Once wl_display_run returns, we shut down the server. */ + wl_display_destroy_clients(server.wl_display); + wl_display_destroy(server.wl_display); + return 0; +} |