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Add a config.h into which configurables can be moved.
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Devin J. Pohly 2020-04-11 17:27:19 -05:00
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dwl
*-protocol.c
*-protocol.h
.ccls-cache

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dwl - dwm for Wayland
Copyright © 2020 Devin J. Pohly
This program is free software: you can redistribute it and/or modify
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GNU General Public License for more details.
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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>.

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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

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# 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.

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static const struct xkb_rule_names xkb_rules = {
.rules = NULL,
.model = NULL,
.layout = "dvorak",
.variant = NULL,
.options = NULL,
};

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/*
* 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(&current_view->link);
wl_list_insert(server->views.prev, &current_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;
}