commit f98435b88f424bb017d8077f910e41da176bf311
parent 23254f500569ce69a49942f2d9014d8d6e818c08
Author: Michael Forney <mforney@mforney.org>
Date: Sat, 25 Jan 2014 15:38:56 -0800
Add example window manager
Diffstat:
4 files changed, 319 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
@@ -19,7 +19,7 @@ VERSION_MINOR := 0
VERSION := $(VERSION_MAJOR).$(VERSION_MINOR)
TARGETS := swc.pc
-SUBDIRS := launch libswc protocol cursor
+SUBDIRS := launch libswc protocol cursor example
CLEAN_FILES := $(TARGETS)
include config.mk
diff --git a/README.md b/README.md
@@ -69,6 +69,9 @@ Finally, run the main event loop.
wl_display_run(display);
```
+An example window manager that arranges it's windows in a grid can be found in
+example/, and can be built with `make example`.
+
Why not write a Weston shell plugin?
------------------------------------
In my opinion the goals of Weston and swc are rather orthogonal. Weston seeks to
diff --git a/example/local.mk b/example/local.mk
@@ -0,0 +1,15 @@
+# swc: example/local.mk
+
+dir := example
+
+$(dir)_PACKAGES = wayland-server
+
+$(dir): $(dir)/wm
+
+$(dir)/wm: $(dir)/wm.o libswc/libswc.so
+ $(link) $(example_PACKAGE_LIBS) -lm
+
+CLEAN_FILES += $(dir)/wm.o $(dir)/wm
+
+include common.mk
+
diff --git a/example/wm.c b/example/wm.c
@@ -0,0 +1,300 @@
+/* swc: example/wm.c
+ *
+ * Copyright (c) 2014 Michael Forney
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <swc.h>
+#include <unistd.h>
+#include <wayland-server.h>
+#include <xkbcommon/xkbcommon.h>
+
+struct screen
+{
+ struct swc_screen * swc;
+ struct wl_listener event_listener;
+ struct wl_list windows;
+ unsigned num_windows;
+};
+
+struct window
+{
+ struct swc_window * swc;
+ struct wl_listener event_listener;
+ struct screen * screen;
+ struct wl_list link;
+};
+
+static const char * terminal_command[] = { "st-wl", NULL };
+static const char * dmenu_command[] = { "dmenu-wl", NULL };
+static const uint32_t border_width = 1;
+static const uint32_t border_color_active = 0xff333388;
+static const uint32_t border_color_normal = 0xff888888;
+
+static struct screen * active_screen;
+static struct window * focused_window;
+static struct wl_event_loop * event_loop;
+static struct wl_event_source * focus_idle_source;
+
+/* This is a basic grid arrange function that tries to give each window an
+ * equal space. */
+static void arrange(struct screen * screen)
+{
+ struct window * window = NULL;
+ unsigned num_columns, num_rows, column_index, row_index;
+ struct swc_rectangle geometry;
+ struct swc_rectangle * screen_geometry = &screen->swc->usable_geometry;
+
+ if (screen->num_windows == 0) return;
+
+ num_columns = round(sqrt(screen->num_windows));
+ num_rows = screen->num_windows / num_columns + 1;
+ window = wl_container_of(screen->windows.next, window, link);
+
+ for (column_index = 0; &window->link != &screen->windows; ++column_index)
+ {
+ geometry.x = screen_geometry->x + border_width
+ + screen_geometry->width * column_index / num_columns + border_width;
+ geometry.width = screen_geometry->width / num_columns
+ - 2 * border_width;
+
+ if (column_index == screen->num_windows % num_columns)
+ --num_rows;
+
+ for (row_index = 0; row_index < num_rows; ++row_index)
+ {
+ geometry.y = screen_geometry->y + border_width
+ + screen_geometry->height * row_index / num_rows;
+ geometry.height = screen_geometry->height / num_rows
+ - 2 * border_width;
+
+ swc_window_set_geometry(window->swc, &geometry);
+ window = wl_container_of(window->link.next, window, link);
+ }
+ }
+}
+
+static void screen_add_window(struct screen * screen, struct window * window)
+{
+ window->screen = screen;
+ wl_list_insert(&screen->windows, &window->link);
+ ++screen->num_windows;
+ swc_window_show(window->swc);
+ arrange(screen);
+}
+
+static void screen_remove_window(struct screen * screen, struct window * window)
+{
+ window->screen = NULL;
+ wl_list_remove(&window->link);
+ --screen->num_windows;
+ swc_window_hide(window->swc);
+ arrange(screen);
+}
+
+/*
+ * We can't immediately change the focus when the currently focused window is
+ * being destroyed. This is because the keyboard registers a destroy listener
+ * for the current focus so it can correctly keep track of it's focus
+ * internally and set it to NULL. However, now we have two separate destroy
+ * listeners which want to change the focus to two different things, and it
+ * isn't defined which order they happen (and if they are adjacent, we end up
+ * breaking the linked list traversal).
+ *
+ * To prevent this, instead of changing the focus immediately, we register an
+ * idle event so that the focus is changed in the next iteration of the event
+ * loop.
+ *
+ * Another way to solve this issue is internally in swc by requiring that all
+ * window managers maintain a valid focus at all times. This way, the keyboard
+ * does not need to register a destroy listener for the focus because it knows
+ * that the window manager will provide a new focus before the old one becomes
+ * invalid.
+ */
+static void commit_focus(void * data)
+{
+ swc_window_focus(focused_window ? focused_window->swc : NULL);
+ focus_idle_source = NULL;
+}
+
+static void focus(struct window * window)
+{
+ /* Add an idle source (if one doesn't already exist) to the event loop to
+ * actually change the keyboard focus. */
+ if (!focus_idle_source)
+ {
+ focus_idle_source = wl_event_loop_add_idle(event_loop,
+ &commit_focus, NULL);
+ }
+
+ if (focused_window)
+ {
+ swc_window_set_border(focused_window->swc,
+ border_color_normal, border_width);
+ }
+
+ if (window)
+ swc_window_set_border(window->swc, border_color_active, border_width);
+
+ focused_window = window;
+}
+
+static void window_event(struct wl_listener * listener, void * data)
+{
+ struct swc_event * event = data;
+ struct window * window = NULL, * next_focus;
+
+
+ window = wl_container_of(listener, window, event_listener);
+
+ switch (event->type)
+ {
+ case SWC_WINDOW_DESTROYED:
+ if (focused_window == window)
+ {
+ /* Try to find a new focus nearby the old one. */
+ next_focus = wl_container_of(window->link.next, window, link);
+
+ if (&next_focus->link == &window->screen->windows)
+ {
+ next_focus = wl_container_of(window->link.prev,
+ window, link);
+
+ if (&next_focus->link == &window->screen->windows)
+ next_focus = NULL;
+ }
+
+ focus(next_focus);
+ }
+
+ screen_remove_window(window->screen, window);
+ free(window);
+ break;
+ case SWC_WINDOW_STATE_CHANGED:
+ /* When the window changes state to TOPLEVEL, we can add it to the
+ * current screen and then rearrange the windows on that screen. */
+ if (window->swc->state == SWC_WINDOW_STATE_TOPLEVEL)
+ {
+ screen_add_window(active_screen, window);
+ focus(window);
+ }
+ break;
+ case SWC_WINDOW_ENTERED:
+ focus(window);
+ break;
+ }
+}
+
+static void new_window(struct swc_window * swc)
+{
+ struct window * window;
+
+ window = malloc(sizeof *window);
+
+ if (!window)
+ return;
+
+ window->swc = swc;
+ window->event_listener.notify = &window_event;
+ window->screen = NULL;
+
+ /* Register a listener for the window's event signal. */
+ wl_signal_add(&swc->event_signal, &window->event_listener);
+}
+
+static void screen_event(struct wl_listener * listener, void * data)
+{
+ struct swc_event * event = data;
+ struct screen * screen = NULL;
+
+ screen = wl_container_of(listener, screen, event_listener);
+
+ switch (event->type)
+ {
+ case SWC_SCREEN_USABLE_GEOMETRY_CHANGED:
+ /* If the usable geometry of the screen changes, for example when a
+ * panel is docked to the edge of the screen, we need to rearrange
+ * the windows to ensure they are all within the new usable
+ * geometry. */
+ arrange(screen);
+ break;
+ }
+}
+
+static void new_screen(struct swc_screen * swc)
+{
+ struct screen * screen;
+
+ screen = malloc(sizeof *screen);
+
+ if (!screen)
+ return;
+
+ screen->swc = swc;
+ screen->event_listener.notify = &screen_event;
+ screen->num_windows = 0;
+ wl_list_init(&screen->windows);
+
+ /* Register a listener for the screen's event signal. */
+ wl_signal_add(&swc->event_signal, &screen->event_listener);
+ active_screen = screen;
+}
+
+const struct swc_manager manager = { &new_window, &new_screen };
+
+static void spawn(uint32_t time, uint32_t value, void * data)
+{
+ char * const * command = data;
+
+ if (fork() == 0)
+ {
+ execvp(command[0], command);
+ exit(EXIT_FAILURE);
+ }
+}
+
+int main(int argc, char * argv[])
+{
+ struct wl_display * display;
+
+ display = wl_display_create();
+
+ if (!display)
+ return EXIT_FAILURE;
+
+ if (wl_display_add_socket(display, NULL) != 0)
+ return EXIT_FAILURE;
+
+ if (wl_display_init_shm(display) != 0)
+ return EXIT_FAILURE;
+
+ if (!swc_initialize(display, NULL, &manager))
+ return EXIT_FAILURE;
+
+ swc_add_key_binding(SWC_MOD_LOGO, XKB_KEY_Return, &spawn, terminal_command);
+ swc_add_key_binding(SWC_MOD_LOGO, XKB_KEY_r, &spawn, dmenu_command);
+
+ event_loop = wl_display_get_event_loop(display);
+ wl_display_run(display);
+
+ return EXIT_SUCCESS;
+}
+
