output: initial support for output scaling

* Not updated run-time; only scale at start up used
* Multiple monitors (outputs) not supported, as we can't track which
  output we're on (yet).

main.c

@@ -20,6 +20,8 @@
 #include <xdg-shell.h>
 #include <xkbcommon/xkbcommon-compose.h>
 
+#include <xdg-output-unstable-v1.h>
+
 #define LOG_MODULE "main"
 #define LOG_ENABLE_DBG 0
 #include "log.h"
@@ -99,6 +101,87 @@ static const struct wl_seat_listener seat_listener = {
     .name = seat_handle_name,
 };
 
+static void
+output_geometry(void *data, struct wl_output *wl_output, int32_t x, int32_t y,
+                int32_t physical_width, int32_t physical_height,
+                int32_t subpixel, const char *make, const char *model,
+                int32_t transform)
+{
+    struct monitor *mon = data;
+    mon->width_mm = physical_width;
+    mon->height_mm = physical_height;
+}
+
+static void
+output_mode(void *data, struct wl_output *wl_output, uint32_t flags,
+            int32_t width, int32_t height, int32_t refresh)
+{
+}
+
+static void
+output_done(void *data, struct wl_output *wl_output)
+{
+}
+
+static void
+output_scale(void *data, struct wl_output *wl_output, int32_t factor)
+{
+    struct monitor *mon = data;
+    mon->scale = factor;
+}
+
+static const struct wl_output_listener output_listener = {
+    .geometry = &output_geometry,
+    .mode = &output_mode,
+    .done = &output_done,
+    .scale = &output_scale,
+};
+
+static void
+xdg_output_handle_logical_position(
+    void *data, struct zxdg_output_v1 *xdg_output, int32_t x, int32_t y)
+{
+    struct monitor *mon = data;
+    mon->x = x;
+    mon->y = y;
+}
+
+static void
+xdg_output_handle_logical_size(void *data, struct zxdg_output_v1 *xdg_output,
+                               int32_t width, int32_t height)
+{
+    struct monitor *mon = data;
+    mon->width_px = width;
+    mon->height_px = height;
+}
+
+static void
+xdg_output_handle_done(void *data, struct zxdg_output_v1 *xdg_output)
+{
+}
+
+static void
+xdg_output_handle_name(void *data, struct zxdg_output_v1 *xdg_output,
+                       const char *name)
+{
+    struct monitor *mon = data;
+    mon->name = strdup(name);
+}
+
+static void
+xdg_output_handle_description(void *data, struct zxdg_output_v1 *xdg_output,
+                              const char *description)
+{
+}
+
+static struct zxdg_output_v1_listener xdg_output_listener = {
+    .logical_position = xdg_output_handle_logical_position,
+    .logical_size = xdg_output_handle_logical_size,
+    .done = xdg_output_handle_done,
+    .name = xdg_output_handle_name,
+    .description = xdg_output_handle_description,
+};
+
 static void
 handle_global(void *data, struct wl_registry *registry,
               uint32_t name, const char *interface, uint32_t version)
@@ -131,6 +214,27 @@ handle_global(void *data, struct wl_registry *registry,
         wl_display_roundtrip(term->wl.display);
     }
 
+    else if (strcmp(interface, zxdg_output_manager_v1_interface.name) == 0) {
+        term->wl.xdg_output_manager = wl_registry_bind(
+            term->wl.registry, name, &zxdg_output_manager_v1_interface, 2);
+    }
+
+    else if (strcmp(interface, wl_output_interface.name) == 0) {
+        struct wl_output *output = wl_registry_bind(
+            term->wl.registry, name, &wl_output_interface, 3);
+
+        tll_push_back(
+            term->wl.monitors, ((struct monitor){.output = output}));
+
+        struct monitor *mon = &tll_back(term->wl.monitors);
+        wl_output_add_listener(output, &output_listener, mon);
+
+        mon->xdg = zxdg_output_manager_v1_get_xdg_output(
+            term->wl.xdg_output_manager, mon->output);
+        zxdg_output_v1_add_listener(mon->xdg, &xdg_output_listener, mon);
+        wl_display_roundtrip(term->wl.display);
+    }
+
     else if (strcmp(interface, wl_data_device_manager_interface.name) == 0) {
         term->wl.data_device_manager = wl_registry_bind(
             term->wl.registry, name, &wl_data_device_manager_interface, 1);
@@ -493,6 +597,18 @@ main(int argc, char *const *argv)
         goto out;
     }
 
+    tll_foreach(term.wl.monitors, it) {
+        LOG_INFO("%s: %dx%d+%dx%d (scale=%d)",
+                 it->item.name, it->item.width_px, it->item.height_px,
+                 it->item.x, it->item.y, it->item.scale);
+    }
+
+    assert(tll_length(term.wl.monitors) == 1 &&
+           "unimplemented: output tracking");
+
+    /* TODO: dynamic tracking */
+    term.scale = tll_back(term.wl.monitors).scale;
+
     /* Clipboard */
     term.wl.data_device = wl_data_device_manager_get_data_device(
         term.wl.data_device_manager, term.wl.seat);
@@ -526,8 +642,7 @@ main(int argc, char *const *argv)
     LOG_INFO("cursor theme: %s, size: %u", cursor_theme, cursor_size);
 
     term.wl.pointer.theme = wl_cursor_theme_load(
-        cursor_theme, cursor_size * 1 /* backend->monitor->scale */,
+        cursor_theme, cursor_size * term.scale, term.wl.shm);
-        term.wl.shm);
     if (term.wl.pointer.theme == NULL) {
         LOG_ERR("failed to load cursor theme");
         goto out;
@@ -814,6 +929,19 @@ out:
     mtx_unlock(&term.render.workers.lock);
 
     shm_fini();
+
+    tll_foreach(term.wl.monitors, it) {
+        free(it->item.name);
+        if (it->item.xdg != NULL)
+            zxdg_output_v1_destroy(it->item.xdg);
+        if (it->item.output != NULL)
+            wl_output_destroy(it->item.output);
+        tll_remove(term.wl.monitors, it);
+    }
+
+    if (term.wl.xdg_output_manager != NULL)
+        zxdg_output_manager_v1_destroy(term.wl.xdg_output_manager);
+
     if (term.render.frame_callback != NULL)
         wl_callback_destroy(term.render.frame_callback);
     if (term.wl.xdg_toplevel != NULL)

meson.build

@@ -60,6 +60,7 @@ wl_proto_src = []
 foreach prot : [
   #'external/wlr-layer-shell-unstable-v1.xml',
   wayland_protocols_datadir + '/stable/xdg-shell/xdg-shell.xml',
+  wayland_protocols_datadir + '/unstable/xdg-output/xdg-output-unstable-v1.xml',
   wayland_protocols_datadir + '/unstable/primary-selection/primary-selection-unstable-v1.xml',
   #wayland_protocols_datadir + '/unstable/xdg-output/xdg-output-unstable-v1.xml']
   ]

render.c

@@ -624,6 +624,7 @@ grid_render(struct terminal *term)
     term->render.frame_callback = wl_surface_frame(term->wl.surface);
     wl_callback_add_listener(term->render.frame_callback, &frame_listener, term);
 
+    wl_surface_set_buffer_scale(term->wl.surface, term->scale);
     wl_surface_commit(term->wl.surface);
 
 #if TIME_FRAME_RENDERING
@@ -676,6 +677,9 @@ reflow(struct row **new_grid, int new_cols, int new_rows,
 void
 render_resize(struct terminal *term, int width, int height)
 {
+    width *= term->scale;
+    height *= term->scale;
+
     if (width == term->width && height == term->height)
         return;
 
@@ -779,11 +783,8 @@ render_update_cursor_surface(struct terminal *term)
     if (term->wl.pointer.cursor == NULL)
         return;
 
-    const int scale = 1;
+    const int scale = term->scale;
-#if 0
-    //const int scale = backend->monitor->scale;
     wl_surface_set_buffer_scale(term->wl.pointer.surface, scale);
-#endif
 
     struct wl_cursor_image *image = term->wl.pointer.cursor->images[0];
 

terminal.h

@@ -20,6 +20,23 @@
 #define likely(c) __builtin_expect(!!(c), 1)
 #define unlikely(c) __builtin_expect(!!(c), 0)
 
+struct monitor {
+    struct wl_output *output;
+    struct zxdg_output_v1 *xdg;
+    char *name;
+
+    int x;
+    int y;
+
+    int width_mm;
+    int height_mm;
+
+    int width_px;
+    int height_px;
+
+    int scale;
+};
+
 struct wayland {
     struct wl_display *display;
     struct wl_registry *registry;
@@ -27,6 +44,7 @@ struct wayland {
     struct wl_surface *surface;
     struct wl_shm *shm;
     struct wl_seat *seat;
+    struct zxdg_output_manager_v1 *xdg_output_manager;
     struct wl_data_device_manager *data_device_manager;
     struct wl_data_device *data_device;
     struct zwp_primary_selection_device_manager_v1 *primary_selection_device_manager;
@@ -44,6 +62,7 @@ struct wayland {
     struct xdg_surface *xdg_surface;
     struct xdg_toplevel *xdg_toplevel;
     bool have_argb8888;
+    tll(struct monitor) monitors;
 };
 
 struct rgb { float r, g, b; };
@@ -246,6 +265,7 @@ struct terminal {
     struct vt vt;
     struct kbd kbd;
 
+    int scale;
     int width;  /* pixels */
     int height; /* pixels */
     int cols;   /* number of columns */