view: Add simple window animations

include/view.h

@@ -201,6 +201,9 @@ struct view {
 	struct wlr_scene_tree *scene_tree;
 	struct wlr_scene_tree *content_tree;
 
+	struct wlr_scene_buffer *animation;
+	uint64_t animation_start_time;
+
 	bool mapped;
 	bool been_mapped;
 	bool ssd_enabled;
@@ -278,6 +281,7 @@ struct view {
 	struct wl_listener request_maximize;
 	struct wl_listener request_fullscreen;
 	struct wl_listener set_title;
+	struct wl_listener output_commit;
 
 	struct foreign_toplevel *foreign_toplevel;
 

src/view-impl-common.c

@@ -2,11 +2,92 @@
 /* view-impl-common.c: common code for shell view->impl functions */
 #include <stdio.h>
 #include <strings.h>
+#include <math.h>
+#include <assert.h>
+#include <wlr/types/wlr_output.h>
 #include "foreign-toplevel.h"
 #include "labwc.h"
 #include "view.h"
 #include "view-impl-common.h"
 #include "window-rules.h"
+#include "workspaces.h"
+
+static inline uint64_t
+timespec_to_us(const struct timespec *ts)
+{
+	return (uint64_t)ts->tv_sec * UINT64_C(1000000) +
+		(uint64_t)ts->tv_nsec / UINT64_C(1000);
+}
+
+static inline uint64_t
+gettime_us(void)
+{
+	struct timespec ts = { 0 };
+	clock_gettime(CLOCK_MONOTONIC, &ts);
+	return timespec_to_us(&ts);
+}
+
+static void
+adjust_scaled_position(struct view *view, double scale)
+{
+	int x = view->current.x;
+	int y = view->current.y;
+	double width = view->current.width;
+	double height = view->current.height;
+
+	int x_pos = x + round(width * (1.0 - scale) / 2.0);
+	int y_pos = y + round(height * (1.0 - scale) / 2.0);
+
+	wlr_scene_node_set_position(&view->scene_tree->node, x_pos, y_pos);
+}
+
+static void
+view_run_animation(struct view *view, uint64_t now)
+{
+	uint64_t elapsed_us = now - view->animation_start_time;
+	double t = (double)elapsed_us * 1e-6;
+	double duration = 0.2; // s
+	double scale = fmax(t / duration, 0.01);
+
+	if (scale < 1.0) {
+		wlr_scene_node_set_scale(&view->scene_tree->node, scale);
+		adjust_scaled_position(view, scale);
+	} else {
+		int x = view->current.x;
+		int y = view->current.y;
+		wlr_scene_node_set_position(&view->scene_tree->node, x, y);
+		wlr_scene_node_set_scale(&view->scene_tree->node, 1.0);
+		wl_list_remove(&view->output_commit.link);
+		wl_list_init(&view->output_commit.link);
+		view->animation_start_time = 0;
+	}
+}
+
+static void
+handle_output_commit(struct wl_listener *listener, void *data)
+{
+	struct wlr_output_event_commit *event = data;
+	struct view *view = wl_container_of(listener, view, output_commit);
+
+	if (!(event->state->committed & WLR_OUTPUT_STATE_BUFFER)) {
+		return;
+	}
+
+	view_run_animation(view, gettime_us());
+
+	wlr_output_update_needs_frame(event->output);
+}
+
+static void
+view_start_animation(struct view *view)
+{
+	view->output_commit.notify = handle_output_commit;
+	wl_signal_add(&view->output->wlr_output->events.commit, &view->output_commit);
+
+	uint64_t now = gettime_us();
+	view->animation_start_time = now;
+	view_run_animation(view, now);
+}
 
 void
 view_impl_map(struct view *view)
@@ -16,6 +97,7 @@ view_impl_map(struct view *view)
 	view_update_app_id(view);
 	if (!view->been_mapped) {
 		window_rules_apply(view, LAB_WINDOW_RULE_EVENT_ON_FIRST_MAP);
+		view_start_animation(view);
 	}
 
 	/*
@@ -104,4 +186,8 @@ view_impl_apply_geometry(struct view *view, int w, int h)
 	if (!wlr_box_equal(current, &old)) {
 		view_moved(view);
 	}
+
+	if (view->animation_start_time) {
+		adjust_scaled_position(view, view->scene_tree->node.scale);
+	}
 }

src/view.c

@@ -2558,6 +2558,9 @@ view_destroy(struct view *view)
 	wl_list_remove(&view->set_title.link);
 	wl_list_remove(&view->destroy.link);
 
+	wl_list_remove(&view->output_commit.link);
+	wl_list_init(&view->output_commit.link);
+
 	if (view->foreign_toplevel) {
 		foreign_toplevel_destroy(view->foreign_toplevel);
 		view->foreign_toplevel = NULL;