ssd: dynamically look up window icons in titlebar for output scales

by introducing scaled_icon_buffer.

include/common/scaled-icon-buffer.h

@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef LABWC_SCALED_ICON_BUFFER_H
+#define LABWC_SCALED_ICON_BUFFER_H
+
+#include <stdbool.h>
+
+struct wlr_scene_tree;
+struct wlr_scene_node;
+struct wlr_scene_buffer;
+
+struct scaled_icon_buffer {
+	struct scaled_scene_buffer *scaled_buffer;
+	struct wlr_scene_buffer *scene_buffer;
+	struct server *server;
+	char *app_id;
+	char *icon_name;
+	int width;
+	int height;
+};
+
+/*
+ * Create an auto scaling icon buffer, providing a wlr_scene_buffer node for
+ * display. It gets destroyed automatically when the backing scaled_scene_buffer
+ * is being destroyed which in turn happens automatically when the backing
+ * wlr_scene_buffer (or one of its parents) is being destroyed.
+ */
+struct scaled_icon_buffer *scaled_icon_buffer_create(
+	struct wlr_scene_tree *parent, struct server *server,
+	int width, int height);
+
+void scaled_icon_buffer_set_app_id(struct scaled_icon_buffer *self,
+	const char *app_id);
+
+void scaled_icon_buffer_set_icon_name(struct scaled_icon_buffer *self,
+	const char *icon_name);
+
+/* Obtain scaled_icon_buffer from wlr_scene_node */
+struct scaled_icon_buffer *scaled_icon_buffer_from_node(struct wlr_scene_node *node);
+
+#endif /* LABWC_SCALED_ICON_BUFFER_H */

include/common/scaled-img-buffer.h

@@ -66,10 +66,6 @@ struct scaled_img_buffer {
 struct scaled_img_buffer *scaled_img_buffer_create(struct wlr_scene_tree *parent,
 	struct lab_img *img, int width, int height);
 
-/* Update image, width and height of the scaled_img_buffer */
-void scaled_img_buffer_update(struct scaled_img_buffer *self,
-	struct lab_img *img, int width, int height);
-
 /* Obtain scaled_img_buffer from wlr_scene_node */
 struct scaled_img_buffer *scaled_img_buffer_from_node(struct wlr_scene_node *node);
 

include/ssd-internal.h

@@ -24,10 +24,16 @@ struct ssd_button {
 	 */
 	uint8_t state_set;
 	/*
-	 * Button nodes for each combination of hover/toggled/rounded states.
-	 * nodes[state_set] should be displayed.
+	 * Image buffers for each combination of hover/toggled/rounded states.
+	 * img_buffers[state_set] is displayed. Some of these can be NULL
+	 * (e.g. img_buffers[LAB_BS_ROUNDED] is set only for corner buttons).
+	 *
+	 * When "type" is LAB_SSD_BUTTON_WINDOW_ICON, these are all NULL and
+	 * window_icon is used instead.
 	 */
-	struct wlr_scene_node *nodes[LAB_BS_ALL + 1];
+	struct scaled_img_buffer *img_buffers[LAB_BS_ALL + 1];
+
+	struct scaled_icon_buffer *window_icon;
 
 	struct wl_listener destroy;
 };

src/common/meson.build

@@ -14,6 +14,7 @@ labwc_sources += files(
   'parse-bool.c',
   'parse-double.c',
   'scaled-font-buffer.c',
+  'scaled-icon-buffer.c',
   'scaled-img-buffer.c',
   'scaled-rect-buffer.c',
   'scaled-scene-buffer.c',

src/common/scaled-icon-buffer.c

@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#define _POSIX_C_SOURCE 200809L
+#include <assert.h>
+#include <string.h>
+#include "common/macros.h"
+#include "common/mem.h"
+#include "common/scaled-icon-buffer.h"
+#include "common/scaled-scene-buffer.h"
+#include "common/string-helpers.h"
+#include "config.h"
+#include "config/rcxml.h"
+#include "desktop-entry.h"
+#include "img/img.h"
+#include "node.h"
+
+static struct lab_data_buffer *
+_create_buffer(struct scaled_scene_buffer *scaled_buffer, double scale)
+{
+#if HAVE_LIBSFDO
+	struct scaled_icon_buffer *self = scaled_buffer->data;
+	int icon_size = MIN(self->width, self->height);
+	struct lab_img *img = NULL;
+
+	if (self->icon_name) {
+		img = desktop_entry_load_icon(self->server,
+			self->icon_name, icon_size, scale);
+	} else if (self->app_id) {
+		img = desktop_entry_load_icon_from_app_id(self->server,
+			self->app_id, icon_size, scale);
+	}
+
+	if (!img) {
+		return NULL;
+	}
+
+	struct lab_data_buffer *buffer =
+		lab_img_render(img, self->width, self->height, scale);
+	lab_img_destroy(img);
+
+	return buffer;
+#else
+	return NULL;
+#endif
+}
+
+static void
+_destroy(struct scaled_scene_buffer *scaled_buffer)
+{
+	struct scaled_icon_buffer *self = scaled_buffer->data;
+	free(self->app_id);
+	free(self->icon_name);
+	free(self);
+}
+
+static bool
+_equal(struct scaled_scene_buffer *scaled_buffer_a,
+	struct scaled_scene_buffer *scaled_buffer_b)
+{
+	struct scaled_icon_buffer *a = scaled_buffer_a->data;
+	struct scaled_icon_buffer *b = scaled_buffer_b->data;
+
+	return str_equal(a->app_id, b->app_id)
+		&& str_equal(a->icon_name, b->icon_name)
+		&& a->width == b->width
+		&& a->height == b->height;
+}
+
+static struct scaled_scene_buffer_impl impl = {
+	.create_buffer = _create_buffer,
+	.destroy = _destroy,
+	.equal = _equal,
+};
+
+struct scaled_icon_buffer *
+scaled_icon_buffer_create(struct wlr_scene_tree *parent, struct server *server,
+	int width, int height)
+{
+	struct scaled_scene_buffer *scaled_buffer = scaled_scene_buffer_create(
+		parent, &impl, /* drop_buffer */ true);
+	struct scaled_icon_buffer *self = znew(*self);
+	self->scaled_buffer = scaled_buffer;
+	self->scene_buffer = scaled_buffer->scene_buffer;
+	self->server = server;
+	self->width = width;
+	self->height = height;
+
+	scaled_buffer->data = self;
+
+	return self;
+}
+
+void
+scaled_icon_buffer_set_app_id(struct scaled_icon_buffer *self,
+	const char *app_id)
+{
+	assert(app_id);
+	if (str_equal(self->app_id, app_id)) {
+		return;
+	}
+	xstrdup_replace(self->app_id, app_id);
+	scaled_scene_buffer_request_update(self->scaled_buffer, self->width, self->height);
+}
+
+void
+scaled_icon_buffer_set_icon_name(struct scaled_icon_buffer *self,
+	const char *icon_name)
+{
+	assert(icon_name);
+	if (str_equal(self->icon_name, icon_name)) {
+		return;
+	}
+	xstrdup_replace(self->icon_name, icon_name);
+	scaled_scene_buffer_request_update(self->scaled_buffer, self->width, self->height);
+}
+
+struct scaled_icon_buffer *
+scaled_icon_buffer_from_node(struct wlr_scene_node *node)
+{
+	struct scaled_scene_buffer *scaled_buffer =
+		node_scaled_scene_buffer_from_node(node);
+	assert(scaled_buffer->impl == &impl);
+	return scaled_buffer->data;
+}

src/common/scaled-img-buffer.c

@@ -66,18 +66,6 @@ scaled_img_buffer_create(struct wlr_scene_tree *parent, struct lab_img *img,
 	return self;
 }
 
-void
-scaled_img_buffer_update(struct scaled_img_buffer *self, struct lab_img *img,
-	int width, int height)
-{
-	assert(img);
-	lab_img_destroy(self->img);
-	self->img = lab_img_copy(img);
-	self->width = width;
-	self->height = height;
-	scaled_scene_buffer_request_update(self->scaled_buffer, width, height);
-}
-
 struct scaled_img_buffer *
 scaled_img_buffer_from_node(struct wlr_scene_node *node)
 {

src/ssd/ssd-part.c

@@ -5,6 +5,7 @@
 #include "common/box.h"
 #include "common/list.h"
 #include "common/mem.h"
+#include "common/scaled-icon-buffer.h"
 #include "common/scaled-img-buffer.h"
 #include "labwc.h"
 #include "node.h"
@@ -92,6 +93,10 @@ add_scene_button(struct wl_list *part_list, enum ssd_part_type type,
 	button_root->node = &parent->node;
 	wlr_scene_node_set_position(button_root->node, x, y);
 
+	struct ssd_button *button = ssd_button_descriptor_create(button_root->node);
+	button->type = type;
+	button->view = view;
+
 	/* Hitbox */
 	float invisible[4] = { 0, 0, 0, 0 };
 	add_scene_rect(part_list, type, parent,
@@ -99,7 +104,28 @@ add_scene_button(struct wl_list *part_list, enum ssd_part_type type,
 		invisible);
 
 	/* Icons */
-	struct wlr_scene_node *nodes[LAB_BS_ALL + 1] = {0};
+	int button_width = rc.theme->window_button_width;
+	int button_height = rc.theme->window_button_height;
+	/*
+	 * Ensure a small amount of horizontal padding within the button
+	 * area (2px on each side with the default 26px button width).
+	 * A new theme setting could be added to configure this. Using
+	 * an existing setting (padding.width or window.button.spacing)
+	 * was considered, but these settings have distinct purposes
+	 * already and are zero by default.
+	 */
+	int icon_padding = button_width / 10;
+
+	if (type == LAB_SSD_BUTTON_WINDOW_ICON) {
+		struct ssd_part *icon_part = add_scene_part(part_list, type);
+		struct scaled_icon_buffer *icon_buffer =
+			scaled_icon_buffer_create(parent, view->server,
+				button_width - 2 * icon_padding, button_height);
+		assert(icon_buffer);
+		icon_part->node = &icon_buffer->scene_buffer->node;
+		wlr_scene_node_set_position(icon_part->node, icon_padding, 0);
+		button->window_icon = icon_buffer;
+	} else {
 		for (uint8_t state_set = LAB_BS_DEFAULT;
 				state_set <= LAB_BS_ALL; state_set++) {
 			if (!imgs[state_set]) {
@@ -112,16 +138,13 @@ add_scene_button(struct wl_list *part_list, enum ssd_part_type type,
 			assert(img_buffer);
 			icon_part->node = &img_buffer->scene_buffer->node;
 			wlr_scene_node_set_enabled(icon_part->node, false);
-		nodes[state_set] = icon_part->node;
+			button->img_buffers[state_set] = img_buffer;
 		}
 		/* Initially show non-hover, non-toggled, unrounded variant */
-	wlr_scene_node_set_enabled(nodes[0], true);
+		wlr_scene_node_set_enabled(
+			&button->img_buffers[LAB_BS_DEFAULT]->scene_buffer->node, true);
+	}
 
-	struct ssd_button *button = ssd_button_descriptor_create(button_root->node);
-	button->type = type;
-	button->view = view;
-	button->state_set = 0;
-	memcpy(button->nodes, nodes, sizeof(nodes));
 	return button_root;
 }
 

src/ssd/ssd-titlebar.c

@@ -7,6 +7,7 @@
 #include "config.h"
 #include "common/mem.h"
 #include "common/scaled-font-buffer.h"
+#include "common/scaled-icon-buffer.h"
 #include "common/scaled-img-buffer.h"
 #include "common/scene-helpers.h"
 #include "common/string-helpers.h"
@@ -127,11 +128,12 @@ update_button_state(struct ssd_button *button, enum lab_button_state state,
 	/* Switch the displayed icon buffer to the new one */
 	for (uint8_t state_set = LAB_BS_DEFAULT;
 			state_set <= LAB_BS_ALL; state_set++) {
-		if (!button->nodes[state_set]) {
+		struct scaled_img_buffer *buffer = button->img_buffers[state_set];
+		if (!buffer) {
 			continue;
 		}
-		wlr_scene_node_set_enabled(
-			button->nodes[state_set], button->state_set == state_set);
+		wlr_scene_node_set_enabled(&buffer->scene_buffer->node,
+			state_set == button->state_set);
 	}
 }
 
@@ -584,37 +586,6 @@ ssd_update_window_icon(struct ssd *ssd)
 	free(ssd->state.app_id);
 	ssd->state.app_id = xstrdup(app_id);
 
-	struct theme *theme = ssd->view->server->theme;
-
-	/*
-	 * Ensure a small amount of horizontal padding within the button
-	 * area (2px on each side with the default 26px button width).
-	 * A new theme setting could be added to configure this. Using
-	 * an existing setting (padding.width or window.button.spacing)
-	 * was considered, but these settings have distinct purposes
-	 * already and are zero by default.
-	 */
-	int icon_padding = theme->window_button_width / 10;
-	int icon_size = MIN(theme->window_button_width - 2 * icon_padding,
-		theme->window_button_height);
-
-	/*
-	 * Load/render icons at the max scale of any usable output (at
-	 * this point in time). We don't want to be constantly reloading
-	 * icons as views are moved between outputs.
-	 *
-	 * TODO: currently there's no signal to reload/render icons if
-	 * outputs are reconfigured and the max scale changes.
-	 */
-	float icon_scale = output_max_scale(ssd->view->server);
-
-	struct lab_img *icon_img = desktop_entry_load_icon_from_app_id(
-		ssd->view->server, app_id, icon_size, icon_scale);
-	if (!icon_img) {
-		wlr_log(WLR_DEBUG, "icon could not be loaded for %s", app_id);
-		return;
-	}
-
 	struct ssd_sub_tree *subtree;
 	FOR_EACH_STATE(ssd, subtree) {
 		struct ssd_part *part = ssd_get_part(
@@ -623,23 +594,10 @@ ssd_update_window_icon(struct ssd *ssd)
 			break;
 		}
 
-		/* Replace all the buffers in the button with the window icon */
 		struct ssd_button *button = node_ssd_button_from_node(part->node);
-		for (uint8_t state_set = LAB_BS_DEFAULT;
-				state_set <= LAB_BS_ALL; state_set++) {
-			struct wlr_scene_node *node = button->nodes[state_set];
-			if (node) {
-				struct scaled_img_buffer *img_buffer =
-					scaled_img_buffer_from_node(node);
-				scaled_img_buffer_update(img_buffer, icon_img,
-					theme->window_button_width - 2 * icon_padding,
-					theme->window_button_height);
-				wlr_scene_node_set_position(node, icon_padding, 0);
-			}
-		}
+		assert(button->window_icon);
+		scaled_icon_buffer_set_app_id(button->window_icon, app_id);
 	} FOR_EACH_END
-
-	lab_img_destroy(icon_img);
 #endif
 }
 

src/theme.c

@@ -293,12 +293,6 @@ load_buttons(struct theme *theme)
 		.type = LAB_SSD_BUTTON_WINDOW_MENU,
 		.state_set = 0,
 		.fallback_button = (const char[]){ 0x00, 0x18, 0x3c, 0x3c, 0x18, 0x00 },
-	}, {
-		/* menu icon is loaded again as a fallback of window icon */
-		.name = "menu",
-		.type = LAB_SSD_BUTTON_WINDOW_ICON,
-		.state_set = 0,
-		.fallback_button = (const char[]){ 0x00, 0x18, 0x3c, 0x3c, 0x18, 0x00 },
 	}, {
 		.name = "iconify",
 		.type = LAB_SSD_BUTTON_ICONIFY,
@@ -344,12 +338,6 @@ load_buttons(struct theme *theme)
 		.type = LAB_SSD_BUTTON_WINDOW_MENU,
 		.state_set = LAB_BS_HOVERD,
 		/* no fallback (non-hover variant is used instead) */
-	}, {
-		/* menu_hover icon is loaded again as a fallback of window icon */
-		.name = "menu_hover",
-		.type = LAB_SSD_BUTTON_WINDOW_ICON,
-		.state_set = LAB_BS_HOVERD,
-		/* no fallback (non-hover variant is used instead) */
 	}, {
 		.name = "iconify_hover",
 		.type = LAB_SSD_BUTTON_ICONIFY,