Fix transparent gdk-pixbuf loading

This makes the thumbnailer able to load at most one directory,
which we don't particularly mind.

fiv-browser.c

@@ -48,11 +48,11 @@ struct _FivBrowser {
 	int item_spacing;                   ///< Space between items in pixels
 
 	char *path;                         ///< Current path
-	GArray *entries;                    ///< [Entry]
-	GArray *layouted_rows;              ///< [Row]
+	GArray *entries;                    ///< []Entry
+	GArray *layouted_rows;              ///< []Row
 	int selected;
 
-	GList *thumbnail_queue;             ///< URIs to thumbnail
+	GList *thumbnail_queue;             ///< Entry pointers
 	GSubprocess *thumbnailer;           ///< A slave for the current queue head
 	GCancellable *thumbnail_cancel;     ///< Cancellable handle
 
@@ -66,8 +66,6 @@ typedef struct entry Entry;
 typedef struct item Item;
 typedef struct row Row;
 
-static const double g_permitted_width_multiplier = 2;
-
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
 struct entry {
@@ -305,8 +303,8 @@ rescale_thumbnail(cairo_surface_t *thumbnail, double row_height)
 
 	double scale_x = 1;
 	double scale_y = 1;
-	if (width > g_permitted_width_multiplier * height) {
-		scale_x = g_permitted_width_multiplier * row_height / width;
+	if (width > FIV_IO_WIDE_THUMBNAIL_COEFFICIENT * height) {
+		scale_x = FIV_IO_WIDE_THUMBNAIL_COEFFICIENT * row_height / width;
 		scale_y = round(scale_x * height) / height;
 	} else {
 		scale_y = row_height / height;
@@ -351,6 +349,8 @@ rescale_thumbnail(cairo_surface_t *thumbnail, double row_height)
 	pixman_image_unref(src);
 	pixman_image_unref(dest);
 
+	cairo_surface_set_user_data(
+		scaled, &fiv_io_key_thumbnail_lq, (void *) (intptr_t) 1, NULL);
 	cairo_surface_destroy(thumbnail);
 	cairo_surface_mark_dirty(scaled);
 	return scaled;
@@ -448,25 +448,11 @@ reload_thumbnails(FivBrowser *self)
 
 // --- Slave management --------------------------------------------------------
 
-static void thumbnailer_step(FivBrowser *self);
+static void thumbnailer_next(FivBrowser *self);
 
 static void
-thumbnailer_process(FivBrowser *self, const gchar *uri)
+thumbnailer_reprocess_entry(FivBrowser *self, Entry *entry)
 {
-	// TODO(p): Consider using Entry pointers directly.
-	Entry *entry = NULL;
-	for (guint i = 0; i < self->entries->len; i++) {
-		Entry *e = &g_array_index(self->entries, Entry, i);
-		if (!g_strcmp0(e->uri, uri)) {
-			entry = e;
-			break;
-		}
-	}
-	if (!entry) {
-		g_warning("finished thumbnailing an unknown URI");
-		return;
-	}
-
 	entry_add_thumbnail(entry, self);
 	materialize_icon(self, entry);
 	gtk_widget_queue_resize(GTK_WIDGET(self));
@@ -491,26 +477,33 @@ on_thumbnailer_ready(GObject *object, GAsyncResult *res, gpointer user_data)
 		return;
 	}
 
-	gchar *uri = self->thumbnail_queue->data;
+	Entry *entry = self->thumbnail_queue->data;
 	self->thumbnail_queue =
 		g_list_delete_link(self->thumbnail_queue, self->thumbnail_queue);
 	if (succeeded)
-		thumbnailer_process(self, uri);
-	g_free(uri);
+		thumbnailer_reprocess_entry(self, entry);
 
 	// TODO(p): Eliminate high recursion depth with non-paths.
-	thumbnailer_step(self);
+	thumbnailer_next(self);
 }
 
 static void
-thumbnailer_step(FivBrowser *self)
+thumbnailer_next(FivBrowser *self)
 {
-	if (!self->thumbnail_queue)
+	// TODO(p): At least launch multiple thumbnailers in parallel.
+	GList *link = self->thumbnail_queue;
+	if (!link)
 		return;
 
-	GFile *file = g_file_new_for_uri(self->thumbnail_queue->data);
+	const Entry *entry = link->data;
+	GFile *file = g_file_new_for_uri(entry->uri);
 	gchar *path = g_file_get_path(file);
 	g_object_unref(file);
+	if (!path) {
+		// TODO(p): Support thumbnailing non-local URIs in some manner.
+		self->thumbnail_queue = g_list_delete_link(self->thumbnail_queue, link);
+		return;
+	}
 
 	GError *error = NULL;
 	self->thumbnailer = g_subprocess_new(G_SUBPROCESS_FLAGS_NONE, &error,
@@ -518,7 +511,6 @@ thumbnailer_step(FivBrowser *self)
 		fiv_io_thumbnail_sizes[self->item_size].thumbnail_spec_name, "--", path,
 		NULL);
 	g_free(path);
-
 	if (error) {
 		g_warning("%s", error->message);
 		g_error_free(error);
@@ -531,28 +523,47 @@ thumbnailer_step(FivBrowser *self)
 }
 
 static void
-thumbnailer_launch(FivBrowser *self)
+thumbnailer_abort(FivBrowser *self)
 {
-	if (self->thumbnailer) {
+	if (self->thumbnail_cancel) {
 		g_cancellable_cancel(self->thumbnail_cancel);
 		g_clear_object(&self->thumbnail_cancel);
-
-		// Just let it exit on its own.
-		g_clear_object(&self->thumbnailer);
-		g_list_free_full(self->thumbnail_queue, g_free);
-		self->thumbnail_queue = NULL;
 	}
 
-	// TODO(p): Also collect rescaled images.
-	GList *missing = NULL, *rescaled = NULL;
+	// Just let it exit on its own.
+	g_clear_object(&self->thumbnailer);
+	g_list_free(self->thumbnail_queue);
+	self->thumbnail_queue = NULL;
+}
+
+static void
+thumbnailer_start(FivBrowser *self)
+{
+	thumbnailer_abort(self);
+
+	// TODO(p): Leave out all paths containing .cache/thumbnails altogether.
+	gchar *thumbnails_dir = fiv_io_get_thumbnail_root();
+	GFile *thumbnails = g_file_new_for_path(thumbnails_dir);
+	g_free(thumbnails_dir);
+	GFile *current = g_file_new_for_path(self->path);
+	gboolean is_a_thumbnail = g_file_has_prefix(current, thumbnails);
+	g_object_unref(current);
+	g_object_unref(thumbnails);
+	if (is_a_thumbnail)
+		return;
+
+	GList *missing = NULL, *lq = NULL;
 	for (guint i = self->entries->len; i--; ) {
-		Entry *e = &g_array_index(self->entries, Entry, i);
-		if (e->icon)
-			missing = g_list_prepend(missing, g_strdup(e->uri));
+		Entry *entry = &g_array_index(self->entries, Entry, i);
+		if (entry->icon)
+			missing = g_list_prepend(missing, entry);
+		else if (cairo_surface_get_user_data(
+			entry->thumbnail, &fiv_io_key_thumbnail_lq))
+			lq = g_list_prepend(lq, entry);
 	}
 
-	self->thumbnail_queue = g_list_concat(missing, rescaled);
-	thumbnailer_step(self);
+	self->thumbnail_queue = g_list_concat(missing, lq);
+	thumbnailer_next(self);
 }
 
 // --- Context menu-------------------------------------------------------------
@@ -742,19 +753,13 @@ static void
 fiv_browser_finalize(GObject *gobject)
 {
 	FivBrowser *self = FIV_BROWSER(gobject);
+	thumbnailer_abort(self);
 	g_free(self->path);
 	g_array_free(self->entries, TRUE);
 	g_array_free(self->layouted_rows, TRUE);
 	cairo_surface_destroy(self->glow);
 	g_clear_object(&self->pointer);
 
-	g_list_free_full(self->thumbnail_queue, g_free);
-	g_clear_object(&self->thumbnailer);
-	if (self->thumbnail_cancel) {
-		g_cancellable_cancel(self->thumbnail_cancel);
-		g_clear_object(&self->thumbnail_cancel);
-	}
-
 	G_OBJECT_CLASS(fiv_browser_parent_class)->finalize(gobject);
 }
 
@@ -816,8 +821,9 @@ fiv_browser_get_preferred_width(GtkWidget *widget, gint *minimum, gint *natural)
 
 	GtkBorder padding = {};
 	gtk_style_context_get_padding(style, GTK_STATE_FLAG_NORMAL, &padding);
-	*minimum = *natural = g_permitted_width_multiplier * self->item_height +
-		padding.left + 2 * self->item_border_x + padding.right;
+	*minimum = *natural =
+		FIV_IO_WIDE_THUMBNAIL_COEFFICIENT * self->item_height + padding.left +
+		2 * self->item_border_x + padding.right;
 }
 
 static void
@@ -1166,6 +1172,9 @@ void
 fiv_browser_load(
 	FivBrowser *self, FivBrowserFilterCallback cb, const char *path)
 {
+	g_return_if_fail(FIV_IS_BROWSER(self));
+
+	thumbnailer_abort(self);
 	g_array_set_size(self->entries, 0);
 	g_array_set_size(self->layouted_rows, 0);
 	g_clear_pointer(&self->path, g_free);
@@ -1198,5 +1207,5 @@ fiv_browser_load(
 	g_array_sort(self->entries, entry_compare);
 
 	reload_thumbnails(self);
-	thumbnailer_launch(self);
+	thumbnailer_start(self);
 }

fiv-io.c

@@ -2210,6 +2210,7 @@ load_gdkpixbuf_argb32_unpremultiplied(GdkPixbuf *pixbuf)
 			p += 4;
 		}
 	}
+	cairo_surface_mark_dirty(surface);
 	return surface;
 }
 
@@ -2288,6 +2289,8 @@ cairo_user_data_key_t fiv_io_key_loops;
 cairo_user_data_key_t fiv_io_key_page_next;
 cairo_user_data_key_t fiv_io_key_page_previous;
 
+cairo_user_data_key_t fiv_io_key_thumbnail_lq;
+
 cairo_surface_t *
 fiv_io_open(
 	const gchar *path, FivIoProfile profile, gboolean enhance, GError **error)
@@ -2761,8 +2764,21 @@ FivIoThumbnailSizeInfo
 		FIV_IO_THUMBNAIL_SIZES(XX)};
 #undef XX
 
-// TODO(p): Put the constant in a header file, share with fiv-browser.c.
-static const double g_wide_thumbnail_factor = 2;
+static void
+mark_thumbnail_lq(cairo_surface_t *surface)
+{
+	cairo_surface_set_user_data(
+		surface, &fiv_io_key_thumbnail_lq, (void *) (intptr_t) 1, NULL);
+}
+
+gchar *
+fiv_io_get_thumbnail_root(void)
+{
+	gchar *cache_dir = get_xdg_home_dir("XDG_CACHE_HOME", ".cache");
+	gchar *thumbnails_dir = g_build_filename(cache_dir, "thumbnails", NULL);
+	g_free(cache_dir);
+	return thumbnails_dir;
+}
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
@@ -2770,13 +2786,14 @@ static const double g_wide_thumbnail_factor = 2;
 static cairo_surface_t *
 rescale_thumbnail(cairo_surface_t *thumbnail, double row_height)
 {
+	cairo_format_t format = cairo_image_surface_get_format(thumbnail);
 	int width = cairo_image_surface_get_width(thumbnail);
 	int height = cairo_image_surface_get_height(thumbnail);
 
 	double scale_x = 1;
 	double scale_y = 1;
-	if (width > g_wide_thumbnail_factor * height) {
-		scale_x = g_wide_thumbnail_factor * row_height / width;
+	if (width > FIV_IO_WIDE_THUMBNAIL_COEFFICIENT * height) {
+		scale_x = FIV_IO_WIDE_THUMBNAIL_COEFFICIENT * row_height / width;
 		scale_y = round(scale_x * height) / height;
 	} else {
 		scale_y = row_height / height;
@@ -2785,13 +2802,13 @@ rescale_thumbnail(cairo_surface_t *thumbnail, double row_height)
 	if (scale_x == 1 && scale_y == 1)
 		return cairo_surface_reference(thumbnail);
 
-	// TODO(p): Don't always include an alpha channel.
-	cairo_format_t cairo_format = CAIRO_FORMAT_ARGB32;
-
 	int projected_width = round(scale_x * width);
 	int projected_height = round(scale_y * height);
 	cairo_surface_t *scaled = cairo_image_surface_create(
-		cairo_format, projected_width, projected_height);
+		(format == CAIRO_FORMAT_RGB24 || format == CAIRO_FORMAT_RGB30)
+			? CAIRO_FORMAT_RGB24
+			: CAIRO_FORMAT_ARGB32,
+		projected_width, projected_height);
 
 	cairo_t *cr = cairo_create(scaled);
 	cairo_scale(cr, scale_x, scale_y);
@@ -2804,6 +2821,7 @@ rescale_thumbnail(cairo_surface_t *thumbnail, double row_height)
 	cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
 	cairo_paint(cr);
 	cairo_destroy(cr);
+	mark_thumbnail_lq(scaled);
 	return scaled;
 }
 
@@ -2847,13 +2865,13 @@ fiv_io_produce_thumbnail(GFile *target, FivIoThumbnailSize size, GError **error)
 	// Boilerplate copied from fiv_io_lookup_thumbnail().
 	gchar *uri = g_file_get_uri(target);
 	gchar *sum = g_compute_checksum_for_string(G_CHECKSUM_MD5, uri, -1);
-	gchar *cache_dir = get_xdg_home_dir("XDG_CACHE_HOME", ".cache");
+	gchar *thumbnails_dir = fiv_io_get_thumbnail_root();
 
 	for (int use = size; use >= FIV_IO_THUMBNAIL_SIZE_MIN; use--) {
 		cairo_surface_t *scaled =
 			rescale_thumbnail(surface, fiv_io_thumbnail_sizes[use].size);
-		gchar *path = g_strdup_printf("%s/thumbnails/wide-%s/%s.webp",
-			cache_dir, fiv_io_thumbnail_sizes[use].thumbnail_spec_name, sum);
+		gchar *path = g_strdup_printf("%s/wide-%s/%s.webp", thumbnails_dir,
+			fiv_io_thumbnail_sizes[use].thumbnail_spec_name, sum);
 
 		GError *e = NULL;
 		while (!fiv_io_save(scaled, scaled, NULL, path, &e)) {
@@ -2880,7 +2898,7 @@ fiv_io_produce_thumbnail(GFile *target, FivIoThumbnailSize size, GError **error)
 		g_free(path);
 	}
 
-	g_free(cache_dir);
+	g_free(thumbnails_dir);
 	g_free(sum);
 	g_free(uri);
 	cairo_surface_destroy(surface);
@@ -3052,44 +3070,52 @@ fiv_io_lookup_thumbnail(GFile *target, FivIoThumbnailSize size)
 
 	gchar *uri = g_file_get_uri(target);
 	gchar *sum = g_compute_checksum_for_string(G_CHECKSUM_MD5, uri, -1);
-	gchar *cache_dir = get_xdg_home_dir("XDG_CACHE_HOME", ".cache");
+	gchar *thumbnails_dir = fiv_io_get_thumbnail_root();
 
 	// The lookup sequence is: nominal..max, then mirroring back to ..min.
 	cairo_surface_t *result = NULL;
 	GError *error = NULL;
 	for (int i = 0; i < FIV_IO_THUMBNAIL_SIZE_COUNT; i++) {
-		int use = size + i;
+		FivIoThumbnailSize use = size + i;
 		if (use > FIV_IO_THUMBNAIL_SIZE_MAX)
 			use = FIV_IO_THUMBNAIL_SIZE_MAX - i;
 
 		const char *name = fiv_io_thumbnail_sizes[use].thumbnail_spec_name;
-		gchar *wide = g_strdup_printf(
-			"%s/thumbnails/wide-%s/%s.webp", cache_dir, name, sum);
+		gchar *wide =
+			g_strdup_printf("%s/wide-%s/%s.webp", thumbnails_dir, name, sum);
 		result = read_wide_thumbnail(wide, uri, st.st_mtim.tv_sec, &error);
 		if (error) {
 			g_debug("%s: %s", wide, error->message);
 			g_clear_error(&error);
 		}
 		g_free(wide);
-		if (result)
+		if (result) {
+			// Higher up we can't distinguish images smaller than the thumbnail.
+			// Also, try not to rescale the already rescaled.
+			if (use != size)
+				mark_thumbnail_lq(result);
 			break;
+		}
 
 		gchar *path =
-			g_strdup_printf("%s/thumbnails/%s/%s.png", cache_dir, name, sum);
+			g_strdup_printf("%s/%s/%s.png", thumbnails_dir, name, sum);
 		result = read_spng_thumbnail(path, uri, st.st_mtim.tv_sec, &error);
 		if (error) {
 			g_debug("%s: %s", path, error->message);
 			g_clear_error(&error);
 		}
 		g_free(path);
-		if (result)
+		if (result) {
+			// Whatever produced it, we may be able to outclass it.
+			mark_thumbnail_lq(result);
 			break;
+		}
 	}
 
 	// TODO(p): We can definitely extract embedded thumbnails, but it should be
 	// done as a separate stage--the file may be stored on a slow device.
 
-	g_free(cache_dir);
+	g_free(thumbnails_dir);
 	g_free(sum);
 	g_free(uri);
 	return result;

fiv-io.h

@@ -67,6 +67,9 @@ extern cairo_user_data_key_t fiv_io_key_page_next;
 /// There is no wrap-around. This is a weak pointer.
 extern cairo_user_data_key_t fiv_io_key_page_previous;
 
+/// If non-NULL, indicates a thumbnail of insufficient quality.
+extern cairo_user_data_key_t fiv_io_key_thumbnail_lq;
+
 cairo_surface_t *fiv_io_open(
 	const gchar *path, FivIoProfile profile, gboolean enhance, GError **error);
 cairo_surface_t *fiv_io_open_from_data(const char *data, size_t len,
@@ -131,6 +134,13 @@ typedef struct _FivIoThumbnailSizeInfo {
 extern FivIoThumbnailSizeInfo
 	fiv_io_thumbnail_sizes[FIV_IO_THUMBNAIL_SIZE_COUNT];
 
+enum {
+	FIV_IO_WIDE_THUMBNAIL_COEFFICIENT = 2
+};
+
+/// Returns this user's root thumbnail directory.
+gchar *fiv_io_get_thumbnail_root(void);
+
 /// Generates wide thumbnails of up to the specified size, saves them in cache.
 gboolean fiv_io_produce_thumbnail(
 	GFile *target, FivIoThumbnailSize size, GError **error);