Adopt shorter identifiers

Also, slightly reformat the source code according to clang-format.

1 files changed, 1064 insertions, 0 deletions

diff --git a/fiv-browser.c b/fiv-browser.c
new file mode 100644
index 0000000..7759c3a
--- /dev/null
+++ b/fiv-browser.c
@@ -0,0 +1,1064 @@
+//
+// fiv-browser.c: fast image viewer - filesystem browser widget
+//
+// Copyright (c) 2021, Přemysl Eric Janouch <p@janouch.name>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+//
+
+#include <math.h>
+#include <pixman.h>
+
+#include "fiv-browser.h"
+#include "fiv-io.h"
+#include "fiv-view.h"
+
+// --- Widget ------------------------------------------------------------------
+//                     _________________________________
+//                    │    p   a   d   d   i   n   g
+//                    │ p ╭───────────────────╮ s ╭┄┄┄┄┄
+//                    │ a │ glow border   ┊   │ p ┊
+//                    │ d │ ┄ ╔═══════════╗ ┄ │ a ┊
+//                    │ d │   ║ thumbnail ║   │ c ┊ ...
+//                    │ i │ ┄ ╚═══════════╝ ┄ │ i ┊
+//                    │ n │   ┊   glow border │ n ┊
+//                    │ g ╰───────────────────╯ g ╰┄┄┄┄┄
+//                    │    s  p  a  c  i  n  g
+//                    │   ╭┄┄┄┄┄┄┄┄┄┄┄┄╮   ╭┄┄┄┄┄┄┄┄┄┄┄┄
+//
+// The glow is actually a glowing margin, the border is rendered in two parts.
+//
+
+struct _FivBrowser {
+	GtkWidget parent_instance;
+
+	FivIoThumbnailSize item_size;       ///< Thumbnail size
+	int item_height;                    ///< Thumbnail height in pixels
+	int item_spacing;                   ///< Space between items in pixels
+
+	GArray *entries;                    ///< [Entry]
+	GArray *layouted_rows;              ///< [Row]
+	int selected;
+
+	GdkCursor *pointer;                 ///< Cached pointer cursor
+	cairo_surface_t *glow;              ///< CAIRO_FORMAT_A8 mask
+	int item_border_x;                  ///< L/R .item margin + border
+	int item_border_y;                  ///< T/B .item margin + border
+};
+
+typedef struct entry Entry;
+typedef struct item Item;
+typedef struct row Row;
+
+static const double g_permitted_width_multiplier = 2;
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+struct entry {
+	char *uri;                          ///< GIO URI
+	cairo_surface_t *thumbnail;         ///< Prescaled thumbnail
+	GIcon *icon;                        ///< If no thumbnail, use this icon
+};
+
+static void
+entry_free(Entry *self)
+{
+	g_free(self->uri);
+	g_clear_pointer(&self->thumbnail, cairo_surface_destroy);
+	g_clear_object(&self->icon);
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+struct item {
+	const Entry *entry;
+	int x_offset;                       ///< Offset within the row
+};
+
+struct row {
+	Item *items;                        ///< Ends with a NULL entry
+	int x_offset;                       ///< Start position outside borders
+	int y_offset;                       ///< Start position inside borders
+};
+
+static void
+row_free(Row *self)
+{
+	g_free(self->items);
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+static void
+append_row(FivBrowser *self, int *y, int x, GArray *items_array)
+{
+	if (self->layouted_rows->len)
+		*y += self->item_spacing;
+
+	*y += self->item_border_y;
+	g_array_append_val(self->layouted_rows, ((Row) {
+		.items = g_array_steal(items_array, NULL),
+		.x_offset = x,
+		.y_offset = *y,
+	}));
+
+	// Not trying to pack them vertically, but this would be the place to do it.
+	*y += self->item_height;
+	*y += self->item_border_y;
+}
+
+static int
+relayout(FivBrowser *self, int width)
+{
+	GtkWidget *widget = GTK_WIDGET(self);
+	GtkStyleContext *style = gtk_widget_get_style_context(widget);
+
+	GtkBorder padding = {};
+	gtk_style_context_get_padding(style, GTK_STATE_FLAG_NORMAL, &padding);
+	int available_width = width - padding.left - padding.right;
+
+	g_array_set_size(self->layouted_rows, 0);
+
+	GArray *items = g_array_new(TRUE, TRUE, sizeof(Item));
+	int x = 0, y = padding.top;
+	for (guint i = 0; i < self->entries->len; i++) {
+		const Entry *entry = &g_array_index(self->entries, Entry, i);
+		if (!entry->thumbnail)
+			continue;
+
+		int width = cairo_image_surface_get_width(entry->thumbnail) +
+			2 * self->item_border_x;
+		if (!items->len) {
+			// Just insert it, whether or not there's any space.
+		} else if (x + self->item_spacing + width <= available_width) {
+			x += self->item_spacing;
+		} else {
+			append_row(self, &y,
+				padding.left + MAX(0, available_width - x) / 2, items);
+			x = 0;
+		}
+
+		g_array_append_val(items,
+			((Item) {.entry = entry, .x_offset = x + self->item_border_x}));
+		x += width;
+	}
+	if (items->len) {
+		append_row(self, &y,
+			padding.left + MAX(0, available_width - x) / 2, items);
+	}
+
+	g_array_free(items, TRUE);
+	return y + padding.bottom;
+}
+
+static void
+draw_outer_border(FivBrowser *self, cairo_t *cr, int width, int height)
+{
+	int offset_x = cairo_image_surface_get_width(self->glow);
+	int offset_y = cairo_image_surface_get_height(self->glow);
+	cairo_pattern_t *mask = cairo_pattern_create_for_surface(self->glow);
+	cairo_matrix_t matrix;
+
+	cairo_pattern_set_extend(mask, CAIRO_EXTEND_PAD);
+	cairo_save(cr);
+	cairo_translate(cr, -offset_x, -offset_y);
+	cairo_rectangle(cr, 0, 0, offset_x + width, offset_y + height);
+	cairo_clip(cr);
+	cairo_mask(cr, mask);
+	cairo_restore(cr);
+	cairo_save(cr);
+	cairo_translate(cr, width + offset_x, height + offset_y);
+	cairo_rectangle(cr, 0, 0, -offset_x - width, -offset_y - height);
+	cairo_clip(cr);
+	cairo_scale(cr, -1, -1);
+	cairo_mask(cr, mask);
+	cairo_restore(cr);
+
+	cairo_pattern_set_extend(mask, CAIRO_EXTEND_NONE);
+	cairo_matrix_init_scale(&matrix, -1, 1);
+	cairo_matrix_translate(&matrix, -width - offset_x, offset_y);
+	cairo_pattern_set_matrix(mask, &matrix);
+	cairo_mask(cr, mask);
+	cairo_matrix_init_scale(&matrix, 1, -1);
+	cairo_matrix_translate(&matrix, offset_x, -height - offset_y);
+	cairo_pattern_set_matrix(mask, &matrix);
+	cairo_mask(cr, mask);
+
+	cairo_pattern_destroy(mask);
+}
+
+static GdkRectangle
+item_extents(FivBrowser *self, const Item *item, const Row *row)
+{
+	int width = cairo_image_surface_get_width(item->entry->thumbnail);
+	int height = cairo_image_surface_get_height(item->entry->thumbnail);
+	return (GdkRectangle) {
+		.x = row->x_offset + item->x_offset,
+		.y = row->y_offset + self->item_height - height,
+		.width = width,
+		.height = height,
+	};
+}
+
+static const Entry *
+entry_at(FivBrowser *self, int x, int y)
+{
+	for (guint i = 0; i < self->layouted_rows->len; i++) {
+		const Row *row = &g_array_index(self->layouted_rows, Row, i);
+		for (Item *item = row->items; item->entry; item++) {
+			GdkRectangle extents = item_extents(self, item, row);
+			if (x >= extents.x &&
+				y >= extents.y &&
+				x <= extents.x + extents.width &&
+				y <= extents.y + extents.height)
+				return item->entry;
+		}
+	}
+	return NULL;
+}
+
+static void
+draw_row(FivBrowser *self, cairo_t *cr, const Row *row)
+{
+	GtkStyleContext *style = gtk_widget_get_style_context(GTK_WIDGET(self));
+	gtk_style_context_save(style);
+	gtk_style_context_add_class(style, "item");
+
+	GdkRGBA glow_color = {};
+	GtkStateFlags state = gtk_style_context_get_state (style);
+	gtk_style_context_get_color(style, state, &glow_color);
+
+	GtkBorder border;
+	gtk_style_context_get_border(style, state, &border);
+	for (Item *item = row->items; item->entry; item++) {
+		cairo_save(cr);
+		GdkRectangle extents = item_extents(self, item, row);
+		cairo_translate(cr, extents.x - border.left, extents.y - border.top);
+
+		gtk_style_context_save(style);
+		if (item->entry->icon) {
+			gtk_style_context_add_class(style, "symbolic");
+		} else {
+			gdk_cairo_set_source_rgba(cr, &glow_color);
+			draw_outer_border(self, cr,
+				border.left + extents.width + border.right,
+				border.top + extents.height + border.bottom);
+		}
+
+		gtk_render_background(
+			style, cr, border.left, border.top, extents.width, extents.height);
+
+		gtk_render_frame(style, cr, 0, 0,
+			border.left + extents.width + border.right,
+			border.top + extents.height + border.bottom);
+
+		if (item->entry->icon) {
+			GdkRGBA color = {};
+			gtk_style_context_get_color(style, state, &color);
+			gdk_cairo_set_source_rgba(cr, &color);
+			cairo_mask_surface(
+				cr, item->entry->thumbnail, border.left, border.top);
+		} else {
+			cairo_set_source_surface(
+				cr, item->entry->thumbnail, border.left, border.top);
+			cairo_paint(cr);
+		}
+
+		cairo_restore(cr);
+		gtk_style_context_restore(style);
+	}
+	gtk_style_context_restore(style);
+}
+
+// --- Thumbnails --------------------------------------------------------------
+
+// NOTE: "It is important to note that when an image with an alpha channel is
+// scaled, linear encoded, pre-multiplied component values must be used!"
+static cairo_surface_t *
+rescale_thumbnail(cairo_surface_t *thumbnail, double row_height)
+{
+	if (!thumbnail)
+		return 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_permitted_width_multiplier * height) {
+		scale_x = g_permitted_width_multiplier * row_height / width;
+		scale_y = round(scale_x * height) / height;
+	} else {
+		scale_y = row_height / height;
+		scale_x = round(scale_y * width) / width;
+	}
+	if (scale_x == 1 && scale_y == 1)
+		return thumbnail;
+
+	int projected_width = round(scale_x * width);
+	int projected_height = round(scale_y * height);
+	cairo_surface_t *scaled = cairo_image_surface_create(
+		CAIRO_FORMAT_ARGB32, projected_width, projected_height);
+
+	// pixman can take gamma into account when scaling, unlike Cairo.
+	struct pixman_f_transform xform_floating;
+	struct pixman_transform xform;
+
+	// PIXMAN_a8r8g8b8_sRGB can be used for gamma-correct results,
+	// but it's an incredibly slow transformation
+	pixman_format_code_t format = PIXMAN_a8r8g8b8;
+
+	pixman_image_t *src = pixman_image_create_bits(format, width, height,
+		(uint32_t *) cairo_image_surface_get_data(thumbnail),
+		cairo_image_surface_get_stride(thumbnail));
+	pixman_image_t *dest = pixman_image_create_bits(format,
+		cairo_image_surface_get_width(scaled),
+		cairo_image_surface_get_height(scaled),
+		(uint32_t *) cairo_image_surface_get_data(scaled),
+		cairo_image_surface_get_stride(scaled));
+
+	pixman_f_transform_init_scale(&xform_floating, scale_x, scale_y);
+	pixman_f_transform_invert(&xform_floating, &xform_floating);
+	pixman_transform_from_pixman_f_transform(&xform, &xform_floating);
+	pixman_image_set_transform(src, &xform);
+	pixman_image_set_filter(src, PIXMAN_FILTER_BILINEAR, NULL, 0);
+	pixman_image_set_repeat(src, PIXMAN_REPEAT_PAD);
+
+	pixman_image_composite(PIXMAN_OP_SRC, src, NULL, dest, 0, 0, 0, 0, 0, 0,
+		projected_width, projected_height);
+	pixman_image_unref(src);
+	pixman_image_unref(dest);
+
+	cairo_surface_destroy(thumbnail);
+	cairo_surface_mark_dirty(scaled);
+	return scaled;
+}
+
+static void
+entry_add_thumbnail(gpointer data, gpointer user_data)
+{
+	Entry *self = data;
+	g_clear_object(&self->icon);
+	g_clear_pointer(&self->thumbnail, cairo_surface_destroy);
+
+	FivBrowser *browser = FIV_BROWSER(user_data);
+	GFile *file = g_file_new_for_uri(self->uri);
+	self->thumbnail = rescale_thumbnail(
+		fiv_io_lookup_thumbnail(file, browser->item_size),
+		browser->item_height);
+	if (self->thumbnail)
+		goto out;
+
+	// Fall back to symbolic icons, though there's only so much we can do
+	// in parallel--GTK+ isn't thread-safe.
+	GFileInfo *info = g_file_query_info(file,
+		G_FILE_ATTRIBUTE_STANDARD_NAME
+		"," G_FILE_ATTRIBUTE_STANDARD_SYMBOLIC_ICON,
+		G_FILE_QUERY_INFO_NONE, NULL, NULL);
+	if (info) {
+		GIcon *icon = g_file_info_get_symbolic_icon(info);
+		if (icon)
+			self->icon = g_object_ref(icon);
+		g_object_unref(info);
+	}
+out:
+	g_object_unref(file);
+}
+
+static void
+materialize_icon(FivBrowser *self, Entry *entry)
+{
+	if (!entry->icon)
+		return;
+
+	// Fucker will still give us non-symbolic icons, no more playing nice.
+	// TODO(p): Investigate a bit closer. We may want to abandon the idea
+	// of using GLib to look up icons for us, derive a list from a guessed
+	// MIME type, with "-symbolic" prefixes and fallbacks,
+	// and use gtk_icon_theme_choose_icon() instead.
+	// TODO(p): Make sure we have /some/ icon for every entry.
+	// TODO(p): We might want to populate these on an as-needed basis.
+	GtkIconInfo *icon_info = gtk_icon_theme_lookup_by_gicon(
+		gtk_icon_theme_get_default(), entry->icon, self->item_height / 2,
+		GTK_ICON_LOOKUP_FORCE_SYMBOLIC);
+	if (!icon_info)
+		return;
+
+	// Bílá, bílá, bílá, bílá... komu by se nelíbí-lá...
+	// We do not want any highlights, nor do we want to remember the style.
+	const GdkRGBA white = {1, 1, 1, 1};
+	GdkPixbuf *pixbuf = gtk_icon_info_load_symbolic(
+		icon_info, &white, &white, &white, &white, NULL, NULL);
+	if (pixbuf) {
+		int outer_size = self->item_height;
+		entry->thumbnail =
+			cairo_image_surface_create(CAIRO_FORMAT_A8, outer_size, outer_size);
+
+		// "Note that the resulting pixbuf may not be exactly this size;"
+		// though GTK_ICON_LOOKUP_FORCE_SIZE is also an option.
+		int x = (outer_size - gdk_pixbuf_get_width(pixbuf)) / 2;
+		int y = (outer_size - gdk_pixbuf_get_height(pixbuf)) / 2;
+
+		cairo_t *cr = cairo_create(entry->thumbnail);
+		gdk_cairo_set_source_pixbuf(cr, pixbuf, x, y);
+		cairo_paint(cr);
+		cairo_destroy(cr);
+
+		g_object_unref(pixbuf);
+	}
+	g_object_unref(icon_info);
+}
+
+static void
+reload_thumbnails(FivBrowser *self)
+{
+	GThreadPool *pool = g_thread_pool_new(
+		entry_add_thumbnail, self, g_get_num_processors(), FALSE, NULL);
+	for (guint i = 0; i < self->entries->len; i++)
+		g_thread_pool_push(pool, &g_array_index(self->entries, Entry, i), NULL);
+	g_thread_pool_free(pool, FALSE, TRUE);
+
+	for (guint i = 0; i < self->entries->len; i++)
+		materialize_icon(self, &g_array_index(self->entries, Entry, i));
+
+	gtk_widget_queue_resize(GTK_WIDGET(self));
+}
+
+// --- Context menu-------------------------------------------------------------
+
+typedef struct _OpenContext {
+	GWeakRef widget;
+	GFile *file;
+	char *content_type;
+	GAppInfo *app_info;
+} OpenContext;
+
+static void
+open_context_notify(gpointer data, G_GNUC_UNUSED GClosure *closure)
+{
+	OpenContext *self = data;
+	g_weak_ref_clear(&self->widget);
+	g_clear_object(&self->app_info);
+	g_clear_object(&self->file);
+	g_free(self->content_type);
+	g_free(self);
+}
+
+static void
+open_context_launch(GtkWidget *widget, OpenContext *self)
+{
+	GdkAppLaunchContext *context =
+		gdk_display_get_app_launch_context(gtk_widget_get_display(widget));
+	gdk_app_launch_context_set_screen(context, gtk_widget_get_screen(widget));
+	gdk_app_launch_context_set_timestamp(context, gtk_get_current_event_time());
+
+	// TODO(p): Display errors.
+	GList *files = g_list_append(NULL, self->file);
+	if (g_app_info_launch(
+			self->app_info, files, G_APP_LAUNCH_CONTEXT(context), NULL)) {
+		g_app_info_set_as_last_used_for_type(
+			self->app_info, self->content_type, NULL);
+	}
+	g_list_free(files);
+	g_object_unref(context);
+}
+
+static void
+append_opener(GtkWidget *menu, GAppInfo *opener, const OpenContext *template)
+{
+	OpenContext *ctx = g_malloc0(sizeof *ctx);
+	g_weak_ref_init(&ctx->widget, NULL);
+	ctx->file = g_object_ref(template->file);
+	ctx->content_type = g_strdup(template->content_type);
+	ctx->app_info = opener;
+
+	// It's documented that we can touch the child, if we want formatting:
+	// https://docs.gtk.org/gtk3/class.MenuItem.html
+	// XXX: Would g_app_info_get_display_name() be any better?
+	gchar *name = g_strdup_printf("Open With %s", g_app_info_get_name(opener));
+	GtkWidget *item = gtk_menu_item_new_with_label(name);
+	g_free(name);
+	g_signal_connect_data(item, "activate", G_CALLBACK(open_context_launch),
+		ctx, open_context_notify, 0);
+	gtk_menu_shell_append(GTK_MENU_SHELL(menu), item);
+}
+
+static void
+on_chooser_activate(GtkMenuItem *item, gpointer user_data)
+{
+	OpenContext *ctx = user_data;
+	GtkWindow *window = NULL;
+	GtkWidget *widget = g_weak_ref_get(&ctx->widget);
+	if (widget) {
+		if (GTK_IS_WINDOW((widget = gtk_widget_get_toplevel(widget))))
+			window = GTK_WINDOW(widget);
+	}
+
+	GtkWidget *dialog = gtk_app_chooser_dialog_new_for_content_type(window,
+		GTK_DIALOG_DESTROY_WITH_PARENT | GTK_DIALOG_MODAL, ctx->content_type);
+	if (gtk_dialog_run(GTK_DIALOG(dialog)) == GTK_RESPONSE_OK) {
+		ctx->app_info = gtk_app_chooser_get_app_info(GTK_APP_CHOOSER(dialog));
+		open_context_launch(GTK_WIDGET(item), ctx);
+	}
+	gtk_widget_destroy(dialog);
+}
+
+static gboolean
+destroy_widget_idle_source_func(GtkWidget *widget)
+{
+	// The whole menu is deactivated /before/ any item is activated,
+	// and a destroyed child item will not activate.
+	gtk_widget_destroy(widget);
+	return FALSE;
+}
+
+static void
+show_context_menu(GtkWidget *widget, const char *uri)
+{
+	GFile *file = g_file_new_for_uri(uri);
+	GFileInfo *info = g_file_query_info(file,
+		G_FILE_ATTRIBUTE_STANDARD_NAME
+		"," G_FILE_ATTRIBUTE_STANDARD_CONTENT_TYPE,
+		G_FILE_QUERY_INFO_NONE, NULL, NULL);
+	if (!info) {
+		g_object_unref(file);
+		return;
+	}
+
+	// This will have no application pre-assigned, for use with GTK+'s dialog.
+	OpenContext *ctx = g_malloc0(sizeof *ctx);
+	g_weak_ref_init(&ctx->widget, widget);
+	ctx->file = file;
+	ctx->content_type = g_strdup(g_file_info_get_content_type(info));
+	g_object_unref(info);
+
+	GAppInfo *default_ =
+		g_app_info_get_default_for_type(ctx->content_type, FALSE);
+	GList *recommended = g_app_info_get_recommended_for_type(ctx->content_type);
+	GList *fallback = g_app_info_get_fallback_for_type(ctx->content_type);
+
+	GtkWidget *menu = gtk_menu_new();
+	if (default_) {
+		append_opener(menu, default_, ctx);
+		gtk_menu_shell_append(
+			GTK_MENU_SHELL(menu), gtk_separator_menu_item_new());
+	}
+
+	for (GList *iter = recommended; iter; iter = iter->next) {
+		if (g_app_info_should_show(iter->data) &&
+			(!default_ || !g_app_info_equal(iter->data, default_)))
+			append_opener(menu, iter->data, ctx);
+		else
+			g_object_unref(iter->data);
+	}
+	if (recommended) {
+		g_list_free(recommended);
+		gtk_menu_shell_append(
+			GTK_MENU_SHELL(menu), gtk_separator_menu_item_new());
+	}
+
+	for (GList *iter = fallback; iter; iter = iter->next) {
+		if (g_app_info_should_show(iter->data) &&
+			(!default_ || !g_app_info_equal(iter->data, default_)))
+			append_opener(menu, iter->data, ctx);
+		else
+			g_object_unref(iter->data);
+	}
+	if (fallback) {
+		g_list_free(fallback);
+		gtk_menu_shell_append(
+			GTK_MENU_SHELL(menu), gtk_separator_menu_item_new());
+	}
+
+	GtkWidget *item = gtk_menu_item_new_with_label("Open With...");
+	g_signal_connect_data(item, "activate", G_CALLBACK(on_chooser_activate),
+		ctx, open_context_notify, 0);
+	gtk_menu_shell_append(GTK_MENU_SHELL(menu), item);
+
+	// As per GTK+ 3 Common Questions, 1.5.
+	g_object_ref_sink(menu);
+	g_signal_connect_swapped(menu, "deactivate",
+		G_CALLBACK(g_idle_add), destroy_widget_idle_source_func);
+	g_signal_connect(menu, "destroy", G_CALLBACK(g_object_unref), NULL);
+
+	gtk_widget_show_all(menu);
+	gtk_menu_popup_at_pointer(GTK_MENU(menu), NULL);
+}
+
+// --- Boilerplate -------------------------------------------------------------
+
+// TODO(p): For proper navigation, we need to implement GtkScrollable.
+G_DEFINE_TYPE_EXTENDED(FivBrowser, fiv_browser, GTK_TYPE_WIDGET, 0,
+	/* G_IMPLEMENT_INTERFACE(GTK_TYPE_SCROLLABLE,
+		fiv_browser_scrollable_init) */)
+
+enum {
+	PROP_THUMBNAIL_SIZE = 1,
+	N_PROPERTIES
+};
+
+static GParamSpec *browser_properties[N_PROPERTIES];
+
+enum {
+	ITEM_ACTIVATED,
+	LAST_SIGNAL,
+};
+
+// Globals are, sadly, the canonical way of storing signal numbers.
+static guint browser_signals[LAST_SIGNAL];
+
+static void
+fiv_browser_finalize(GObject *gobject)
+{
+	FivBrowser *self = FIV_BROWSER(gobject);
+	g_array_free(self->entries, TRUE);
+	g_array_free(self->layouted_rows, TRUE);
+	cairo_surface_destroy(self->glow);
+	g_clear_object(&self->pointer);
+
+	G_OBJECT_CLASS(fiv_browser_parent_class)->finalize(gobject);
+}
+
+static void
+fiv_browser_get_property(
+	GObject *object, guint property_id, GValue *value, GParamSpec *pspec)
+{
+	FivBrowser *self = FIV_BROWSER(object);
+	switch (property_id) {
+	case PROP_THUMBNAIL_SIZE:
+		g_value_set_enum(value, self->item_size);
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, property_id, pspec);
+	}
+}
+
+static void
+set_item_size(FivBrowser *self, FivIoThumbnailSize size)
+{
+	if (size < FIV_IO_THUMBNAIL_SIZE_MIN || size > FIV_IO_THUMBNAIL_SIZE_MAX)
+		return;
+
+	if (size != self->item_size) {
+		self->item_size = size;
+		self->item_height = fiv_io_thumbnail_sizes[self->item_size].size;
+		reload_thumbnails(self);
+
+		g_object_notify_by_pspec(
+			G_OBJECT(self), browser_properties[PROP_THUMBNAIL_SIZE]);
+	}
+}
+
+static void
+fiv_browser_set_property(
+	GObject *object, guint property_id, const GValue *value, GParamSpec *pspec)
+{
+	FivBrowser *self = FIV_BROWSER(object);
+	switch (property_id) {
+	case PROP_THUMBNAIL_SIZE:
+		set_item_size(self, g_value_get_enum(value));
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, property_id, pspec);
+	}
+}
+
+static GtkSizeRequestMode
+fiv_browser_get_request_mode(G_GNUC_UNUSED GtkWidget *widget)
+{
+	return GTK_SIZE_REQUEST_HEIGHT_FOR_WIDTH;
+}
+
+static void
+fiv_browser_get_preferred_width(GtkWidget *widget, gint *minimum, gint *natural)
+{
+	FivBrowser *self = FIV_BROWSER(widget);
+	GtkStyleContext *style = gtk_widget_get_style_context(widget);
+
+	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;
+}
+
+static void
+fiv_browser_get_preferred_height_for_width(
+	GtkWidget *widget, gint width, gint *minimum, gint *natural)
+{
+	// XXX: This is rather ugly, the caller is only asking.
+	*minimum = *natural = relayout(FIV_BROWSER(widget), width);
+}
+
+static void
+fiv_browser_realize(GtkWidget *widget)
+{
+	GtkAllocation allocation;
+	gtk_widget_get_allocation(widget, &allocation);
+
+	GdkWindowAttr attributes = {
+		.window_type = GDK_WINDOW_CHILD,
+		.x = allocation.x,
+		.y = allocation.y,
+		.width = allocation.width,
+		.height = allocation.height,
+
+		// Input-only would presumably also work (as in GtkPathBar, e.g.),
+		// but it merely seems to involve more work.
+		.wclass = GDK_INPUT_OUTPUT,
+
+		.visual = gtk_widget_get_visual(widget),
+		.event_mask = gtk_widget_get_events(widget) | GDK_KEY_PRESS_MASK |
+			GDK_POINTER_MOTION_MASK | GDK_BUTTON_PRESS_MASK | GDK_SCROLL_MASK,
+	};
+
+	// We need this window to receive input events at all.
+	// TODO(p): See if input events bubble up to parents.
+	GdkWindow *window = gdk_window_new(gtk_widget_get_parent_window(widget),
+		&attributes, GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL);
+	gtk_widget_register_window(widget, window);
+	gtk_widget_set_window(widget, window);
+	gtk_widget_set_realized(widget, TRUE);
+
+	FivBrowser *self = FIV_BROWSER(widget);
+	g_clear_object(&self->pointer);
+	self->pointer =
+		gdk_cursor_new_from_name(gdk_window_get_display(window), "pointer");
+}
+
+static void
+fiv_browser_size_allocate(GtkWidget *widget, GtkAllocation *allocation)
+{
+	GTK_WIDGET_CLASS(fiv_browser_parent_class)
+		->size_allocate(widget, allocation);
+
+	relayout(FIV_BROWSER(widget), allocation->width);
+}
+
+static gboolean
+fiv_browser_draw(GtkWidget *widget, cairo_t *cr)
+{
+	FivBrowser *self = FIV_BROWSER(widget);
+	if (!gtk_cairo_should_draw_window(cr, gtk_widget_get_window(widget)))
+		return TRUE;
+
+	GtkAllocation allocation;
+	gtk_widget_get_allocation(widget, &allocation);
+	gtk_render_background(gtk_widget_get_style_context(widget), cr, 0, 0,
+		allocation.width, allocation.height);
+
+	GdkRectangle clip = {};
+	gboolean have_clip = gdk_cairo_get_clip_rectangle(cr, &clip);
+
+	for (guint i = 0; i < self->layouted_rows->len; i++) {
+		const Row *row = &g_array_index(self->layouted_rows, Row, i);
+		GdkRectangle extents = {
+			.x = 0,
+			.y = row->y_offset - self->item_border_y,
+			.width = allocation.width,
+			.height = self->item_height + 2 * self->item_border_y,
+		};
+		if (!have_clip || gdk_rectangle_intersect(&clip, &extents, NULL))
+			draw_row(self, cr, row);
+	}
+	return TRUE;
+}
+
+static gboolean
+open_entry(GtkWidget *self, const Entry *entry, gboolean new_window)
+{
+	GFile *location = g_file_new_for_uri(entry->uri);
+	g_signal_emit(self, browser_signals[ITEM_ACTIVATED], 0, location,
+		new_window ? GTK_PLACES_OPEN_NEW_WINDOW : GTK_PLACES_OPEN_NORMAL);
+	g_object_unref(location);
+	return TRUE;
+}
+
+static gboolean
+fiv_browser_button_press_event(GtkWidget *widget, GdkEventButton *event)
+{
+	GTK_WIDGET_CLASS(fiv_browser_parent_class)
+		->button_press_event(widget, event);
+
+	FivBrowser *self = FIV_BROWSER(widget);
+	if (event->type != GDK_BUTTON_PRESS)
+		return FALSE;
+
+	guint state = event->state & gtk_accelerator_get_default_mod_mask();
+	if (event->button == GDK_BUTTON_PRIMARY && state == 0 &&
+		gtk_widget_get_focus_on_click(widget))
+		gtk_widget_grab_focus(widget);
+
+	const Entry *entry = entry_at(self, event->x, event->y);
+	if (!entry)
+		return FALSE;
+
+	switch (event->button) {
+	case GDK_BUTTON_PRIMARY:
+		if (state == 0)
+			return open_entry(widget, entry, FALSE);
+		if (state == GDK_CONTROL_MASK)
+			return open_entry(widget, entry, TRUE);
+		return FALSE;
+	case GDK_BUTTON_MIDDLE:
+		if (state == 0)
+			return open_entry(widget, entry, TRUE);
+		return FALSE;
+	case GDK_BUTTON_SECONDARY:
+		// On X11, after closing the menu, the pointer otherwise remains,
+		// no matter what its new location is.
+		gdk_window_set_cursor(gtk_widget_get_window(widget), NULL);
+		show_context_menu(widget, entry->uri);
+		return TRUE;
+	default:
+		return FALSE;
+	}
+}
+
+gboolean
+fiv_browser_motion_notify_event(GtkWidget *widget, GdkEventMotion *event)
+{
+	GTK_WIDGET_CLASS(fiv_browser_parent_class)
+		->motion_notify_event(widget, event);
+
+	FivBrowser *self = FIV_BROWSER(widget);
+	if (event->state != 0)
+		return FALSE;
+
+	const Entry *entry = entry_at(self, event->x, event->y);
+	GdkWindow *window = gtk_widget_get_window(widget);
+	gdk_window_set_cursor(window, entry ? self->pointer : NULL);
+	return TRUE;
+}
+
+static gboolean
+fiv_browser_scroll_event(GtkWidget *widget, GdkEventScroll *event)
+{
+	FivBrowser *self = FIV_BROWSER(widget);
+	if ((event->state & gtk_accelerator_get_default_mod_mask()) !=
+		GDK_CONTROL_MASK)
+		return FALSE;
+
+	switch (event->direction) {
+	case GDK_SCROLL_UP:
+		set_item_size(self, self->item_size + 1);
+		return TRUE;
+	case GDK_SCROLL_DOWN:
+		set_item_size(self, self->item_size - 1);
+		return TRUE;
+	default:
+		// For some reason, we can also get GDK_SCROLL_SMOOTH.
+		// Left/right are good to steal from GtkScrolledWindow for consistency.
+		return TRUE;
+	}
+}
+
+static gboolean
+fiv_browser_query_tooltip(GtkWidget *widget, gint x, gint y,
+	G_GNUC_UNUSED gboolean keyboard_tooltip, GtkTooltip *tooltip)
+{
+	FivBrowser *self = FIV_BROWSER(widget);
+	const Entry *entry = entry_at(self, x, y);
+	if (!entry)
+		return FALSE;
+
+	GFile *file = g_file_new_for_uri(entry->uri);
+	GFileInfo *info = g_file_query_info(file,
+		G_FILE_ATTRIBUTE_STANDARD_NAME
+		"," G_FILE_ATTRIBUTE_STANDARD_DISPLAY_NAME,
+		G_FILE_QUERY_INFO_NONE, NULL, NULL);
+	g_object_unref(file);
+	if (!info)
+		return FALSE;
+
+	gtk_tooltip_set_text(tooltip, g_file_info_get_display_name(info));
+	g_object_unref(info);
+	return TRUE;
+}
+
+static void
+fiv_browser_style_updated(GtkWidget *widget)
+{
+	GTK_WIDGET_CLASS(fiv_browser_parent_class)->style_updated(widget);
+
+	FivBrowser *self = FIV_BROWSER(widget);
+	GtkStyleContext *style = gtk_widget_get_style_context(widget);
+	GtkBorder border = {}, margin = {};
+
+	int item_spacing = self->item_spacing;
+	gtk_widget_style_get(widget, "spacing", &self->item_spacing, NULL);
+	if (item_spacing != self->item_spacing)
+		gtk_widget_queue_resize(widget);
+
+	// Using a pseudo-class, because GTK+ regions are deprecated.
+	gtk_style_context_save(style);
+	gtk_style_context_add_class(style, "item");
+	gtk_style_context_get_margin(style, GTK_STATE_FLAG_NORMAL, &margin);
+	gtk_style_context_get_border(style, GTK_STATE_FLAG_NORMAL, &border);
+	gtk_style_context_restore(style);
+
+	const int glow_w = (margin.left + margin.right) / 2;
+	const int glow_h = (margin.top + margin.bottom) / 2;
+
+	// Don't set different opposing sides, it will misrender, your problem.
+	// When the style of the class changes, this virtual method isn't invoked,
+	// so the update check is mildly pointless.
+	int item_border_x = glow_w + (border.left + border.right) / 2;
+	int item_border_y = glow_h + (border.top + border.bottom) / 2;
+	if (item_border_x != self->item_border_x ||
+		item_border_y != self->item_border_y) {
+		self->item_border_x = item_border_x;
+		self->item_border_y = item_border_y;
+		gtk_widget_queue_resize(widget);
+	}
+
+	if (self->glow)
+		cairo_surface_destroy(self->glow);
+	if (glow_w <= 0 || glow_h <= 0) {
+		self->glow = cairo_image_surface_create(CAIRO_FORMAT_A1, 0, 0);
+		return;
+	}
+
+	self->glow = cairo_image_surface_create(CAIRO_FORMAT_A8, glow_w, glow_h);
+	unsigned char *data = cairo_image_surface_get_data(self->glow);
+	int stride = cairo_image_surface_get_stride(self->glow);
+
+	// Smooth out the curve, so that the edge of the glow isn't too jarring.
+	const double fade_factor = 1.5;
+
+	const int x_max = glow_w - 1;
+	const int y_max = glow_h - 1;
+	const double x_scale = 1. / MAX(1, x_max);
+	const double y_scale = 1. / MAX(1, y_max);
+	for (int y = 0; y <= y_max; y++)
+		for (int x = 0; x <= x_max; x++) {
+			const double xn = x_scale * (x_max - x);
+			const double yn = y_scale * (y_max - y);
+			double v = MIN(sqrt(xn * xn + yn * yn), 1);
+			data[y * stride + x] = round(pow(1 - v, fade_factor) * 255);
+		}
+	cairo_surface_mark_dirty(self->glow);
+}
+
+static void
+fiv_browser_class_init(FivBrowserClass *klass)
+{
+	GObjectClass *object_class = G_OBJECT_CLASS(klass);
+	object_class->finalize = fiv_browser_finalize;
+	object_class->get_property = fiv_browser_get_property;
+	object_class->set_property = fiv_browser_set_property;
+
+	browser_properties[PROP_THUMBNAIL_SIZE] = g_param_spec_enum(
+		"thumbnail-size", "Thumbnail size", "The thumbnail height to use",
+		FIV_TYPE_IO_THUMBNAIL_SIZE, FIV_IO_THUMBNAIL_SIZE_NORMAL,
+		G_PARAM_READWRITE);
+	g_object_class_install_properties(
+		object_class, N_PROPERTIES, browser_properties);
+
+	browser_signals[ITEM_ACTIVATED] = g_signal_new("item-activated",
+		G_TYPE_FROM_CLASS(klass), 0, 0, NULL, NULL, NULL,
+		G_TYPE_NONE, 2, G_TYPE_FILE, GTK_TYPE_PLACES_OPEN_FLAGS);
+
+	GtkWidgetClass *widget_class = GTK_WIDGET_CLASS(klass);
+	widget_class->get_request_mode = fiv_browser_get_request_mode;
+	widget_class->get_preferred_width = fiv_browser_get_preferred_width;
+	widget_class->get_preferred_height_for_width =
+		fiv_browser_get_preferred_height_for_width;
+	widget_class->realize = fiv_browser_realize;
+	widget_class->draw = fiv_browser_draw;
+	widget_class->size_allocate = fiv_browser_size_allocate;
+	widget_class->button_press_event = fiv_browser_button_press_event;
+	widget_class->motion_notify_event = fiv_browser_motion_notify_event;
+	widget_class->scroll_event = fiv_browser_scroll_event;
+	widget_class->query_tooltip = fiv_browser_query_tooltip;
+	widget_class->style_updated = fiv_browser_style_updated;
+
+	// Could be split to also-idiomatic row-spacing/column-spacing properties.
+	// The GParamSpec is sinked by this call.
+	gtk_widget_class_install_style_property(widget_class,
+		g_param_spec_int("spacing", "Spacing", "Space between items",
+			0, G_MAXINT, 1, G_PARAM_READWRITE));
+
+	// TODO(p): Later override "screen_changed", recreate Pango layouts there,
+	// if we get to have any, or otherwise reflect DPI changes.
+	gtk_widget_class_set_css_name(widget_class, "fiv-browser");
+}
+
+static void
+fiv_browser_init(FivBrowser *self)
+{
+	gtk_widget_set_can_focus(GTK_WIDGET(self), TRUE);
+	gtk_widget_set_has_tooltip(GTK_WIDGET(self), TRUE);
+
+	self->entries = g_array_new(FALSE, TRUE, sizeof(Entry));
+	g_array_set_clear_func(self->entries, (GDestroyNotify) entry_free);
+	self->layouted_rows = g_array_new(FALSE, TRUE, sizeof(Row));
+	g_array_set_clear_func(self->layouted_rows, (GDestroyNotify) row_free);
+
+	set_item_size(self, FIV_IO_THUMBNAIL_SIZE_NORMAL);
+	self->selected = -1;
+	self->glow = cairo_image_surface_create(CAIRO_FORMAT_A1, 0, 0);
+
+	g_signal_connect_swapped(gtk_settings_get_default(),
+		"notify::gtk-icon-theme-name", G_CALLBACK(reload_thumbnails), self);
+}
+
+// --- Public interface --------------------------------------------------------
+
+static gint
+entry_compare(gconstpointer a, gconstpointer b)
+{
+	const Entry *entry1 = a;
+	const Entry *entry2 = b;
+	GFile *location1 = g_file_new_for_uri(entry1->uri);
+	GFile *location2 = g_file_new_for_uri(entry2->uri);
+	gint result = fiv_io_filecmp(location1, location2);
+	g_object_unref(location1);
+	g_object_unref(location2);
+	return result;
+}
+
+void
+fiv_browser_load(
+	FivBrowser *self, FivBrowserFilterCallback cb, const char *path)
+{
+	g_array_set_size(self->entries, 0);
+	g_array_set_size(self->layouted_rows, 0);
+
+	GFile *file = g_file_new_for_path(path);
+	GFileEnumerator *enumerator = g_file_enumerate_children(file,
+		G_FILE_ATTRIBUTE_STANDARD_NAME "," G_FILE_ATTRIBUTE_STANDARD_TYPE,
+		G_FILE_QUERY_INFO_NONE, NULL, NULL);
+	g_object_unref(file);
+	if (!enumerator)
+		return;
+
+	while (TRUE) {
+		GFileInfo *info = NULL;
+		GFile *child = NULL;
+		if (!g_file_enumerator_iterate(enumerator, &info, &child, NULL, NULL) ||
+			!info)
+			break;
+		if (g_file_info_get_file_type(info) == G_FILE_TYPE_DIRECTORY)
+			continue;
+		if (cb && !cb(g_file_info_get_name(info)))
+			continue;
+
+		g_array_append_val(self->entries,
+			((Entry) {.thumbnail = NULL, .uri = g_file_get_uri(child)}));
+	}
+	g_object_unref(enumerator);
+
+	// TODO(p): Support being passed a sort function.
+	g_array_sort(self->entries, entry_compare);
+
+	reload_thumbnails(self);
+}