Second commit

Signed-off-by: Mattias Andrée <m@maandree.se>

1 files changed, 250 insertions, 1350 deletions

diff --git a/gbild.c b/gbild.c
index 7ab22ee..ffe51b0 100644
--- a/gbild.c
+++ b/gbild.c
@@ -1,171 +1,9 @@
 /* See LICENSE file for copyright and license details. */
-#if defined(__GNUC__)
-# pragma GCC diagnostic push
-# pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-# pragma GCC diagnostic ignored "-Wstrict-prototypes"
-#endif
-#include <gdk/gdkkeysyms.h>
-#include <gtk/gtk.h>
-#include <libsimple.h>
-#include <libsimple-arg.h>
-#if defined(__GNUC__)
-# pragma GCC diagnostic pop
-#endif
-
-#if defined(__GNUC__)
-# pragma GCC diagnostic ignored "-Wunsuffixed-float-constants"
-#endif
+#include "common.h"
 
 USAGE("[-f] [file] ...");
 
-#define SCROLL_AMOUNT 30
-
-#define FLOAT_EQ(A, B) ((A) >= (B) && (A) <= (B))
-
-#define COMMA ,
-
-#define LIST_MENU(TOPLEVEL, SEPARATOR, ACTION, TOGGLE, D)\
-	TOPLEVEL(0, "", "File", D)\
-	ACTION(0, 0u, "", "Open", GTK_STOCK_OPEN, "<control>0", "Ctrl+0", open_action, D)\
-	ACTION(0, 1u, "", "Reload", GTK_STOCK_REFRESH, "F5", "F5", reload_action, D)\
-	SEPARATOR(0, D)\
-	ACTION(0, 1u, "", "Print", GTK_STOCK_PRINT, "<control>P", "Ctrl+P", print_action, D)\
-	SEPARATOR(0, D)\
-	ACTION(0, 1u, "Proper", "ties", GTK_STOCK_PROPERTIES, "<alt>Return", "Alt+Return", properties_action, D)\
-	SEPARATOR(0, D)\
-	ACTION(0, 0u, "", "Close", GTK_STOCK_CLOSE, "<control>W", "Ctrl+W", close_action, D)\
-	TOPLEVEL(0, "", "View", D)\
-	TOGGLE(1, 1u, "F", "ullscreen", GTK_STOCK_FULLSCREEN, "F11", "F11", fullscreen_action, GROUP_NONE, 0, D)\
-	SEPARATOR(1, D)\
-	ACTION(0, 1u, "Re", "set transformations", "document-revert", "<alt>R", "Alt+R", reset_transformations_action, D)\
-	ACTION(1, 1u, "Rotate anti", "clockwise", "image-rotate-left", "<shift>R", "Shift+R", rotate_anticlockwise_action, D)\
-	ACTION(0, 1u, "R", "otate 180°", "image-rotate", "<control>space", "Ctrl+Space", rotate_180_degrees_action, D)\
-	ACTION(1, 1u, "", "Rotate clockwise", "image-rotate-right", "R", "R", rotate_clockwise_action, D)\
-	ACTION(1, 1u, "", "Mirror horizontally", "object-flip-horizontal", "H", "H", flop_action, D)\
-	ACTION(1, 1u, "Mirror ", "vertically", "object-flip-vertical", "V", "V", flip_action, D)\
-	ACTION(1, 1u, "", "Transpose", "object-transpose", "T", "T", transpose_action, D)\
-	ACTION(1, 1u, "", "Antitranspose", "object-transpose-mirrored", "<shift>T", "Shift+T", antitranspose_action, D)\
-	SEPARATOR(1, D)\
-	TOGGLE(1, 1u, "", "Invert colours", "filters-invert", "<control>I", "Ctrl+I", invert_action, GROUP_NONE, 0, D)\
-	SEPARATOR(1, D)\
-	/* TODO these are not properly honoured */\
-	ACTION(1, 1u, "", "Zoom in", "zoom-in", "plus", "+", zoom_in_action, D)\
-	ACTION(1, 1u, "Zoom ", "out", "zoom-out", "minus", "-", zoom_out_action, D)\
-	TOGGLE(1, 1u, "", "Normal size", "zoom-original", "0", "0", normal_size_action, GROUP_ZOOM, 0, D)\
-	TOGGLE(1, 1u, "Fit to ", "width", "zoom-fit-width", "<control>H", "Ctrl+H", width_fit_action, GROUP_ZOOM, 0, D)\
-	TOGGLE(1, 1u, "Fit to ", "height", "zoom-fit-height", "<control>V", "Ctrl+V", height_fit_action, GROUP_ZOOM, 0, D)\
-	TOGGLE(1, 1u, "", "Fit to window", "zoom-fit-page", "<control><shift>F", "Ctrl+Shift+F", window_fit_action, GROUP_ZOOM, 0, D)\
-	TOGGLE(1, 1u, "", "Best fit", "zoom-fit-best", "<control>F", "Ctrl+F", best_fit_action, GROUP_ZOOM, 1, D)\
-	TOPLEVEL(1, "", "Go", D)\
-	ACTION(1, 2u, "", "Previous image", GTK_STOCK_GO_BACK, "<control>Left", "Ctrl+Left", previous_action, D)\
-	ACTION(1, 2u, "", "Next image", GTK_STOCK_GO_FORWARD, "<control>Right", "Ctrl+Right", next_action, D)\
-	SEPARATOR(0, D)\
-	ACTION(1, 2u, "", "First image", GTK_STOCK_GOTO_FIRST, "<control>Home", "Ctrl+Home", first_action, D)\
-	ACTION(1, 2u, "", "Last image", GTK_STOCK_GOTO_LAST, "<control>End", "Ctrl+End", last_action,)
-
-enum toggle_group {
-	GROUP_NONE,
-	GROUP_ZOOM
-};
-
-enum transformation {
-	TRANS_NONE,          /* 1   */
-	TRANS_CLOCKWISE,     /* r   */
-	TRANS_180_DEGREES,   /* r²  */
-	TRANS_ANTICLOCKWISE, /* r³  */
-	TRANS_TRANSPOSE,     /* t   */
-	TRANS_FLOP,          /* rt  */
-	TRANS_ANTITRANSPOSE, /* r²t */
-	TRANS_FLIP,          /* r³t */
-	/*
-	 * t² = r⁴ = 1
-	 * trⁿ = r⁻ⁿt
-	 */
-	TRANS_NEGATIVE = 0x08
-};
-
-struct file {
-	char *path;
-	off_t size;
-	GdkPixbuf *image;
-};
-
-struct filter {
-	char *name;
-	size_t suffixes_start;
-	size_t suffixes_end;
-};
-
-static struct file *files = NULL;
-static size_t nfiles = 0u;
-static size_t current_file = 0u;
-static enum transformation trans = TRANS_NONE;
-static GdkPixbuf *transformed_image = NULL;
-
-static double zoom = 1.0;
-static int clearing_toggles = 0;
-static int dragging = 0;
-static int drag_x, drag_y;
-
-static GtkWidget *window;
-static GtkWidget *menubar;
-static GtkWidget *statusbar;
-static GtkWidget *toolbar;
-static GtkWidget *display_area;
-static GtkWidget *scroll;
-static GtkToggleAction *fullscreen;
-static GtkActionGroup *actions;
-
-static const char *home_directory;
-static char *suffixes = NULL;
-static struct filter *filters = NULL;
-static size_t nfilters = 0u;
-static struct filter anyfilter = {NULL, 0u, 0u};
-static char image_target_name[] = "text/uri-list";
-static GtkTargetEntry image_target = {image_target_name, 0u, 0u};
-
-static double
-zoom_in(double z)
-{
-	return z * 1.25;
-}
-
-static double
-zoom_out(double z)
-{
-	return z * 0.8;
-}
-
-static GtkAction *
-get_action(const char *name)
-{
-	return gtk_action_group_get_action(actions, name);
-}
-
-static void
-set_actions_sensitive(void)
-{
-#if defined(__GNUC__)
-# pragma GCC diagnostic push
-# pragma GCC diagnostic ignored "-Wtype-limits"
-#endif
-
-#define X_SKIP(...)
-#define X_ACTION(T, N, A, B, ICON, ACCEL, ATEXT, F, ...)\
-	if (N) gtk_action_set_sensitive(get_action(A B), nfiles >= N) __VA_ARGS__
-#define X_TOGGLE(T, N, A, B, ICON, ACCEL, ATEXT, F, GROUP, ACTIVE, ...)\
-	if (N) gtk_action_set_sensitive(get_action(A B), nfiles >= N) __VA_ARGS__
-
-	LIST_MENU(X_SKIP, X_SKIP, X_ACTION, X_TOGGLE, ;);
-
-#undef X_SKIP
-#undef X_ACTION
-#undef X_TOGGLE
-
-#if defined(__GNUC__)
-# pragma GCC diagnostic pop
-#endif
-}
+static int suspend_expose = 0;
 
 static size_t
 format_statusbar_message(char *buffer, size_t size, struct file *file)
@@ -194,11 +32,11 @@ format_statusbar_message(char *buffer, size_t size, struct file *file)
 
 done:
 	r = snprintf(buffer, size,
-	             "Image %zu of %zu | %ju%s %c | %i × %i pixels", /* TODO LATER add zoom */
+	             "Image %zu of %zu | %ju%s %c | %i × %i pixels | %g%% scale",
 	             current_file + 1u, nfiles,
 	             fsize, fsize_decimals, units[unit],
-	             gdk_pixbuf_get_width(file->image),
-	             gdk_pixbuf_get_height(file->image));
+	             gdk_pixbuf_get_width(file->image), gdk_pixbuf_get_height(file->image),
+	             100.0 * get_zoom(zoom));
 
 	if (r < 0)
 		eprintf("snprintf:");
@@ -208,1245 +46,372 @@ done:
 static void
 update_status(void)
 {
-	char *message;
+	struct file *file = get_file();
+	char *message = NULL;
 	size_t len;
-
-	gtk_statusbar_pop(GTK_STATUSBAR(statusbar), 0u);
-
-	if (current_file >= nfiles || !files[current_file].image)
-		return;
-
-	len = format_statusbar_message(NULL, 0u, &files[current_file]);
-	message = malloc(++len);
-	format_statusbar_message(message, len, &files[current_file]);
-
-	gtk_statusbar_push(GTK_STATUSBAR(statusbar), 0u, message);
-
-	free(message);
-}
-
-static void
-show_image(void)
-{
-	GdkPixbuf *new_image, *current_image;
-	int channels, height, rowstride, width, x, y;
-	uint8_t *pixels;
-
-	if (current_file >= nfiles || !files[current_file].image) {
-		if (transformed_image)
-			g_object_unref(transformed_image);
-		gtk_image_clear(GTK_IMAGE(display_area));
-		return;
+	if (file) {
+		len = format_statusbar_message(NULL, 0u, file);
+		message = malloc(++len);
+		format_statusbar_message(message, len, file);
 	}
-
-	current_image = files[current_file].image;
-
-	switch (trans & 7u) {
-	case TRANS_NONE:
-		new_image = NULL;
-		goto transformed;
-	case TRANS_CLOCKWISE:
-		new_image = gdk_pixbuf_rotate_simple(current_image, GDK_PIXBUF_ROTATE_CLOCKWISE);
-		break;
-	case TRANS_180_DEGREES:
-		new_image = gdk_pixbuf_rotate_simple(current_image, GDK_PIXBUF_ROTATE_UPSIDEDOWN);
-		break;
-	case TRANS_ANTICLOCKWISE:
-		new_image = gdk_pixbuf_rotate_simple(current_image, GDK_PIXBUF_ROTATE_COUNTERCLOCKWISE);
-		break;
-	case TRANS_FLIP:
-	case TRANS_TRANSPOSE:
-		new_image = gdk_pixbuf_flip(current_image, 0);
-		break;
-	case TRANS_FLOP:
-	case TRANS_ANTITRANSPOSE:
-		new_image = gdk_pixbuf_flip(current_image, 1);
-		break;
-	}
-	if (!new_image)
-		exit(1);
-
-	switch (trans & 7u) {
-	case TRANS_TRANSPOSE:
-	case TRANS_ANTITRANSPOSE:
-		current_image = new_image;
-		new_image = gdk_pixbuf_rotate_simple(current_image, GDK_PIXBUF_ROTATE_CLOCKWISE);
-		if (!new_image)
-			exit(1);
-		g_object_unref(current_image);
-		break;
-	default:
-		break;
-	}
-
-transformed:
-	if (trans & TRANS_NEGATIVE) {
-		if (!new_image) {
-			new_image = gdk_pixbuf_copy(current_image);
-			if (!new_image)
-				exit(1);
-		}
-
-		pixels    = gdk_pixbuf_get_pixels(new_image);
-		width     = gdk_pixbuf_get_width(new_image);
-		height    = gdk_pixbuf_get_height(new_image);
-		rowstride = gdk_pixbuf_get_rowstride(new_image);
-		channels  = gdk_pixbuf_get_n_channels(new_image);
-
-		for (y = 0; y < height; y++) {
-			for (x = 0; x < width * channels; x += channels) {
-				/* TODO LATER perceptual inversion rather than sRGB */
-				pixels[x + 0] = 255 - pixels[x + 0];
-				pixels[x + 1] = 255 - pixels[x + 1];
-				pixels[x + 2] = 255 - pixels[x + 2];
-			}
-			pixels = &pixels[rowstride];
-		}
-	}
-
-	current_image = new_image ? new_image : files[current_file].image;
-
-	if (FLOAT_EQ(zoom, 1.0)) {
-		gtk_image_set_from_pixbuf(GTK_IMAGE(display_area), current_image);
-	} else {
-		/* TODO do not create an up scaled image, draw it dynamically upscaled (just the exposed region) */
-		current_image = gdk_pixbuf_scale_simple(current_image,
-		                                         (int)(zoom * gdk_pixbuf_get_width(current_image)),
-		                                         (int)(zoom * gdk_pixbuf_get_height(current_image)),
-		                                         GDK_INTERP_BILINEAR);
-		gtk_image_set_from_pixbuf(GTK_IMAGE(display_area), current_image);
-		g_object_unref(current_image);
-	}
-
-	if (transformed_image)
-		g_object_unref(transformed_image);
-	transformed_image = new_image;
-}
-
-static void
-free_files(void)
-{
-	while (nfiles) {
-		--nfiles;
-		free(files[nfiles].path);
-		g_clear_object(&files[nfiles].image);
-	}
-	free(files);
-	files = NULL;
-	current_file = 0u;
-}
-
-static void
-clear_images(void)
-{
-	gtk_image_clear(GTK_IMAGE(display_area));
-	gtk_statusbar_pop(GTK_STATUSBAR(statusbar), 0u);
-	g_clear_object(&transformed_image);
-	free_files();
+	set_statusbar_message(message);
+	free(message);
 }
 
-static int
-load_image(struct file *file, int errors_to_stderr)
+int
+expose_image(GtkWidget *widget, GdkEventExpose *event, void *user)
 {
-	const char *error_message;
-	GError *error = NULL;
-	GtkWidget *dialog;
 	GdkPixbuf *image;
-	GdkPixbufLoader *loader = NULL;
-	struct stat st;
-	unsigned char buffer[8 << 10];
-	ssize_t r;
-	int fd, ret = 1;
+	cairo_t *cr;
+	double height, width, x, y, s;
 
-	fd = open(file->path, O_RDONLY | O_NOCTTY);
-	if (fd < 0)
-		goto fail_errno;
+	(void) user;
 
-	if (fstat(fd, &st))
-		goto fail_errno;
+	if (suspend_expose)
+		return 1;
 
-	if (!S_ISREG(st.st_mode)) {
-		error_message = "Not a regular file";
-		goto fail;
-	}
+	cr = gdk_cairo_create(widget->window);
+	gdk_cairo_set_source_color(cr, &widget->style->bg[GTK_STATE_NORMAL]);
 
-	loader = gdk_pixbuf_loader_new();
-	if (!loader)
-		goto fail_errno;
-	for (;;) {
-		r = read(fd, buffer, sizeof(buffer));
-		if (r <= 0) {
-			if (!r)
-				break;
-			if (errno == EINTR)
-				continue;
-			goto fail_errno;
-		}
-		if (!gdk_pixbuf_loader_write(loader, buffer, (size_t)r, &error))
-			goto fail_gerror;
-	}
-	if (!gdk_pixbuf_loader_close(loader, &error)) {
-	fail_gerror:
-		error_message = error->message;
-		goto fail;
-	}
-	image = gdk_pixbuf_loader_get_pixbuf(loader);
+	cairo_set_fill_rule(cr, CAIRO_FILL_RULE_EVEN_ODD);
+	cairo_rectangle(cr, event->area.x, event->area.y, event->area.width, event->area.height);
+
+	image = get_image();
 	if (!image) {
-		error_message = "Unsupported image format";
-		goto fail;
+		cairo_fill(cr);
+		goto out;
 	}
-	g_object_ref(image);
-
-	g_clear_object(&file->image);
 
-	file->size = st.st_size;
-	file->image = image;
-
-out:
-	g_clear_object(&loader);
-	if (fd >= 0)
-		close(fd);
-	return ret;
+	s = get_zoom(zoom);
+	width = s * gdk_pixbuf_get_width(image);
+	height = s * gdk_pixbuf_get_height(image);
+	if (width < widget->allocation.width)
+		x = 0.5 * ((double)widget->allocation.width - width);
+	else
+		x = -logical_scroll_pane_get_hadjustment(LOGICAL_SCROLL_PANE(scroll))->value;
+	if (height < widget->allocation.height)
+		y = 0.5 * ((double)widget->allocation.height - height);
+	else
+		y = -logical_scroll_pane_get_vadjustment(LOGICAL_SCROLL_PANE(scroll))->value;
 
-fail_errno:
-	error_message = strerror(errno);
+	cairo_fill(cr);
 
-fail:
-	if (errors_to_stderr) {
-		weprintf("Cannot open %s: %s", file->path, error_message);
-	} else {
-		dialog = gtk_message_dialog_new(GTK_WINDOW(window), GTK_DIALOG_MODAL, GTK_MESSAGE_ERROR,
-		                                GTK_BUTTONS_CLOSE, "Cannot open %s", file->path);
-		gtk_message_dialog_format_secondary_text(GTK_MESSAGE_DIALOG(dialog), "%s", error_message);
-		gtk_dialog_run(GTK_DIALOG(dialog));
-		gtk_widget_destroy(dialog);
-	}
+	cairo_translate(cr, x, y);
+	cairo_scale(cr, s, s);
+	gdk_cairo_set_source_pixbuf(cr, image, 0.0, 0.0);
 
-	g_clear_error(&error);
-	ret = 0;
-	goto out;
+out:
+	cairo_paint(cr);
+	cairo_destroy(cr);
+	return 1;
 }
 
 static void
-set_images_from_array(struct file *selected_files, size_t nselected_files)
+show_image(int update_zoom)
 {
-	size_t i, n;
+	GdkPixbuf *new_image, *original_image, *display_image;
+	double s;
 
-	for (i = 0u, n = 0u; i < nselected_files; i++) {
-		selected_files[i].image = NULL;
-		if (load_image(&selected_files[i], 0)) {
-			if (i != n)
-				selected_files[n] = selected_files[i];
-			n += 1u;
-		} else {
-			free(selected_files[i].path);
-		}
-	}
-
-	if (!n) {
-		free(selected_files);
+	original_image = get_original_image();
+	if (!original_image) {
+		logical_scroll_pane_set_content_size(LOGICAL_SCROLL_PANE(scroll), 1, 1);
+		gtk_widget_queue_draw(display_area);
 		return;
 	}
 
-	clear_images();
-	files = selected_files;
-	nfiles = n;
-	show_image();
-	update_status();
-	set_actions_sensitive();
-}
+	new_image = apply_transformations(original_image);
+	display_image = new_image ? new_image : original_image;
 
-static void
-set_images_from_list(GSList *selected_files)
-{
-	struct file *new_files;
-	GSList *file;
-	size_t i;
+	if (update_zoom && zoom_mode != ZOOM_CUSTOM && zoom_mode != ZOOM_NORMAL)
+		zoom = calculate_zoom_mode(display_image, zoom_mode);
 
-	for (file = selected_files, i = 0u; file; file = file->next)
-		i += 1u;
-	if (!i)
-		return;
-	new_files = ecalloc(i, sizeof(*files));
+	s = get_zoom(zoom);
+	logical_scroll_pane_set_content_size(LOGICAL_SCROLL_PANE(scroll),
+	                                     (int)(s * gdk_pixbuf_get_width(display_image)),
+	                                     (int)(s * gdk_pixbuf_get_height(display_image)));
 
-	for (file = selected_files, i = 0u; file; file = file->next) {
-		new_files[i].path = estrdup(file->data);
-		new_files[i].image = NULL;
-		g_free(file->data);
-
-		if (load_image(&new_files[i], 0))
-			i += 1u;
-		else
-			free(new_files[i].path);
-	}
-	g_slist_free(selected_files);
-
-	if (!i) {
-		free(new_files);
-		return;
-	}
-
-	clear_images();
-	files = new_files;
-	nfiles = i;
-	show_image();
-	update_status();
-	set_actions_sensitive();
-}
-
-static int
-file_filter(const GtkFileFilterInfo *info, void *user)
-{
-	struct filter *filter = user;
-	size_t pos, name_len, suffix_len;
-	const char *name, *suffix;
-	size_t backup;
-
-	if (!info->filename)
-		return 0;
-	if (!filter || g_file_test(info->filename, G_FILE_TEST_IS_DIR))
-		return 1;
-
-	name = info->filename;
-	name_len = strlen(name);
-	if (!name_len)
-		return 0;
-
-	for (pos = filter->suffixes_start; pos != filter->suffixes_end; pos += suffix_len + 1u) {
-		suffix = &suffixes[pos];
-		suffix_len = strlen(suffix);
-
-		backup = (size_t)(name[name_len - 1u] == '~');
-
-		if (name_len <= 1u + suffix_len + backup)
-			continue;
-		if (name[name_len - (1u + suffix_len + backup)] != '.')
-			continue;
-		if (memcmp(&name[name_len - (suffix_len + backup)], suffix, suffix_len))
-			continue;
-
-		return 1;
-	}
-
-	return 0;
-}
-
-static int
-filtercmp(const void *a_void, const void *b_void)
-{
-	const struct filter *a = a_void, *b = b_void;
-	return strcmp(a->name, b->name);
-}
-
-static void
-populate_filters(void)
-{
-	GSList *formats, *item;
-	GdkPixbufFormat *format;
-	char **extensions, **extension, *p;
-	const char *name;
-	size_t i, len = 0u;
-	size_t ext_len, need, count;
-
-	formats = gdk_pixbuf_get_formats();
-
-	for (item = formats; item; item = item->next) {
-		format = item->data;
-		if (gdk_pixbuf_format_is_disabled(format))
-			continue;
-
-		name = gdk_pixbuf_format_get_description(format);
-		extensions = gdk_pixbuf_format_get_extensions(format);
-
-		need = 0u;
-		count = 0u;
-		for (extension = extensions; *extension; extension++) {
-			ext_len = strlen(*extension);
-			if (need > SIZE_MAX - 1u - ext_len)
-				eprintf("Out of address space");
-			need += ext_len + 1u;
-			count += 1u;
-		}
-		if (need > SIZE_MAX - len)
-			eprintf("Out of address space");
-		if (!count)
-			goto next;
-
-		filters = ereallocarray(filters, nfilters + 1u, sizeof(*filters));
-		filters[nfilters].suffixes_start = len;
-		filters[nfilters].name = emalloc(strlen(name) + sizeof(" ()") + need + (count - 1u));
-
-		p = stpcpy(stpcpy(filters[nfilters].name, name), " (");
-		suffixes = erealloc(suffixes, need + len);
-		for (extension = extensions;;) {
-			ext_len = strlen(*extension);
-			memcpy(&suffixes[len], *extension, ext_len + 1u);
-			len += ext_len + 1u;
-
-			memcpy(p, *extension, ext_len);
-			p = &p[ext_len];
-
-			if (!*++extension)
-				break;
-			p = stpcpy(p, ", ");
-		}
-		p = stpcpy(p, ")");
-
-		for (i = 0u; i < nfilters; i++) {
-			if (!strcmp(filters[nfilters].name, filters[i].name)) {
-				free(filters[nfilters].name);
-				len = filters[nfilters].suffixes_start;
-				goto next;
-			}
-		}
-
-		filters[nfilters].suffixes_end = len;
-		nfilters += 1u;
-
-	next:
-		g_strfreev(extensions);
-	}
-
-	qsort(filters, nfilters, sizeof(*filters), &filtercmp);
-
-	anyfilter.suffixes_end = len;
-
-	g_slist_free(formats);
-}
-
-static void
-add_image_filters(GtkFileChooser *chooser)
-{
-	GtkFileFilter *filter;
-	size_t i;
-
-	filter = gtk_file_filter_new();
-	gtk_file_filter_set_name(filter, "All images");
-	gtk_file_filter_add_custom(filter, GTK_FILE_FILTER_FILENAME, file_filter, &anyfilter, NULL);
-	gtk_file_chooser_add_filter(chooser, filter);
-
-	for (i = 0u; i < nfilters; i++) {
-		filter = gtk_file_filter_new();
-		gtk_file_filter_set_name(filter, filters[i].name);
-		gtk_file_filter_add_custom(filter, GTK_FILE_FILTER_FILENAME, file_filter, &filters[i], NULL);
-		gtk_file_chooser_add_filter(chooser, filter);
-	}
-
-	filter = gtk_file_filter_new();
-	gtk_file_filter_set_name(filter, "All files");
-	gtk_file_filter_add_custom(filter, GTK_FILE_FILTER_FILENAME, file_filter, NULL, NULL);
-	gtk_file_chooser_add_filter(chooser, filter);
-}
-
-static void
-preview_image(GtkFileChooser *chooser, GtkWidget *preview_widget)
-{
-	char *filename;
-	GdkPixbuf *preview;
-
-	filename = gtk_file_chooser_get_preview_filename(chooser);
-	preview = filename ? gdk_pixbuf_new_from_file_at_scale(filename, 192, 192, 1, NULL) : NULL;
-	gtk_image_set_from_pixbuf(GTK_IMAGE(g_object_get_data(G_OBJECT(preview_widget), "image")), preview);
-	if (preview)
-		g_object_unref(preview);
-	g_free(filename);
+	if (transformed_image)
+		g_object_unref(transformed_image);
+	transformed_image = new_image;
 }
 
 static void
-open_action(GtkAction *action, void *user)
+set_images(struct file *new_files, size_t nnew_files)
 {
-	/* TODO The preview widget should have a fixed size (although it may be subject
-	 *      to manual resize by the user). When there is no preview the preview widge
-	 *      shall just say "Preview" (centered on both dimensions) */
-
-	/* TODO The preview widget shall not have a filename header */
-
-	GtkWidget *chooser_widget, *image, *preview;
-	GtkFileChooser *chooser;
-
-	(void) action;
-	(void) user;
-
-	chooser_widget = gtk_file_chooser_dialog_new("Open",
-	                                             GTK_WINDOW(window),
-	                                             GTK_FILE_CHOOSER_ACTION_OPEN,
-	                                             GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
-	                                             GTK_STOCK_OPEN, GTK_RESPONSE_ACCEPT,
-	                                             NULL);
-	chooser = GTK_FILE_CHOOSER(chooser_widget);
-
-	g_object_set(gtk_settings_get_default(), "gtk-recent-files-enabled", 0, NULL);
-	gtk_file_chooser_set_select_multiple(chooser, 1);
-	gtk_file_chooser_set_current_folder(chooser, home_directory);
-	gtk_file_chooser_set_local_only(chooser, 1);
-	gtk_file_chooser_set_do_overwrite_confirmation(chooser, 0);
-
-	preview = gtk_vbox_new(0, 6);
-	image = gtk_image_new();
-	gtk_box_pack_start(GTK_BOX(preview), image, 0, 0, 0u);
-	gtk_box_pack_start(GTK_BOX(preview), gtk_label_new("Preview"), 0, 0, 0u);
-	g_object_set_data(G_OBJECT(preview), "image", image);
-	gtk_file_chooser_set_preview_widget(chooser, preview);
-	gtk_file_chooser_set_preview_widget_active(chooser, 1);
-	g_signal_connect(chooser, "update-preview", G_CALLBACK(preview_image), preview);
-
-	add_image_filters(chooser);
-	if (gtk_dialog_run(GTK_DIALOG(chooser)) == GTK_RESPONSE_ACCEPT)
-		set_images_from_list(gtk_file_chooser_get_filenames(chooser));
-	gtk_widget_destroy(GTK_WIDGET(chooser));
+	g_clear_object(&transformed_image);
+	free_files();
+	files = new_files;
+	nfiles = nnew_files;
+	navigate_redraw();
+	set_actions_sensitive();
 }
 
-static void
-reload_action(GtkAction *action, void *user)
+void
+add_images(struct file *new_files, size_t nnew_files)
 {
-	(void) action;
-	(void) user;
-	if (current_file >= nfiles)
-		return;
-	if (load_image(&files[current_file], 0)) {
-		show_image();
+	files = ereallocarray(files, nfiles + nnew_files, sizeof(*files));
+	memcpy(&files[nfiles], new_files, nnew_files * sizeof(*files));
+	nfiles += nnew_files;
+	if (nfiles == nnew_files)
+		navigate_redraw();
+	else
 		update_status();
-	}
-}
-
-static void
-close_action(GtkAction *action, void *user)
-{
-	(void) action;
-	(void) user;
-	gtk_main_quit();
-}
-
-static void
-begin_print(GtkPrintOperation *operation, GtkPrintContext *context, void *user)
-{
-	(void) context;
-	(void) user;
-	gtk_print_operation_set_n_pages(operation, 1);
-}
-
-static void
-draw_page(GtkPrintOperation *operation, GtkPrintContext *context, int page, void *user)
-{
-	GdkPixbuf *image = user;
-	double height, width, x, y;
-	double scale_x, scale_y, scale;
-	cairo_t *cr;
-
-	(void) operation;
-	(void) page;
-
-	width = gtk_print_context_get_width(context);
-	height = gtk_print_context_get_height(context);
-	scale_x = width / gdk_pixbuf_get_width(image);
-	scale_y = height / gdk_pixbuf_get_height(image);
-	scale = MIN(scale_x, scale_y);
-	x = 0.5 * (width - scale * gdk_pixbuf_get_width(image));
-	y = 0.5 * (height - scale * gdk_pixbuf_get_height(image));
-
-	cr = gtk_print_context_get_cairo_context(context);
-	cairo_translate(cr, x, y);
-	cairo_scale(cr, scale, scale);
-	gdk_cairo_set_source_pixbuf(cr, image, 0.0f, 0.0f);
-	cairo_paint(cr);
+	set_actions_sensitive();
 }
 
-static void
-print_action(GtkAction *action, void *user)
+void
+set_images_from_array(struct file *selected_files, size_t nselected_files)
 {
-	/* TODO the print dialogue needs a positioning tab that lets the user scale and pan */
-
-	GdkPixbuf *image;
-	GtkPrintOperation *operation;
-	GtkPageSetup *setup;
-	GtkPageOrientation orientation = GTK_PAGE_ORIENTATION_PORTRAIT;
-
-	(void) action;
-	(void) user;
-
-	if (current_file >= nfiles || !files[current_file].image)
-		return;
-
-	image = transformed_image ? transformed_image : files[current_file].image;
-	g_object_ref(image);
-	operation = gtk_print_operation_new();
-
-	if (gdk_pixbuf_get_width(image) > gdk_pixbuf_get_height(image))
-		orientation = GTK_PAGE_ORIENTATION_LANDSCAPE;
-	setup = gtk_page_setup_new();
-	gtk_page_setup_set_orientation(setup, orientation);
-	gtk_print_operation_set_default_page_setup(operation, setup);
-	g_object_unref(setup);
-
-	gtk_print_operation_set_embed_page_setup(operation, 1);
-	g_signal_connect(operation, "begin-print", G_CALLBACK(begin_print), image);
-	g_signal_connect(operation, "draw-page", G_CALLBACK(draw_page), image);
-	gtk_print_operation_run(operation, GTK_PRINT_OPERATION_ACTION_PRINT_DIALOG, GTK_WINDOW(window), NULL);
-	g_object_unref(operation);
-	g_object_unref(image);
+	size_t n = files_from_array(selected_files, nselected_files);
+	if (n)
+		set_images(selected_files, n);
+	else
+		free(selected_files);
 }
 
-static void
-properties_action(GtkAction *action, void *user)
+void
+set_images_from_list(GSList *selected_files)
 {
-	/* TODO LATER What shall "Properties" display? */
-
-	GtkWidget *dialog;
-	struct file *file;
-	const char *name;
-
-	(void) action;
-	(void) user;
-
-	if (current_file >= nfiles || !files[current_file].image)
-		return;
-
-	file = &files[current_file];
-	name = strrchr(file->path, '/');
-	name = name ? &name[1u] : file->path;
-
-	dialog = gtk_message_dialog_new(GTK_WINDOW(window), 0, GTK_MESSAGE_INFO,
-	                                GTK_BUTTONS_CLOSE, "%s", name);
-	gtk_message_dialog_format_secondary_text(GTK_MESSAGE_DIALOG(dialog),
-	                                         "%i × %i pixels",
-	                                         gdk_pixbuf_get_width(file->image),
-	                                         gdk_pixbuf_get_height(file->image));
-	g_signal_connect_swapped(dialog, "response", G_CALLBACK(gtk_widget_destroy), dialog);
-	gtk_widget_show(dialog);
+	struct file *new_files;
+	size_t n = files_from_list(&new_files, selected_files);
+	if (n)
+		set_images(new_files, n);
 }
 
-static void
-scroll_by(int horizontally, double vertically)
+void
+scroll_by(double horizontally, double vertically)
 {
 	GtkAdjustment *adjustment;
 	double min, val, max;
 
-	adjustment = gtk_scrolled_window_get_hadjustment(GTK_SCROLLED_WINDOW(scroll));
+	adjustment = logical_scroll_pane_get_hadjustment(LOGICAL_SCROLL_PANE(scroll));
 	min = adjustment->lower;
-	val = adjustment->value + (double)horizontally;
+	val = adjustment->value + horizontally;
 	max = adjustment->upper - adjustment->page_size;
 	val = MIN(MAX(min, val), max);
 	gtk_adjustment_set_value(adjustment, val);
 
-	adjustment = gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(scroll));
+	adjustment = logical_scroll_pane_get_vadjustment(LOGICAL_SCROLL_PANE(scroll));
 	min = adjustment->lower;
-	val = adjustment->value + (double)vertically;
+	val = adjustment->value + vertically;
 	max = adjustment->upper - adjustment->page_size;
 	val = MIN(MAX(min, val), max);
 	gtk_adjustment_set_value(adjustment, val);
 }
 
-static void
-set_zoom(double new_zoom, double x, double y)
+void
+set_zoom_around_point(Zoom new_zoom, double x, double y)
 {
 	GtkAdjustment *hadjustment, *vadjustment;
-	double old_zoom;
+	double old_s, new_s, old_x0, old_y0, new_x0, new_y0;
+	double iw, ih, vw, vh, hx, hy, adj_x, adj_y, max;
+	int w, h;
+	GdkPixbuf *image;
 
-	if (current_file >= nfiles || !files[current_file].image)
-		return;
-	if (FLOAT_EQ(new_zoom, zoom))
+	if (zoom_eq(new_zoom, zoom))
 		return;
+	image = get_image();
+	if (!image)
+		goto out;
 
-	hadjustment = gtk_scrolled_window_get_hadjustment(GTK_SCROLLED_WINDOW(scroll));
-	vadjustment = gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(scroll));
-	old_zoom = zoom;
+	old_s = get_zoom(zoom);
+	new_s = get_zoom(new_zoom);
 	zoom = new_zoom;
-	show_image();
-	gtk_adjustment_set_value(hadjustment, (hadjustment->value + x) * zoom / old_zoom - x);
-	gtk_adjustment_set_value(vadjustment, (vadjustment->value + y) * zoom / old_zoom - y);
-	update_status();
-}
-
-static void
-clear_toggles(enum toggle_group group, GtkToggleAction *except)
-{
-	GtkToggleAction *action;
 
-	clearing_toggles = 1;
+	w = gdk_pixbuf_get_width(image);
+	h = gdk_pixbuf_get_height(image);
 
-#define X_SKIP(...)
-#define X_TOGGLE(T, N, A, B, ICON, ACCEL, ATEXT, F, GROUP, ACTIVE, ...)\
-	do {\
-		if (GROUP == group) {\
-			action = GTK_TOGGLE_ACTION(get_action(A B));\
-			if (action != except)\
-				gtk_toggle_action_set_active(action, 0);\
-		}\
-	} while (0) __VA_ARGS__
+	hadjustment = logical_scroll_pane_get_hadjustment(LOGICAL_SCROLL_PANE(scroll));
+	vadjustment = logical_scroll_pane_get_vadjustment(LOGICAL_SCROLL_PANE(scroll));
+	vw = hadjustment->page_size;
+	vh = vadjustment->page_size;
 
-	LIST_MENU(X_SKIP, X_SKIP, X_SKIP, X_TOGGLE, ;);
+	iw = old_s * (double)w;
+	ih = old_s * (double)h;
+	old_x0 = vw > iw ? 0.5 * (vw - iw) : 0.0;
+	old_y0 = vh > ih ? 0.5 * (vh - ih) : 0.0;
 
-#undef X_SKIP
-#undef X_TOGGLE
-
-	clearing_toggles = 0;
-}
+	iw = new_s * (double)w;
+	ih = new_s * (double)h;
+	new_x0 = vw > iw ? 0.5 * (vw - iw) : 0.0;
+	new_y0 = vh > ih ? 0.5 * (vh - ih) : 0.0;
 
-static int
-scroll_event(GtkWidget *widget, GdkEventScroll *event, void *user)
-{
-	int shift = !!(event->state & GDK_SHIFT_MASK);
-	int ctrl  = !!(event->state & GDK_CONTROL_MASK);
-	int up    = event->direction == GDK_SCROLL_UP;
-	int down  = event->direction == GDK_SCROLL_DOWN;
-	int left  = event->direction == GDK_SCROLL_LEFT;
-	int right = event->direction == GDK_SCROLL_RIGHT;
+	hx = (x - old_x0 + hadjustment->value) / old_s;
+	hy = (y - old_y0 + vadjustment->value) / old_s;
+	adj_x = new_x0 + hx * new_s - x;
+	adj_y = new_y0 + hy * new_s - y;
 
-	(void) widget;
-	(void) user;
+	suspend_expose++;
 
-	if (shift) {
-		left = up, up = 0;
-		right = down, down = 0;
-	}
+	show_image(0);
 
-	if (!ctrl) {
-		scroll_by(left ? -SCROLL_AMOUNT : right ? +SCROLL_AMOUNT : 0,
-		          up   ? -SCROLL_AMOUNT : down  ? +SCROLL_AMOUNT : 0);
-	} else if (up | down) {
-		clear_toggles(GROUP_ZOOM, NULL);
-		set_zoom(up ? zoom_in(zoom) : zoom_out(zoom), event->x, event->y);
-	} else {
-		return 0;
-	}
+	max = hadjustment->upper - hadjustment->page_size;
+	x = MAX(hadjustment->lower, adj_x);
+	x = MIN(x, max);
+	gtk_adjustment_set_value(hadjustment, x);
 
-	return 1;
-}
+	max = vadjustment->upper - vadjustment->page_size;
+	y = MAX(vadjustment->lower, adj_y);
+	y = MIN(y, max);
+	gtk_adjustment_set_value(vadjustment, y);
 
-static int
-button_pressed(GtkWidget *widget, GdkEventButton *event, void *user)
-{
-	(void) widget;
-	(void) user;
-
-	if (event->button != 2u && !(event->state & GDK_CONTROL_MASK))
-		return 0;
-
-	dragging = 1;
-	drag_x = (int)event->x;
-	drag_y = (int)event->y;
-	return 1;
-}
-
-static int
-button_released(GtkWidget *widget, GdkEventButton *event, void *user)
-{
-	(void) widget;
-	(void) event;
-	(void) user;
-	dragging = 0;
-	return 0;
+	suspend_expose--;
+	if (!suspend_expose)
+		gtk_widget_queue_draw(display_area);
+out:
+	update_status();
 }
 
-static int
-pointer_moved(GtkWidget *widget, GdkEventMotion *event, void *user)
+void
+set_zoom_around_centre(Zoom new_zoom)
 {
-	double x, y;
-
-	(void) widget;
-	(void) user;
-
-	if (!dragging)
-		return 0;
+	GtkAdjustment *hadjustment = logical_scroll_pane_get_hadjustment(LOGICAL_SCROLL_PANE(scroll));
+	GtkAdjustment *vadjustment = logical_scroll_pane_get_vadjustment(LOGICAL_SCROLL_PANE(scroll));
 
-	gdk_event_get_coords((GdkEvent *)event, &x, &y);
-	scroll_by(drag_x - (int)x, drag_y - (int)y);
-	drag_x = (int)x;
-	drag_y = (int)y;
-
-	return 1;
+	set_zoom_around_point(new_zoom, 0.5 * hadjustment->page_size, 0.5 * vadjustment->page_size);
 }
 
 static void
-zoom_in_action(GtkAction *action, void *user)
+centre_image(void)
 {
-	(void) action;
-	(void) user;
-	clear_toggles(GROUP_ZOOM, NULL);
-	set_zoom(zoom_in(zoom), 0.0, 0.0);
-	/* TODO keep center point */
-}
+	GtkAdjustment *hadjustment = logical_scroll_pane_get_hadjustment(LOGICAL_SCROLL_PANE(scroll));
+	GtkAdjustment *vadjustment = logical_scroll_pane_get_vadjustment(LOGICAL_SCROLL_PANE(scroll));
 
-static void
-zoom_out_action(GtkAction *action, void *user)
-{
-	(void) action;
-	(void) user;
-	clear_toggles(GROUP_ZOOM, NULL);
-	set_zoom(zoom_out(zoom), 0.0, 0.0);
-	/* TODO keep center point */
+	gtk_adjustment_set_value(hadjustment, 0.5 * (hadjustment->upper - hadjustment->page_size));
+	gtk_adjustment_set_value(vadjustment, 0.5 * (vadjustment->upper - vadjustment->page_size));
 }
 
-static void
-set_zoom_fit(GtkToggleAction *action, int xfit, int yfit, int cap)
+void
+set_zoom_and_recentre(Zoom new_zoom)
 {
-	GtkAdjustment *adjustment;
-	GdkPixbuf *image;
-	double s = 1.0, y;
-	int w, h;
-
-	if (!gtk_toggle_action_get_active(action) || current_file >= nfiles || !files[current_file].image) {
-		if (!clearing_toggles)
-			clear_toggles(GROUP_ZOOM, action);
+	if (zoom_eq(new_zoom, zoom))
 		return;
-	}
 
-	image = transformed_image ? transformed_image : files[current_file].image;
+	suspend_expose++;
 
-	if (xfit) {
-		adjustment = gtk_scrolled_window_get_hadjustment(GTK_SCROLLED_WINDOW(scroll));
-		w = gdk_pixbuf_get_width(image);
-		s = adjustment->page_size / (double)w;
-	}
-
-	if (yfit) {
-		adjustment = gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(scroll));
-		h = gdk_pixbuf_get_height(image);
-		y = adjustment->page_size / (double)h;
-		s = xfit ? MIN(s, y) : y;
-	}
-
-	if (cap && s > 1.0)
-		s = 1.0;
-
-	clear_toggles(GROUP_ZOOM, action);
-	set_zoom(s, 0.0, 0.0);
-	/* TODO center image */
-}
-
-static void
-normal_size_action(GtkToggleAction *action, void *user)
-{
-	(void) user;
-	set_zoom_fit(action, 0, 0, 0);
-}
-
-static void
-width_fit_action(GtkToggleAction *action, void *user)
-{
-	(void) user;
-	set_zoom_fit(action, 1, 0, 0);
-}
-
-static void
-height_fit_action(GtkToggleAction *action, void *user)
-{
-	(void) user;
-	set_zoom_fit(action, 0, 1, 0);
-}
-
-static void
-window_fit_action(GtkToggleAction *action, void *user)
-{
-	(void) user;
-	set_zoom_fit(action, 1, 1, 0);
-}
+	zoom = new_zoom;
+	show_image(0);
+	centre_image();
 
-static void
-best_fit_action(GtkToggleAction *action, void *user)
-{
-	(void) user;
-	set_zoom_fit(action, 1, 1, 1);
+	suspend_expose--;
+	if (!suspend_expose)
+		gtk_widget_queue_draw(display_area);
+	update_status();
 }
 
-static int
-key_pressed(GtkWidget *widget, GdkEventKey *event, void *user)
+void
+reload_redraw(void)
 {
-	int left, right, up, down, amount;
+	GtkAdjustment *hadjustment, *vadjustment;
+	double x, y, max;
 
-	(void) widget;
-	(void) user;
+	hadjustment = logical_scroll_pane_get_hadjustment(LOGICAL_SCROLL_PANE(scroll));
+	vadjustment = logical_scroll_pane_get_vadjustment(LOGICAL_SCROLL_PANE(scroll));
 
-	if (event->keyval == GDK_Escape && gtk_toggle_action_get_active(fullscreen)) {
-		gtk_toggle_action_set_active(fullscreen, 0);
-		return 1;
-	}
+	x = hadjustment->value + 0.5 * hadjustment->page_size;
+	x = hadjustment->upper > hadjustment->page_size ? x / hadjustment->upper : 0.5;
+	y = vadjustment->value + 0.5 * vadjustment->page_size;
+	y = vadjustment->upper > vadjustment->page_size ? y / vadjustment->upper : 0.5;
 
-	if (event->state & GDK_CONTROL_MASK)
-		return 0;
+	suspend_expose++;
 
-	amount = (event->state & GDK_MOD1_MASK) ? 1 : SCROLL_AMOUNT;
+	show_image(0);
 
-	left  = event->keyval == GDK_Left;
-	right = event->keyval == GDK_Right;
-	up    = event->keyval == GDK_Up;
-	down  = event->keyval == GDK_Down;
+	max = hadjustment->upper - hadjustment->page_size;
+	x = x * hadjustment->upper - 0.5 * hadjustment->page_size;
+	x = MIN(MAX(hadjustment->lower, x), max);
+	gtk_adjustment_set_value(hadjustment, x);
 
-	if (left | right | up | down) {
-		scroll_by(left ? -amount : right ? +amount : 0,
-		          up   ? -amount : down  ? +amount : 0);
-		return 1;
-	}
+	max = vadjustment->upper - vadjustment->page_size;
+	y = y * vadjustment->upper - 0.5 * vadjustment->page_size;
+	y = MIN(MAX(vadjustment->lower, y), max);
+	gtk_adjustment_set_value(vadjustment, y);
 
-	return 0;
-}
-
-static int
-window_state_changed(GtkWidget *widget, GdkEventWindowState *event, void *user)
-{
-	(void) widget;
-	(void) user;
-	gtk_toggle_action_set_active(fullscreen, !!(event->new_window_state & GDK_WINDOW_STATE_FULLSCREEN));
-	return 0;
+	suspend_expose--;
+	if (!suspend_expose)
+		gtk_widget_queue_draw(display_area);
+	update_status();
 }
 
-static void
-fullscreen_action(GtkToggleAction *action, void *user)
+void
+transform_redraw(enum transformation augment)
 {
-	int active = gtk_toggle_action_get_active(action);
-
-	(void) user;
+	GdkPixbuf *image;
+	GtkAdjustment *hadjustment, *vadjustment;
+	double s, x, y, width, height, max;
 
-	if (active && current_file >= nfiles) {
-		gtk_toggle_action_set_active(action, 0);
+	hadjustment = logical_scroll_pane_get_hadjustment(LOGICAL_SCROLL_PANE(scroll));
+	vadjustment = logical_scroll_pane_get_vadjustment(LOGICAL_SCROLL_PANE(scroll));
+	image = get_image();
+	if (!image)
 		return;
-	}
 
-	gtk_widget_set_visible(menubar, !active);
-	gtk_widget_set_visible(toolbar, !active);
-	gtk_widget_set_visible(statusbar, !active);
-	gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(scroll),
-	                               active ? GTK_POLICY_NEVER : GTK_POLICY_ALWAYS,
-	                               active ? GTK_POLICY_NEVER : GTK_POLICY_ALWAYS);
+	s = get_zoom(zoom);
+	width = gdk_pixbuf_get_width(image);
+	height = gdk_pixbuf_get_height(image);
 
-	if (active)
-		gtk_window_fullscreen(GTK_WINDOW(window));
-	else
-		gtk_window_unfullscreen(GTK_WINDOW(window));
-}
+	x = hadjustment->value + 0.5 * hadjustment->page_size;
+	x = s * width > hadjustment->page_size ? x / s : 0.5 * width;
+	y = vadjustment->value + 0.5 * vadjustment->page_size;
+	y = s * height > vadjustment->page_size ? y / s : 0.5 * height;
+	transform_point(augment, &x, &y, &width, &height);
 
-static void
-reset_transformations_action(GtkAction *action, void *user)
-{
-	(void) action;
-	(void) user;
-	trans &= ~7u;
-	show_image();
-	/* TODO keep center point */
-}
+	suspend_expose++;
 
-static void
-transform(enum transformation augment)
-{
-	if (augment & TRANS_TRANSPOSE)
-		trans = ((augment - trans) & 3u) | ((augment ^ trans) & ~3u);
-	else
-		trans = ((augment + trans) & 3u) | ((augment ^ trans) & ~3u);
-	show_image();
-	/* TODO keep center point */
-}
+	show_image(0);
 
-static void
-rotate_clockwise_action(GtkAction *action, void *user)
-{
-	(void) action;
-	(void) user;
-	transform(TRANS_CLOCKWISE);
-}
+	max = hadjustment->upper - hadjustment->page_size;
+	x = s * x - 0.5 * hadjustment->page_size;
+	x = MIN(MAX(hadjustment->lower, x), max);
+	gtk_adjustment_set_value(hadjustment, x);
 
-static void
-rotate_180_degrees_action(GtkAction *action, void *user)
-{
-	(void) action;
-	(void) user;
-	transform(TRANS_180_DEGREES);
-}
+	max = vadjustment->upper - vadjustment->page_size;
+	y = s * y - 0.5 * vadjustment->page_size;
+	y = MIN(MAX(vadjustment->lower, y), max);
+	gtk_adjustment_set_value(vadjustment, y);
 
-static void
-rotate_anticlockwise_action(GtkAction *action, void *user)
-{
-	(void) action;
-	(void) user;
-	transform(TRANS_ANTICLOCKWISE);
+	suspend_expose--;
+	if (!suspend_expose)
+		gtk_widget_queue_draw(display_area);
 }
 
-static void
-flop_action(GtkAction *action, void *user)
+void
+navigate_redraw(void)
 {
-	(void) action;
-	(void) user;
-	transform(TRANS_FLOP);
-}
+	suspend_expose++;
 
-static void
-flip_action(GtkAction *action, void *user)
-{
-	(void) action;
-	(void) user;
-	transform(TRANS_FLIP);
-}
-
-static void
-transpose_action(GtkAction *action, void *user)
-{
-	(void) action;
-	(void) user;
-	transform(TRANS_TRANSPOSE);
-}
-
-static void
-antitranspose_action(GtkAction *action, void *user)
-{
-	(void) action;
-	(void) user;
-	transform(TRANS_ANTITRANSPOSE);
-}
-
-static void
-invert_action(GtkToggleAction *action, void *user)
-{
+	show_image(1);
+	centre_image();
 
-	enum transformation tr;
-	(void) user;
-	tr = gtk_toggle_action_get_active(action) ? TRANS_NEGATIVE : TRANS_NONE;
-	transform(tr ^ (trans & TRANS_NEGATIVE));
-}
-
-static void
-navigate(size_t jump, size_t move)
-{
-	if (!nfiles)
-		return;
-	current_file = jump;
-	current_file += move;
-	current_file %= nfiles;
-	show_image();
+	suspend_expose--;
+	if (!suspend_expose)
+		gtk_widget_queue_draw(display_area);
 	update_status();
 }
 
-static void
-next_action(GtkAction *action, void *user)
-{
-	(void) action;
-	(void) user;
-	navigate(current_file, +(size_t)1);
-}
-
-static void
-previous_action(GtkAction *action, void *user)
-{
-	(void) action;
-	(void) user;
-	navigate(current_file ? current_file : nfiles, -(size_t)1);
-}
-
-static void
-first_action(GtkAction *action, void *user)
-{
-	(void) action;
-	(void) user;
-	navigate(0u, 0u);
-}
-
-static void
-last_action(GtkAction *action, void *user)
-{
-	(void) action;
-	(void) user;
-	navigate(nfiles, -(size_t)1);
-}
-
-static void
-drag_data_get(GtkWidget *widget, GdkDragContext *context, GtkSelectionData *data,
-              unsigned int info, unsigned int time, void *user)
-{
-	GError *error = NULL;
-	char *uri;
-
-	(void) widget;
-	(void) context;
-	(void) info;
-	(void) time;
-	(void) user;
-
-	if (current_file >= nfiles || !files[current_file].path)
-		return;
-
-	uri = g_filename_to_uri(files[current_file].path, NULL, &error);
-	if (!uri) {
-		weprintf("g_filename_to_uri: %s", error->message);
-		g_error_free(error);
-		return;
-	}
-	gtk_selection_data_set_uris(data, (char *[]){uri, NULL});
-	g_free(uri);
-}
-
-static void
-drop_files(GtkWidget *widget, GdkDragContext *context, int x, int y,
-           GtkSelectionData *data, unsigned int info, unsigned int time, void *user)
+int
+recalculate_zoom_mode(void *user)
 {
-	GError *error = NULL;
-	char **uris, **uri, *path;
-	struct file *dropped_files;
-	size_t i, j;
-	GdkModifierType modifiers;
-	GdkWindow *event_window;
-
-	(void) widget;
-	(void) x;
-	(void) y;
-	(void) info;
+	GdkPixbuf *image = get_image();
 	(void) user;
-
-	uris = gtk_selection_data_get_uris(data);
-	if (!uris) {
-		gtk_drag_finish(context, 0, 0, time);
-		return;
-	}
-
-	for (uri = uris, i = 0u; *uri; uri++)
-		i += 1u;
-	if (!i)
-		goto out;
-	dropped_files = ecalloc(i, sizeof(*dropped_files));
-
-	for (uri = uris, i = 0u; *uri; uri++) {
-		error = NULL; /* g_filename_from_uri requires this initialisation */
-		path = g_filename_from_uri(*uri, NULL, &error);
-		if (!path) {
-			weprintf("g_filename_from_uri: %s", error->message);
-			g_error_free(error);
-			continue;
-		}
-		dropped_files[i++].path = estrdup(path);
-		g_free(path);
-		/* the other fields are set by set_images_from_array */
-	}
-
-	event_window = gtk_widget_get_window(widget);
-	if (!event_window)
-		goto out;
-	if (!gdk_window_get_pointer(event_window, NULL, NULL, &modifiers))
-		goto out;
-	if ((modifiers & GDK_CONTROL_MASK) && nfiles) {
-		files = ereallocarray(files, nfiles + i, sizeof(*files));
-		for (j = 0u; j < i; j++) {
-			if (load_image(&dropped_files[j], 0))
-				files[nfiles++] = dropped_files[j];
-			else
-				free(dropped_files[j].path);
-		}
-		free(dropped_files);
-		update_status();
-	} else {
-		set_images_from_array(dropped_files, i);
-	}
-
-out:
-	gtk_drag_finish(context, 1, 0, time);
-	g_strfreev(uris);
-}
-
-static GtkWidget *
-append_toplevel_menu(int add_separator_to_toolbar, const char *name)
-{
-	GtkWidget *item, *menu;
-
-	if (add_separator_to_toolbar)
-		gtk_toolbar_insert(GTK_TOOLBAR(toolbar), gtk_separator_tool_item_new(), -1);
-
-	item = gtk_action_create_menu_item(get_action(name));
-	menu = gtk_menu_new();
-	gtk_menu_item_set_submenu(GTK_MENU_ITEM(item), menu);
-	gtk_menu_shell_append(GTK_MENU_SHELL(menubar), item);
-	return gtk_menu_item_get_submenu(GTK_MENU_ITEM(item));
-}
-
-static void
-append_separator(int add_to_toolbar, GtkWidget *menu)
-{
-	if (add_to_toolbar)
-		gtk_toolbar_insert(GTK_TOOLBAR(toolbar), gtk_separator_tool_item_new(), -1);
-	if (menu)
-		gtk_menu_shell_append(GTK_MENU_SHELL(menu), gtk_separator_menu_item_new());
-}
-
-static void
-append_action(int add_to_toolbar, GtkWidget *menu, const char *name, const char *tooltip)
-{
-	GtkWidget *item;
-	if (add_to_toolbar) {
-		item = gtk_action_create_tool_item(get_action(name));
-		gtk_toolbar_insert(GTK_TOOLBAR(toolbar), GTK_TOOL_ITEM(item), -1);
-		if (tooltip)
-			gtk_tool_item_set_tooltip_text(GTK_TOOL_ITEM(item), tooltip);
-	}
-	if (menu) {
-		item = gtk_action_create_menu_item(get_action(name));
-		gtk_menu_shell_append(GTK_MENU_SHELL(menu), item);
-	}
-}
-
-static void
-create_menu_and_toolbar(void)
-{
-	GtkWidget *menu;
-
-	menubar = gtk_menu_bar_new();
-	toolbar = gtk_toolbar_new();
-
-#define X_TOPLEVEL(T, A, B, D)                                         menu = append_toplevel_menu(T, A B) D
-#define X_SEPARTOR(T, D)                                               append_separator(T, menu) D
-#define X_ACTION(T, N, A, B, ICON, ACCEL, ACCEL_TEXT, F, D)            append_action(T, menu, A B, A B " (" ACCEL_TEXT ")") D
-#define X_TOGGLE(T, N, A, B, ICON, ACCEL, ACCEL_TEXT, F, G, ACTIVE, D) append_action(T, menu, A B, A B " (" ACCEL_TEXT ")") D
-
-	LIST_MENU(X_TOPLEVEL, X_SEPARTOR, X_ACTION, X_TOGGLE, ;);
-
-#undef X_TOPLEVEL
-#undef X_SEPARTOR
-#undef X_ACTION
-#undef X_TOGGLE
-}
-
-static void
-connect_accelerators(GtkAccelGroup *accelerators)
-{
-	GList *item, *list;
-
-	list = gtk_action_group_list_actions(actions);
-	for (item = list; item; item = item->next) {
-		gtk_action_set_accel_group(item->data, accelerators);
-		gtk_action_connect_accelerator(item->data);
-	}
-	g_list_free(list);
+	if (image && zoom_mode != ZOOM_CUSTOM && zoom_mode != ZOOM_NORMAL)
+		set_zoom_and_recentre(calculate_zoom_mode(image, zoom_mode));
+	return 0;
 }
 
 static int
-activate_fullscreen(void *user)
+initial_draw(void *user)
 {
 	(void) user;
-	gtk_toggle_action_set_active(fullscreen, 1);
+	navigate_redraw();
 	return 0;
 }
 
-#define X_SKIP(...)
-#define X_TOPLEVEL(T, A, B, ...)                                    {A B, NULL, A "_" B, NULL, NULL, NULL} __VA_ARGS__
-#define X_ACTION(T, N, A, B, ICON, ACCEL, ATEXT, F, ...)            {A B, ICON, A "_" B, ACCEL, NULL, G_CALLBACK(F)} __VA_ARGS__
-#define X_TOGGLE(T, N, A, B, ICON, ACCEL, ATEXT, F, G, ACTIVE, ...) {A B, ICON, A "_" B, ACCEL, NULL, G_CALLBACK(F), ACTIVE} __VA_ARGS__
-
-static GtkActionEntry entries[] = {
-	LIST_MENU(X_TOPLEVEL, X_SKIP, X_ACTION, X_SKIP, COMMA)
-};
-
-static GtkToggleActionEntry toggle_entries[] = {
-	LIST_MENU(X_SKIP, X_SKIP, X_SKIP, X_TOGGLE, COMMA)
-};
-
-#undef X_SKIP
-#undef X_TOPLEVEL
-#undef X_ACTION
-#undef X_TOGGLE
-
 int
 main(int argc, char *argv[])
 {
-	struct passwd *pwd;
-	GtkAccelGroup *accelerators;
-	GtkWidget *box;
-	size_t i;
-	int failed = 0;
 	int start_fullscreen = 0;
+	int failed = 0;
 
 	ARGBEGIN {
 	case 'f':
@@ -1456,97 +421,32 @@ main(int argc, char *argv[])
 		usage();
 	} ARGEND;
 
-	nfiles = (size_t)argc;
-	if (nfiles) {
-		files = ecalloc(nfiles, sizeof(*files));
-		for (i = 0u; i < nfiles; i++) {
-			files[i].path = estrdup(argv[i]);
-			files[i].image = NULL;
-			if (!load_image(&files[i], 1)) {
-				free(files[i].path);
-				failed = 1;
-			}
-		}
-	}
-	if (failed)
+	if (!set_files_from_argv(argc, argv))
 		goto fail;
 
-	home_directory = getenv("HOME");
-	if (!home_directory || !*home_directory) {
-		pwd = getpwuid(getuid());
-		if (pwd && pwd->pw_dir && *pwd->pw_dir)
-			home_directory = pwd->pw_dir;
-		else
-			home_directory = ".";
-	}
-
 	gtk_init(NULL, NULL);
 
-	populate_filters();
-
-	window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
-	gtk_window_set_title(GTK_WINDOW(window), "gbild");
-	gtk_window_set_icon_name(GTK_WINDOW(window), "image-viewer");
-	gtk_window_set_default_size(GTK_WINDOW(window), 900, 700);
-	gtk_window_set_wmclass(GTK_WINDOW(window), "gbild", "gbild");
-
-	g_signal_connect(window, "destroy", G_CALLBACK(gtk_main_quit), NULL);
-	g_signal_connect(window, "key-press-event", G_CALLBACK(key_pressed), NULL);
-	g_signal_connect(window, "window-state-event", G_CALLBACK(window_state_changed), NULL);
-
-	actions = gtk_action_group_new("gbild");
-	gtk_action_group_add_actions(actions, entries, ELEMSOF(entries), NULL);
-	gtk_action_group_add_toggle_actions(actions, toggle_entries, ELEMSOF(toggle_entries), NULL);
-	fullscreen = GTK_TOGGLE_ACTION(gtk_action_group_get_action(actions, "Fullscreen"));
-	accelerators = gtk_accel_group_new();
-	gtk_window_add_accel_group(GTK_WINDOW(window), accelerators);
-	connect_accelerators(accelerators);
-	create_menu_and_toolbar();
-
-	box = gtk_vbox_new(0, 0);
-	gtk_container_add(GTK_CONTAINER(window), box);
-	gtk_box_pack_start(GTK_BOX(box), menubar, 0, 0, 0u);
-	gtk_box_pack_start(GTK_BOX(box), toolbar, 0, 0, 0u);
-	display_area = gtk_image_new();
-	scroll = gtk_scrolled_window_new(NULL, NULL);
-	gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(scroll), GTK_POLICY_ALWAYS, GTK_POLICY_ALWAYS);
-	gtk_scrolled_window_add_with_viewport(GTK_SCROLLED_WINDOW(scroll), display_area);
-	gtk_widget_add_events(scroll, GDK_SCROLL_MASK);
-	g_signal_connect(scroll, "scroll-event", G_CALLBACK(scroll_event), NULL);
-	gtk_box_pack_start(GTK_BOX(box), scroll, 1, 1, 0u);
-	statusbar = gtk_statusbar_new();
-	gtk_box_pack_end(GTK_BOX(box), statusbar, 0, 0, 0u);
-
-	gtk_widget_add_events(display_area, GDK_BUTTON_PRESS_MASK |
-	                                    GDK_BUTTON_RELEASE_MASK |
-	                                    GDK_POINTER_MOTION_MASK);
-	g_signal_connect(display_area, "button-press-event", G_CALLBACK(button_pressed), NULL);
-	g_signal_connect(display_area, "button-release-event", G_CALLBACK(button_released), NULL);
-	g_signal_connect(display_area, "motion-notify-event", G_CALLBACK(pointer_moved), NULL);
-
-	gtk_drag_source_set(display_area, GDK_BUTTON1_MASK, &image_target, 1u, GDK_ACTION_COPY);
-	g_signal_connect(display_area, "drag-data-get", G_CALLBACK(drag_data_get), NULL);
+	set_up_ui();
+	set_up_dragging();
+	set_up_dropping();
 
-	gtk_drag_dest_set(window, GTK_DEST_DEFAULT_ALL, &image_target, 1u, GDK_ACTION_COPY);
-	g_signal_connect(window, "drag-data-received", G_CALLBACK(drop_files), NULL);
-
-	show_image();
-	update_status();
 	set_actions_sensitive();
 	gtk_widget_show_all(window);
+	g_idle_add(&initial_draw, NULL);
 	if (start_fullscreen && nfiles)
-		g_idle_add(activate_fullscreen, NULL);
+		g_idle_add(&activate_fullscreen, NULL);
 
 	gtk_main();
 
-	g_object_unref(actions);
 	if (transformed_image)
 		g_object_unref(transformed_image);
-fail:
+	free_ui();
+out:
 	free_files();
-	free(suffixes);
-	while (nfilters)
-		free(filters[--nfilters].name);
-	free(filters);
+	free_image_filters();
 	return failed;
+
+fail:
+	failed = 1;
+	goto out;
 }