Allow manual animation frame iteration

fastiv-io.c

@@ -994,8 +994,14 @@ open_gdkpixbuf(const gchar *data, gsize len, GError **error)
 	cairo_surface_t *surface =
 		gdk_cairo_surface_create_from_pixbuf(pixbuf, 1, NULL);
 
-	// TODO(p): Also pass the pre-decoded Exif "orientation" option,
-	// which is an ASCII digit from 1 to 8.
+	const char *orientation = gdk_pixbuf_get_option(pixbuf, "orientation");
+	if (orientation && strlen(orientation) == 1) {
+		int n = *orientation - '0';
+		if (n >= 1 && n <= 8)
+			cairo_surface_set_user_data(surface, &fastiv_io_key_orientation,
+				(void *) (uintptr_t) n, NULL);
+	}
+
 	const char *icc_profile = gdk_pixbuf_get_option(pixbuf, "icc-profile");
 	if (icc_profile) {
 		gsize out_len = 0;
@@ -1014,6 +1020,7 @@ open_gdkpixbuf(const gchar *data, gsize len, GError **error)
 #endif  // HAVE_GDKPIXBUF ------------------------------------------------------
 
 cairo_user_data_key_t fastiv_io_key_exif;
+cairo_user_data_key_t fastiv_io_key_orientation;
 cairo_user_data_key_t fastiv_io_key_icc;
 
 cairo_user_data_key_t fastiv_io_key_frame_next;
@@ -1120,6 +1127,19 @@ fastiv_io_open_from_data(const char *data, size_t len, const gchar *path,
 
 		set_error(error, "unsupported file type");
 	}
+
+	// gdk-pixbuf only gives out this single field--cater to its limitations,
+	// since we'd really like to have it.
+	GBytes *exif = NULL;
+	gsize exif_len = 0;
+	gconstpointer exif_data = NULL;
+	if (surface &&
+		(exif = cairo_surface_get_user_data(surface, &fastiv_io_key_exif)) &&
+		(exif_data = g_bytes_get_data(exif, &exif_len))) {
+		cairo_surface_set_user_data(surface, &fastiv_io_key_orientation,
+			(void *) (uintptr_t) fastiv_io_exif_orientation(
+				exif_data, exif_len), NULL);
+	}
 	return surface;
 }
 
@@ -1160,11 +1180,11 @@ fastiv_io_exif_orientation(const guint8 *tiff, gsize len)
 		SBYTE, UNDEFINED, SSHORT, SLONG, SRATIONAL, FLOAT, DOUBLE };
 	enum { Orientation = 274 };
 	for (const guint8 *p = ifd0 + 2; fields-- && p + 12 <= end; p += 12) {
-		uint16_t tag = u16(p), type = u16(p + 2);
-		uint32_t count = u32(p + 4), value = u32(p + 8);
+		uint16_t tag = u16(p), type = u16(p + 2), value16 = u16(p + 8);
+		uint32_t count = u32(p + 4);
 		if (tag == Orientation && type == SHORT && count == 1 &&
-			value >= 1 && value <= 8)
-			return value;
+			value16 >= 1 && value16 <= 8)
+			return value16;
 	}
 	return FastivIoOrientationUnknown;
 }

fastiv-io.h

@@ -29,6 +29,8 @@ char **fastiv_io_all_supported_media_types(void);
 
 /// GBytes with plain Exif data.
 extern cairo_user_data_key_t fastiv_io_key_exif;
+/// FastivIoOrientation, as a uintptr_t.
+extern cairo_user_data_key_t fastiv_io_key_orientation;
 /// GBytes with plain ICC profile data.
 extern cairo_user_data_key_t fastiv_io_key_icc;
 

fastiv-view.c

@@ -31,7 +31,8 @@
 
 struct _FastivView {
 	GtkWidget parent_instance;
-	cairo_surface_t *surface;
+	cairo_surface_t *surface;           ///< The loaded image (sequence)
+	cairo_surface_t *frame;             ///< Current frame within, unreferenced
 	bool scale_to_fit;
 	double scale;
 };
@@ -237,12 +238,12 @@ fastiv_view_draw(GtkWidget *widget, cairo_t *cr)
 
 	// FIXME: Recording surfaces do not work well with CAIRO_SURFACE_TYPE_XLIB,
 	// we always get a shitty pixmap, where transparency contains junk.
-	if (cairo_surface_get_type(self->surface) == CAIRO_SURFACE_TYPE_RECORDING) {
+	if (cairo_surface_get_type(self->frame) == CAIRO_SURFACE_TYPE_RECORDING) {
 		cairo_surface_t *image =
 			cairo_image_surface_create(CAIRO_FORMAT_ARGB32, w, h);
 		cairo_t *tcr = cairo_create(image);
 		cairo_scale(tcr, self->scale, self->scale);
-		cairo_set_source_surface(tcr, self->surface, 0, 0);
+		cairo_set_source_surface(tcr, self->frame, 0, 0);
 		cairo_paint(tcr);
 		cairo_destroy(tcr);
 
@@ -259,7 +260,7 @@ fastiv_view_draw(GtkWidget *widget, cairo_t *cr)
 
 	cairo_scale(cr, self->scale, self->scale);
 	cairo_set_source_surface(
-		cr, self->surface, x / self->scale, y / self->scale);
+		cr, self->frame, x / self->scale, y / self->scale);
 
 	cairo_pattern_t *pattern = cairo_get_source(cr);
 	cairo_pattern_set_extend(pattern, CAIRO_EXTEND_PAD);
@@ -339,6 +340,8 @@ fastiv_view_key_press_event(GtkWidget *widget, GdkEventKey *event)
 	FastivView *self = FASTIV_VIEW(widget);
 	if (event->state & ~GDK_SHIFT_MASK & gtk_accelerator_get_default_mod_mask())
 		return FALSE;
+	if (!self->surface)
+		return FALSE;
 
 	switch (event->keyval) {
 	case GDK_KEY_1:
@@ -349,6 +352,13 @@ fastiv_view_key_press_event(GtkWidget *widget, GdkEventKey *event)
 		return set_scale(self, self->scale / SCALE_STEP);
 	case GDK_KEY_F:
 		return set_scale_to_fit(self, !self->scale_to_fit);
+	case GDK_KEY_greater: {
+		if (!(self->frame = cairo_surface_get_user_data(
+				  self->frame, &fastiv_io_key_frame_next)))
+			self->frame = self->surface;
+		gtk_widget_queue_draw(widget);
+		return TRUE;
+	}
 	}
 	return FALSE;
 }
@@ -404,7 +414,7 @@ fastiv_view_open(FastivView *self, const gchar *path, GError **error)
 	if (self->surface)
 		cairo_surface_destroy(self->surface);
 
-	self->surface = surface;
+	self->frame = self->surface = surface;
 	set_scale_to_fit(self, true);
 	return TRUE;
 }