tests: add a test for GtkOverlay position style classes

https://bugzilla.gnome.org/show_bug.cgi?id=669342

tests/Makefile.am

@@ -76,6 +76,7 @@ noinst_PROGRAMS =  $(TEST_PROGS)	\
 	testoffscreenwindow		\
 	testorientable			\
 	testoverlay			\
+	testoverlaystyleclass		\
 	testprint			\
 	testrecentchooser 		\
 	testrecentchoosermenu		\
@@ -195,6 +196,7 @@ testappchooser_DEPENDENCIES = $(TEST_DEPS)
 testappchooserbutton_DEPENDENCIES = $(TEST_DEPS)
 testorientable_DEPENDENCIES = $(TEST_DEPS)
 testoverlay_DEPENDENCIES = $(TEST_DEPS)
+testoverlaystyleclass_DEPENDENCIES = $(TEST_DEPS)
 testprint_DEPENDENCIES = $(TEST_DEPS)
 testrecentchooser_DEPENDENCIES = $(TEST_DEPS)
 testrecentchoosermenu_DEPENDENCIES = $(TEST_DEPS)
@@ -294,6 +296,7 @@ testappchooser_LDADD = $(LDADDS)
 testappchooserbutton_LDADD = $(LDADDS)
 testorientable_LDADD = $(LDADDS)
 testoverlay_LDADD = $(LDADDS)
+testoverlaystyleclass_LDADD = $(LDADDS)
 testprint_LDADD = $(LDADDS)
 testrecentchooser_LDADD = $(LDADDS)
 testrecentchoosermenu_LDADD = $(LDADDS)
@@ -493,6 +496,9 @@ testoffscreenwindow_SOURCES =	\
 testoverlay_SOURCES =	\
 	testoverlay.c
 
+testoverlaystyleclass_SOURCES =	\
+	testoverlaystyleclass.c
+
 testappchooser_SOURCES = \
 	testappchooser.c
 

tests/testoverlaystyleclass.c

@@ -0,0 +1,154 @@
+#include <gtk/gtk.h>
+
+static void
+child_size_allocate (GtkWidget *child,
+                     GdkRectangle *allocation,
+                     gpointer user_data)
+{
+  GtkStyleContext *context;
+  context = gtk_widget_get_style_context (child);
+
+  g_print ("Child %p\nHas left? %d\nHas right? %d\nHas top? %d\nHas bottom? %d\n",
+           child,
+           gtk_style_context_has_class (context, "left"),
+           gtk_style_context_has_class (context, "right"),
+           gtk_style_context_has_class (context, "top"),
+           gtk_style_context_has_class (context, "bottom"));
+}
+
+static gboolean
+overlay_get_child_position (GtkOverlay *overlay,
+                            GtkWidget *child,
+                            GdkRectangle *allocation,
+                            gpointer user_data)
+{
+  GtkWidget *custom_child = user_data;
+  GtkRequisition req;
+
+  if (child != custom_child)
+    return FALSE;
+
+  gtk_widget_get_preferred_size (child, NULL, &req);
+
+  allocation->x = 120;
+  allocation->y = 0;
+  allocation->width = req.width;
+  allocation->height = req.height;
+
+  return TRUE;
+}
+
+int 
+main (int argc, char *argv[])
+{
+  GtkWidget *win, *overlay, *grid, *main_child, *child, *label, *sw;
+  GdkRGBA color;
+  gchar *str;
+
+  gtk_init (&argc, &argv);
+
+  win = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+  gtk_window_set_default_size (GTK_WINDOW (win), 600, 600);
+
+  grid = gtk_grid_new ();
+  child = gtk_event_box_new ();
+  gdk_rgba_parse (&color, "red");
+  gtk_widget_override_background_color (child, 0, &color);
+  gtk_widget_set_hexpand (child, TRUE);
+  gtk_widget_set_vexpand (child, TRUE);
+  gtk_container_add (GTK_CONTAINER (grid), child);
+  label = gtk_label_new ("Out of overlay");
+  gtk_container_add (GTK_CONTAINER (child), label);
+
+  overlay = gtk_overlay_new ();
+  sw = gtk_scrolled_window_new (NULL, NULL);
+  gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw),
+                                  GTK_POLICY_ALWAYS,
+                                  GTK_POLICY_ALWAYS);
+  gtk_container_add (GTK_CONTAINER (overlay), sw);
+
+  main_child = gtk_event_box_new ();
+  gtk_scrolled_window_add_with_viewport (GTK_SCROLLED_WINDOW (sw),
+                                         main_child);
+  gdk_rgba_parse (&color, "green");
+  gtk_widget_override_background_color (main_child, 0, &color);
+  gtk_widget_set_hexpand (main_child, TRUE);
+  gtk_widget_set_vexpand (main_child, TRUE);
+  label = gtk_label_new ("Main child");
+  gtk_container_add (GTK_CONTAINER (main_child), label);
+
+  child = gtk_label_new (NULL);
+  str = g_strdup_printf ("%p", child);
+  gtk_label_set_text (GTK_LABEL (child), str);
+  g_free (str);
+  g_print ("Bottom/Right child: %p\n", child);
+  gtk_widget_set_halign (child, GTK_ALIGN_END);
+  gtk_widget_set_valign (child, GTK_ALIGN_END);
+  gtk_overlay_add_overlay (GTK_OVERLAY (overlay), child);
+
+  g_signal_connect (child, "size-allocate",
+                    G_CALLBACK (child_size_allocate), overlay);
+
+  child = gtk_label_new (NULL);
+  str = g_strdup_printf ("%p", child);
+  gtk_label_set_text (GTK_LABEL (child), str);
+  g_free (str);
+  g_print ("Left/Top child: %p\n", child);
+  gtk_widget_set_halign (child, GTK_ALIGN_START);
+  gtk_widget_set_valign (child, GTK_ALIGN_START);
+  gtk_overlay_add_overlay (GTK_OVERLAY (overlay), child);
+
+  g_signal_connect (child, "size-allocate",
+                    G_CALLBACK (child_size_allocate), overlay);
+
+  child = gtk_label_new (NULL);
+  str = g_strdup_printf ("%p", child);
+  gtk_label_set_text (GTK_LABEL (child), str);
+  g_free (str);
+  g_print ("Right/Center child: %p\n", child);
+  gtk_widget_set_halign (child, GTK_ALIGN_END);
+  gtk_widget_set_valign (child, GTK_ALIGN_CENTER);
+  gtk_overlay_add_overlay (GTK_OVERLAY (overlay), child);
+
+  g_signal_connect (child, "size-allocate",
+                    G_CALLBACK (child_size_allocate), overlay);
+
+  child = gtk_label_new (NULL);
+  str = g_strdup_printf ("%p", child);
+  gtk_label_set_text (GTK_LABEL (child), str);
+  g_free (str);
+  gtk_widget_set_margin_left (child, 55);
+  gtk_widget_set_margin_top (child, 4);
+  g_print ("Left/Top margined child: %p\n", child);
+  gtk_widget_set_halign (child, GTK_ALIGN_START);
+  gtk_widget_set_valign (child, GTK_ALIGN_START);
+  gtk_overlay_add_overlay (GTK_OVERLAY (overlay), child);
+
+  g_signal_connect (child, "size-allocate",
+                    G_CALLBACK (child_size_allocate), overlay);
+
+  child = gtk_label_new (NULL);
+  str = g_strdup_printf ("%p", child);
+  gtk_label_set_text (GTK_LABEL (child), str);
+  g_free (str);
+  g_print ("Custom get-child-position child: %p\n", child);
+  gtk_widget_set_halign (child, GTK_ALIGN_START);
+  gtk_widget_set_valign (child, GTK_ALIGN_START);
+  gtk_overlay_add_overlay (GTK_OVERLAY (overlay), child);
+
+  g_signal_connect (child, "size-allocate",
+                    G_CALLBACK (child_size_allocate), overlay);
+  g_signal_connect (overlay, "get-child-position",
+                    G_CALLBACK (overlay_get_child_position), child);
+
+  gtk_grid_attach (GTK_GRID (grid), overlay, 1, 0, 1, 3);
+  gtk_container_add (GTK_CONTAINER (win), grid);
+
+  g_print ("\n");
+
+  gtk_widget_show_all (win);
+
+  gtk_main ();
+
+  return 0;
+}