overlay: add initial version of gtkoverlay

1 files changed, 635 insertions, 0 deletions

diff --git a/gtk/gtkoverlay.c b/gtk/gtkoverlay.c
new file mode 100644
index 0000000000..40125babaa
--- /dev/null
+++ b/gtk/gtkoverlay.c
@@ -0,0 +1,635 @@
+/*
+ * gtkoverlay.c
+ * This file is part of gtk
+ *
+ * Copyright (C) 2011 - Ignacio Casal Quinteiro, Mike Krüger
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "config.h"
+
+#include "gtkoverlay.h"
+#include "gtkbuildable.h"
+#include "gtkscrolledwindow.h"
+#include "gtkmainprivate.h"
+#include "gtkmarshalers.h"
+
+#include "gtkprivate.h"
+#include "gtkintl.h"
+
+/**
+ * SECTION:gtkoverlay
+ * @short_description: A container which overlays widgets on top of each other
+ * @title: GtkOverlay
+ *
+ * GtkOverlay is a container which contains a single main child, on top
+ * of which it can place <firstterm>overlay</firstterm> widgets. The
+ * position of each overlay widget is determined by its #GtkWidget::halign
+ * and #GtkWidget::valign properties. E.g. a widget with both alignments
+ * set to %GTK_ALIGN_START will be placed at the top left corner of the
+ * main widget, whereas an overlay with halign set to %GTK_ALIGN_CENTER
+ * and valign set to %GTK_ALIGN_END will be placed a the bottom edge of
+ * the main widget, horizontally centered. The position can be adjusted
+ * by setting the margin properties of the child to non-zero values.
+ *
+ * More complicated placement of overlays is possible by connecting
+ * to the #GtkOverlay::get-child-position signal.
+ *
+ * <refsect2 id="GtkOverlay-BUILDER-UI">
+ * <title>GtkOverlay as GtkBuildable</title>
+ * <para>
+ * The GtkOverlay implementation of the GtkBuildable interface
+ * supports placing a child as an overlay by specifying "overlay" as
+ * the "type" attribute of a <tag class="starttag">child</tag> element.
+ * </para>
+ * </refsect2>
+ */
+
+struct _GtkOverlayPrivate
+{
+  GSList *children;
+};
+
+typedef struct _GtkOverlayChild GtkOverlayChild;
+
+struct _GtkOverlayChild
+{
+  GtkWidget *widget;
+  GdkWindow *window;
+};
+
+enum {
+  GET_CHILD_POSITION,
+  LAST_SIGNAL
+};
+
+static guint signals[LAST_SIGNAL] = { 0 };
+
+static void gtk_overlay_buildable_init (GtkBuildableIface *iface);
+
+G_DEFINE_TYPE_WITH_CODE (GtkOverlay, gtk_overlay, GTK_TYPE_BIN,
+                         G_IMPLEMENT_INTERFACE (GTK_TYPE_BUILDABLE,
+                                                gtk_overlay_buildable_init))
+
+static GdkWindow *
+gtk_overlay_create_child_window (GtkOverlay *overlay,
+                                 GtkWidget  *child)
+{
+  GtkWidget *widget = GTK_WIDGET (overlay);
+  GtkAllocation allocation;
+  GdkWindow *window;
+  GdkWindowAttr attributes;
+  gint attributes_mask;
+
+  gtk_widget_get_allocation (child, &allocation);
+
+  attributes.window_type = GDK_WINDOW_CHILD;
+  attributes.wclass = GDK_INPUT_OUTPUT;
+  attributes.width = allocation.width;
+  attributes.height = allocation.height;
+  attributes.x = allocation.x;
+  attributes.y = allocation.y;
+  attributes_mask = GDK_WA_X | GDK_WA_Y;
+  attributes.event_mask = gtk_widget_get_events (widget) | GDK_EXPOSURE_MASK;
+
+  window = gdk_window_new (gtk_widget_get_window (widget),
+                           &attributes, attributes_mask);
+  gdk_window_set_user_data (window, overlay);
+  gtk_style_context_set_background (gtk_widget_get_style_context (widget), window);
+
+  gtk_widget_set_parent_window (child, window);
+
+  return window;
+}
+
+static void
+gtk_overlay_child_allocate (GtkOverlayChild *child,
+                            GtkAllocation   *allocation)
+{
+  gint left, right, top, bottom;
+  GtkAllocation child_allocation;
+
+  /* put the margins outside the window; also arrange things
+   * so that the adjusted child allocation still ends up at 0, 0
+   */
+  left = gtk_widget_get_margin_left (child->widget);
+  right = gtk_widget_get_margin_right (child->widget);
+  top = gtk_widget_get_margin_top (child->widget);
+  bottom = gtk_widget_get_margin_bottom (child->widget);
+
+  child_allocation.x = - left;
+  child_allocation.y = - top;
+  child_allocation.width = allocation->width;
+  child_allocation.height = allocation->height;
+
+  allocation->x += left;
+  allocation->y += top;
+  allocation->width -= left + right;
+  allocation->height -= top + bottom;
+
+  if (child->window)
+    gdk_window_move_resize (child->window,
+                            allocation->x, allocation->y,
+                            allocation->width, allocation->height);
+
+  gtk_widget_size_allocate (child->widget, &child_allocation);
+}
+
+static void
+gtk_overlay_get_preferred_width (GtkWidget *widget,
+                                 gint      *minimum,
+                                 gint      *natural)
+{
+  GtkBin *bin = GTK_BIN (widget);
+  GtkWidget *child;
+
+  if (minimum)
+    *minimum = 0;
+
+  if (natural)
+    *natural = 0;
+
+  child = gtk_bin_get_child (bin);
+  if (child && gtk_widget_get_visible (child))
+    gtk_widget_get_preferred_width (child, minimum, natural);
+}
+
+static void
+gtk_overlay_get_preferred_height (GtkWidget *widget,
+                                  gint      *minimum,
+                                  gint      *natural)
+{
+  GtkBin *bin = GTK_BIN (widget);
+  GtkWidget *child;
+
+  if (minimum)
+    *minimum = 0;
+
+  if (natural)
+    *natural = 0;
+
+  child = gtk_bin_get_child (bin);
+  if (child && gtk_widget_get_visible (child))
+    gtk_widget_get_preferred_height (child, minimum, natural);
+}
+
+static void
+gtk_overlay_size_allocate (GtkWidget     *widget,
+                           GtkAllocation *allocation)
+{
+  GtkOverlay *overlay = GTK_OVERLAY (widget);
+  GtkOverlayPrivate *priv = overlay->priv;
+  GSList *children;
+  GtkWidget *main_widget;
+
+  GTK_WIDGET_CLASS (gtk_overlay_parent_class)->size_allocate (widget, allocation);
+
+  main_widget = gtk_bin_get_child (GTK_BIN (overlay));
+  if (!main_widget || !gtk_widget_get_visible (main_widget))
+    return;
+
+  gtk_widget_size_allocate (main_widget, allocation);
+
+  for (children = priv->children; children; children = children->next)
+    {
+      GtkOverlayChild *child;
+      GtkAllocation alloc;
+      gboolean result;
+
+      child = children->data;
+
+      if (gtk_widget_get_mapped (GTK_WIDGET (overlay)))
+        {
+          if (gtk_widget_get_visible (child->widget))
+            gdk_window_show (child->window);
+          else if (gdk_window_is_visible (child->window))
+            gdk_window_hide (child->window);
+        }
+
+      if (!gtk_widget_get_visible (child->widget))
+        continue;
+
+      g_signal_emit (overlay, signals[GET_CHILD_POSITION],
+                     0, child->widget, &alloc, &result);
+
+      alloc.x += allocation->x;
+      alloc.y += allocation->y;
+
+      gtk_overlay_child_allocate (child, &alloc);
+    }
+}
+
+static GtkAlign
+effective_align (GtkAlign         align,
+                 GtkTextDirection direction)
+{
+  switch (align)
+    {
+    case GTK_ALIGN_START:
+      return direction == GTK_TEXT_DIR_RTL ? GTK_ALIGN_END : GTK_ALIGN_START;
+    case GTK_ALIGN_END:
+      return direction == GTK_TEXT_DIR_RTL ? GTK_ALIGN_START : GTK_ALIGN_END;
+    default:
+      return align;
+    }
+}
+
+static gboolean
+gtk_overlay_get_child_position (GtkOverlay    *overlay,
+                                GtkWidget     *widget,
+                                GtkAllocation *alloc)
+{
+  GtkWidget *main_widget;
+  GtkAllocation main_alloc;
+  GtkRequisition req;
+  GtkAlign halign;
+  GtkTextDirection direction;
+
+  main_widget = gtk_bin_get_child (GTK_BIN (overlay));
+
+  /* special-case scrolled windows */
+  if (GTK_IS_SCROLLED_WINDOW (main_widget))
+    {
+      GtkWidget *grandchild;
+      gint x, y;
+
+      grandchild = gtk_bin_get_child (GTK_BIN (main_widget));
+      gtk_widget_translate_coordinates (grandchild, main_widget, 0, 0, &x, &y);
+
+      main_alloc.x = x;
+      main_alloc.y = y;
+      main_alloc.width = gtk_widget_get_allocated_width (grandchild);
+      main_alloc.height = gtk_widget_get_allocated_height (grandchild);
+    }
+  else
+    {
+      main_alloc.x = 0;
+      main_alloc.y = 0;
+      main_alloc.width = gtk_widget_get_allocated_width (main_widget);
+      main_alloc.height = gtk_widget_get_allocated_height (main_widget);
+    }
+
+  gtk_widget_get_preferred_size (widget, NULL, &req);
+
+  alloc->x = main_alloc.x;
+  alloc->width = MIN (main_alloc.width, req.width);
+
+  direction = gtk_widget_get_direction (widget);
+
+  halign = gtk_widget_get_halign (widget);
+  switch (effective_align (halign, direction))
+    {
+    case GTK_ALIGN_START:
+      /* nothing to do */
+      break;
+    case GTK_ALIGN_FILL:
+      alloc->width = main_alloc.width;
+      break;
+    case GTK_ALIGN_CENTER:
+      alloc->x += main_alloc.width / 2 - req.width / 2;
+      break;
+    case GTK_ALIGN_END:
+      alloc->x += main_alloc.width - req.width;
+      break;
+    }
+
+  alloc->y = main_alloc.y;
+  alloc->height = MIN (main_alloc.height, req.height);
+
+  switch (gtk_widget_get_valign (widget))
+    {
+    case GTK_ALIGN_START:
+      /* nothing to do */
+      break;
+    case GTK_ALIGN_FILL:
+      alloc->height = main_alloc.height;
+      break;
+    case GTK_ALIGN_CENTER:
+      alloc->y += main_alloc.height / 2 - req.height / 2;
+      break;
+    case GTK_ALIGN_END:
+      alloc->y += main_alloc.height - req.height;
+      break;
+    }
+
+  return TRUE;
+}
+
+static void
+gtk_overlay_realize (GtkWidget *widget)
+{
+  GtkOverlay *overlay = GTK_OVERLAY (widget);
+  GtkOverlayPrivate *priv = overlay->priv;
+  GtkOverlayChild *child;
+  GSList *children;
+
+  GTK_WIDGET_CLASS (gtk_overlay_parent_class)->realize (widget);
+
+  for (children = priv->children; children; children = children->next)
+    {
+      child = children->data;
+
+      if (child->window == NULL)
+        child->window = gtk_overlay_create_child_window (overlay, child->widget);
+    }
+}
+
+static void
+gtk_overlay_unrealize (GtkWidget *widget)
+{
+  GtkOverlay *overlay = GTK_OVERLAY (widget);
+  GtkOverlayPrivate *priv = overlay->priv;
+  GtkOverlayChild *child;
+  GSList *children;
+
+  for (children = priv->children; children; children = children->next)
+    {
+      child = children->data;
+
+      gtk_widget_set_parent_window (child->widget, NULL);
+      gdk_window_set_user_data (child->window, NULL);
+      gdk_window_destroy (child->window);
+      child->window = NULL;
+    }
+
+  GTK_WIDGET_CLASS (gtk_overlay_parent_class)->unrealize (widget);
+}
+
+static void
+gtk_overlay_map (GtkWidget *widget)
+{
+  GtkOverlay *overlay = GTK_OVERLAY (widget);
+  GtkOverlayPrivate *priv = overlay->priv;
+  GtkOverlayChild *child;
+  GSList *children;
+
+  GTK_WIDGET_CLASS (gtk_overlay_parent_class)->map (widget);
+
+  for (children = priv->children; children; children = children->next)
+    {
+      child = children->data;
+
+      if (child->window != NULL &&
+          gtk_widget_get_visible (child->widget) &&
+          gtk_widget_get_child_visible (child->widget))
+        gdk_window_show (child->window);
+    }
+}
+
+static void
+gtk_overlay_unmap (GtkWidget *widget)
+{
+  GtkOverlay *overlay = GTK_OVERLAY (widget);
+  GtkOverlayPrivate *priv = overlay->priv;
+  GtkOverlayChild *child;
+  GSList *children;
+
+  for (children = priv->children; children; children = children->next)
+    {
+      child = children->data;
+
+      if (child->window != NULL &&
+          gdk_window_is_visible (child->window))
+        gdk_window_hide (child->window);
+    }
+
+  GTK_WIDGET_CLASS (gtk_overlay_parent_class)->unmap (widget);
+}
+
+static gboolean
+gtk_overlay_draw (GtkWidget *widget,
+                  cairo_t   *cr)
+{
+  GtkOverlay *overlay = GTK_OVERLAY (widget);
+  GtkOverlayPrivate *priv = overlay->priv;
+  GtkOverlayChild *child;
+  GSList *children;
+
+  for (children = priv->children; children; children = children->next)
+    {
+      child = children->data;
+
+      if (gtk_cairo_should_draw_window (cr, child->window))
+        {
+          cairo_save (cr);
+          gtk_cairo_transform_to_window (cr, widget, child->window);
+          gtk_render_background (gtk_widget_get_style_context (widget),
+                                 cr,
+                                 0, 0,
+                                 gdk_window_get_width (child->window),
+                                 gdk_window_get_height (child->window));
+          cairo_restore (cr);
+        }
+    }
+
+  GTK_WIDGET_CLASS (gtk_overlay_parent_class)->draw (widget, cr);
+
+  return FALSE;
+}
+
+static void
+gtk_overlay_remove (GtkContainer *container,
+                    GtkWidget    *widget)
+{
+  GtkOverlayPrivate *priv = GTK_OVERLAY (container)->priv;
+  GtkOverlayChild *child;
+  GSList *children;
+
+  for (children = priv->children; children; children = children->next)
+    {
+      child = children->data;
+
+      if (child->widget == widget)
+        {
+          if (child->window != NULL)
+            {
+              gdk_window_set_user_data (child->window, NULL);
+              gdk_window_destroy (child->window);
+            }
+
+          gtk_widget_unparent (widget);
+
+          priv->children = g_slist_delete_link (priv->children, children);
+          g_slice_free (GtkOverlayChild, child);
+
+          return;
+        }
+    }
+
+  GTK_CONTAINER_CLASS (gtk_overlay_parent_class)->remove (container, widget);
+}
+
+static void
+gtk_overlay_forall (GtkContainer *overlay,
+                    gboolean      include_internals,
+                    GtkCallback   callback,
+                    gpointer      callback_data)
+{
+  GtkOverlayPrivate *priv = GTK_OVERLAY (overlay)->priv;
+  GtkOverlayChild *child;
+  GSList *children;
+  GtkWidget *main_widget;
+
+  main_widget = gtk_bin_get_child (GTK_BIN (overlay));
+  if (main_widget)
+    (* callback) (main_widget, callback_data);
+
+  children = priv->children;
+  while (children)
+    {
+      child = children->data;
+      children = children->next;
+
+      (* callback) (child->widget, callback_data);
+    }
+}
+
+static void
+gtk_overlay_class_init (GtkOverlayClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
+  GtkContainerClass *container_class = GTK_CONTAINER_CLASS (klass);
+
+  widget_class->get_preferred_width = gtk_overlay_get_preferred_width;
+  widget_class->get_preferred_height = gtk_overlay_get_preferred_height;
+  widget_class->size_allocate = gtk_overlay_size_allocate;
+  widget_class->realize = gtk_overlay_realize;
+  widget_class->unrealize = gtk_overlay_unrealize;
+  widget_class->map = gtk_overlay_map;
+  widget_class->unmap = gtk_overlay_unmap;
+  widget_class->draw = gtk_overlay_draw;
+
+  container_class->remove = gtk_overlay_remove;
+  container_class->forall = gtk_overlay_forall;
+
+  klass->get_child_position = gtk_overlay_get_child_position;
+
+  /**
+   * GtkOverlay::get-child-position:
+   * @overlay: the #GtkOverlay
+   * @widget: the child widget to position
+   * @allocation: (out): return location for the allocation
+   *
+   * The ::get-child-position signal is emitted to determine
+   * the position and size of any overlay child widgets. A
+   * handler for this signal should fill @allocation with
+   * the desired position and size for @widget, relative to
+   * the 'main' child of @overlay.
+   *
+   * The default handler for this signal uses the @widget's
+   * halign and valign properties to determine the position
+   * and gives the widget its natural size (except that an
+   * alignment of %GTK_ALIGN_FILL will cause the overlay to
+   * be full-width/height). If the main child is a
+   * #GtkScrolledWindow, the overlays are placed relative
+   * to its contents.
+   *
+   * Return: %TRUE if the @allocation has been filled
+   */
+  signals[GET_CHILD_POSITION] =
+    g_signal_new (I_("get-child-position"),
+                  G_TYPE_FROM_CLASS (object_class),
+                  G_SIGNAL_RUN_LAST,
+                  G_STRUCT_OFFSET (GtkOverlayClass, get_child_position),
+                  _gtk_boolean_handled_accumulator, NULL,
+                  _gtk_marshal_BOOLEAN__OBJECT_BOXED,
+                  G_TYPE_BOOLEAN, 2,
+                  GTK_TYPE_WIDGET,
+                  GDK_TYPE_RECTANGLE | G_SIGNAL_TYPE_STATIC_SCOPE);
+
+  g_type_class_add_private (object_class, sizeof (GtkOverlayPrivate));
+}
+
+static void
+gtk_overlay_init (GtkOverlay *overlay)
+{
+  overlay->priv = G_TYPE_INSTANCE_GET_PRIVATE (overlay, GTK_TYPE_OVERLAY, GtkOverlayPrivate);
+
+  gtk_widget_set_has_window (GTK_WIDGET (overlay), FALSE);
+}
+
+static void
+gtk_overlay_buildable_add_child (GtkBuildable *buildable,
+                                 GtkBuilder   *builder,
+                                 GObject      *child,
+                                 const gchar  *type)
+{
+  if (type && strcmp (type, "overlay") == 0)
+    gtk_overlay_add_overlay (GTK_OVERLAY (buildable), GTK_WIDGET (child));
+  else if (!type)
+    gtk_container_add (GTK_CONTAINER (buildable), GTK_WIDGET (child));
+  else
+    GTK_BUILDER_WARN_INVALID_CHILD_TYPE (buildable, type);
+}
+
+static void
+gtk_overlay_buildable_init (GtkBuildableIface *iface)
+{
+  iface->add_child = gtk_overlay_buildable_add_child;
+}
+
+/**
+ * gtk_overlay_new:
+ *
+ * Creates a new #GtkOverlay.
+ *
+ * Returns: a new #GtkOverlay object.
+ *
+ * Since: 3.2
+ */
+GtkWidget *
+gtk_overlay_new (void)
+{
+  return g_object_new (GTK_TYPE_OVERLAY, NULL);
+}
+
+/**
+ * gtk_overlay_add_overlay:
+ * @overlay: a #GtkOverlay
+ * @widget: a #GtkWidget to be added to the container
+ *
+ * Adds @widget to @overlay.
+ *
+ * The widget will be stacked on top of the main widget
+ * added with gtk_container_add().
+ *
+ * The position at which @widget is placed is determined
+ * from its #GtkWidget::halign and #GtkWidget::valign properties.
+ *
+ * Since: 3.2
+ */
+void
+gtk_overlay_add_overlay (GtkOverlay *overlay,
+                         GtkWidget  *widget)
+{
+  GtkOverlayPrivate *priv = overlay->priv;
+  GtkOverlayChild *child;
+
+  g_return_if_fail (GTK_IS_OVERLAY (overlay));
+  g_return_if_fail (GTK_IS_WIDGET (widget));
+
+  child = g_slice_new0 (GtkOverlayChild);
+  child->widget = widget;
+
+  gtk_widget_set_parent (widget, GTK_WIDGET (overlay));
+
+  priv->children = g_slist_append (priv->children, child);
+
+  if (gtk_widget_get_realized (GTK_WIDGET (overlay)))
+    child->window = gtk_overlay_create_child_window (overlay, widget);
+}