[gtk/drag-icon: 2/7] Add GtkDragIcon

[Matthias Clasen <matthiasc src gnome org>]

commit a6244a95bec5988a98bf8f27bd6b36e1d47f4a36
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Dec 29 22:47:26 2019 -0500

    Add GtkDragIcon
    
    This is a GtkRoot implemntation for drag icons,
    using the surface provided by GdkDrag. This lets
    us avoid GTK_WINDOW_POPUP and
    gtk_window_set_hardcoded_surface.

 gtk/gtkdragicon.c        | 398 +++++++++++++++++++++++++++++++++++++++++++++++
 gtk/gtkdragiconprivate.h |  46 ++++++
 gtk/meson.build          |   1 +
 3 files changed, 445 insertions(+)
---
diff --git a/gtk/gtkdragicon.c b/gtk/gtkdragicon.c
new file mode 100644
index 0000000000..8b6edbbf97
--- /dev/null
+++ b/gtk/gtkdragicon.c
@@ -0,0 +1,398 @@
+/* GTK - The GIMP Toolkit
+ * Copyright 2019 Matthias Clasen
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include "gtkdragiconprivate.h"
+
+#include "gtkprivate.h"
+#include "gtkintl.h"
+#include "gtkwidgetprivate.h"
+#include "gtkcssnodeprivate.h"
+
+
+struct _GtkDragIcon
+{
+  GtkWidget parent_instance;
+
+  GdkSurface *surface;
+  GskRenderer *renderer;
+  GtkWidget *widget;
+};
+
+struct _GtkDragIconClass
+{
+  GtkWidgetClass parent_class;
+};
+
+enum {
+  LAST_ARG = 1
+};
+
+static void gtk_drag_icon_root_init   (GtkRootInterface *iface);
+static void gtk_drag_icon_native_init (GtkNativeInterface *iface);
+
+G_DEFINE_TYPE_WITH_CODE (GtkDragIcon, gtk_drag_icon, GTK_TYPE_CONTAINER,
+                         G_IMPLEMENT_INTERFACE (GTK_TYPE_NATIVE,
+                                                gtk_drag_icon_native_init)
+                         G_IMPLEMENT_INTERFACE (GTK_TYPE_ROOT,
+                                                gtk_drag_icon_root_init))
+
+static GdkDisplay *
+gtk_drag_icon_root_get_display (GtkRoot *self)
+{
+  GtkDragIcon *icon = GTK_DRAG_ICON (self);
+
+  if (icon->surface)
+    return gdk_surface_get_display (icon->surface);
+
+  return gdk_display_get_default ();
+}
+
+static void
+gtk_drag_icon_root_init (GtkRootInterface *iface)
+{
+  iface->get_display = gtk_drag_icon_root_get_display;
+}
+
+static GdkSurface *
+gtk_drag_icon_native_get_surface (GtkNative *native)
+{
+  GtkDragIcon *icon = GTK_DRAG_ICON (native);
+
+  return icon->surface;
+}
+
+static GskRenderer *
+gtk_drag_icon_native_get_renderer (GtkNative *native)
+{
+  GtkDragIcon *icon = GTK_DRAG_ICON (native);
+
+  return icon->renderer;
+}
+
+static void
+gtk_drag_icon_native_get_surface_transform (GtkNative *native,
+                                            int       *x,
+                                            int       *y)
+{
+  GtkStyleContext *context;
+  GtkBorder margin, border, padding;
+
+  context = gtk_widget_get_style_context (GTK_WIDGET (native));
+  gtk_style_context_get_margin (context, &margin);
+  gtk_style_context_get_border (context, &border);
+  gtk_style_context_get_padding (context, &padding);
+
+  *x = margin.left + border.left + padding.left;
+  *y = margin.top + border.top + padding.top;
+}
+
+static void
+gtk_drag_icon_move_resize (GtkDragIcon *icon)
+{
+  GtkRequisition req;
+
+  if (icon->surface)
+    {
+      gtk_widget_get_preferred_size (GTK_WIDGET (icon), NULL, &req);
+      gdk_surface_resize (icon->surface, req.width, req.height);
+    }
+}
+
+static void
+gtk_drag_icon_native_check_resize (GtkNative *native)
+{
+  GtkDragIcon *icon = GTK_DRAG_ICON (native);
+  GtkWidget *widget = GTK_WIDGET (native);
+
+  if (!_gtk_widget_get_alloc_needed (widget))
+    gtk_widget_ensure_allocate (widget);
+  else if (gtk_widget_get_visible (widget))
+    {
+      gtk_drag_icon_move_resize (icon);
+      if (icon->surface)
+        gtk_widget_allocate (widget,
+                             gdk_surface_get_width (icon->surface),
+                             gdk_surface_get_height (icon->surface),
+                             -1, NULL);
+    }
+}
+
+static void
+gtk_drag_icon_native_init (GtkNativeInterface *iface)
+{
+  iface->get_surface = gtk_drag_icon_native_get_surface;
+  iface->get_renderer = gtk_drag_icon_native_get_renderer;
+  iface->get_surface_transform = gtk_drag_icon_native_get_surface_transform;
+  iface->check_resize = gtk_drag_icon_native_check_resize;
+}
+
+static gboolean
+surface_render (GdkSurface     *surface,
+                cairo_region_t *region,
+                GtkWidget      *widget)
+{
+  gtk_widget_render (widget, surface, region);
+  return TRUE;
+}
+
+static void
+gtk_drag_icon_realize (GtkWidget *widget)
+{
+  GtkDragIcon *icon = GTK_DRAG_ICON (widget);
+
+  g_warn_if_fail (icon->surface != NULL);
+
+  gdk_surface_set_widget (icon->surface, widget);
+
+  g_signal_connect (icon->surface, "render", G_CALLBACK (surface_render), widget);
+
+  GTK_WIDGET_CLASS (gtk_drag_icon_parent_class)->realize (widget);
+
+  icon->renderer = gsk_renderer_new_for_surface (icon->surface);
+}
+
+static void
+gtk_drag_icon_unrealize (GtkWidget *widget)
+{
+  GtkDragIcon *icon = GTK_DRAG_ICON (widget);
+
+  GTK_WIDGET_CLASS (gtk_drag_icon_parent_class)->unrealize (widget);
+
+  gsk_renderer_unrealize (icon->renderer);
+  g_clear_object (&icon->renderer);
+
+  if (icon->surface)
+    {
+      g_signal_handlers_disconnect_by_func (icon->surface, surface_render, widget);
+      gdk_surface_set_widget (icon->surface, NULL);
+    }
+}
+
+static void
+gtk_drag_icon_map (GtkWidget *widget)
+{
+  GtkDragIcon *icon = GTK_DRAG_ICON (widget);
+
+  gdk_surface_show (icon->surface);
+
+  GTK_WIDGET_CLASS (gtk_drag_icon_parent_class)->map (widget);
+
+  if (icon->widget && gtk_widget_get_visible (icon->widget))
+    gtk_widget_map (icon->widget);
+}
+
+static void
+gtk_drag_icon_unmap (GtkWidget *widget)
+{
+  GtkDragIcon *icon = GTK_DRAG_ICON (widget);
+
+  g_warn_if_fail (icon->surface != NULL);
+  GTK_WIDGET_CLASS (gtk_drag_icon_parent_class)->unmap (widget);
+  if (icon->surface)
+    gdk_surface_hide (icon->surface);
+
+  if (icon->widget)
+    gtk_widget_unmap (icon->widget);
+}
+
+static void
+gtk_drag_icon_measure (GtkWidget      *widget,
+                       GtkOrientation  orientation,
+                       int             for_size,
+                       int            *minimum,
+                       int            *natural,
+                       int            *minimum_baseline,
+                       int            *natural_baseline)
+{
+  GtkDragIcon *icon = GTK_DRAG_ICON (widget);
+
+  if (icon->widget)
+    gtk_widget_measure (icon->widget,
+                        orientation, for_size,
+                        minimum, natural,
+                        minimum_baseline, natural_baseline);
+}
+
+static void
+gtk_drag_icon_size_allocate (GtkWidget *widget,
+                             int        width,
+                             int        height,
+                             int        baseline)
+{
+  GtkDragIcon *icon = GTK_DRAG_ICON (widget);
+
+  gtk_drag_icon_move_resize (icon);
+
+  if (icon->widget)
+    gtk_widget_allocate (icon->widget, width, height, baseline, NULL);
+}
+
+static void
+gtk_drag_icon_show (GtkWidget *widget)
+{
+  _gtk_widget_set_visible_flag (widget, TRUE);
+  gtk_css_node_validate (gtk_widget_get_css_node (widget));
+  gtk_widget_realize (widget);
+  gtk_drag_icon_native_check_resize (GTK_NATIVE (widget));
+  gtk_widget_map (widget);
+}
+
+static void
+gtk_drag_icon_hide (GtkWidget *widget)
+{
+  _gtk_widget_set_visible_flag (widget, FALSE);
+  gtk_widget_unmap (widget);
+}
+
+static void
+gtk_drag_icon_dispose (GObject *object)
+{
+  GtkDragIcon *icon = GTK_DRAG_ICON (object);
+
+  g_clear_pointer (&icon->widget, gtk_widget_unparent);
+
+  G_OBJECT_CLASS (gtk_drag_icon_parent_class)->dispose (object);
+
+  g_clear_object (&icon->surface);
+}
+
+static void
+gtk_drag_icon_get_property (GObject     *object,
+                            guint        prop_id,
+                            GValue      *value,
+                            GParamSpec  *pspec)
+{
+  switch (prop_id)
+    {
+    case LAST_ARG + GTK_ROOT_PROP_FOCUS_WIDGET:
+      g_value_set_object (value, NULL);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+gtk_drag_icon_set_property (GObject      *object,
+                            guint         prop_id,
+                            const GValue *value,
+                            GParamSpec    *pspec)
+{
+  switch (prop_id)
+    {
+    case LAST_ARG + GTK_ROOT_PROP_FOCUS_WIDGET:
+      // do nothing
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+gtk_drag_icon_add (GtkContainer *self,
+                   GtkWidget    *widget)
+{
+  GtkDragIcon *icon = GTK_DRAG_ICON (self);
+
+  if (icon->widget)
+    {
+      g_warning ("GtkDragIcon already has a child");
+      return;
+    }
+
+  gtk_widget_set_parent (widget, GTK_WIDGET (icon));
+  icon->widget = widget;
+}
+
+static void
+gtk_drag_icon_remove (GtkContainer *self,
+                      GtkWidget    *widget)
+{
+  GtkDragIcon *icon = GTK_DRAG_ICON (self);
+
+  if (icon->widget == widget)
+    {
+      gtk_widget_unparent (widget);
+      icon->widget = NULL;
+    }
+}
+
+static void
+gtk_drag_icon_class_init (GtkDragIconClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
+  GtkContainerClass *container_class = GTK_CONTAINER_CLASS (klass);
+
+  object_class->dispose = gtk_drag_icon_dispose;
+  object_class->get_property = gtk_drag_icon_get_property;
+  object_class->set_property = gtk_drag_icon_set_property;
+
+  widget_class->realize = gtk_drag_icon_realize;
+  widget_class->unrealize = gtk_drag_icon_unrealize;
+  widget_class->map = gtk_drag_icon_map;
+  widget_class->unmap = gtk_drag_icon_unmap;
+  widget_class->measure = gtk_drag_icon_measure;
+  widget_class->size_allocate = gtk_drag_icon_size_allocate;
+  widget_class->show = gtk_drag_icon_show;
+  widget_class->hide = gtk_drag_icon_hide;
+
+  container_class->add = gtk_drag_icon_add;
+  container_class->remove = gtk_drag_icon_remove;
+
+  gtk_root_install_properties (object_class, LAST_ARG);
+
+  gtk_widget_class_set_css_name (widget_class, "dnd");
+}
+
+static void
+gtk_drag_icon_init (GtkDragIcon *self)
+{
+}
+
+GtkWidget *
+gtk_drag_icon_new (void)
+{
+  return g_object_new (GTK_TYPE_DRAG_ICON, NULL);
+}
+
+void
+gtk_drag_icon_set_surface (GtkDragIcon *icon,
+                           GdkSurface  *surface)
+{
+  g_set_object (&icon->surface, surface);
+}
+
+void
+gtk_drag_icon_set_widget (GtkDragIcon *icon,
+                          GtkWidget   *widget)
+{
+  if (icon->widget == widget)
+    return;
+
+  if (icon->widget)
+    gtk_widget_unparent (icon->widget);
+
+  icon->widget = widget;
+
+  if (icon->widget)
+    gtk_widget_set_parent (icon->widget, GTK_WIDGET (icon));
+}
diff --git a/gtk/gtkdragiconprivate.h b/gtk/gtkdragiconprivate.h
new file mode 100644
index 0000000000..507ac908ea
--- /dev/null
+++ b/gtk/gtkdragiconprivate.h
@@ -0,0 +1,46 @@
+/* GTK - The GIMP Toolkit
+ * Copyright 2019 Matthias Clasen
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * Modified by the GTK+ Team and others 1997-2000.  See the AUTHORS
+ * file for a list of people on the GTK+ Team.  See the ChangeLog
+ * files for a list of changes.  These files are distributed with
+ * GTK+ at ftp://ftp.gtk.org/pub/gtk/.
+ */
+
+#ifndef __GTK_DRAG_ICON_PRIVATE_H__
+#define __GTK_DRAG_ICON_PRIVATE_H__
+
+#include <gio/gio.h>
+#include <gtk/gtk.h>
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_DRAG_ICON (gtk_drag_icon_get_type ())
+
+G_DECLARE_FINAL_TYPE (GtkDragIcon, gtk_drag_icon, GTK, DRAG_ICON, GtkContainer)
+
+GtkWidget *     gtk_drag_icon_new                          (void);
+
+void            gtk_drag_icon_set_surface                  (GtkDragIcon *icon,
+                                                            GdkSurface  *surface);
+void            gtk_drag_icon_set_widget                   (GtkDragIcon *icon,
+                                                            GtkWidget   *widget);
+
+G_END_DECLS
+
+#endif /* __GTK_DRAG_ICON_PRIVATE_H__ */
diff --git a/gtk/meson.build b/gtk/meson.build
index 85a25212a6..d93c94ac60 100644
--- a/gtk/meson.build
+++ b/gtk/meson.build
@@ -103,6 +103,7 @@ gtk_private_sources = files([
   'gtkcssvalue.c',
   'gtkcsswidgetnode.c',
   'gtkcustomlayout.c',
+  'gtkdragicon.c',
   'gtkfilechooserembed.c',
   'gtkfilechooserentry.c',
   'gtkfilechoosererrorstack.c',