[gnome-photos] export-dialog: Show a progress message while we are guessing the sizes

[Debarshi Ray <debarshir src gnome org>]

commit 3ce13b4675b8098efad5c9af31536c6cac712a7b
Author: Debarshi Ray <debarshir gnome org>
Date:   Tue Jan 19 12:31:49 2016 +0100

    export-dialog: Show a progress message while we are guessing the sizes
    
    We use GtkWidget::opacity instead of only relying on GtkWidget::visible
    because "hidden" widgets are zero-sized. When we show and hide the
    controls the rows jump around and the dialog changes its height. This
    looks awkward. We want the rows to hold their positions even when they
    are hidden.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=759363

 src/photos-export-dialog.c  |   72 ++++++++++++++++++++++++++++++++----------
 src/photos-export-dialog.ui |   16 +++++++++-
 2 files changed, 70 insertions(+), 18 deletions(-)
---
diff --git a/src/photos-export-dialog.c b/src/photos-export-dialog.c
index 0a4f808..2f75ea9 100644
--- a/src/photos-export-dialog.c
+++ b/src/photos-export-dialog.c
@@ -35,6 +35,7 @@ struct _PhotosExportDialog
   GtkWidget *folder_name_label;
   GtkWidget *full_button;
   GtkWidget *full_label;
+  GtkWidget *progress_label;
   GtkWidget *reduced_button;
   GtkWidget *reduced_label;
   GtkWidget *size_label;
@@ -62,6 +63,38 @@ static const gint PIXEL_SIZES[] = {2048, 1024};
 
 
 static void
+photos_export_dialog_show_size_options (PhotosExportDialog *self, gboolean progress)
+{
+  gdouble progress_opacity;
+  gdouble progress_opacity_invert;
+
+  gtk_widget_set_margin_bottom (self->dir_entry, 6);
+  gtk_widget_set_margin_bottom (self->folder_name_label, 6);
+
+  progress_opacity = progress ? 1.0 : 0.0;
+  progress_opacity_invert = !progress ? 1.0 : 0.0;
+
+  gtk_widget_show (self->progress_label);
+  gtk_widget_set_opacity (self->progress_label, progress_opacity);
+
+  gtk_widget_show (self->full_label);
+  gtk_widget_set_opacity (self->full_label, progress_opacity_invert);
+
+  gtk_widget_show (self->full_button);
+  gtk_widget_set_opacity (self->full_button, progress_opacity_invert);
+
+  gtk_widget_show (self->reduced_button);
+  gtk_widget_set_opacity (self->reduced_button, progress_opacity_invert);
+
+  gtk_widget_show (self->reduced_label);
+  gtk_widget_set_opacity (self->reduced_label, progress_opacity_invert);
+
+  gtk_widget_show (self->size_label);
+  gtk_widget_set_opacity (self->size_label, progress_opacity_invert);
+}
+
+
+static void
 photos_export_dialog_guess_sizes (GObject *source_object, GAsyncResult *res, gpointer user_data)
 {
   PhotosExportDialog *self;
@@ -74,10 +107,17 @@ photos_export_dialog_guess_sizes (GObject *source_object, GAsyncResult *res, gpo
   error = NULL;
   if (!photos_base_item_save_guess_sizes_finish (item, res, &sizes[0], &sizes[1], &error))
     {
-      if (!g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
-        g_warning ("Unable to guess sizes: %s", error->message);
-      g_error_free (error);
-      return;
+      if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+        {
+          g_error_free (error);
+          return;
+        }
+      else
+        {
+          g_warning ("Unable to guess sizes: %s", error->message);
+          g_error_free (error);
+          goto out;
+        }
     }
 
   self = PHOTOS_EXPORT_DIALOG (user_data);
@@ -99,19 +139,9 @@ photos_export_dialog_guess_sizes (GObject *source_object, GAsyncResult *res, gpo
       g_free (size_str);
       g_free (size_str_markup);
     }
-}
-
 
-static void
-photos_export_dialog_show_size_options (PhotosExportDialog *self)
-{
-  gtk_widget_set_margin_bottom (self->dir_entry, 6);
-  gtk_widget_set_margin_bottom (self->folder_name_label, 6);
-  gtk_widget_show (self->full_label);
-  gtk_widget_show (self->full_button);
-  gtk_widget_show (self->reduced_button);
-  gtk_widget_show (self->reduced_label);
-  gtk_widget_show (self->size_label);
+ out:
+  photos_export_dialog_show_size_options (self, FALSE);
 }
 
 
@@ -147,7 +177,7 @@ photos_export_dialog_constructed (GObject *object)
           if (max_dimension > PIXEL_SIZES[i])
             {
               self->reduced_zoom = (gdouble) PIXEL_SIZES[i] / (gdouble) max_dimension;
-              photos_export_dialog_show_size_options (self);
+              photos_export_dialog_show_size_options (self, TRUE);
               photos_base_item_save_guess_sizes_async (self->item,
                                                        self->cancellable,
                                                        photos_export_dialog_guess_sizes,
@@ -207,9 +237,16 @@ photos_export_dialog_set_property (GObject *object, guint prop_id, const GValue
 static void
 photos_export_dialog_init (PhotosExportDialog *self)
 {
+  gchar *progress_str_markup;
+
   gtk_widget_init_template (GTK_WIDGET (self));
 
   self->cancellable = g_cancellable_new ();
+
+  progress_str_markup = g_strdup_printf ("<small>%s</small>", _("Calculating export size…"));
+  gtk_label_set_markup (GTK_LABEL (self->progress_label), progress_str_markup);
+  g_free (progress_str_markup);
+
   self->reduced_zoom = -1.0;
 }
 
@@ -237,6 +274,7 @@ photos_export_dialog_class_init (PhotosExportDialogClass *class)
   gtk_widget_class_bind_template_child (widget_class, PhotosExportDialog, folder_name_label);
   gtk_widget_class_bind_template_child (widget_class, PhotosExportDialog, full_button);
   gtk_widget_class_bind_template_child (widget_class, PhotosExportDialog, full_label);
+  gtk_widget_class_bind_template_child (widget_class, PhotosExportDialog, progress_label);
   gtk_widget_class_bind_template_child (widget_class, PhotosExportDialog, reduced_button);
   gtk_widget_class_bind_template_child (widget_class, PhotosExportDialog, reduced_label);
   gtk_widget_class_bind_template_child (widget_class, PhotosExportDialog, size_label);
diff --git a/src/photos-export-dialog.ui b/src/photos-export-dialog.ui
index 9f9bda9..345466f 100644
--- a/src/photos-export-dialog.ui
+++ b/src/photos-export-dialog.ui
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
  Photos - access, organize and share your photos on GNOME
- Copyright © 2015 Red Hat, Inc.
+ Copyright © 2015, 2016 Red Hat, Inc.
 
  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License
@@ -134,6 +134,20 @@
                 <property name="top_attach">3</property>
               </packing>
             </child>
+            <child>
+              <object class="GtkLabel" id="progress_label">
+                <property name="halign">center</property>
+                <property name="no_show_all">1</property>
+                <style>
+                  <class name="dim-label"/>
+                </style>
+              </object>
+              <packing>
+                <property name="left_attach">0</property>
+                <property name="top_attach">4</property>
+                <property name="width">3</property>
+              </packing>
+            </child>
           </object>
           <packing>
             <property name="expand">1</property>