Merge lp:~stefan-schwarzburg/qreator/drag_n_drop_support into lp:~dpm/qreator/trunk

[Schwarzburg]

This adds basic drag support: the qrcode image can be draged into other applications. This behaves like the save feature: not the pixbuf is dragged, but the uri to a temporary file.

[lp:~stefan-schwarzburg/qreator/drag_n_drop_support]

88. By David Planella on 2012-06-09

Merged drag and drop support from lp:~stefan-schwarzburg/qreator/drag_n_drop_support

[David Planella (dpm)]

I like it, so merged it, thanks! :-)

A couple of things:

- I've changed the names of the callbacks to follow the same convention across the file (on_something instead of something_cb)
- Just an alternative, but instead of relying on a timeout to delete the temp file, you could have also used the atexit() function to delete it on exit
- I've tested the feature to work with Nautilus, but it does not work with Eye Of GNOME (on dragging and dropping the QR code, eog tells me it cannot find the file pointed by the UIR). Any ideas why not?

review: Approve

=== modified file 'qreator/QreatorWindow.py'
--- qreator/QreatorWindow.py	2012-06-09 00:06:51 +0000
+++ qreator/QreatorWindow.py	2012-06-09 15:58:19 +0000
@@ -14,6 +14,8 @@
 # with this program.  If not, see <http://www.gnu.org/licenses/>.
 ### END LICENSE
 
+import os
+import tempfile
 import cairo
 import math
 from gi.repository import Gtk, Gdk, GdkPixbuf, GObject  # pylint: disable=E0611
@@ -77,6 +79,36 @@
         # Add an initial text, so that there is an initial QR code
         self.qr_code_placeholder = 'http://launchpad.net/qreator'
 
+        # Prepare the qrcode for drag n drop
+        self.tempfilepath = None
+
+        def drag_data_get_cb(widget, drag_context, selection_data,
+                             info, time):
+            if self.tempfilepath is None:
+                handle, self.tempfilepath = tempfile.mkstemp(
+                    suffix=".png", prefix="qreator_")
+                pixbuf = self.get_pixbuf_from_drawing_area()
+                pixbuf.savev(self.tempfilepath, 'png', [], [])
+            selection_data.set_uris(["file://{}".format(self.tempfilepath)])
+            return True
+
+        def remove_tempfile(path):
+            if os.path.exists(path):
+                os.remove(path)
+            return False
+
+        def drag_end_cb(widget, drag_context):
+            GObject.timeout_add(5, remove_tempfile, self.tempfilepath)
+            self.tempfilepath = None
+
+        self.ui.qr_drawingarea.drag_source_set(Gdk.ModifierType.BUTTON1_MASK,
+                                               [], Gdk.DragAction.COPY)
+        self.ui.qr_drawingarea.drag_source_set_target_list(None)
+        self.ui.qr_drawingarea.drag_source_add_uri_targets()
+        self.ui.qr_drawingarea.connect("drag_data_get", drag_data_get_cb)
+        self.ui.qr_drawingarea.connect("drag_end", drag_end_cb)
+
+
     def init_qr_types(self):
         # Set up the QR types shown in the main icon view
         self.ui.qr_types_view.set_text_column(COL_DESC)