Show preview when pasting image from clipboard

gajim/chat_control_base.py

@@ -53,7 +53,7 @@
 
 from gajim.gtk.dialogs import DialogButton
 from gajim.gtk.dialogs import NewConfirmationDialog
-from gajim.gtk.dialogs import NewConfirmationCheckDialog
+from gajim.gtk.dialogs import PastePreviewDialog
 from gajim.gtk.message_input import MessageInputTextView
 from gajim.gtk.util import at_the_end
 from gajim.gtk.util import get_show_in_roster
@@ -731,12 +731,13 @@ def _on_message_textview_paste_event(self, _texview):
             if not app.settings.get('confirm_paste_image'):
                 self._paste_event_confirmed(True, image)
                 return
-            NewConfirmationCheckDialog(
+            PastePreviewDialog(
                 _('Paste Image'),
                 _('You are trying to paste an image'),
                 _('Are you sure you want to paste your '
                   'clipboard\'s image into the chat window?'),
                 _('_Do not ask me again'),
+                image,
                 [DialogButton.make('Cancel'),
                  DialogButton.make('Accept',
                                    text=_('_Paste'),

gajim/gtk/dialogs.py

@@ -18,6 +18,7 @@
 from gi.repository import GLib
 from gi.repository import Gtk
 from gi.repository import Gdk
+from gi.repository import GdkPixbuf
 from gi.repository import Pango
 
 from gajim.common import app
@@ -26,6 +27,7 @@
 from gajim.common.helpers import convert_gio_to_openssl_cert
 
 from gajim.gtk.util import get_builder
+from gajim.gtk.util import get_thumbnail_size
 
 
 class DialogButton(namedtuple('DialogButton', ('response text callback args '
@@ -489,6 +491,38 @@ def _on_response(self, _dialog, response):
         super()._on_response(_dialog, response)
 
 
+class PastePreviewDialog(NewConfirmationCheckDialog):
+    def __init__(self, title, text, sec_text, check_text, image,
+                 buttons, modal=True, transient_for=None):
+        NewConfirmationCheckDialog.__init__(self,
+                                            title,
+                                            text,
+                                            sec_text,
+                                            check_text,
+                                            buttons,
+                                            transient_for=transient_for,
+                                            modal=modal)
+
+        preview = Gtk.Image()
+        preview.set_halign(Gtk.Align.CENTER)
+        preview.get_style_context().add_class('preview-image')
+        size = 300
+        image_width = image.get_width()
+        image_height = image.get_height()
+
+        if size > image_width and size > image_height:
+            preview.set_from_pixbuf(image)
+        else:
+            thumb_width, thumb_height = get_thumbnail_size(image, size)
+            pixbuf_scaled = image.scale_simple(
+                thumb_width, thumb_height, GdkPixbuf.InterpType.BILINEAR)
+            preview.set_from_pixbuf(pixbuf_scaled)
+
+        content_area = self.get_content_area()
+        content_area.pack_start(preview, True, True, 0)
+        content_area.reorder_child(preview, 2)
+
+
 class InputDialog(NewConfirmationDialog):
     def __init__(self, title, text, sec_text, buttons, input_str=None,
                  transient_for=None, modal=True):

gajim/gtk/util.py

@@ -23,6 +23,7 @@
 import sys
 import weakref
 import logging
+import math
 import textwrap
 import functools
 from importlib import import_module
@@ -757,6 +758,25 @@ def load_pixbuf(path, size=None):
         return pixbuf
 
 
+def get_thumbnail_size(pixbuf, size):
+    # Calculates the new thumbnail size while preserving the aspect ratio
+    image_width = pixbuf.get_width()
+    image_height = pixbuf.get_height()
+
+    if image_width > image_height:
+        if image_width > size:
+            image_height = math.ceil(
+                (size / float(image_width) * image_height))
+            image_width = int(size)
+    else:
+        if image_height > size:
+            image_width = math.ceil(
+                (size / float(image_height) * image_width))
+            image_height = int(size)
+
+    return image_width, image_height
+
+
 def make_href_markup(string):
     url_color = app.css_config.get_value('.gajim-url', StyleAttr.COLOR)
     color = convert_rgb_to_hex(url_color)