Add mouse wheel scrolling

This is implemented by a callout to the widget's existing handler for
key_up and key_down events, and letting the key_* event propagate into
an appropriate place where it's handled as the user's input. Reusing
that handler makes it possible to work in a generic manner, so the code
has no builtin knowledge of the type or layout of the class it's
operating on. The same code is used for project listing, change listing,
single change history view and a diff view as well.

Change-Id: I14600f9dbdf1c066cf5f497f9afcf4e213f03257

gertty/view/change.py

@@ -24,6 +24,7 @@ from gertty import mywid
 from gertty import sync
 from gertty.view import side_diff as view_side_diff
 from gertty.view import unified_diff as view_unified_diff
+from gertty.view import mouse_scroll_decorator
 import gertty.view
 
 class EditTopicDialog(mywid.ButtonDialog):
@@ -389,6 +390,7 @@ class CommitMessageBox(mywid.HyperText):
             text = commentlink.run(self.app, text)
         super(CommitMessageBox, self).set_text(text)
 
+@mouse_scroll_decorator.ScrollByWheel
 class ChangeView(urwid.WidgetWrap):
     def help(self):
         key = self.app.config.keymap.formatKeys

gertty/view/change_list.py

@@ -21,6 +21,7 @@ from gertty import keymap
 from gertty import mywid
 from gertty import sync
 from gertty.view import change as view_change
+from gertty.view import mouse_scroll_decorator
 import gertty.view
 
 
@@ -139,6 +140,7 @@ class ChangeListHeader(urwid.WidgetWrap):
         for category in categories:
             self._w.contents.append((urwid.Text(' %s' % category[0]), self._w.options('given', 2)))
 
+@mouse_scroll_decorator.ScrollByWheel
 class ChangeListView(urwid.WidgetWrap):
     def help(self):
         key = self.app.config.keymap.formatKeys

gertty/view/diff.py

@@ -21,6 +21,7 @@ from gertty import keymap
 from gertty import mywid
 from gertty import gitrepo
 from gertty import sync
+from gertty.view import mouse_scroll_decorator
 
 class PatchsetDialog(urwid.WidgetWrap):
     signals = ['ok', 'cancel']
@@ -145,6 +146,7 @@ class DiffContextButton(urwid.WidgetWrap):
     def next(self, button):
         self.view.expandChunk(self.diff, self.chunk, from_end=-10)
 
+@mouse_scroll_decorator.ScrollByWheel
 class BaseDiffView(urwid.WidgetWrap):
     def help(self):
         key = self.app.config.keymap.formatKeys

gertty/view/mouse_scroll_decorator.py

@@ -0,0 +1,33 @@
+# coding=utf8
+#
+# Copyright 2014 Jan Kundrát <jkt@kde.org>
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+def mouse_event_scrolling(class_type):
+    def mouse_event_scrolling(self, size, event, button, col, row, focus):
+        if event == 'mouse press':
+            if button == 4:
+                self.keypress(size, 'up')
+                return True
+            if button == 5:
+                self.keypress(size, 'down')
+                return True
+
+        return super(class_type, self).mouse_event(size, event, button, col,
+                                                   row, focus)
+    return mouse_event_scrolling
+
+def ScrollByWheel(original_class):
+    original_class.mouse_event = mouse_event_scrolling(original_class)
+    return original_class

gertty/view/project_list.py

@@ -20,6 +20,7 @@ from gertty import keymap
 from gertty import mywid
 from gertty import sync
 from gertty.view import change_list as view_change_list
+from gertty.view import mouse_scroll_decorator
 
 class ProjectRow(urwid.Button):
     project_focus_map = {None: 'focused',
@@ -67,6 +68,7 @@ class ProjectListHeader(urwid.WidgetWrap):
                 (5, urwid.Text(u'Open'))]
         super(ProjectListHeader, self).__init__(urwid.Columns(cols))
 
+@mouse_scroll_decorator.ScrollByWheel
 class ProjectListView(urwid.WidgetWrap):
     def help(self):
         key = self.app.config.keymap.formatKeys