@@ -25,7 +25,7 @@ from gi.repository import GLib

 class Animation(object):

-    step = 0.03 # seconds

+    step = 0.03  # seconds

     def __init__(self, dot_widget):

         self.dot_widget = dot_widget

@@ -45,7 +45,7 @@ class Animation(object):

             if not self.tick():

                 self.stop()

                 return False

-        except e:

+        except AttributeError as e:

             self.stop()

             raise e

         return True

@@ -92,8 +92,8 @@ class MoveToAnimation(LinearAnimation):

     def animate(self, t):

         sx, sy = self.source_x, self.source_y

         tx, ty = self.target_x, self.target_y

-        self.dot_widget.x = tx * t + sx * (1-t)

-        self.dot_widget.y = ty * t + sy * (1-t)

+        self.dot_widget.x = tx * t + sx * (1 - t)

+        self.dot_widget.y = ty * t + sy * (1 - t)

         self.dot_widget.queue_draw()

@@ -118,6 +118,6 @@ class ZoomToAnimation(MoveToAnimation):

     def animate(self, t):

         a, b, c = self.source_zoom, self.extra_zoom, self.target_zoom

-        self.dot_widget.zoom_ratio = c*t + b*t*(1-t) + a*(1-t)

+        self.dot_widget.zoom_ratio = c*t + b*t*(1 - t) + a*(1 - t)

         self.dot_widget.zoom_to_fit_on_resize = False

         MoveToAnimation.animate(self, t)

new file mode 100644

@@ -0,0 +1,123 @@

+# Copyright 2008-2015 Jose Fonseca

+#

+# This program 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 3 of the License, or

+# (at your option) any later version.

+#

+# This program 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 program.  If not, see <http://www.gnu.org/licenses/>.

+#

+import math

+import time

+

+import gi

+gi.require_version('Gtk', '3.0')

+gi.require_version('PangoCairo', '1.0')

+

+from gi.repository import GLib

+

+

+class Animation(object):

+

+    step = 0.03 # seconds

+

+    def __init__(self, dot_widget):

+        self.dot_widget = dot_widget

+        self.timeout_id = None

+

+    def start(self):

+        self.timeout_id = GLib.timeout_add(int(self.step * 1000), self.__real_tick)

+

+    def stop(self):

+        self.dot_widget.animation = NoAnimation(self.dot_widget)

+        if self.timeout_id is not None:

+            GLib.source_remove(self.timeout_id)

+            self.timeout_id = None

+

+    def __real_tick(self):

+        try:

+            if not self.tick():

+                self.stop()

+                return False

+        except e:

+            self.stop()

+            raise e

+        return True

+

+    def tick(self):

+        return False

+

+

+class NoAnimation(Animation):

+

+    def start(self):

+        pass

+

+    def stop(self):

+        pass

+

+

+class LinearAnimation(Animation):

+

+    duration = 0.6

+

+    def start(self):

+        self.started = time.time()

+        Animation.start(self)

+

+    def tick(self):

+        t = (time.time() - self.started) / self.duration

+        self.animate(max(0, min(t, 1)))

+        return (t < 1)

+

+    def animate(self, t):

+        pass

+

+

+class MoveToAnimation(LinearAnimation):

+

+    def __init__(self, dot_widget, target_x, target_y):

+        Animation.__init__(self, dot_widget)

+        self.source_x = dot_widget.x

+        self.source_y = dot_widget.y

+        self.target_x = target_x

+        self.target_y = target_y

+

+    def animate(self, t):

+        sx, sy = self.source_x, self.source_y

+        tx, ty = self.target_x, self.target_y

+        self.dot_widget.x = tx * t + sx * (1-t)

+        self.dot_widget.y = ty * t + sy * (1-t)

+        self.dot_widget.queue_draw()

+

+

+class ZoomToAnimation(MoveToAnimation):

+

+    def __init__(self, dot_widget, target_x, target_y):

+        MoveToAnimation.__init__(self, dot_widget, target_x, target_y)

+        self.source_zoom = dot_widget.zoom_ratio

+        self.target_zoom = self.source_zoom

+        self.extra_zoom = 0

+

+        middle_zoom = 0.5 * (self.source_zoom + self.target_zoom)

+

+        distance = math.hypot(self.source_x - self.target_x,

+                              self.source_y - self.target_y)

+        rect = self.dot_widget.get_allocation()

+        visible = min(rect.width, rect.height) / self.dot_widget.zoom_ratio

+        visible *= 0.9

+        if distance > 0:

+            desired_middle_zoom = visible / distance

+            self.extra_zoom = min(0, 4 * (desired_middle_zoom - middle_zoom))

+

+    def animate(self, t):

+        a, b, c = self.source_zoom, self.extra_zoom, self.target_zoom

+        self.dot_widget.zoom_ratio = c*t + b*t*(1-t) + a*(1-t)

+        self.dot_widget.zoom_to_fit_on_resize = False

+        MoveToAnimation.animate(self, t)