From b0e066894ab52d4dc7a8e7273b04d885953b870b Mon Sep 17 00:00:00 2001
From: Manuel Quiñones <manuq@laptop.org>
Date: Wed, 15 May 2013 04:32:36 +0000
Subject: Basic pinch to zoom

---
diff --git a/ImageView.py b/ImageView.py
index e74f3e9..7bc9095 100644
--- a/ImageView.py
+++ b/ImageView.py
@@ -15,6 +15,7 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
+import logging
 import cairo
 
 from gi.repository import Gtk
@@ -47,6 +48,9 @@ class ImageViewer(Gtk.DrawingArea):
         self._surface = None
         self._zoom = None
 
+        self._in_zoomtouch = False
+        self._zoomtouch_scale = 1
+
         self.connect('draw', self.__draw_cb)
 
     def set_file_location(self, file_location):
@@ -102,6 +106,27 @@ class ImageViewer(Gtk.DrawingArea):
         self._zoom = 1
         self.queue_draw()
 
+    def start_zoomtouch(self, center):
+        logging.debug("start_zoomtouch %r", center)
+        self._in_zoomtouch = True
+        self._zoomtouch_scale = 1
+        self.queue_draw()
+
+    def update_zoomtouch(self, center, scale):
+        logging.debug("update_zoomtouch %r", (center, scale))
+        self._zoomtouch_scale = scale
+        self.queue_draw()
+
+    def finish_zoomtouch(self):
+        logging.debug("finish_zoomtouch")
+
+        # apply zoom
+        self._zoom = self._zoom * self._zoomtouch_scale
+
+        self._in_zoomtouch = False
+        self._zoomtouch_scale = 1
+        self.queue_draw()
+
     def __draw_cb(self, widget, ctx):
 
         # If the image surface is not set, it reads it from the file
@@ -120,15 +145,18 @@ class ImageViewer(Gtk.DrawingArea):
 
         # Scale and center the image according to the current zoom.
 
-        scaled_width = int(self._surface.get_width() * self._zoom)
-        scaled_height = int(self._surface.get_height() * self._zoom)
+        zoom_absolute = self._zoom * self._zoomtouch_scale
+
+        scaled_width = int(self._surface.get_width() * zoom_absolute)
+        scaled_height = int(self._surface.get_height() * zoom_absolute)
+
 
         alloc = self.get_allocation()
         x_offset = (alloc.width * 1.0 - scaled_width) / 2
         y_offset = (alloc.height * 1.0 - scaled_height) / 2
 
         ctx.translate(x_offset, y_offset)
-        ctx.scale(self._zoom, self._zoom)
+        ctx.scale(zoom_absolute, zoom_absolute)
         ctx.set_source_surface(self._surface, 0, 0)
 
         # FIXME investigate
diff --git a/ImageViewerActivity.py b/ImageViewerActivity.py
index 4e5c6d1..ab1424c 100644
--- a/ImageViewerActivity.py
+++ b/ImageViewerActivity.py
@@ -116,13 +116,14 @@ class ImageViewerActivity(activity.Activity):
 
         if GESTURES_AVAILABLE:
             zoom_controller = SugarGestures.ZoomController()
-            zoom_controller.connect('scale-changed',
-                    self.__scale_changed_cb)
-            zoom_controller.connect('began',
-                    self.__scale_began_cb)
             zoom_controller.attach(self,
                     SugarGestures.EventControllerFlags.NONE)
 
+            zoom_controller.connect('began', self.__zoomtouch_began_cb)
+            zoom_controller.connect('scale-changed',
+                                    self.__zoomtouch_changed_cb)
+            zoom_controller.connect('ended', self.__zoomtouch_ended_cb)
+
         self.progressdialog = None
 
         toolbar_box = ToolbarBox()
@@ -130,9 +131,6 @@ class ImageViewerActivity(activity.Activity):
         self.set_toolbar_box(toolbar_box)
         toolbar_box.show()
 
-        self._last_angle = 0.0
-        self._last_scale = 1.0
-
         if self._object_id is None:
             empty_widgets = Gtk.EventBox()
             empty_widgets.modify_bg(Gtk.StateType.NORMAL,
@@ -195,16 +193,14 @@ class ImageViewerActivity(activity.Activity):
                 # Wait for a successful join before trying to get the document
                 self.connect("joined", self._joined_cb)
 
-    def __scale_began_cb(self, controller):
-        self.view._zoom_ori = self.view.zoom
+    def __zoomtouch_began_cb(self, controller):
+        self.view.start_zoomtouch(controller.get_center())
 
-    def __scale_changed_cb(self, controller, scale):
-        if scale != self._last_scale:
-            self._last_scale = scale
+    def __zoomtouch_changed_cb(self, controller, scale):
+        self.view.update_zoomtouch(controller.get_center(), scale)
 
-            self.view._is_touching = True
-            self.view._touch_center = controller.get_center()
-            self.view.set_zoom_relative(scale)
+    def __zoomtouch_ended_cb(self, controller):
+        self.view.finish_zoomtouch()
 
     def _add_toolbar_buttons(self, toolbar_box):
         activity_button = ActivityToolbarButton(self)
--
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