[PythonCAD] zooming with mouse wheel

[Russ Nelson]

This patch allows you to zoom in and out using the mouse wheel.  I
think it has three problems:
  1) the scroll increment is too large for a wheel.
  2) it's a little hackish to be calling a menu item (but I wanted the
     patch to be short).
  3) The scrolling should also pan at the same time so that the object
     you're pointing at remains underneath the pointer.

Anyway, if people try this patch and think this is useful, I'll keep
working on it.  Any suggestions beyond the three above?


Index: PythonCAD/Interface/Gtk/gtkimage.py
===================================================================
--- PythonCAD/Interface/Gtk/gtkimage.py (revision 2387)
+++ PythonCAD/Interface/Gtk/gtkimage.py (working copy)
@@ -107,6 +107,14 @@
         return _entry.event(event)
     return False
 
+def window_scroll_event(widget, event, gtkimage):
+    from PythonCAD.Interface.Gtk.gtkmenus import zoom_in_cb
+    from PythonCAD.Interface.Gtk.gtkmenus import zoom_out_cb
+    if event.direction == gtk.gdk.SCROLL_UP:
+        zoom_in_cb(widget, gtkimage)
+    elif event.direction == gtk.gdk.SCROLL_DOWN:
+        zoom_out_cb(widget, gtkimage)
+
 def window_general_event(widget, event, gtkimage):
     _type = event.type
     debug_print("window_general_event: Event type: %d" % _type)
@@ -316,6 +324,7 @@
         self.__window.connect("destroy", close_image, self)
         self.__window.connect("event", window_general_event, self)
         self.__window.connect("key_press_event", window_key_press_event, self)
+        self.__window.connect("scroll_event", window_scroll_event, self)
         _width = min(1024, int(0.8 * float(gtk.gdk.screen_width())))
         _height = min(768, int(0.8 * float(gtk.gdk.screen_height())))
         self.__window.set_default_size(_width, _height)

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