From 445dc0cc5770f9aa62264efb37c35d5964e41c0f Mon Sep 17 00:00:00 2001
From: Walter Bender <walter@sugarlabs.org>
Date: Wed, 11 Dec 2013 18:24:21 +0000
Subject: unpacking elements so as to be able to remove cjson dependency

---
(limited to 'elements/camera.py')

diff --git a/elements/camera.py b/elements/camera.py
new file mode 100644
index 0000000..c45b27d
--- /dev/null
+++ b/elements/camera.py
@@ -0,0 +1,124 @@
+"""
+This file is part of the 'Elements' Project
+Elements is a 2D Physics API for Python (supporting Box2D2)
+
+Copyright (C) 2008, The Elements Team, <elements@linuxuser.at>
+
+Home:  http://elements.linuxuser.at
+IRC:   #elements on irc.freenode.org
+
+Code:  http://www.assembla.com/wiki/show/elements
+       svn co http://svn2.assembla.com/svn/elements                     
+
+License:  GPLv3 | See LICENSE for the full text
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU 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 General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.              
+"""
+from locals import *
+
+class Camera:
+    """ The Camera class. We will see :)
+        Please also see: http://www.assembla.com/spaces/elements/tickets/31
+        
+        This class currently handles:
+        - Scaling factor
+        - Screen Offset from the World Coordinate System
+        
+        Inputs from the user have to be checked for them.
+        - Places to check for it: elements.py, drawing.py, add_objects.py
+        
+    """
+    scale_factor = 1.0          # All coords to the renderer are multiplied with the scale factor in elements.draw()
+    track_body = None           # Body which means to be tracked. Offset is set at each elements.draw()
+    
+    def __init__(self, parent):
+        self.parent = parent
+            
+    def track(self, body):
+        """ Start tracking a specific body
+        """
+        self.track_body = body
+
+    def track_stop(self):
+        """ Stop tracking a body
+        """
+        self.track_body = None
+            
+    def center(self, pos, screenCoord=True, stopTrack=True):
+        """ Centers the camera at given screen coordinates -- in pixel
+            Typical call: world.camera.center(event.pos)
+            
+            Problem: Works ONLY WITH screenCoord now!
+        """        
+        x, y = pos
+
+        x -= self.parent.display_width / 2
+        y -= self.parent.display_height  / 2
+
+        if screenCoord:
+            x /= self.scale_factor
+            y /= self.scale_factor
+
+        # Set the offset
+        self.inc_offset((x, y), screenCoord, stopTrack)
+        
+    def set_offset(self, offset, screenCoord=True, stopTrack=True):
+        """ Set an offset from the screen to the world cs 
+            -- in screen (or world) coordinates and in pixel
+        """
+        # Stop tracking of an object
+        if stopTrack: self.track_stop()
+
+        # If screenCoords, we have to bring them to the world cs
+        if screenCoord: x, y = self.parent.to_world(offset)
+        else: x, y = offset
+
+        self._set_offset((x/self.parent.ppm, y/self.parent.ppm))
+
+    def inc_offset(self, offset, screenCoord=True, stopTrack=True):
+        """ Increment an offset from the screen to the world cs -- in world coordinates and in pixel
+        """
+        # Stop tracking of an object
+        if stopTrack: self.track_stop()
+
+        # Get Current Offset
+        x, y = self.parent.screen_offset_pixel
+        dx, dy = offset
+
+        # Bring the directions into the world coordinate system
+        if screenCoord:
+            if self.parent.inputAxis_x_left: dx *= -1
+            if self.parent.inputAxis_y_down: dy *= -1
+                
+        # Set New Offset
+        self._set_offset(((x+dx)/self.parent.ppm, (y+dy)/self.parent.ppm))
+                
+    def _set_offset(self, offset):
+        """ Set the screen offset to the world coordinate system
+            (using meters and the world coordinate system's orientation)
+        """
+        x, y = offset            
+        self.parent.screen_offset = (x, y)
+        self.parent.screen_offset_pixel = (x*self.parent.ppm, y*self.parent.ppm)
+        
+    def set_scale_factor(self, factor=1.0):
+        """ Zoom factor for the renderer 1.0 = 1:1 (original)
+        """
+        self.scale_factor = factor
+        
+    def inc_scale_factor(self, factor=0.0):
+        """ Increases the zooms for the renderer a given factor
+        """
+        self.scale_factor += factor
+        
+        
\ No newline at end of file
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