rocon_gateway_graph: interactive_graphics

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00001 #!/usr/bin/env python
00002 #
00003 # License: BSD
00004 #   https://raw.github.com/robotics-in-concert/rocon_multimaster/master/rocon_gateway_graph/LICENSE 
00005 #
00006 ##############################################################################
00007 # Imports
00008 ##############################################################################
00009 
00010 from __future__ import division
00011 
00012 from python_qt_binding.QtCore import QPointF, QRectF, Qt
00013 from python_qt_binding.QtGui import QGraphicsView, QTransform
00014 
00015 ##############################################################################
00016 # Class
00017 ##############################################################################
00018 
00019 
00020 class InteractiveGraphicsView(QGraphicsView):
00021 
00022     def __init__(self, parent=None):
00023         super(InteractiveGraphicsView, self).__init__(parent)
00024         self.setObjectName('InteractiveGraphicsView')
00025 
00026         self._last_pan_point = None
00027         self._last_scene_center = None
00028 
00029     def mousePressEvent(self, mouse_event):
00030         self._last_pan_point = mouse_event.pos()
00031         self._last_scene_center = self._map_to_scene_f(QRectF(self.frameRect()).center())
00032         self.setCursor(Qt.ClosedHandCursor)
00033 
00034     def mouseReleaseEvent(self, mouse_event):
00035         self.setCursor(Qt.OpenHandCursor)
00036         self._last_pan_point = None
00037 
00038     def mouseMoveEvent(self, mouse_event):
00039         if self._last_pan_point is not None:
00040             delta_scene = self.mapToScene(mouse_event.pos()) - self.mapToScene(self._last_pan_point)
00041             if not delta_scene.isNull():
00042                 self.centerOn(self._last_scene_center - delta_scene)
00043                 self._last_scene_center -= delta_scene
00044             self._last_pan_point = mouse_event.pos()
00045         QGraphicsView.mouseMoveEvent(self, mouse_event)
00046 
00047     def wheelEvent(self, wheel_event):
00048         if wheel_event.modifiers() == Qt.NoModifier:
00049             num_degrees = wheel_event.delta() / 8.0
00050             num_steps = num_degrees / 15.0
00051             mouse_before_scale_in_scene = self.mapToScene(wheel_event.pos())
00052 
00053             scale_factor = 1.2 * num_steps
00054             if num_steps < 0:
00055                 scale_factor = -1.0 / scale_factor
00056             scaling = QTransform(scale_factor, 0, 0, scale_factor, 0, 0)
00057             self.setTransform(self.transform() * scaling)
00058 
00059             mouse_after_scale_in_scene = self.mapToScene(wheel_event.pos())
00060             center_in_scene = self.mapToScene(self.frameRect().center())
00061             self.centerOn(center_in_scene + mouse_before_scale_in_scene - mouse_after_scale_in_scene)
00062 
00063             wheel_event.accept()
00064         else:
00065             QGraphicsView.wheelEvent(self, wheel_event)
00066 
00067     def _map_to_scene_f(self, pointf):
00068         point = pointf.toPoint()
00069         if pointf.x() == point.x() and pointf.y() == point.y():
00070             # map integer coordinates
00071             return self.mapToScene(point)
00072         elif pointf.x() == point.x():
00073             # map integer x and decimal y coordinates
00074             pointA = self.mapToScene((pointf + QPointF(0, -0.5)).toPoint())
00075             pointB = self.mapToScene((pointf + QPointF(0, 0.5)).toPoint())
00076             return (pointA + pointB) / 2.0
00077         elif pointf.y() == point.y():
00078             # map decimal x  and integer y and coordinates
00079             pointA = self.mapToScene((pointf + QPointF(-0.5, 0)).toPoint())
00080             pointB = self.mapToScene((pointf + QPointF(0.5, 0)).toPoint())
00081             return (pointA + pointB) / 2.0
00082         else:
00083             # map decimal coordinates
00084             pointA = self.mapToScene((pointf + QPointF(-0.5, -0.5)).toPoint())
00085             pointB = self.mapToScene((pointf + QPointF(-0.5, 0.5)).toPoint())
00086             pointC = self.mapToScene((pointf + QPointF(0.5, -0.5)).toPoint())
00087             pointD = self.mapToScene((pointf + QPointF(0.5, 0.5)).toPoint())
00088             return (pointA + pointB + pointC + pointD) / 4.0