interactive_graphics_view.py
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00001 # Copyright (c) 2011, Dirk Thomas, TU Darmstadt
00002 # All rights reserved.
00003 # Copyright (c) 2013, Jonathan Bohren, The Johns Hopkins University
00004 # All rights reserved
00005 #
00006 # Redistribution and use in source and binary forms, with or without
00007 # modification, are permitted provided that the following conditions
00008 # are met:
00009 #
00010 #   * Redistributions of source code must retain the above copyright
00011 #     notice, this list of conditions and the following disclaimer.
00012 #   * Redistributions in binary form must reproduce the above
00013 #     copyright notice, this list of conditions and the following
00014 #     disclaimer in the documentation and/or other materials provided
00015 #     with the distribution.
00016 #   * Neither the name of the TU Darmstadt nor the names of its
00017 #     contributors may be used to endorse or promote products derived
00018 #     from this software without specific prior written permission.
00019 #
00020 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00021 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00022 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
00023 # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
00024 # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
00025 # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
00026 # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
00027 # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00028 # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00029 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
00030 # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00031 # POSSIBILITY OF SUCH DAMAGE.
00032 
00033 from __future__ import division
00034 
00035 from python_qt_binding.QtCore import QPointF, QRectF, Qt
00036 from python_qt_binding.QtGui import QGraphicsView, QTransform
00037 
00038 
00039 class InteractiveGraphicsView(QGraphicsView):
00040 
00041     def __init__(self, parent=None):
00042         super(InteractiveGraphicsView, self).__init__(parent)
00043         self.setObjectName('InteractiveGraphicsView')
00044 
00045         self._last_pan_point = None
00046         self._last_scene_center = None
00047 
00048     def mousePressEvent(self, mouse_event):
00049         self._last_pan_point = mouse_event.pos()
00050         self._last_scene_center = self._map_to_scene_f(QRectF(self.frameRect()).center())
00051         self.setCursor(Qt.ClosedHandCursor)
00052 
00053     def mouseReleaseEvent(self, mouse_event):
00054         self.setCursor(Qt.OpenHandCursor)
00055         self._last_pan_point = None
00056 
00057     def mouseMoveEvent(self, mouse_event):
00058         if self._last_pan_point is not None:
00059             delta_scene = self.mapToScene(mouse_event.pos()) - self.mapToScene(self._last_pan_point)
00060             if not delta_scene.isNull():
00061                 self.centerOn(self._last_scene_center - delta_scene)
00062                 self._last_scene_center -= delta_scene
00063             self._last_pan_point = mouse_event.pos()
00064         QGraphicsView.mouseMoveEvent(self, mouse_event)
00065 
00066     def wheelEvent(self, wheel_event):
00067         if wheel_event.modifiers() == Qt.NoModifier:
00068             num_degrees = wheel_event.delta() / 8.0
00069             num_steps = num_degrees / 15.0
00070             mouse_before_scale_in_scene = self.mapToScene(wheel_event.pos())
00071 
00072             scale_factor = 1.2 * num_steps
00073             if num_steps < 0:
00074                 scale_factor = -1.0 / scale_factor
00075             scaling = QTransform(scale_factor, 0, 0, scale_factor, 0, 0)
00076             self.setTransform(self.transform() * scaling)
00077 
00078             mouse_after_scale_in_scene = self.mapToScene(wheel_event.pos())
00079             center_in_scene = self.mapToScene(self.frameRect().center())
00080             self.centerOn(center_in_scene + mouse_before_scale_in_scene - mouse_after_scale_in_scene)
00081 
00082             wheel_event.accept()
00083         else:
00084             QGraphicsView.wheelEvent(self, wheel_event)
00085 
00086     def _map_to_scene_f(self, pointf):
00087         point = pointf.toPoint()
00088         if pointf.x() == point.x() and pointf.y() == point.y():
00089             # map integer coordinates
00090             return self.mapToScene(point)
00091         elif pointf.x() == point.x():
00092             # map integer x and decimal y coordinates
00093             pointA = self.mapToScene((pointf + QPointF(0, -0.5)).toPoint())
00094             pointB = self.mapToScene((pointf + QPointF(0, 0.5)).toPoint())
00095             return (pointA + pointB) / 2.0
00096         elif pointf.y() == point.y():
00097             # map decimal x  and integer y and coordinates
00098             pointA = self.mapToScene((pointf + QPointF(-0.5, 0)).toPoint())
00099             pointB = self.mapToScene((pointf + QPointF(0.5, 0)).toPoint())
00100             return (pointA + pointB) / 2.0
00101         else:
00102             # map decimal coordinates
00103             pointA = self.mapToScene((pointf + QPointF(-0.5, -0.5)).toPoint())
00104             pointB = self.mapToScene((pointf + QPointF(-0.5, 0.5)).toPoint())
00105             pointC = self.mapToScene((pointf + QPointF(0.5, -0.5)).toPoint())
00106             pointD = self.mapToScene((pointf + QPointF(0.5, 0.5)).toPoint())
00107             return (pointA + pointB + pointC + pointD) / 4.0
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rqt_smach
Author(s): Jonathan Bohren
autogenerated on Fri Jun 28 2013 11:08:56