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# -*- coding: utf-8 -*-
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.
from __future__ import division
import numpy as np
from .linear import STTransform
class PanZoomTransform(STTransform):
"""Pan-zoom transform
Parameters
----------
canvas : instance of Canvas | None
The canvas to attch to.
aspect : float | None
The aspect ratio to apply.
**kwargs : dict
Keyword arguments to pass to the underlying `STTransform`.
"""
def __init__(self, canvas=None, aspect=None, **kwargs):
self._aspect = aspect
self.attach(canvas)
STTransform.__init__(self, **kwargs)
self.on_resize(None)
def attach(self, canvas):
"""Attach this tranform to a canvas
Parameters
----------
canvas : instance of Canvas
The canvas.
"""
self._canvas = canvas
canvas.events.resize.connect(self.on_resize)
canvas.events.mouse_wheel.connect(self.on_mouse_wheel)
canvas.events.mouse_move.connect(self.on_mouse_move)
@property
def canvas_tr(self):
return STTransform.from_mapping(
[(0, 0), self._canvas.size],
[(-1, 1), (1, -1)])
def on_resize(self, event):
"""Resize handler
Parameters
----------
event : instance of Event
The event.
"""
if self._aspect is None:
return
w, h = self._canvas.size
aspect = self._aspect / (w / h)
self.scale = (self.scale[0], self.scale[0] / aspect)
self.shader_map()
def on_mouse_move(self, event):
"""Mouse move handler
Parameters
----------
event : instance of Event
The event.
"""
if event.is_dragging:
dxy = event.pos - event.last_event.pos
button = event.press_event.button
if button == 1:
dxy = self.canvas_tr.map(dxy)
o = self.canvas_tr.map([0, 0])
t = dxy - o
self.move(t)
elif button == 2:
center = self.canvas_tr.map(event.press_event.pos)
if self._aspect is None:
self.zoom(np.exp(dxy * (0.01, -0.01)), center)
else:
s = dxy[1] * -0.01
self.zoom(np.exp(np.array([s, s])), center)
self.shader_map()
def on_mouse_wheel(self, event):
"""Mouse wheel handler
Parameters
----------
event : instance of Event
The event.
"""
self.zoom(np.exp(event.delta * (0.01, -0.01)), event.pos)
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