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# -*- coding: utf-8 -*-
# vispy: gallery 30
# -----------------------------------------------------------------------------
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.
# -----------------------------------------------------------------------------
""" Display Windbarbs.
"""
import itertools
import numpy as np
from vispy import app
from vispy.visuals import WindbarbVisual
from vispy.visuals.transforms import NullTransform
class Canvas(app.Canvas):
def __init__(self):
app.Canvas.__init__(self, title="Windbarb plot", keys="interactive",
size=(830, 430))
self.windbarb_length = 25
self.grid_spacing = 50
self.grid_coords = None
self.line_vertices = None
self.last_mouse = (0, 0)
self.generate_grid()
direction_vectors = (self.grid_coords - self.last_mouse).astype(
np.float32)
direction_vectors[:] /= 10
direction_vectors[:, 1] *= -1
self.visual = WindbarbVisual(pos=self.grid_coords,
wind=direction_vectors,
trig=False,
edge_color='black',
face_color='black',
size=self.windbarb_length)
self.visual.events.update.connect(lambda evt: self.update())
self.visual.transform = NullTransform()
self.show()
def generate_grid(self):
n = self.grid_spacing / 2.
num_cols = int(self.physical_size[0] / n * 2)
num_rows = int(self.physical_size[1] / n * 2)
coords = []
# Generate grid
for i, j in itertools.product(range(num_rows), range(num_cols)):
x = n + (n * 2 * j)
y = n + (n * 2 * i)
coords.append((x, y))
self.grid_coords = np.array(coords)
def on_resize(self, event):
self.generate_grid()
self.rotate_arrows(np.array(self.last_mouse))
vp = (0, 0, self.physical_size[0], self.physical_size[1])
self.context.set_viewport(*vp)
self.visual.transforms.configure(canvas=self, viewport=vp)
def rotate_arrows(self, point_towards):
direction_vectors = (self.grid_coords - point_towards).astype(
np.float32)
direction_vectors[:] /= 10
direction_vectors[:, 1] *= -1
self.visual.set_data(
pos=self.grid_coords,
wind=direction_vectors,
size=self.windbarb_length,
)
def on_mouse_move(self, event):
self.last_mouse = event.pos
self.rotate_arrows(np.array(event.pos))
def on_draw(self, event):
self.context.clear(color='white')
self.visual.draw()
if __name__ == '__main__':
canvas = Canvas()
canvas.measure_fps()
app.run()
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