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"""
Demonstrates very basic use of PColorMeshItem
"""
import numpy as np
import pyqtgraph as pg
from pyqtgraph.Qt import QtCore
from utils import FrameCounter
app = pg.mkQApp("PColorMesh Example")
## Create window with GraphicsView widget
win = pg.GraphicsLayoutWidget()
win.show() ## show widget alone in its own window
win.setWindowTitle('pyqtgraph example: pColorMeshItem')
view_auto_scale = win.addPlot(0,0,1,1, title="Auto-scaling colorscheme", enableMenu=False)
view_consistent_scale = win.addPlot(1,0,1,1, title="Consistent colorscheme", enableMenu=False)
## Create data
# To enhance the non-grid meshing, we randomize the polygon vertices per and
# certain amount
randomness = 5
# x and y being the vertices of the polygons, they share the same shape
# However the shape can be different in both dimension
xn = 50 # nb points along x
yn = 40 # nb points along y
x = np.repeat(np.arange(1, xn+1), yn).reshape(xn, yn)\
+ np.random.random((xn, yn))*randomness
y = np.tile(np.arange(1, yn+1), xn).reshape(xn, yn)\
+ np.random.random((xn, yn))*randomness
x.sort(axis=0)
y.sort(axis=0)
# z being the color of the polygons its shape must be decreased by one in each dimension
z = np.exp(-(x*xn)**2/1000)[:-1,:-1]
## Create autoscaling image item
edgecolors = None
antialiasing = False
cmap = pg.colormap.get('viridis')
levels = (-2,2) # Will be overwritten unless enableAutoLevels is set to False
# edgecolors = {'color':'w', 'width':2} # May be uncommented to see edgecolor effect
# antialiasing = True # May be uncommented to see antialiasing effect
# cmap = pg.colormap.get('plasma') # May be uncommented to see a different colormap than the default 'viridis'
pcmi_auto = pg.PColorMeshItem(edgecolors=edgecolors, antialiasing=antialiasing, colorMap=cmap, levels=levels, enableAutoLevels=True)
view_auto_scale.addItem(pcmi_auto)
# Add colorbar
bar = pg.ColorBarItem(
label = "Z value [arbitrary unit]",
interactive=False, # Setting `interactive=True` would override `enableAutoLevels=True` of pcmi_auto (resulting in consistent colors)
rounding=0.1)
bar.setImageItem( [pcmi_auto] )
win.addItem(bar, 0,1,1,1)
# Create image item with consistent colors and an interactive colorbar
pcmi_consistent = pg.PColorMeshItem(edgecolors=edgecolors, antialiasing=antialiasing, colorMap=cmap, levels=levels, enableAutoLevels=False)
view_consistent_scale.addItem(pcmi_consistent)
# Add colorbar
bar_static = pg.ColorBarItem(
label = "Z value [arbitrary unit]",
interactive=True,
rounding=0.1)
bar_static.setImageItem( [pcmi_consistent] )
win.addItem(bar_static,1,1,1,1)
# Add timing label to the autoscaling view
textitem = pg.TextItem(anchor=(1, 0))
view_auto_scale.addItem(textitem)
# Wave parameters
wave_amplitude = 3
wave_speed = 0.3
wave_length = 10
color_speed = 0.3
color_noise_freq = 0.05
# display info in top-right corner
miny = np.min(y) - wave_amplitude
maxy = np.max(y) + wave_amplitude
view_auto_scale.setYRange(miny, maxy)
textitem.setPos(np.max(x), maxy)
textpos = None
i=0
def updateData():
global i
global textpos
## Display the new data set
color_noise = np.sin(i * 2*np.pi*color_noise_freq)
new_x = x
new_y = y+wave_amplitude*np.cos(x/wave_length+i)
new_z = np.exp(-(x-np.cos(i*color_speed)*xn)**2/1000)[:-1,:-1] + color_noise
pcmi_auto.setData(new_x,
new_y,
new_z)
pcmi_consistent.setData(new_x,
new_y,
new_z)
i += wave_speed
framecnt.update()
timer = QtCore.QTimer()
timer.timeout.connect(updateData)
timer.start()
framecnt = FrameCounter()
framecnt.sigFpsUpdate.connect(lambda fps: textitem.setText(f'{fps:.1f} fps'))
if __name__ == '__main__':
pg.exec()
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