Thanks for the great graphics library!
I've been trying to incorporate the new colorbar into my app, with partial
success. The widget works in every way, except that the actual "color map"
ImageItem shows up as a blank image (with possibly a compressed image at
the bottom?)
[image: colorbar.png]
My ignorance about Qt can't be helping.. perhaps there's a problem with the
way I'm setting up the panel where these items live. Within a
GraphicsLayoutWidget, I do
1) addLayout to get a new panel
2) create ImageItem, layout.addPlot to get plot, add image to plot
3) create ColorBarItem, attach to ImageItem
4) layout.addItem for colorbar
Attached: I have successfully modified the colorbar demo to use the same
steps (bottom left image). Just don't know why it's blank in my app.
Appreciate any insights..
cheers
Mike
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# -*- coding: utf-8 -*-
"""
This example demonstrates the use of ColorBarItem, which displays a simple interactive color bar.
"""
## Add path to library (just for examples; you do not need this)
#import initExample
import numpy as np
from pyqtgraph.Qt import QtWidgets, mkQApp
import pyqtgraph as pg
class MainWindow(QtWidgets.QMainWindow):
""" example application main window """
def __init__(self, *args, **kwargs):
super(MainWindow, self).__init__(*args, **kwargs)
gr_wid = pg.GraphicsLayoutWidget(show=True)
self.setCentralWidget(gr_wid)
self.setWindowTitle('pyqtgraph example: Interactive color bar')
self.resize(800,700)
self.show()
## Create image items
data = np.fromfunction(lambda i, j: (1+0.3*np.sin(i)) * (i)**2 + (j)**2, (100, 100))
noisy_data = data * (1 + 0.2 * np.random.random(data.shape) )
noisy_transposed = noisy_data.transpose()
#--- add non-interactive image with integrated color -----------------
i1 = pg.ImageItem(image=data)
p1 = gr_wid.addPlot(title="non-interactive")
p1.addItem( i1 )
p1.setMouseEnabled( x=False, y=False)
p1.disableAutoRange()
p1.hideButtons()
p1.setRange(xRange=(0,100), yRange=(0,100), padding=0)
for key in ['left','right','top','bottom']:
p1.showAxis(key)
axis = p1.getAxis(key)
axis.setZValue(1)
if key in ['top', 'right']:
p1.getAxis(key).setStyle( showValues=False )
#cmap = pg.colormap.get('CET-L9')
cmap = pg.colormap.get('viridis', source='matplotlib')
bar = pg.ColorBarItem(
interactive=False, values= (0, 30_000), cmap=cmap,
label='vertical fixed color bar'
)
bar.setImageItem( i1, insert_in=p1 )
#--- add interactive image with integrated horizontal color bar --------------
# Modification: use a layout for manage this panel
gr_wid.ci.nextRow()
panel = gr_wid.ci.addLayout()
i2 = pg.ImageItem(image=noisy_data)
# Modification: add a plot on the panel
p2 = panel.addPlot(1,0, 1,1, title="interactive")
p2.addItem( i2, title='' )
# inserted color bar also works with labels on the right.
p2.showAxis('right')
p2.getAxis('left').setStyle( showValues=False )
p2.getAxis('bottom').setLabel('bottom axis label')
p2.getAxis('right').setLabel('right axis label')
cmap = pg.colormap.get('CET-L4')
bar = pg.ColorBarItem(
values = (0, 30_000),
cmap=cmap,
label='horizontal color bar',
limits = (0, None),
rounding=1000,
orientation = 'horizontal',
pen='#8888FF', hoverPen='#EEEEFF', hoverBrush='#EEEEFF80'
)
# bar.setImageItem( i2, insert_in=p2 )
bar.setImageItem(i2)
# Modification: add the colorbar to the panel
panel.addItem(bar, 2, 0, 1, 1)
#--- multiple images adjusted by a separate color bar ------------------------
i3 = pg.ImageItem(image=noisy_data)
p3 = gr_wid.addPlot(0,1, 1,1, title="shared 1")
p3.addItem( i3 )
i4 = pg.ImageItem(image=noisy_transposed)
p4 = gr_wid.addPlot(1,1, 1,1, title="shared 2")
p4.addItem( i4 )
cmap = pg.colormap.get('CET-L8')
bar = pg.ColorBarItem(
# values = (-15_000, 15_000),
limits = (-30_000, 30_000), # start with full range...
rounding=1000,
width = 10,
cmap=cmap )
bar.setImageItem( [i3, i4] )
bar.setLevels( low=-5_000, high=15_000) # ... then adjust to retro sunset.
# manually adjust reserved space at top and bottom to align with plot
bar.getAxis('bottom').setHeight(21)
bar.getAxis('top').setHeight(31)
gr_wid.addItem(bar, 0,2, 2,1) # large bar spanning both rows
mkQApp("ColorBarItem Example")
main_window = MainWindow()
## Start Qt event loop
if __name__ == '__main__':
mkQApp().exec_()
