import sys
import numpy as np
from qwt.qt.QtGui import QApplication, QPen, qRgb
from qwt.qt.QtCore import Qt
from qwt import (QwtPlot, QwtPlotMarker, QwtLegend, QwtPlotGrid, QwtPlotCurve,
QwtPlotItem, QwtText, QwtLegendData, QwtLinearColorMap,
QwtInterval, QwtScaleMap, toQImage)
def bytescale(data, cmin=None, cmax=None, high=255, low=0):
if ((hasattr(data, 'dtype') and data.dtype.char == np.uint8)
or (hasattr(data, 'typecode') and data.typecode == np.uint8)
):
return data
high = high - low
if cmin is None:
cmin = min(np.ravel(data))
if cmax is None:
cmax = max(np.ravel(data))
scale = high * 1.0 / (cmax-cmin or 1)
bytedata = ((data*1.0-cmin)*scale + 0.4999).astype(np.uint8)
return bytedata + np.asarray(low).astype(np.uint8)
def linearX(nx, ny):
return np.repeat(np.arange(nx, typecode = np.float32)[:, np.newaxis], ny, -1)
def linearY(nx, ny):
return np.repeat(np.arange(ny, typecode = np.float32)[np.newaxis, :], nx, 0)
def square(n, min, max):
t = np.arange(min, max, float(max-min)/(n-1))
#return outer(cos(t), sin(t))
return np.cos(t)*np.sin(t)[:,np.newaxis]
class PlotImage(QwtPlotItem):
def __init__(self, title = QwtText()):
QwtPlotItem.__init__(self)
self.setTitle(title)
self.setItemAttribute(QwtPlotItem.Legend);
self.xyzs = None
def setData(self, xyzs, xRange = None, yRange = None):
self.xyzs = xyzs
shape = xyzs.shape
if not xRange:
xRange = (0, shape[0])
if not yRange:
yRange = (0, shape[1])
self.xMap = QwtScaleMap(0, xyzs.shape[0], *xRange)
self.plot().setAxisScale(QwtPlot.xBottom, *xRange)
self.yMap = QwtScaleMap(0, xyzs.shape[1], *yRange)
self.plot().setAxisScale(QwtPlot.yLeft, *yRange)
self.image = toQImage(bytescale(self.xyzs)).mirrored(False, True)
for i in range(0, 256):
self.image.setColor(i, qRgb(i, 0, 255-i))
def updateLegend(self, legend):
QwtPlotItem.updateLegend(self, legend)
legend.find(self).setText(self.title())
def draw(self, painter, xMap, yMap, rect):
"""Paint image zoomed to xMap, yMap
Calculate (x1, y1, x2, y2) so that it contains at least 1 pixel,
and copy the visible region to scale it to the canvas.
"""
assert(isinstance(self.plot(), QwtPlot))
# calculate y1, y2
# the scanline order (index y) is inverted with respect to the y-axis
y1 = y2 = self.image.height()
y1 *= (self.yMap.s2() - yMap.s2())
y1 /= (self.yMap.s2() - self.yMap.s1())
y1 = max(0, int(y1-0.5))
y2 *= (self.yMap.s2() - yMap.s1())
y2 /= (self.yMap.s2() - self.yMap.s1())
y2 = min(self.image.height(), int(y2+0.5))
# calculate x1, x2 -- the pixel order (index x) is normal
x1 = x2 = self.image.width()
x1 *= (xMap.s1() - self.xMap.s1())
x1 /= (self.xMap.s2() - self.xMap.s1())
x1 = max(0, int(x1-0.5))
x2 *= (xMap.s2() - self.xMap.s1())
x2 /= (self.xMap.s2() - self.xMap.s1())
x2 = min(self.image.width(), int(x2+0.5))
# copy
image = self.image.copy(x1, y1, x2-x1, y2-y1)
# zoom
image = image.scaled(xMap.p2()-xMap.p1()+1, yMap.p1()-yMap.p2()+1)
# draw
painter.drawImage(xMap.p1(), yMap.p2(), image)
class ImagePlot(QwtPlot):
def __init__(self, *args):
QwtPlot.__init__(self, *args)
# set plot title
self.setTitle('ImagePlot')
# set plot layout
self.plotLayout().setCanvasMargin(0)
self.plotLayout().setAlignCanvasToScales(True)
# set legend
legend = QwtLegend()
legend.setDefaultItemMode(QwtLegendData.Clickable)
self.insertLegend(legend, QwtPlot.RightLegend)
# set axis titles
self.setAxisTitle(QwtPlot.xBottom, 'time (s)')
self.setAxisTitle(QwtPlot.yLeft, 'frequency (Hz)')
colorMap = QwtLinearColorMap(Qt.blue, Qt.red)
interval = QwtInterval(-1, 1)
self.enableAxis(QwtPlot.yRight)
self.setAxisScale(QwtPlot.yRight, -1, 1)
self.axisWidget(QwtPlot.yRight).setColorBarEnabled(True)
self.axisWidget(QwtPlot.yRight).setColorMap(interval, colorMap)
# calculate 3 NumPy arrays
x = np.arange(-2*np.pi, 2*np.pi, 0.01)
y = np.pi*np.sin(x)
z = 4*np.pi*np.cos(x)*np.cos(x)*np.sin(x)
# attach a curve
curve = QwtPlotCurve('y = pi*sin(x)')
curve.attach(self)
curve.setPen(QPen(Qt.green, 2))
curve.setData(x, y)
# attach another curve
curve = QwtPlotCurve('y = 4*pi*sin(x)*cos(x)**2')
curve.attach(self)
curve.setPen(QPen(Qt.black, 2))
curve.setData(x, z)
# attach a grid
grid = QwtPlotGrid()
grid.attach(self)
grid.setPen(QPen(Qt.black, 0, Qt.DotLine))
# attach a horizontal marker at y = 0
marker = QwtPlotMarker()
marker.attach(self)
marker.setValue(0.0, 0.0)
marker.setLineStyle(QwtPlotMarker.HLine)
marker.setLabelAlignment(Qt.AlignRight | Qt.AlignTop)
marker.setLabel(QwtText('y = 0'))
# attach a vertical marker at x = pi
marker = QwtPlotMarker()
marker.attach(self)
marker.setValue(np.pi, 0.0)
marker.setLineStyle(QwtPlotMarker.VLine)
marker.setLabelAlignment(Qt.AlignRight | Qt.AlignBottom)
marker.setLabel(QwtText('x = pi'))
# attach a plot image
plotImage = PlotImage('Image')
plotImage.attach(self)
plotImage.setData(square(512, -2*np.pi, 2*np.pi),
(-2*np.pi, 2*np.pi), (-2*np.pi, 2*np.pi))
legend.SIG_CLICKED.connect(self.toggleVisibility)
# replot
self.replot()
def toggleVisibility(self, plotItem, idx):
"""Toggle the visibility of a plot item
"""
plotItem.setVisible(not plotItem.isVisible())
self.replot()
def make():
demo = ImagePlot()
demo.resize(600, 400)
demo.show()
return demo
if __name__ == '__main__':
app = QApplication(sys.argv)
demo = make()
sys.exit(app.exec_())
