# -*- coding: utf-8 -*-
"""
GraphicsWidget displaying an image histogram along with gradient editor. Can be used to adjust the appearance of images.
"""
from ..Qt import QtGui, QtCore
from .. import functions as fn
from .GraphicsWidget import GraphicsWidget
from .ViewBox import *
from .GradientEditorItem import *
from .LinearRegionItem import *
from .PlotDataItem import *
from .AxisItem import *
from .GridItem import *
from ..Point import Point
from .. import functions as fn
import numpy as np
from .. import debug as debug
import weakref
__all__ = ['HistogramLUTItem']
[docs]class HistogramLUTItem(GraphicsWidget):
"""
This is a graphicsWidget which provides controls for adjusting the display of an image.
Includes:
- Image histogram
- Movable region over histogram to select black/white levels
- Gradient editor to define color lookup table for single-channel images
================ ===========================================================
image (:class:`~pyqtgraph.ImageItem` or ``None``) If *image* is
provided, then the control will be automatically linked to
the image and changes to the control will be immediately
reflected in the image's appearance.
fillHistogram (bool) By default, the histogram is rendered with a fill.
For performance, set ``fillHistogram=False``
rgbHistogram (bool) Sets whether the histogram is computed once over all
channels of the image, or once per channel.
levelMode 'mono' or 'rgba'. If 'mono', then only a single set of
black/white level lines is drawn, and the levels apply to
all channels in the image. If 'rgba', then one set of
levels is drawn for each channel.
================ ===========================================================
"""
sigLookupTableChanged = QtCore.Signal(object)
sigLevelsChanged = QtCore.Signal(object)
sigLevelChangeFinished = QtCore.Signal(object)
[docs] def __init__(self, image=None, fillHistogram=True, rgbHistogram=False, levelMode='mono'):
GraphicsWidget.__init__(self)
self.lut = None
self.imageItem = lambda: None # fake a dead weakref
self.levelMode = levelMode
self.rgbHistogram = rgbHistogram
self.layout = QtGui.QGraphicsGridLayout()
self.setLayout(self.layout)
self.layout.setContentsMargins(1,1,1,1)
self.layout.setSpacing(0)
self.vb = ViewBox(parent=self)
self.vb.setMaximumWidth(152)
self.vb.setMinimumWidth(45)
self.vb.setMouseEnabled(x=False, y=True)
self.gradient = GradientEditorItem()
self.gradient.setOrientation('right')
self.gradient.loadPreset('grey')
self.regions = [
LinearRegionItem([0, 1], 'horizontal', swapMode='block'),
LinearRegionItem([0, 1], 'horizontal', swapMode='block', pen='r',
brush=fn.mkBrush((255, 50, 50, 50)), span=(0., 1/3.)),
LinearRegionItem([0, 1], 'horizontal', swapMode='block', pen='g',
brush=fn.mkBrush((50, 255, 50, 50)), span=(1/3., 2/3.)),
LinearRegionItem([0, 1], 'horizontal', swapMode='block', pen='b',
brush=fn.mkBrush((50, 50, 255, 80)), span=(2/3., 1.)),
LinearRegionItem([0, 1], 'horizontal', swapMode='block', pen='w',
brush=fn.mkBrush((255, 255, 255, 50)), span=(2/3., 1.))]
for region in self.regions:
region.setZValue(1000)
self.vb.addItem(region)
region.lines[0].addMarker('<|', 0.5)
region.lines[1].addMarker('|>', 0.5)
region.sigRegionChanged.connect(self.regionChanging)
region.sigRegionChangeFinished.connect(self.regionChanged)
self.region = self.regions[0] # for backward compatibility.
self.axis = AxisItem('left', linkView=self.vb, maxTickLength=-10, parent=self)
self.layout.addItem(self.axis, 0, 0)
self.layout.addItem(self.vb, 0, 1)
self.layout.addItem(self.gradient, 0, 2)
self.range = None
self.gradient.setFlag(self.gradient.ItemStacksBehindParent)
self.vb.setFlag(self.gradient.ItemStacksBehindParent)
self.gradient.sigGradientChanged.connect(self.gradientChanged)
self.vb.sigRangeChanged.connect(self.viewRangeChanged)
add = QtGui.QPainter.CompositionMode_Plus
self.plots = [
PlotCurveItem(pen=(200, 200, 200, 100)), # mono
PlotCurveItem(pen=(255, 0, 0, 100), compositionMode=add), # r
PlotCurveItem(pen=(0, 255, 0, 100), compositionMode=add), # g
PlotCurveItem(pen=(0, 0, 255, 100), compositionMode=add), # b
PlotCurveItem(pen=(200, 200, 200, 100), compositionMode=add), # a
]
self.plot = self.plots[0] # for backward compatibility.
for plot in self.plots:
plot.setRotation(90)
self.vb.addItem(plot)
self.fillHistogram(fillHistogram)
self._showRegions()
self.vb.addItem(self.plot)
self.autoHistogramRange()
if image is not None:
self.setImageItem(image)
def fillHistogram(self, fill=True, level=0.0, color=(100, 100, 200)):
colors = [color, (255, 0, 0, 50), (0, 255, 0, 50), (0, 0, 255, 50), (255, 255, 255, 50)]
for i,plot in enumerate(self.plots):
if fill:
plot.setFillLevel(level)
plot.setBrush(colors[i])
else:
plot.setFillLevel(None)
def paint(self, p, *args):
if self.levelMode != 'mono':
return
pen = self.region.lines[0].pen
rgn = self.getLevels()
p1 = self.vb.mapFromViewToItem(self, Point(self.vb.viewRect().center().x(), rgn[0]))
p2 = self.vb.mapFromViewToItem(self, Point(self.vb.viewRect().center().x(), rgn[1]))
gradRect = self.gradient.mapRectToParent(self.gradient.gradRect.rect())
p.setRenderHint(QtGui.QPainter.Antialiasing)
for pen in [fn.mkPen((0, 0, 0, 100), width=3), pen]:
p.setPen(pen)
p.drawLine(p1 + Point(0, 5), gradRect.bottomLeft())
p.drawLine(p2 - Point(0, 5), gradRect.topLeft())
p.drawLine(gradRect.topLeft(), gradRect.topRight())
p.drawLine(gradRect.bottomLeft(), gradRect.bottomRight())
[docs] def setHistogramRange(self, mn, mx, padding=0.1):
"""Set the Y range on the histogram plot. This disables auto-scaling."""
self.vb.enableAutoRange(self.vb.YAxis, False)
self.vb.setYRange(mn, mx, padding)
[docs] def autoHistogramRange(self):
"""Enable auto-scaling on the histogram plot."""
self.vb.enableAutoRange(self.vb.XYAxes)
[docs] def setImageItem(self, img):
"""Set an ImageItem to have its levels and LUT automatically controlled
by this HistogramLUTItem.
"""
self.imageItem = weakref.ref(img)
img.sigImageChanged.connect(self.imageChanged)
self._setImageLookupTable()
self.regionChanged()
self.imageChanged(autoLevel=True)
def viewRangeChanged(self):
self.update()
def gradientChanged(self):
if self.imageItem() is not None:
self._setImageLookupTable()
self.lut = None
self.sigLookupTableChanged.emit(self)
def _setImageLookupTable(self):
if self.gradient.isLookupTrivial():
self.imageItem().setLookupTable(None) #lambda x: x.astype(np.uint8))
else:
self.imageItem().setLookupTable(self.getLookupTable) ## send function pointer, not the result
[docs] def getLookupTable(self, img=None, n=None, alpha=None):
"""Return a lookup table from the color gradient defined by this
HistogramLUTItem.
"""
if self.levelMode != 'mono':
return None
if n is None:
if img.dtype == np.uint8:
n = 256
else:
n = 512
if self.lut is None:
self.lut = self.gradient.getLookupTable(n, alpha=alpha)
return self.lut
def regionChanged(self):
if self.imageItem() is not None:
self.imageItem().setLevels(self.getLevels())
self.sigLevelChangeFinished.emit(self)
def regionChanging(self):
if self.imageItem() is not None:
self.imageItem().setLevels(self.getLevels())
self.update()
self.sigLevelsChanged.emit(self)
def imageChanged(self, autoLevel=False, autoRange=False):
if self.imageItem() is None:
return
if self.levelMode == 'mono':
for plt in self.plots[1:]:
plt.setVisible(False)
self.plots[0].setVisible(True)
# plot one histogram for all image data
profiler = debug.Profiler()
h = self.imageItem().getHistogram()
profiler('get histogram')
if h[0] is None:
return
self.plot.setData(*h)
profiler('set plot')
if autoLevel:
mn = h[0][0]
mx = h[0][-1]
self.region.setRegion([mn, mx])
profiler('set region')
else:
mn, mx = self.imageItem().levels
self.region.setRegion([mn, mx])
else:
# plot one histogram for each channel
self.plots[0].setVisible(False)
ch = self.imageItem().getHistogram(perChannel=True)
if ch[0] is None:
return
for i in range(1, 5):
if len(ch) >= i:
h = ch[i-1]
self.plots[i].setVisible(True)
self.plots[i].setData(*h)
if autoLevel:
mn = h[0][0]
mx = h[0][-1]
self.region[i].setRegion([mn, mx])
else:
# hide channels not present in image data
self.plots[i].setVisible(False)
# make sure we are displaying the correct number of channels
self._showRegions()
[docs] def getLevels(self):
"""Return the min and max levels.
For rgba mode, this returns a list of the levels for each channel.
"""
if self.levelMode == 'mono':
return self.region.getRegion()
else:
nch = self.imageItem().channels()
if nch is None:
nch = 3
return [r.getRegion() for r in self.regions[1:nch+1]]
[docs] def setLevels(self, min=None, max=None, rgba=None):
"""Set the min/max (bright and dark) levels.
Arguments may be *min* and *max* for single-channel data, or
*rgba* = [(rmin, rmax), ...] for multi-channel data.
"""
if self.levelMode == 'mono':
if min is None:
min, max = rgba[0]
assert None not in (min, max)
self.region.setRegion((min, max))
else:
if rgba is None:
raise TypeError("Must specify rgba argument when levelMode != 'mono'.")
for i, levels in enumerate(rgba):
self.regions[i+1].setRegion(levels)
[docs] def setLevelMode(self, mode):
""" Set the method of controlling the image levels offered to the user.
Options are 'mono' or 'rgba'.
"""
assert mode in ('mono', 'rgba')
if mode == self.levelMode:
return
oldLevels = self.getLevels()
self.levelMode = mode
self._showRegions()
# do our best to preserve old levels
if mode == 'mono':
levels = np.array(oldLevels).mean(axis=0)
self.setLevels(*levels)
else:
levels = [oldLevels] * 4
self.setLevels(rgba=levels)
# force this because calling self.setLevels might not set the imageItem
# levels if there was no change to the region item
self.imageItem().setLevels(self.getLevels())
self.imageChanged()
self.update()
def _showRegions(self):
for i in range(len(self.regions)):
self.regions[i].setVisible(False)
if self.levelMode == 'rgba':
imax = 4
if self.imageItem() is not None:
# Only show rgb channels if connected image lacks alpha.
nch = self.imageItem().channels()
if nch is None:
nch = 3
xdif = 1.0 / nch
for i in range(1, nch+1):
self.regions[i].setVisible(True)
self.regions[i].setSpan((i-1) * xdif, i * xdif)
self.gradient.hide()
elif self.levelMode == 'mono':
self.regions[0].setVisible(True)
self.gradient.show()
else:
raise ValueError("Unknown level mode %r" % self.levelMode)
def saveState(self):
return {
'gradient': self.gradient.saveState(),
'levels': self.getLevels(),
'mode': self.levelMode,
}
def restoreState(self, state):
if 'mode' in state:
self.setLevelMode(state['mode'])
self.gradient.restoreState(state['gradient'])
self.setLevels(*state['levels'])