from __future__ import division
from ..Qt import QtGui, QtCore
import numpy as np
from .. import functions as fn
from .. import debug as debug
from .GraphicsObject import GraphicsObject
from ..Point import Point
from .. import getConfigOption
try:
from collections.abc import Callable
except ImportError:
# fallback for python < 3.3
from collections import Callable
__all__ = ['ImageItem']
[docs]class ImageItem(GraphicsObject):
"""
**Bases:** :class:`GraphicsObject <pyqtgraph.GraphicsObject>`
GraphicsObject displaying an image. Optimized for rapid update (ie video display).
This item displays either a 2D numpy array (height, width) or
a 3D array (height, width, RGBa). This array is optionally scaled (see
:func:`setLevels <pyqtgraph.ImageItem.setLevels>`) and/or colored
with a lookup table (see :func:`setLookupTable <pyqtgraph.ImageItem.setLookupTable>`)
before being displayed.
ImageItem is frequently used in conjunction with
:class:`HistogramLUTItem <pyqtgraph.HistogramLUTItem>` or
:class:`HistogramLUTWidget <pyqtgraph.HistogramLUTWidget>` to provide a GUI
for controlling the levels and lookup table used to display the image.
"""
sigImageChanged = QtCore.Signal()
sigRemoveRequested = QtCore.Signal(object) # self; emitted when 'remove' is selected from context menu
[docs] def __init__(self, image=None, **kargs):
"""
See :func:`setImage <pyqtgraph.ImageItem.setImage>` for all allowed initialization arguments.
"""
GraphicsObject.__init__(self)
self.menu = None
self.image = None ## original image data
self.qimage = None ## rendered image for display
self.paintMode = None
self.levels = None ## [min, max] or [[redMin, redMax], ...]
self.lut = None
self.autoDownsample = False
self._lastDownsample = (1, 1)
self.axisOrder = getConfigOption('imageAxisOrder')
# In some cases, we use a modified lookup table to handle both rescaling
# and LUT more efficiently
self._effectiveLut = None
self.drawKernel = None
self.border = None
self.removable = False
if image is not None:
self.setImage(image, **kargs)
else:
self.setOpts(**kargs)
[docs] def setCompositionMode(self, mode):
"""Change the composition mode of the item (see QPainter::CompositionMode
in the Qt documentation). This is useful when overlaying multiple ImageItems.
============================================ ============================================================
**Most common arguments:**
QtGui.QPainter.CompositionMode_SourceOver Default; image replaces the background if it
is opaque. Otherwise, it uses the alpha channel to blend
the image with the background.
QtGui.QPainter.CompositionMode_Overlay The image color is mixed with the background color to
reflect the lightness or darkness of the background.
QtGui.QPainter.CompositionMode_Plus Both the alpha and color of the image and background pixels
are added together.
QtGui.QPainter.CompositionMode_Multiply The output is the image color multiplied by the background.
============================================ ============================================================
"""
self.paintMode = mode
self.update()
def setBorder(self, b):
self.border = fn.mkPen(b)
self.update()
def width(self):
if self.image is None:
return None
axis = 0 if self.axisOrder == 'col-major' else 1
return self.image.shape[axis]
def height(self):
if self.image is None:
return None
axis = 1 if self.axisOrder == 'col-major' else 0
return self.image.shape[axis]
def channels(self):
if self.image is None:
return None
return self.image.shape[2] if self.image.ndim == 3 else 1
def boundingRect(self):
if self.image is None:
return QtCore.QRectF(0., 0., 0., 0.)
return QtCore.QRectF(0., 0., float(self.width()), float(self.height()))
[docs] def setLevels(self, levels, update=True):
"""
Set image scaling levels. Can be one of:
* [blackLevel, whiteLevel]
* [[minRed, maxRed], [minGreen, maxGreen], [minBlue, maxBlue]]
Only the first format is compatible with lookup tables. See :func:`makeARGB <pyqtgraph.makeARGB>`
for more details on how levels are applied.
"""
if levels is not None:
levels = np.asarray(levels)
if not fn.eq(levels, self.levels):
self.levels = levels
self._effectiveLut = None
if update:
self.updateImage()
def getLevels(self):
return self.levels
#return self.whiteLevel, self.blackLevel
[docs] def setLookupTable(self, lut, update=True):
"""
Set the lookup table (numpy array) to use for this image. (see
:func:`makeARGB <pyqtgraph.makeARGB>` for more information on how this is used).
Optionally, lut can be a callable that accepts the current image as an
argument and returns the lookup table to use.
Ordinarily, this table is supplied by a :class:`HistogramLUTItem <pyqtgraph.HistogramLUTItem>`
or :class:`GradientEditorItem <pyqtgraph.GradientEditorItem>`.
"""
if lut is not self.lut:
self.lut = lut
self._effectiveLut = None
if update:
self.updateImage()
[docs] def setAutoDownsample(self, ads):
"""
Set the automatic downsampling mode for this ImageItem.
Added in version 0.9.9
"""
self.autoDownsample = ads
self.qimage = None
self.update()
def setOpts(self, update=True, **kargs):
if 'axisOrder' in kargs:
val = kargs['axisOrder']
if val not in ('row-major', 'col-major'):
raise ValueError('axisOrder must be either "row-major" or "col-major"')
self.axisOrder = val
if 'lut' in kargs:
self.setLookupTable(kargs['lut'], update=update)
if 'levels' in kargs:
self.setLevels(kargs['levels'], update=update)
#if 'clipLevel' in kargs:
#self.setClipLevel(kargs['clipLevel'])
if 'opacity' in kargs:
self.setOpacity(kargs['opacity'])
if 'compositionMode' in kargs:
self.setCompositionMode(kargs['compositionMode'])
if 'border' in kargs:
self.setBorder(kargs['border'])
if 'removable' in kargs:
self.removable = kargs['removable']
self.menu = None
if 'autoDownsample' in kargs:
self.setAutoDownsample(kargs['autoDownsample'])
if update:
self.update()
[docs] def setRect(self, rect):
"""Scale and translate the image to fit within rect (must be a QRect or QRectF)."""
self.resetTransform()
self.translate(rect.left(), rect.top())
self.scale(rect.width() / self.width(), rect.height() / self.height())
def clear(self):
self.image = None
self.prepareGeometryChange()
self.informViewBoundsChanged()
self.update()
[docs] def setImage(self, image=None, autoLevels=None, **kargs):
"""
Update the image displayed by this item. For more information on how the image
is processed before displaying, see :func:`makeARGB <pyqtgraph.makeARGB>`
================= =========================================================================
**Arguments:**
image (numpy array) Specifies the image data. May be 2D (width, height) or
3D (width, height, RGBa). The array dtype must be integer or floating
point of any bit depth. For 3D arrays, the third dimension must
be of length 3 (RGB) or 4 (RGBA). See *notes* below.
autoLevels (bool) If True, this forces the image to automatically select
levels based on the maximum and minimum values in the data.
By default, this argument is true unless the levels argument is
given.
lut (numpy array) The color lookup table to use when displaying the image.
See :func:`setLookupTable <pyqtgraph.ImageItem.setLookupTable>`.
levels (min, max) The minimum and maximum values to use when rescaling the image
data. By default, this will be set to the minimum and maximum values
in the image. If the image array has dtype uint8, no rescaling is necessary.
opacity (float 0.0-1.0)
compositionMode See :func:`setCompositionMode <pyqtgraph.ImageItem.setCompositionMode>`
border Sets the pen used when drawing the image border. Default is None.
autoDownsample (bool) If True, the image is automatically downsampled to match the
screen resolution. This improves performance for large images and
reduces aliasing. If autoDownsample is not specified, then ImageItem will
choose whether to downsample the image based on its size.
================= =========================================================================
**Notes:**
For backward compatibility, image data is assumed to be in column-major order (column, row).
However, most image data is stored in row-major order (row, column) and will need to be
transposed before calling setImage()::
imageitem.setImage(imagedata.T)
This requirement can be changed by calling ``image.setOpts(axisOrder='row-major')`` or
by changing the ``imageAxisOrder`` :ref:`global configuration option <apiref_config>`.
"""
profile = debug.Profiler()
gotNewData = False
if image is None:
if self.image is None:
return
else:
gotNewData = True
shapeChanged = (self.image is None or image.shape != self.image.shape)
image = image.view(np.ndarray)
if self.image is None or image.dtype != self.image.dtype:
self._effectiveLut = None
self.image = image
if self.image.shape[0] > 2**15-1 or self.image.shape[1] > 2**15-1:
if 'autoDownsample' not in kargs:
kargs['autoDownsample'] = True
if shapeChanged:
self.prepareGeometryChange()
self.informViewBoundsChanged()
profile()
if autoLevels is None:
if 'levels' in kargs:
autoLevels = False
else:
autoLevels = True
if autoLevels:
img = self.image
while img.size > 2**16:
img = img[::2, ::2]
mn, mx = np.nanmin(img), np.nanmax(img)
# mn and mx can still be NaN if the data is all-NaN
if mn == mx or np.isnan(mn) or np.isnan(mx):
mn = 0
mx = 255
kargs['levels'] = [mn,mx]
profile()
self.setOpts(update=False, **kargs)
profile()
self.qimage = None
self.update()
profile()
if gotNewData:
self.sigImageChanged.emit()
def mapToData(self, obj):
tr = self.inverseDataTransform()
return tr.map(obj)
def mapFromData(self, obj):
tr = self.dataTransform()
return tr.map(obj)
[docs] def quickMinMax(self, targetSize=1e6):
"""
Estimate the min/max values of the image data by subsampling.
"""
data = self.image
while data.size > targetSize:
ax = np.argmax(data.shape)
sl = [slice(None)] * data.ndim
sl[ax] = slice(None, None, 2)
data = data[sl]
return np.nanmin(data), np.nanmax(data)
def updateImage(self, *args, **kargs):
## used for re-rendering qimage from self.image.
## can we make any assumptions here that speed things up?
## dtype, range, size are all the same?
defaults = {
'autoLevels': False,
}
defaults.update(kargs)
return self.setImage(*args, **defaults)
def render(self):
# Convert data to QImage for display.
profile = debug.Profiler()
if self.image is None or self.image.size == 0:
return
# Request a lookup table if this image has only one channel
if self.image.ndim == 2 or self.image.shape[2] == 1:
if isinstance(self.lut, Callable):
lut = self.lut(self.image)
else:
lut = self.lut
else:
lut = None
if self.autoDownsample:
# reduce dimensions of image based on screen resolution
o = self.mapToDevice(QtCore.QPointF(0,0))
x = self.mapToDevice(QtCore.QPointF(1,0))
y = self.mapToDevice(QtCore.QPointF(0,1))
# Check if graphics view is too small to render anything
if o is None or x is None or y is None:
return
w = Point(x-o).length()
h = Point(y-o).length()
if w == 0 or h == 0:
self.qimage = None
return
xds = max(1, int(1.0 / w))
yds = max(1, int(1.0 / h))
axes = [1, 0] if self.axisOrder == 'row-major' else [0, 1]
image = fn.downsample(self.image, xds, axis=axes[0])
image = fn.downsample(image, yds, axis=axes[1])
self._lastDownsample = (xds, yds)
# Check if downsampling reduced the image size to zero due to inf values.
if image.size == 0:
return
else:
image = self.image
# if the image data is a small int, then we can combine levels + lut
# into a single lut for better performance
levels = self.levels
if levels is not None and levels.ndim == 1 and image.dtype in (np.ubyte, np.uint16):
if self._effectiveLut is None:
eflsize = 2**(image.itemsize*8)
ind = np.arange(eflsize)
minlev, maxlev = levels
levdiff = maxlev - minlev
levdiff = 1 if levdiff == 0 else levdiff # don't allow division by 0
if lut is None:
efflut = fn.rescaleData(ind, scale=255./levdiff,
offset=minlev, dtype=np.ubyte)
else:
lutdtype = np.min_scalar_type(lut.shape[0]-1)
efflut = fn.rescaleData(ind, scale=(lut.shape[0]-1)/levdiff,
offset=minlev, dtype=lutdtype, clip=(0, lut.shape[0]-1))
efflut = lut[efflut]
self._effectiveLut = efflut
lut = self._effectiveLut
levels = None
# Convert single-channel image to 2D array
if image.ndim == 3 and image.shape[-1] == 1:
image = image[..., 0]
# Assume images are in column-major order for backward compatibility
# (most images are in row-major order)
if self.axisOrder == 'col-major':
image = image.transpose((1, 0, 2)[:image.ndim])
argb, alpha = fn.makeARGB(image, lut=lut, levels=levels)
self.qimage = fn.makeQImage(argb, alpha, transpose=False)
def paint(self, p, *args):
profile = debug.Profiler()
if self.image is None:
return
if self.qimage is None:
self.render()
if self.qimage is None:
return
profile('render QImage')
if self.paintMode is not None:
p.setCompositionMode(self.paintMode)
profile('set comp mode')
shape = self.image.shape[:2] if self.axisOrder == 'col-major' else self.image.shape[:2][::-1]
p.drawImage(QtCore.QRectF(0,0,*shape), self.qimage)
profile('p.drawImage')
if self.border is not None:
p.setPen(self.border)
p.drawRect(self.boundingRect())
[docs] def save(self, fileName, *args):
"""Save this image to file. Note that this saves the visible image (after scale/color changes), not the original data."""
if self.qimage is None:
self.render()
self.qimage.save(fileName, *args)
[docs] def getHistogram(self, bins='auto', step='auto', perChannel=False, targetImageSize=200,
targetHistogramSize=500, **kwds):
"""Returns x and y arrays containing the histogram values for the current image.
For an explanation of the return format, see numpy.histogram().
The *step* argument causes pixels to be skipped when computing the histogram to save time.
If *step* is 'auto', then a step is chosen such that the analyzed data has
dimensions roughly *targetImageSize* for each axis.
The *bins* argument and any extra keyword arguments are passed to
np.histogram(). If *bins* is 'auto', then a bin number is automatically
chosen based on the image characteristics:
* Integer images will have approximately *targetHistogramSize* bins,
with each bin having an integer width.
* All other types will have *targetHistogramSize* bins.
If *perChannel* is True, then the histogram is computed once per channel
and the output is a list of the results.
This method is also used when automatically computing levels.
"""
if self.image is None or self.image.size == 0:
return None, None
if step == 'auto':
step = (max(1, int(np.ceil(self.image.shape[0] / targetImageSize))),
max(1, int(np.ceil(self.image.shape[1] / targetImageSize))))
if np.isscalar(step):
step = (step, step)
stepData = self.image[::step[0], ::step[1]]
if isinstance(bins, str) and bins == 'auto':
mn = np.nanmin(stepData)
mx = np.nanmax(stepData)
if mx == mn:
# degenerate image, arange will fail
mx += 1
if np.isnan(mn) or np.isnan(mx):
# the data are all-nan
return None, None
if stepData.dtype.kind in "ui":
# For integer data, we select the bins carefully to avoid aliasing
step = np.ceil((mx-mn) / 500.)
bins = np.arange(mn, mx+1.01*step, step, dtype=np.int)
else:
# for float data, let numpy select the bins.
bins = np.linspace(mn, mx, 500)
if len(bins) == 0:
bins = [mn, mx]
kwds['bins'] = bins
if perChannel:
hist = []
for i in range(stepData.shape[-1]):
stepChan = stepData[..., i]
stepChan = stepChan[np.isfinite(stepChan)]
h = np.histogram(stepChan, **kwds)
hist.append((h[1][:-1], h[0]))
return hist
else:
stepData = stepData[np.isfinite(stepData)]
hist = np.histogram(stepData, **kwds)
return hist[1][:-1], hist[0]
[docs] def setPxMode(self, b):
"""
Set whether the item ignores transformations and draws directly to screen pixels.
If True, the item will not inherit any scale or rotation transformations from its
parent items, but its position will be transformed as usual.
(see GraphicsItem::ItemIgnoresTransformations in the Qt documentation)
"""
self.setFlag(self.ItemIgnoresTransformations, b)
def setScaledMode(self):
self.setPxMode(False)
def getPixmap(self):
if self.qimage is None:
self.render()
if self.qimage is None:
return None
return QtGui.QPixmap.fromImage(self.qimage)
[docs] def pixelSize(self):
"""return scene-size of a single pixel in the image"""
br = self.sceneBoundingRect()
if self.image is None:
return 1,1
return br.width()/self.width(), br.height()/self.height()
def viewTransformChanged(self):
if self.autoDownsample:
o = self.mapToDevice(QtCore.QPointF(0,0))
x = self.mapToDevice(QtCore.QPointF(1,0))
y = self.mapToDevice(QtCore.QPointF(0,1))
w = Point(x-o).length()
h = Point(y-o).length()
if w == 0 or h == 0:
self.qimage = None
return
xds = max(1, int(1.0 / w))
yds = max(1, int(1.0 / h))
if (xds, yds) != self._lastDownsample:
self.qimage = None
self.update()
def mouseDragEvent(self, ev):
if ev.button() != QtCore.Qt.LeftButton:
ev.ignore()
return
elif self.drawKernel is not None:
ev.accept()
self.drawAt(ev.pos(), ev)
def mouseClickEvent(self, ev):
if ev.button() == QtCore.Qt.RightButton:
if self.raiseContextMenu(ev):
ev.accept()
if self.drawKernel is not None and ev.button() == QtCore.Qt.LeftButton:
self.drawAt(ev.pos(), ev)
def raiseContextMenu(self, ev):
menu = self.getMenu()
if menu is None:
return False
menu = self.scene().addParentContextMenus(self, menu, ev)
pos = ev.screenPos()
menu.popup(QtCore.QPoint(pos.x(), pos.y()))
return True
def getMenu(self):
if self.menu is None:
if not self.removable:
return None
self.menu = QtGui.QMenu()
self.menu.setTitle("Image")
remAct = QtGui.QAction("Remove image", self.menu)
remAct.triggered.connect(self.removeClicked)
self.menu.addAction(remAct)
self.menu.remAct = remAct
return self.menu
def hoverEvent(self, ev):
if not ev.isExit() and self.drawKernel is not None and ev.acceptDrags(QtCore.Qt.LeftButton):
ev.acceptClicks(QtCore.Qt.LeftButton) ## we don't use the click, but we also don't want anyone else to use it.
ev.acceptClicks(QtCore.Qt.RightButton)
elif not ev.isExit() and self.removable:
ev.acceptClicks(QtCore.Qt.RightButton) ## accept context menu clicks
def tabletEvent(self, ev):
pass
#print(ev.device())
#print(ev.pointerType())
#print(ev.pressure())
def drawAt(self, pos, ev=None):
pos = [int(pos.x()), int(pos.y())]
dk = self.drawKernel
kc = self.drawKernelCenter
sx = [0,dk.shape[0]]
sy = [0,dk.shape[1]]
tx = [pos[0] - kc[0], pos[0] - kc[0]+ dk.shape[0]]
ty = [pos[1] - kc[1], pos[1] - kc[1]+ dk.shape[1]]
for i in [0,1]:
dx1 = -min(0, tx[i])
dx2 = min(0, self.image.shape[0]-tx[i])
tx[i] += dx1+dx2
sx[i] += dx1+dx2
dy1 = -min(0, ty[i])
dy2 = min(0, self.image.shape[1]-ty[i])
ty[i] += dy1+dy2
sy[i] += dy1+dy2
ts = (slice(tx[0],tx[1]), slice(ty[0],ty[1]))
ss = (slice(sx[0],sx[1]), slice(sy[0],sy[1]))
mask = self.drawMask
src = dk
if isinstance(self.drawMode, Callable):
self.drawMode(dk, self.image, mask, ss, ts, ev)
else:
src = src[ss]
if self.drawMode == 'set':
if mask is not None:
mask = mask[ss]
self.image[ts] = self.image[ts] * (1-mask) + src * mask
else:
self.image[ts] = src
elif self.drawMode == 'add':
self.image[ts] += src
else:
raise Exception("Unknown draw mode '%s'" % self.drawMode)
self.updateImage()
def setDrawKernel(self, kernel=None, mask=None, center=(0,0), mode='set'):
self.drawKernel = kernel
self.drawKernelCenter = center
self.drawMode = mode
self.drawMask = mask
def removeClicked(self):
## Send remove event only after we have exited the menu event handler
self.removeTimer = QtCore.QTimer()
self.removeTimer.timeout.connect(self.emitRemoveRequested)
self.removeTimer.start(0)
def emitRemoveRequested(self):
self.removeTimer.timeout.disconnect(self.emitRemoveRequested)
self.sigRemoveRequested.emit(self)