import os import pathlib import warnings from collections.abc import Callable import numpy as np import numpy.typing as npt from .. import colormap from .. import debug as debug from .. import functions as fn from .. import functions_qimage from .. import getConfigOption from ..Point import Point from ..Qt import QtCore, QtGui, QtWidgets from ..util.cupy_helper import getCupy from .GraphicsObject import GraphicsObject translate = QtCore.QCoreApplication.translate __all__ = ['ImageItem'] class ImageItem(GraphicsObject): """ Graphics object used to display image data. ImageItem can render images with 1, 3 or 4 channels, use lookup tables to apply false colors to images, and users can either set levels limits, or rely on the auto-sampling. Performance can vary wildly based on the attributes of the inputs provided, see :ref:`performance ` for guidance if performance is an important factor. There is optional `numba` and `cupy` support. **Bases:** :class:`pyqtgraph.GraphicsObject` Parameters ---------- image : np.ndarray or None, default None Image data. **kargs : dict, optional Arguments directed to `setImage` and `setOpts`, refer to each method for documentation for possible arguments. Signals ------- sigImageChanged: :class:`Signal` Emitted when the image is changed. sigRemoveRequested: :class:`Signal` Emitted when there is a request to remove the image. Signal emits the instance of the :class:`~pyqtgraph.ImageItem` whose removal is requested. See Also -------- setImage : For descriptions of available keyword arguments. setOpts : For information on supported formats. """ sigImageChanged = QtCore.Signal() sigRemoveRequested = QtCore.Signal(object) def __init__(self, image: np.ndarray | None=None, **kargs): super().__init__() 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._nanPolicy = 'propagate' self._colorMap = None # This is only set if a color map is assigned directly self._lastDownsample = (1, 1) self._processingBuffer = None self._displayBuffer = None self._renderRequired = True self._unrenderable = False self._xp = None # either numpy or cupy, to match the image data self._defferedLevels = None self._imageHasNans = None # None : not yet known self._imageNanLocations = None self._defaultAutoLevels = True self.axisOrder = getConfigOption('imageAxisOrder') self._dataTransform = self._inverseDataTransform = QtGui.QTransform() self._update_data_transforms( self.axisOrder ) # install initial transforms self.drawKernel = None self.border = None self.removable = False if image is not None: self.setImage(image, **kargs) else: self.setOpts(**kargs) def setCompositionMode(self, mode: QtGui.QPainter.CompositionMode): """ Change the composition mode of the item, useful when overlaying multiple items. Parameters ---------- mode : :class:`QPainter.CompositionMode ` Composition of the item, often used when overlaying items. Common options include: * `QPainter.CompositionMode.CompositionMode_SourceOver` Image replaces the background if it is opaque. Otherwise, it uses the alpha channel to blend the image with the background, default. * `QPainter.CompositionMode.CompositionMode_Overlay` Image color is mixed with the background color to reflect the lightness or darkness of the background. * `QPainter.CompositionMode.CompositionMode_Plus` Both the alpha and color of the image and background pixels are added together. * `QPainter.CompositionMode.CompositionMode_Plus` The output is the image color multiplied by the background. See :class:`QPainter.CompositionMode ` in the Qt documentation for more options and details. See Also -------- :class:`QPainter.CompositionMode ` : Details all the possible composition mode options accepted. """ self.paintMode = mode self.update() def setBorder(self, b): """ Define the color of the border drawn around the image. Parameters ---------- b : color_like Accepts all arguments supported by :func:`~pyqtgraph.mkPen`. """ self.border = fn.mkPen(b) self.update() def width(self) -> int | None: if self.image is None: return None axis = 0 if self.axisOrder == 'col-major' else 1 return self.image.shape[axis] def height(self) -> int | None: if self.image is None: return None axis = 1 if self.axisOrder == 'col-major' else 0 return self.image.shape[axis] def channels(self) -> int | None: if self.image is None: return None return self.image.shape[2] if self.image.ndim == 3 else 1 def boundingRect(self) -> QtCore.QRectF: if self.image is None: return QtCore.QRectF(0., 0., 0., 0.) if (width := self.width()) is None: width = 0. if (height := self.height()) is None: height = 0. return QtCore.QRectF(0., 0., float(width), float(height)) def setAutoLevels(self, bState: bool): """ Controls whether automatic image scaling takes place for this ImageItem, if not otherwise overridden by ``autoLevels`` or ``levels`` keyword arguments in a call to :func:`~pyqtgraph.ImageItem.setImage`. """ self._defaultAutoLevels = bState def setLevels(self, levels: npt.ArrayLike | None, update: bool=True): """ Set image scaling levels. Calling this method, even with ``levels=None`` will disable auto leveling which is equivalent to :meth:`setImage` with ``autoLevels=False``. Parameters ---------- levels : array_like or None Sets the numerical values that correspond to the limits of the color range. * ``[blackLevel, whiteLevel]`` sets black and white levels for monochrome data and can be used with a lookup table. * ``[[minR, maxR], [minG, maxG], [minB, maxB]]`` sets individual scaling for RGB values. Not compatible with lookup tables. * ``None`` Disables the application of levels, but setting to ``None`` prevents the auto-levels mechanism from sampling the image. Not compatible with images that use floating point dtypes. update : bool, default True Update the image immediately to reflect the new levels. See Also -------- pyqtgraph.functions.makeARGB For more details on how levels are applied. """ if self._xp is None: self.levels = levels self._defferedLevels = levels return if levels is not None: levels = self._xp.asarray(levels) self.levels = levels if update: self.updateImage() def getLevels(self) -> np.ndarray | None: """ Return the array representing the current level settings. See :meth:`setLevels`. When `autoLevels` is active, the format is ``[blackLevel, whiteLevel]``. Returns ------- np.ndarray or None The value that the levels are set to. """ return self.levels def setColorMap(self, colorMap: colormap.ColorMap | str): """ Set a color map for false color display of a monochrome image. Parameters ---------- colorMap : :class:`~pyqtgraph.ColorMap` or `str` A string argument will be passed to :func:`colormap.get() `. Raises ------ TypeError Raised when `colorMap` is not of type `str` or :class:`~pyqtgraph.ColorMap`. """ if isinstance(colorMap, colormap.ColorMap): self._colorMap = colorMap elif isinstance(colorMap, str): self._colorMap = colormap.get(colorMap) else: raise TypeError("'colorMap' argument must be ColorMap or string") self.setLookupTable( self._colorMap.getLookupTable(nPts=256) ) def getColorMap(self) -> colormap.ColorMap | None: """ Retrieve the :class:`~pyqtgraph.ColorMap` object currently used. Returns ------- ColorMap or None The assigned :class:`~pyqtgraph.ColorMap`, or `None` if not available. """ return self._colorMap def setLookupTable(self, lut: npt.ArrayLike | Callable, update: bool=True): """ Set lookup table `lut` to use for false color display of a monochrome image. Ordinarily, this table is supplied by a :class:`~pyqtgraph.HistogramLUTItem`, :class:`~pyqtgraph.GradientEditorItem` or :class:`~pyqtgraph.ColorBarItem`. Parameters ---------- lut : array_like or callable If `lut` is an np.ndarray, ensure the dtype is `np.uint8`. Alternatively can be a callable that accepts the current image as an argument and returns the lookup table to use. Support for callable will be removed in a future version of pyqtgraph. update : bool, default True Update the intermediate image. See Also -------- :func:`pyqtgraph.functions.makeARGB` See this function for more information on how this is used. :meth:`ColorMap.getLookupTable ` Can construct a lookup table from a :class:`~pyqtgraph.ColorMap` object. Notes ----- For performance reasons, if not passing a callable, every effort should be made to keep the number of entries to `<= 256`. """ if lut is not self.lut: if self._xp is not None: lut = self._ensure_proper_substrate(lut, self._xp) self.lut = lut if update: self.updateImage() @staticmethod def _ensure_proper_substrate(data: Callable | npt.ArrayLike, substrate) -> np.ndarray: if data is None or isinstance(data, (Callable, substrate.ndarray)): return data cupy = getCupy() if substrate == cupy and not isinstance(data, cupy.ndarray): data = cupy.asarray(data) elif substrate == np: if cupy is not None and isinstance(data, cupy.ndarray): data = data.get() else: data = np.asarray(data) return data def setAutoDownsample(self, active: bool=True): """ Control automatic downsampling for this ImageItem. Parameters ---------- active : bool, default True If `active` is ``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. ``False`` disables automatic downsampling. """ self.autoDownsample = active self._renderRequired = True self.update() def nanPolicy(self) -> str: """ Retrieve the string representing the current NaN policy. See :meth:setNanPolicy. Returns ------- { 'propagate', 'omit' } The NaN policy that this ImageItem uses during downsampling. """ return self._nanPolicy def setNanPolicy(self, nanPolicy: str): """ Control how NaN values are handled during downsampling for this ImageItem. Parameters ---------- nanPolicy : { 'propagate', 'omit' } If 'nanPolicy' is 'ignore', NaNs are automatically ignored during downsampling, at the expense of performance. If 'nanPolicy' is 'propagate', NaNs are kept during downsampling. Unless a different policy was specified, a new ImageItem is created with ``nanPolicy='propagate'``. """ if nanPolicy not in ['propagate', 'omit']: raise ValueError(f"{nanPolicy=} must be one of {'propagate', 'omit'}") self._nanPolicy = nanPolicy self._renderRequired = True self.update() def setOpts(self, update: bool=True, **kwargs): """ Set display and processing options for this ImageItem. :class:`~pyqtgraph.ImageItem` and :meth:`setImage` support all keyword arguments listed here. Parameters ---------- update : bool, default True Controls if image immediately updates to reflect the new options. **kwargs : dict, optional Extra arguments that are directed to the respective methods. Expected keys include: * `autoDownsample` whose value is directed to :meth:`setAutoDownsample` * `nanPolicy` whose value is directed to :meth:`setNanPolicy` * `axisOrder`, which needs to be one of {'row-major', 'col-major'}, determines the relationship between the numpy axis and visual axis of the data. * `border`, whose value is directed to :meth:`setBorder` * `colorMap`, whose value is directed to :meth:`setColorMap` * `compositionMode`, whose value is directed to :meth:`setCompositionMode` * `levels` whose value is directed to :meth:`setLevels` * `lut`, whose value is directed to :meth:`setLookupTable` * `opacify` whose value is directed to :meth:`QGraphicsItem.setOpacity ` * `rect` whose value is directed to :meth:`setRect` * `removable` boolean, determines if the context menu is available See Also -------- :meth:`setAutoDownsample` Accepts the value of ``kwargs['autoDownsample']``. :meth:`setAutoLevels` Accepts the value of ``kwargs['autoLevels']``. :meth:`setNanPolicy` Accepts the value of ``kwargs['nanPolicy']``. :meth:`setBorder` Accepts the value of ``kwargs['border']``. :meth:`setColorMap` Accepts the value of ``kwargs['colorMap']``. :meth:`setCompositionMode` Accepts the value of ``kwargs['compositionMode']``. :meth:`setImage` Accepts the value of ``kwargs['image']``. :meth:`setLevels` Accepts the value of ``kwargs['levels']``. :meth:`setLookupTable` Accepts the value of ``kwargs['lut']``. :meth:`QGraphicsItem.setOpacity ` Accepts the value of ``kwargs['opacity']``. :meth:`setRect` Accepts the value of ``kwargs['rect']``. """ if 'axisOrder' in kwargs: val = kwargs['axisOrder'] if val not in ('row-major', 'col-major'): raise ValueError("axisOrder must be either 'row-major' or 'col-major'") self.axisOrder = val self._update_data_transforms(self.axisOrder) # update cached transforms if 'colorMap' in kwargs: self.setColorMap(kwargs['colorMap']) if 'lut' in kwargs: self.setLookupTable(kwargs['lut'], update=update) if 'levels' in kwargs: self.setLevels(kwargs['levels'], update=update) #if 'clipLevel' in kargs: #self.setClipLevel(kargs['clipLevel']) if 'opacity' in kwargs: self.setOpacity(kwargs['opacity']) if 'compositionMode' in kwargs: self.setCompositionMode(kwargs['compositionMode']) if 'border' in kwargs: self.setBorder(kwargs['border']) if 'removable' in kwargs: self.removable = kwargs['removable'] self.menu = None if 'autoDownsample' in kwargs: self.setAutoDownsample(kwargs['autoDownsample']) if 'autoLevels' in kwargs: self.setAutoLevels(kwargs['autoLevels']) if 'nanPolicy' in kwargs: self.setNanPolicy(kwargs['nanPolicy']) if 'rect' in kwargs: self.setRect(kwargs['rect']) if update: self.update() def setRect(self, *args): """ Set view rectangle for the :class:`~pyqtgraph.ImageItem` to occupy. In addition to accepting a :class:`QRectF`, you can pass the numerical values representing the `x, y, w, h`, where `x, y` represent the x, y coordinates of the top left corner, and `w` and `h` represent the width and height respectively. Parameters ---------- *args : tuple Contains one of :class:`QRectF`, :class:`QRect`, or arguments that can be used to construct :class:`QRectF`. See Also -------- :class:`QRectF` : See constructor methods for allowable `*args`. Notes ----- This method cannot be used before an image is assigned. See the :ref:`examples ` for how to manually set transformations. """ if not args: # reset scaling and rotation when called without argument self.resetTransform() return if isinstance(args[0], (QtCore.QRectF, QtCore.QRect)): rect = args[0] # use QRectF or QRect directly else: if hasattr(args[0],'__len__'): args = args[0] # promote tuple or list of values # QRectF(x,y,w,h), but also accepts other initializers rect = QtCore.QRectF( *args ) tr = QtGui.QTransform() tr.translate(rect.left(), rect.top()) if (width := self.width()) is None: width = 1. if (height := self.height()) is None: height = 1. tr.scale(rect.width() / width, rect.height() / height) self.setTransform(tr) def clear(self): """ Clear the assigned image. """ self.image = None self.prepareGeometryChange() self.informViewBoundsChanged() self.update() def _buildQImageBuffer(self, shape: tuple[int, int, int]): self._displayBuffer = np.empty(shape[:2] + (4,), dtype=np.ubyte) if self._xp == getCupy(): self._processingBuffer = self._xp.empty( shape[:2] + (4,), dtype=self._xp.ubyte ) else: self._processingBuffer = self._displayBuffer self.qimage = None def setImage( self, image: np.ndarray | None=None, autoLevels: bool | None=None, levelSamples: int = 65536, **kwargs ): """ Update the image displayed by this ImageItem. All keywords supported by :meth:`setOpts` are also allowed here. Parameters ---------- image : np.ndarray or None, default None Image data given as NumPy array with an integer or floating point dtype of any bit depth. A 2-dimensional array describes single-valued (monochromatic) data. A 3-dimensional array is used to give individual color components. The third dimension must be of length 3 (RGB) or 4 (RGBA). ``np.nan`` values are treated as transparent pixels. autoLevels : bool or None, default None If ``True``, ImageItem will automatically select levels based on the maximum and minimum values encountered in the data. For performance reasons, this search sub-samples the images and may miss individual bright or dark points in the data set. If ``False``, the search will be omitted. If ``None``, the value set by :func:`~pyqtgraph.ImageItem.setOpts` is used, unless a ``levels`` keyword argument is given, which implies `False`. levelSamples : int, default 65536 Only used when ``autoLevels is None``. When determining minimum and maximum values, ImageItem only inspects a subset of pixels no larger than this number. Setting this larger than the total number of pixels considers all values. See `quickMinMax`. **kwargs : dict, optional Extra arguments that are passed to `setOpts`. See Also -------- quickMinMax See this method for how levelSamples value is utilized. :func:`pyqtgraph.functions.makeARGB` See this function for how image data is modified prior to rendering. Notes ----- For backward compatibility, image data is assumed to be in column-major order (column, row) by default. However, most data is stored in row-major order (row, column). It can either be transposed before assignment .. code-block:: python imageitem.setImage(imagedata.T) or the interpretation of the data can be changed locally through the `axisOrder` keyword or by changing the `imageAxisOrder` :ref:`global configuration option `. """ profile = debug.Profiler() gotNewData = False if image is None: if self.image is None: return else: old_xp = self._xp cp = getCupy() self._xp = cp.get_array_module(image) if cp else np gotNewData = True processingSubstrateChanged = old_xp != self._xp if processingSubstrateChanged: self._processingBuffer = None shapeChanged = ( processingSubstrateChanged or self.image is None or image.shape != self.image.shape ) image = image.view() self.image = image self._imageHasNans = None self._imageNanLocations = None if 'autoDownsample' not in kwargs and ( self.image.shape[0] > 2**15-1 or self.image.shape[1] > 2**15-1 ): kwargs['autoDownsample'] = True if shapeChanged: self.prepareGeometryChange() self.informViewBoundsChanged() profile() if autoLevels is None: autoLevels = False if 'levels' in kwargs else self._defaultAutoLevels if autoLevels: mn, mx = self.quickMinMax( targetSize=levelSamples ) # mn and mx can still be NaN if the data is all-NaN if mn == mx or self._xp.isnan(mn) or self._xp.isnan(mx): mn = 0 mx = 255 kwargs['levels'] = self._xp.asarray((mn,mx)) profile() self.setOpts(update=False, **kwargs) profile() self._renderRequired = True self.update() profile() if gotNewData: self.sigImageChanged.emit() if self._defferedLevels is not None: levels = self._defferedLevels self._defferedLevels = None self.setLevels((levels)) def _update_data_transforms(self, axisOrder: str='col-major'): """ Set up the transforms needed to map between input array and display. Parameters ---------- axisOrder : { 'col-major', 'row-major' } The axis order to update the data transformation to. """ self._dataTransform = QtGui.QTransform() self._inverseDataTransform = QtGui.QTransform() if self.axisOrder == 'row-major': # transpose both self._dataTransform.scale(1, -1) self._dataTransform.rotate(-90) self._inverseDataTransform.scale(1, -1) self._inverseDataTransform.rotate(-90) def dataTransform(self): """ Get the transform mapping image array to local coordinate system. This transform corrects for the transposition that occurs when image data is interpreted in row-major order. :meta private: Returns ------- :class:`QTransform` The transform that is used for mapping. """ # Might eventually need to account for downsampling / clipping here # transforms are updated in setOpts call. return self._dataTransform def inverseDataTransform(self) -> QtGui.QTransform: """ Get the transform mapping local coordinate system to image array. :meta private: Returns ------- :class:`QTransform` The transform that is used for mapping. See Also -------- dataTransform See dataTransform() for more information. """ # transforms are updated in setOpts call. return self._inverseDataTransform def mapToData(self, obj): return self._inverseDataTransform.map(obj) def mapFromData(self, obj): return self._dataTransform.map(obj) def quickMinMax(self, targetSize: int=1_000_000) -> tuple[float, float]: """ Estimate the min and max values of the image data by sub-sampling. Sampling is performed at regular strides chosen to evaluate a number of samples equal to or less than `targetSize`. Returns the estimated min and max values of the image data. Parameters ---------- targetSize : int, default 1_000_000 The number of pixels to downsample the image to. Returns ------- float, float Estimated minimum and maximum values of the image data. """ data = self.image if data is None: # image hasn't been set yet return 0., 0. targetSize = max(targetSize, 2) # keep at least 2 pixels while True: h, w = data.shape[:2] if h * w <= targetSize: break data = data[::2, ::] if h > w else data[::, ::2] return self._xp.nanmin(data), self._xp.nanmax(data) def updateImage(self, *args, **kargs): defaults = { 'autoLevels': False, } | kargs return self.setImage(*args, **defaults) def render(self): # Convert data to QImage for display. self._unrenderable = True 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: self.lut = self._ensure_proper_substrate(self.lut, self._xp) if isinstance(self.lut, Callable): lut = self._ensure_proper_substrate( self.lut(self.image, 256), self._xp ) else: lut = self.lut else: lut = None if self._imageHasNans is None: # awkward, but fastest numpy native nan evaluation self._imageHasNans = ( self.image.dtype.kind == 'f' and self._xp.isnan(self.image.min()) ) self._imageNanLocations = None image = self.image if self.autoDownsample: xds, yds = self._computeDownsampleFactors() if xds is None: return axes = [1, 0] if self.axisOrder == 'row-major' else [0, 1] nan_policy = self._nanPolicy if self._imageHasNans else 'propagate' image = fn.downsample(image, xds, axis=axes[0], nanPolicy=nan_policy) image = fn.downsample(image, yds, axis=axes[1], nanPolicy=nan_policy) self._lastDownsample = (xds, yds) # changes in view transform cause changes in downsampling factors, # which invalidates any previously calculated nan locations self._imageNanLocations = None # Check if downsampling reduced the image size to zero due to inf values. if image.size == 0: return # 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.swapaxes(0, 1) levels = self.levels qimage = None if lut is not None and lut.dtype != self._xp.uint8: # try_make_image() assumes that lut is of type uint8. # It is considered a usage error if that is not the case. # However, the makeARGB() code-path has previously allowed such # a usage to work. Rather than fail outright, we delegate this # case to makeARGB(). warnings.warn( ("Using non-uint8 LUTs is an undocumented accidental feature and may " "be removed at some point in the future. Please open an issue if you " "instead believe this to be worthy of protected inclusion in " "pyqtgraph."), DeprecationWarning, stacklevel=2 ) elif not self._imageHasNans: qimage = functions_qimage.try_make_qimage(image, levels=levels, lut=lut) elif image.ndim in (2, 3): # float images with nans if self._imageNanLocations is None: # the number of nans is expected to be small nanmask = self._xp.isnan(image) if nanmask.ndim == 3: nanmask = nanmask.any(axis=2) self._imageNanLocations = nanmask.nonzero() qimage = functions_qimage.try_make_qimage( image, levels=levels, lut=lut, transparentLocations=self._imageNanLocations ) if qimage is not None: self._processingBuffer = None self._displayBuffer = None self.qimage = qimage self._renderRequired = False self._unrenderable = False return if ( self._processingBuffer is None or self._processingBuffer.shape[:2] != image.shape[:2] ): self._buildQImageBuffer(image.shape) fn.makeARGB(image, lut=lut, levels=levels, output=self._processingBuffer) if self._xp == getCupy(): self._processingBuffer.get(out=self._displayBuffer) self.qimage = fn.ndarray_to_qimage( self._displayBuffer, QtGui.QImage.Format.Format_ARGB32 ) self._renderRequired = False self._unrenderable = False def paint(self, painter, *args): profile = debug.Profiler() if self.image is None: return if self._renderRequired: self.render() if self._unrenderable: return profile('render QImage') if self.paintMode is not None: painter.setCompositionMode(self.paintMode) profile('set comp mode') shape = ( self.image.shape[:2] if self.axisOrder == 'col-major' else self.image.shape[:2][::-1] ) painter.drawImage(QtCore.QRectF(0,0,*shape), self.qimage) profile('p.drawImage') if self.border is not None: painter.setPen(self.border) painter.drawRect(self.boundingRect()) def save(self, fileName: str | pathlib.Path, *args) -> None: """ Save this image to file. Note that this saves the visible image, after scale/color changes, not the original data. Parameters ---------- fileName : os.PathLike File path to save the image data to. *args : tuple Arguments that are passed to :meth:`QImage.save `. See Also -------- :meth:`QImage.save ` : ``*args`` is relayed to this method. """ if self.qimage is None: return None if self._renderRequired: self.render() self.qimage.save(os.fsdecode(fileName), *args) def getHistogram( self, bins: str | int='auto', step: str | np.generic='auto', perChannel: bool=False, targetImageSize: int=200, **kwargs ) -> list[tuple[np.ndarray, np.ndarray]] | tuple[np.ndarray, np.ndarray] | tuple[None, None]: """ Generate arrays containing the histogram values. Similar to :func:`numpy.histogram` Parameters ---------- bins : int or str, default 'auto' The `bins` argument and any extra keyword arguments are passed to :func:`numpy.histogram()`. If ``bins == 'auto'``, a bin number is automatically chosen based on the image characteristics. step : int or str, default 'auto' 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 approximating `targetImageSize` for each axis. perChannel : bool, default False If ``True``, then a histogram is computed for each channel, and the output is a list of the results. targetImageSize : int, default 200 This parameter is used if ``step == 'auto'``, If so, the `step` size is calculated by ``step = ceil(image.shape[0] / targetImageSize)``. **kwargs : dict, optional Dictionary of arguments passed to :func:`numpy.histogram()`. Returns ------- numpy.ndarray, numpy.ndarray or None, None or list of tuple of numpy.ndarray, numpy.ndarray Returns `x` and `y` arrays containing the histogram values for the current image. For an explanation of the return format, see :func:`numpy.histogram()`. Returns ``[(numpy.ndarray, numpy.ndarray),...]`` if ``perChannel=True``, one element per channel. Returns ``(None, None)`` is there is no image, or image size is 0. Warns ----- RuntimeWarning Emits when `targetHistogramSize` argument is passed in, which does nothing. See Also -------- numpy.histogram : Describes return format in greater detail. numpy.histogram_bin_edges: Details the different string values accepted as the `bins` parameter. """ if 'targetHistogramSize' in kwargs: warnings.warn( "'targetHistogramSize' option is not used", RuntimeWarning, stacklevel=2 ) # 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(self._xp.ceil(self.image.shape[0] / targetImageSize))), max(1, int(self._xp.ceil(self.image.shape[1] / targetImageSize)))) if self._xp.isscalar(step): step = (step, step) stepData = self.image[::step[0], ::step[1]] if isinstance(bins, str) and bins == 'auto': mn = self._xp.nanmin(stepData).item() mx = self._xp.nanmax(stepData).item() if mx == mn: # degenerate image, arange will fail mx += 1 if self._xp.isnan(mn) or self._xp.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 = int(self._xp.ceil((mx - mn) / 500.)) bins = [] if step > 0.0: bins = self._xp.arange(mn, mx + 1.01 * step, step, dtype=int) else: # for float data, let numpy select the bins. bins = self._xp.linspace(mn, mx, 500) if len(bins) == 0: bins = self._xp.asarray((mn, mx)) kwargs['bins'] = bins cp = getCupy() if perChannel: hist = [] for i in range(stepData.shape[-1]): stepChan = stepData[..., i] stepChan = stepChan[self._xp.isfinite(stepChan)] h = self._xp.histogram(stepChan, **kwargs) if cp: hist.append((cp.asnumpy(h[1][:-1]), cp.asnumpy(h[0]))) else: hist.append((h[1][:-1], h[0])) return hist else: stepData = stepData[self._xp.isfinite(stepData)] hist = self._xp.histogram(stepData, **kwargs) if cp: return cp.asnumpy(hist[1][:-1]), cp.asnumpy(hist[0]) else: return hist[1][:-1], hist[0] def setPxMode(self, b: bool): """ Set whether item ignores transformations and draws directly to screen pixels. Parameters ---------- b : bool 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 Also -------- :class:`QGraphicsItem.GraphicsItemFlag ` : Read the description of `ItemIgnoresTransformations` for more information. """ self.setFlag( QtWidgets.QGraphicsItem.GraphicsItemFlag.ItemIgnoresTransformations, b ) def setScaledMode(self): self.setPxMode(False) def getPixmap(self) -> QtGui.QPixmap | None: if self._renderRequired: self.render() if self._unrenderable: return None if self.qimage is None: return QtGui.QPixmap() return QtGui.QPixmap.fromImage(self.qimage) def pixelSize(self) -> tuple[float, float]: """ Get the `x` and `y` size of each pixel in the view coordinate system. Returns ------- float, float The `x` and `y` size of each pixel in scene space. """ br = self.sceneBoundingRect() if self.image is None: return 1.,1. if (width := self.width()) is None: width = 0. if (height := self.height()) is None: height = 0. return br.width() / width, br.height() / height def viewTransformChanged(self): if self.autoDownsample: xds, yds = self._computeDownsampleFactors() if xds is None: self._renderRequired = True self._unrenderable = True return if (xds, yds) != self._lastDownsample: self._renderRequired = True self.update() def _computeDownsampleFactors(self) -> tuple[int, int]: # 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)) # scene may not be available yet if o is None: return 1, 1 w = Point(x - o).length() h = Point(y - o).length() if w == 0 or h == 0: return 1, 1 return max(1, int(1.0 / w)), max(1, int(1.0 / h)) def mouseDragEvent(self, ev): if ev.button() != QtCore.Qt.MouseButton.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.MouseButton.RightButton and self.raiseContextMenu(ev) ): ev.accept() if self.drawKernel is not None and ev.button() == QtCore.Qt.MouseButton.LeftButton: self.drawAt(ev.pos(), ev) def raiseContextMenu(self, ev): menu = self.getMenu() if menu is None: return False if self.scene() is None: warnings.warn( ( "Attempting to raise a context menu with the GraphicsScene has " "not been set. Returning None" ), RuntimeWarning, stacklevel=2 ) return None menu = self.scene().addParentContextMenus(self, menu, ev) pos = ev.screenPos() menu.popup(QtCore.QPoint(int(pos.x()), int(pos.y()))) return True def getMenu(self): if self.menu is None: if not self.removable: return None self.menu = QtWidgets.QMenu() self.menu.setTitle(translate("ImageItem", "Image")) remAct = QtGui.QAction(translate("ImageItem", "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(): if self.drawKernel is not None and ev.acceptDrags( QtCore.Qt.MouseButton.LeftButton ): # we don't use the click, but we also don't want anyone else to use it ev.acceptClicks(QtCore.Qt.MouseButton.LeftButton) ev.acceptClicks(QtCore.Qt.MouseButton.RightButton) elif self.removable: # accept context menu clicks ev.acceptClicks(QtCore.Qt.MouseButton.RightButton) def tabletEvent(self, ev): pass def drawAt(self, pos, ev=None): if self.axisOrder == "col-major": pos = [int(pos.x()), int(pos.y())] else: pos = [int(pos.y()), int(pos.x())] 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 ValueError(f"Unknown draw mode '{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)