Source code for pyqtgraph.graphicsItems.ColorBarItem

import math
import weakref

import numpy as np

from .. import colormap
from .. import functions as fn
from ..Qt import QtCore, QtGui, QtWidgets
from .LinearRegionItem import LinearRegionItem
from .PlotItem import PlotItem

__all__ = ['ColorBarItem']

[docs] class ColorBarItem(PlotItem): """ **Bases:** :class:`PlotItem <pyqtgraph.PlotItem>` :class:`ColorBarItem` controls the application of a :ref:`color map <apiref_colormap>` to one (or more) :class:`~pyqtgraph.ImageItem`. It is a simpler, compact alternative to :class:`~pyqtgraph.HistogramLUTItem`, without histogram or the option to adjust the colors of the look-up table. A labeled axis is displayed directly next to the gradient to help identify values. Handles included in the color bar allow for interactive adjustment. A ColorBarItem can be assigned one or more :class:`~pyqtgraph.ImageItem` s that will be displayed according to the selected color map and levels. The ColorBarItem can be used as a separate element in a :class:`~pyqtgraph.GraphicsLayout` or added to the layout of a :class:`~pyqtgraph.PlotItem` used to display image data with coordinate axes. ============================= ============================================= **Signals:** sigLevelsChanged(self) Emitted when the range sliders are moved sigLevelsChangeFinished(self) Emitted when the range sliders are released ============================= ============================================= """ sigLevelsChanged = QtCore.Signal(object) sigLevelsChangeFinished = QtCore.Signal(object)
[docs] def __init__(self, values=None, width=25, colorMap=None, label=None, interactive=True, limits=None, rounding=1, orientation='vertical', pen='w', hoverPen='r', hoverBrush='#FF000080' ): """ Creates a new ColorBarItem. Parameters ---------- colorMap: `str` or :class:`~pyqtgraph.ColorMap` Determines the color map displayed and applied to assigned ImageItem(s). values: tuple of float, optional The range of values that will be represented by the color bar, as ``(min, max)``. If no values are supplied, the default is to use user-specified values from an assigned image. If that does not exist, values will default to (0,1). width: float, default=25.0 The width of the displayed color bar. label: str, optional Label applied to the color bar axis. interactive: bool, default=True If `True`, handles are displayed to interactively adjust the level range. limits: `tuple of float`, optional Limits the adjustment range to `(low, high)`, `None` disables the limit. rounding: float, default=1 Adjusted range values are rounded to multiples of this value. orientation: str, default 'vertical' 'horizontal' or 'h' gives a horizontal color bar instead of the default vertical bar pen: :class:`QPen` or color_like Sets the color of adjustment handles in interactive mode. hoverPen: :class:`QPen` or color_like Sets the color of adjustment handles when hovered over. hoverBrush: :class:`QBrush` or color_like Sets the color of movable center region when hovered over. """ super().__init__() self.img_list = [] # list of controlled ImageItems self._actively_adjusted_values = False if values is None: # Use default values # NOTE: User-specified values from the assigned item will be preferred over the default values of ColorBarItem values = (0,1) else: # The user explicitly entered values, prefer these over values from assigned image. self._actively_adjusted_values = True self.values = values self._colorMap = None self.rounding = rounding self.horizontal = bool( orientation in ('h', 'horizontal') ) self.lo_prv, self.hi_prv = self.values # remember previous values while adjusting range self.lo_lim = None self.hi_lim = None if limits is not None: self.lo_lim, self.hi_lim = limits # slightly expand the limits to match the rounding steps: if self.lo_lim is not None: self.lo_lim = self.rounding * math.floor( self.lo_lim/self.rounding ) if self.hi_lim is not None: self.hi_lim = self.rounding * math.ceil( self.hi_lim/self.rounding ) self.disableAutoRange() self.hideButtons() self.setMouseEnabled(x=False, y=False) self.setMenuEnabled( False) if self.horizontal: self.setRange( xRange=(0,256), yRange=(0,1), padding=0 ) self.layout.setRowFixedHeight(2, width) else: self.setRange( xRange=(0,1), yRange=(0,256), padding=0 ) self.layout.setColumnFixedWidth(1, width) # width of color bar for key in ['left','right','top','bottom']: self.showAxis(key) axis = self.getAxis(key) axis.setZValue(0.5) # select main axis: if self.horizontal and key == 'bottom': self.axis = axis elif not self.horizontal and key == 'right': self.axis = axis self.axis.setWidth(45) else: # show other axes to create frame axis.setTicks( [] ) axis.setStyle( showValues=False ) self.axis.setStyle( showValues=True ) self.axis.unlinkFromView() self.axis.setRange( self.values[0], self.values[1] ) if self.horizontal: if label is not None: self.getAxis('bottom').setLabel(label) else: if label is not None: self.getAxis('left').setLabel(label) self.bar = QtWidgets.QGraphicsPixmapItem() self.bar.setShapeMode(self.bar.ShapeMode.BoundingRectShape) self.addItem(self.bar) if colorMap is not None: self.setColorMap(colorMap) self.interactive = interactive if interactive: if self.horizontal: align = 'vertical' else: align = 'horizontal' self.region = LinearRegionItem( [63, 191], align, swapMode='block', # span=(0.15, 0.85), # limited span looks better, but disables grabbing the region pen=pen, brush=fn.mkBrush(None), hoverPen=hoverPen, hoverBrush=hoverBrush ) self.region.setZValue(1000) self.region.lines[0].addMarker('<|>', size=6) self.region.lines[1].addMarker('<|>', size=6) self.region.sigRegionChanged.connect(self._regionChanging) self.region.sigRegionChangeFinished.connect(self._regionChanged) self.addItem(self.region) self.region_changed_enable = True self.region.setRegion( (63, 191) ) # place handles at 25% and 75% locations else: self.region = None self.region_changed_enable = False
[docs] def setImageItem(self, img, insert_in=None): """ Assigns an item or list of items to be represented and controlled. Supported "image items": class:`~pyqtgraph.ImageItem`, class:`~pyqtgraph.PColorMeshItem` Parameters ---------- image: :class:`~pyqtgraph.ImageItem` or list of :class:`~pyqtgraph.ImageItem` Assigns one or more image items to this ColorBarItem. If a :class:`~pyqtgraph.ColorMap` is defined for ColorBarItem, this will be assigned to the ImageItems. Otherwise, the ColorBarItem will attempt to retrieve a color map from the image items. In interactive mode, ColorBarItem will control the levels of the assigned image items, simultaneously if there is more than one. If the ColorBarItem was initialized without a specified ``values`` parameter, it will attempt to retrieve a set of user-defined ``levels`` from one of the image items. If this fails, the default values of ColorBarItem will be used as the (min, max) levels of the colorbar. Note that, for non-interactive ColorBarItems, levels may be overridden by image items with auto-scaling colors (defined by ``enableAutoLevels``). When using an interactive ColorBarItem in an animated plot, auto-scaling for its assigned image items should be *manually* disabled. insert_in: :class:`~pyqtgraph.PlotItem`, optional If a PlotItem is given, the color bar is inserted on the right or bottom of the plot, depending on the specified orientation. """ try: self.img_list = [ weakref.ref(item) for item in img ] except TypeError: # failed to iterate, make a single-item list self.img_list = [ weakref.ref( img ) ] colormap_is_undefined = self._colorMap is None for img_weakref in self.img_list: img = img_weakref() if img is not None: if hasattr(img, "sigLevelsChanged"): img.sigLevelsChanged.connect(self._levelsChangedHandler) if colormap_is_undefined and hasattr(img, 'getColorMap'): # check if one of the assigned images has a defined color map img_cm = img.getColorMap() if img_cm is not None: self._colorMap = img_cm colormap_is_undefined = False if not self._actively_adjusted_values: # check if one of the assigned images has a non-default set of levels if hasattr(img, 'getLevels'): img_levels = img.getLevels() if img_levels is not None: self.setLevels(img_levels, update_items=False) if insert_in is not None: if self.horizontal: insert_in.layout.addItem( self, 5, 1 ) # insert in layout below bottom axis insert_in.layout.setRowFixedHeight(4, 10) # enforce some space to axis above else: insert_in.layout.addItem( self, 2, 5 ) # insert in layout after right-hand axis insert_in.layout.setColumnFixedWidth(4, 5) # enforce some space to axis on the left self._update_items( update_cmap = True )
[docs] def setColorMap(self, colorMap): """ Sets a color map to determine the ColorBarItem's look-up table. The same look-up table is applied to any assigned ImageItem. `colorMap` can be a :class:`~pyqtgraph.ColorMap` or a string argument that is passed to :func:`colormap.get() <pyqtgraph.colormap.get>`. """ if isinstance(colorMap, str): colorMap = colormap.get(colorMap) self._colorMap = colorMap self._update_items( update_cmap = True )
[docs] def colorMap(self): """ Returns the assigned ColorMap object. """ return self._colorMap
[docs] def setLevels(self, values=None, low=None, high=None, update_items=True): """ Sets the displayed range of image levels. Parameters ---------- values: tuple of float Specifies levels as tuple ``(low, high)``. Either value can be `None` to leave the previous value unchanged. Takes precedence over `low` and `high` parameters. low: float Applies a new low level to color bar and assigned images high: float Applies a new high level to color bar and assigned images """ if values is not None: # values setting takes precendence low, high = values lo_new, hi_new = low, high lo_cur, hi_cur = self.values # allow None values to preserve original values: if lo_new is None: lo_new = lo_cur if hi_new is None: hi_new = hi_cur if lo_new > hi_new: # prevent reversal lo_new = hi_new = (lo_new + hi_new) / 2 # clip to limits if set: if self.lo_lim is not None and lo_new < self.lo_lim: lo_new = self.lo_lim if self.hi_lim is not None and hi_new > self.hi_lim: hi_new = self.hi_lim self.values = self.lo_prv, self.hi_prv = (lo_new, hi_new) if update_items: self._update_items() else: # update color bar only: self.axis.setRange( self.values[0], self.values[1] )
[docs] def levels(self): """ Returns the currently set levels as the tuple ``(low, high)``. """ return self.values
def _update_items(self, update_cmap=False): """ internal: update color maps for bar and assigned ImageItems """ # update color bar: self.axis.setRange( self.values[0], self.values[1] ) if update_cmap and self._colorMap is not None: lut = self._colorMap.getLookupTable(nPts=256, alpha=True) lut = np.expand_dims(lut, axis=0 if self.horizontal else 1) qimg = fn.ndarray_to_qimage(lut, QtGui.QImage.Format.Format_RGBA8888) self.bar.setPixmap(QtGui.QPixmap.fromImage(qimg)) # update assigned ImageItems, too: for img_weakref in self.img_list: img = img_weakref() if img is None: continue # dereference weakref img.setLevels( self.values ) # (min,max) tuple if update_cmap and self._colorMap is not None: img.setColorMap(self._colorMap) def _levelsChangedHandler(self, levels): """ internal: called when child item for some reason decides to update its levels without using ColorBarItem. Will update colormap for the bar based on child items new levels """ if levels != self.values: self.setLevels(levels, update_items=False) def _regionChanged(self): """ internal: snap adjusters back to default positions on release """ self.lo_prv, self.hi_prv = self.values self.region_changed_enable = False # otherwise this affects the region again self.region.setRegion( (63, 191) ) self.region_changed_enable = True self.sigLevelsChangeFinished.emit(self) def _regionChanging(self): """ internal: recalculate levels based on new position of adjusters """ if not self.region_changed_enable: return bot, top = self.region.getRegion() bot = ( (bot - 63) / 64 ) # -1 to +1 over half-bar range top = ( (top - 191) / 64 ) # -1 to +1 over half-bar range bot = math.copysign( bot**2, bot ) # quadratic behaviour for sensitivity to small changes top = math.copysign( top**2, top ) # These are the new values if adjuster is released now, rate of change depends on original separation span_prv = self.hi_prv - self.lo_prv # previous span of values hi_new = self.hi_prv + (span_prv + 2*self.rounding) * top # make sure that we can always lo_new = self.lo_prv + (span_prv + 2*self.rounding) * bot # reach 2x the minimal step # Alternative model with speed depending on level magnitude: # mean_val = abs(self.lo_prv) + abs(self.hi_prv) / 2 # hi_new = self.hi_prv + (mean_val + 2*self.rounding) * top # make sure that we can always # lo_new = self.lo_prv + (mean_val + 2*self.rounding) * bot # reach 2x the minimal step if self.hi_lim is not None: if hi_new > self.hi_lim: # limit maximum value hi_new = self.hi_lim if top!=0 and bot!=0: # moving entire region? lo_new = hi_new - span_prv # avoid collapsing the span against top limit if self.lo_lim is not None: if lo_new < self.lo_lim: # limit minimum value lo_new = self.lo_lim if top!=0 and bot!=0: # moving entire region? hi_new = lo_new + span_prv # avoid collapsing the span against bottom limit if hi_new-lo_new < self.rounding: # do not allow less than one "rounding" unit of span if bot == 0: hi_new = lo_new + self.rounding elif top == 0: lo_new = hi_new - self.rounding else: # this should never happen, but let's try to recover if it does: mid = (hi_new + lo_new) / 2 hi_new = mid + self.rounding / 2 lo_new = mid - self.rounding / 2 lo_new = self.rounding * round( lo_new/self.rounding ) hi_new = self.rounding * round( hi_new/self.rounding ) self.values = (lo_new, hi_new) self._update_items() self.sigLevelsChanged.emit(self)