HistogramLUTItem¶
-
class
pyqtgraph.
HistogramLUTItem
(image=None, fillHistogram=True, levelMode='mono', gradientPosition='right', orientation='vertical')[source]¶ GraphicsWidget
with controls for adjusting the display of anImageItem
.Includes:
Image histogram
Movable region over the histogram to select black/white levels
Gradient editor to define color lookup table for single-channel images
- Parameters
image (pyqtgraph.ImageItem, optional) – If provided, control will be automatically linked to the image and changes to the control will be reflected in the image’s appearance. This may also be set via
setImageItem()
.fillHistogram (bool, optional) – By default, the histogram is rendered with a fill. Performance may be improved by disabling the fill. Additional control over the fill is provided by
fillHistogram()
.levelMode (str, optional) –
- ‘mono’ (default)
One histogram with a
LinearRegionItem
is displayed to control the black/white levels of the image. This option may be used for color images, in which case the histogram and levels correspond to all channels of the image.- ’rgba’
A histogram and level control pair is provided for each image channel. The alpha channel histogram and level control are only shown if the image contains an alpha channel.
gradientPosition (str, optional) – Position of the gradient editor relative to the histogram. Must be one of {‘right’, ‘left’, ‘top’, ‘bottom’}. ‘right’ and ‘left’ options should be used with a ‘vertical’ orientation; ‘top’ and ‘bottom’ options are for ‘horizontal’ orientation.
orientation (str, optional) – The orientation of the axis along which the histogram is displayed. Either ‘vertical’ (default) or ‘horizontal’.
-
sigLookupTableChanged
¶ Emits the HistogramLUTItem itself when the gradient changes
- Type
signal
-
sigLevelsChanged
¶ Emits the HistogramLUTItem itself while the movable region is changing
- Type
signal
-
sigLevelChangeFinished
¶ Emits the HistogramLUTItem itself when the movable region is finished changing
- Type
signal
See also
ImageItem
HistogramLUTItem is most useful when paired with an ImageItem.
ImageView
Widget containing a paired ImageItem and HistogramLUTItem.
HistogramLUTWidget
QWidget containing a HistogramLUTItem for widget-based layouts.
-
__init__
(image=None, fillHistogram=True, levelMode='mono', gradientPosition='right', orientation='vertical')[source]¶
-
fillHistogram
(fill=True, level=0.0, color=(100, 100, 200))[source]¶ Control fill of the histogram curve(s).
- Parameters
fill (bool, optional) – Set whether or not the histogram should be filled.
level (float, optional) – Set the fill level. See
PlotCurveItem.setFillLevel
. Only used iffill
is True.color (color, optional) – Color to use for the fill when the histogram
levelMode == "mono"
. SeePlotCurveItem.setBrush
.
-
getLevels
()[source]¶ Return the min and max levels.
For rgba mode, this returns a list of the levels for each channel.
-
getLookupTable
(img=None, n=None, alpha=None)[source]¶ Return a lookup table from the color gradient defined by this HistogramLUTItem.
-
setHistogramRange
(mn, mx, padding=0.1)[source]¶ Set the Y range on the histogram plot. This disables auto-scaling.
-
setImageItem
(img)[source]¶ Set an ImageItem to have its levels and LUT automatically controlled by this HistogramLUTItem.