PlotWidget

The PlotWidget is a Qt widget providing the plot API initially provided in PyMca.

Examples

As this widget is a Qt widget, a Qt application must be running in order to use this widget. The following sample code be included in a script that already created a Qt application or from IPython.

To use this widget from IPython, IPython (and matplotlib) need to integrate with Qt. You need to either start IPython with the following option ipython --pylab=qt or use the %pylab qt magic from IPython prompt.

%pylab qt

Basics

Displaying a curve:

from silx.gui.plot import PlotWidget

plot = PlotWidget()  # Create the plot widget
plot.addCurve(x=(1, 2, 3), y=(3, 2, 1))  # Add a curve with default style
plot.show()  # Make the PlotWidget visible

Updating a curve:

plot.addCurve(x=(1, 2, 3), y=(1, 2, 3))  # Replace the existing curve

Displaying an image:

import numpy
from silx.gui.plot import PlotWidget

data = numpy.random.random(512 * 512).reshape(512, -1)  # Create 2D data

plot = PlotWidget()  # Create the plot widget
plot.addImage(data)  # Add a 2D data set with default colormap
plot.show()  # Make the PlotWidget visible

API

This is a choosen subset of the complete plot API, the full API is documented in silx.gui.plot.Plot.

class silx.gui.plot.PlotWidget.PlotWidget(parent=None, backend=None, legends=False, callback=None, autoreplot=True, **kw)

Bases: PyQt4.QtGui.QMainWindow, silx.gui.plot.Plot.Plot

Qt Widget providing a 1D/2D plot.

This widget is a QMainWindow. It provides Qt signals for the Plot and add supports for panning with arrow keys.

Parameters:

• parent – The parent of this widget or None.
• backend (str or BackendBase.BackendBase) – The backend to use for the plot. The default is to use matplotlib.
• autoreplot (bool) – Toggle autoreplot mode (Default: True).

clear()

Remove everything from the plot.

remove(legend=None, kind=('curve', 'image', 'item', 'marker'))

Remove one or all element(s) of the given legend and kind.

Examples:

• remove() clears the plot
• remove(kind=’curve’) removes all curves from the plot
• remove(‘myCurve’, kind=’curve’) removes the curve with legend ‘myCurve’ from the plot.
• remove(‘myImage, kind=’image’) removes the image with legend ‘myImage’ from the plot.
• remove(‘myImage’) removes elements (for instance curve, image, item and marker) with legend ‘myImage’.

Parameters:

• legend (str) – The legend associated to the element to remove, or None to remove
• kind (str or tuple of str to specify multiple kinds.) – The kind of elements to remove from the plot. In: ‘all’, ‘curve’, ‘image’, ‘item’, ‘marker’. By default, it removes all kind of elements.

replot()

Redraw the plot immediately.

resetZoom(dataMargins=None)

Reset the plot limits to the bounds of the data and redraw the plot.

It automatically scale limits of axes that are in autoscale mode (See setXAxisAutoScale(), setYAxisAutoScale()). It keeps current limits on axes that are not in autoscale mode.

Extra margins can be added around the data inside the plot area. Margins are given as one ratio of the data range per limit of the data (xMin, xMax, yMin and yMax limits). For log scale, extra margins are applied in log10 of the data.

Parameters:dataMargins (A 4-tuple of float as (xMin, xMax, yMin, yMax).) – Ratios of margins to add around the data inside the plot area for each side (Default: no margins).

saveGraph(filename, fileFormat=None, dpi=None, **kw)

Save a snapshot of the plot.

Supported file formats: “png”, “svg”, “pdf”, “ps”, “eps”, “tif”, “tiff”, “jpeg”, “jpg”.

Parameters:

• filename (str, StringIO or BytesIO) – Destination
• fileFormat (str) – String specifying the format

Returns:

False if cannot save the plot, True otherwise

sigPlotSignal

Signal for all events of the plot.

The signal information is provided as a dict. See Plot for documentation of the content of the dict.

Curves

PlotWidget.addCurve(x, y, legend=None, info=None, replace=False, replot=None, color=None, symbol=None, linestyle=None, xlabel=None, ylabel=None, yaxis=None, xerror=None, yerror=None, z=None, selectable=None, fill=None, resetzoom=True, **kw)

Add a 1D curve given by x an y to the graph.

Curves are uniquely identified by their legend. To add multiple curves, call addCurve() multiple times with different legend argument. To replace/update an existing curve, call addCurve() with the existing curve legend.

When curve parameters are not provided, if a curve with the same legend is displayed in the plot, its parameters are used.

Parameters:

• x (numpy.ndarray) – The data corresponding to the x coordinates
• y (numpy.ndarray) – The data corresponding to the y coordinates
• legend (str) – The legend to be associated to the curve (or None)
• info – User-defined information associated to the curve
• replace (bool) – True (the default) to delete already existing curves
• color (str (“#RRGGBB”) or (npoints, 4) unsigned byte array or one of the predefined color names defined in Colors.py) – color(s) to be used
• symbol (str) –

  Symbol to be drawn at each (x, y) position:

  - 'o' circle
  - '.' point
  - ',' pixel
  - '+' cross
  - 'x' x-cross
  - 'd' diamond
  - 's' square
  - None (the default) to use default symbol
  

• linewidth (float) – The width of the curve in pixels (Default: 1).
• linestyle (str) –

  Type of line:

  - ' '  no line
  - '-'  solid line
  - '--' dashed line
  - '-.' dash-dot line
  - ':'  dotted line
  - None (the default) to use default line style
  

• xlabel (str) – Label to show on the X axis when the curve is active
• ylabel (str) – Label to show on the Y axis when the curve is active
• yaxis (str) – The Y axis this curve is attached to. Either ‘left’ (the default) or ‘right’
• xerror (A float, or a numpy.ndarray of float32. If it is an array, it can either be a 1D array of same length as the data or a 2D array with 2 rows of same length as the data: row 0 for positive errors, row 1 for negative errors.) – Values with the uncertainties on the x values
• yerror (A float, or a numpy.ndarray of float32. See xerror.) – Values with the uncertainties on the y values
• z (int) – Layer on which to draw the curve (default: 1) This allows to control the overlay.
• selectable (bool) – Indicate if the curve can be selected. (Default: True)
• fill (bool) – True to fill the curve, False otherwise (default).
• resetzoom (bool) – True (the default) to reset the zoom.

Returns:

The key string identify this curve

PlotWidget.removeCurve(legend)

Remove the curve associated to legend from the graph.

Parameters:legend (str) – The legend associated to the curve to be deleted

PlotWidget.clearCurves()

Remove all the curves from the plot.

Images

PlotWidget.addImage(data, legend=None, info=None, replace=True, replot=None, xScale=None, yScale=None, z=None, selectable=False, draggable=False, colormap=None, pixmap=None, xlabel=None, ylabel=None, origin=None, scale=None, resetzoom=True, **kw)

Add a 2D dataset or an image to the plot.

It displays either an array of data using a colormap or a RGB(A) image.

Images are uniquely identified by their legend. To add multiple images, call addImage() multiple times with different legend argument. To replace/update an existing image, call addImage() with the existing image legend.

When image parameters are not provided, if an image with the same legend is displayed in the plot, its parameters are used.

Parameters:

• data (numpy.ndarray) – (nrows, ncolumns) data or (nrows, ncolumns, RGBA) ubyte array
• legend (str) – The legend to be associated to the image (or None)
• info – User-defined information associated to the image
• replace (bool) – True (default) to delete already existing images
• z (int) – Layer on which to draw the image (default: 0) This allows to control the overlay.
• selectable (bool) – Indicate if the image can be selected. (default: False)
• draggable (bool) – Indicate if the image can be moved. (default: False)
• colormap (dict) – Description of the colormap to use (or None) This is ignored if data is a RGB(A) image. See Plot for the documentation of the colormap dict.
• pixmap ((nrows, ncolumns, RGBA) ubyte array or None (default)) – Pixmap representation of the data (if any)
• xlabel (str) – X axis label to show when this curve is active.
• ylabel (str) – Y axis label to show when this curve is active.
• origin (2-tuple of float) – (origin X, origin Y) of the data. Default: (0., 0.)
• scale (2-tuple of float) – (scale X, scale Y) of the data. Default: (1., 1.)
• resetzoom (bool) – True (the default) to reset the zoom.

Returns:

The key string identify this image

PlotWidget.removeImage(legend)

Remove the image associated to legend from the graph.

Parameters:legend (str) – The legend associated to the image to be deleted

PlotWidget.clearImages()

Remove all the images from the plot.

Markers

PlotWidget.addMarker(x, y, legend=None, text=None, color=None, selectable=False, draggable=False, symbol='+', constraint=None, **kw)

Add a point marker to the plot.

Markers are uniquely identified by their legend. As opposed to curves, images and items, two calls to addMarker() without legend argument adds two markers with different identifying legends.

Parameters:

• x (float) – Position of the marker on the X axis in data coordinates
• y (float) – Position of the marker on the Y axis in data coordinates
• legend (str) – Legend associated to the marker to identify it
• text (str) – Text to display next to the marker
• color (str) – Color of the marker, e.g., ‘blue’, ‘b’, ‘#FF0000’ (Default: ‘black’)
• selectable (bool) – Indicate if the marker can be selected. (default: False)
• draggable (bool) – Indicate if the marker can be moved. (default: False)
• symbol (str) –

  Symbol representing the marker in:

  - 'o' circle
  - '.' point
  - ',' pixel
  - '+' cross (the default)
  - 'x' x-cross
  - 'd' diamond
  - 's' square
  

• constraint (None or a callable that takes the coordinates of the current cursor position in the plot as input and that returns the filtered coordinates.) – A function filtering marker displacement by dragging operations or None for no filter. This function is called each time a marker is moved. This parameter is only used if draggable is True.

Returns:

The key string identify this marker

PlotWidget.addXMarker(x, legend=None, text=None, color=None, selectable=False, draggable=False, constraint=None, **kw)

Add a vertical line marker to the plot.

Markers are uniquely identified by their legend. As opposed to curves, images and items, two calls to addXMarker() without legend argument adds two markers with different identifying legends.

Parameters:

• x (float) – Position of the marker on the X axis in data coordinates
• legend (str) – Legend associated to the marker to identify it
• text (str) – Text to display on the marker.
• color (str) – Color of the marker, e.g., ‘blue’, ‘b’, ‘#FF0000’ (Default: ‘black’)
• selectable (bool) – Indicate if the marker can be selected. (default: False)
• draggable (bool) – Indicate if the marker can be moved. (default: False)
• constraint (None or a callable that takes the coordinates of the current cursor position in the plot as input and that returns the filtered coordinates.) – A function filtering marker displacement by dragging operations or None for no filter. This function is called each time a marker is moved. This parameter is only used if draggable is True.

Returns:

The key string identify this marker

PlotWidget.addYMarker(y, legend=None, text=None, color=None, selectable=False, draggable=False, constraint=None, **kw)

Add a horizontal line marker to the plot.

Markers are uniquely identified by their legend. As opposed to curves, images and items, two calls to addYMarker() without legend argument adds two markers with different identifying legends.

Parameters:

• y (float) – Position of the marker on the Y axis in data coordinates
• legend (str) – Legend associated to the marker to identify it
• text (str) – Text to display next to the marker.
• color (str) – Color of the marker, e.g., ‘blue’, ‘b’, ‘#FF0000’ (Default: ‘black’)
• selectable (bool) – Indicate if the marker can be selected. (default: False)
• draggable (bool) – Indicate if the marker can be moved. (default: False)
• constraint (None or a callable that takes the coordinates of the current cursor position in the plot as input and that returns the filtered coordinates.) – A function filtering marker displacement by dragging operations or None for no filter. This function is called each time a marker is moved. This parameter is only used if draggable is True.

Returns:

The key string identify this marker

PlotWidget.removeMarker(legend)

Remove the marker associated to legend from the graph.

Parameters:legend (str) – The legend associated to the marker to be deleted

PlotWidget.clearMarkers()

Remove all the markers from the plot.

Title and labels

PlotWidget.getGraphTitle()

Return the plot main title as a str.

PlotWidget.setGraphTitle(title='')

Set the plot main title.

Parameters:title (str) – Main title of the plot (default: ‘’)

PlotWidget.getGraphXLabel()

Return the current X axis label as a str.

PlotWidget.setGraphXLabel(label='X')

Set the plot X axis label.

The provided label can be temporarily replaced by the X label of the active curve if any.

Parameters:label (str) – The X axis label (default: ‘X’)

PlotWidget.getGraphYLabel()

Return the current Y axis label as a str.

PlotWidget.setGraphYLabel(label='Y')

Set the plot Y axis label.

The provided label can be temporarily replaced by the Y label of the active curve if any.

Parameters:label (str) – The Y axis label (default: ‘Y’)

Axes limits

Those methods change the range of data values displayed on each axis.

PlotWidget.getGraphXLimits()

Get the graph X (bottom) limits.

Returns:Minimum and maximum values of the X axis

PlotWidget.setGraphXLimits(xmin, xmax, replot=None)

Set the graph X (bottom) limits.

Parameters:

• xmin (float) – minimum bottom axis value
• xmax (float) – maximum bottom axis value

PlotWidget.getGraphYLimits(axis='left')

Get the graph Y limits.

Parameters:axis (str) – The axis for which to get the limits: Either ‘left’ or ‘right’ Returns:Minimum and maximum values of the X axis

PlotWidget.setGraphYLimits(ymin, ymax, axis='left', replot=None)

Set the graph Y limits.

Parameters:

• xmin (float) – minimum bottom axis value
• xmax (float) – maximum bottom axis value
• axis (str) – The axis for which to get the limits: Either ‘left’ or ‘right’

PlotWidget.setLimits(xmin, xmax, ymin, ymax, y2min=None, y2max=None)

Set the limits of the X and Y axes at once.

If y2min or y2max is None, the right Y axis limits are not updated.

Parameters:

• xmin (float) – minimum bottom axis value
• xmax (float) – maximum bottom axis value
• ymin (float) – minimum left axis value
• ymax (float) – maximum left axis value
• y2min (float) – minimum right axis value or None (the default)
• y2max (float) – maximum right axis value or None (the default)

Axes

PlotWidget.isXAxisLogarithmic()

Return True if X axis scale is logarithmic, False if linear.

PlotWidget.setXAxisLogarithmic(flag)

Set the bottom X axis scale (either linear or logarithmic).

Parameters:flag (bool) – True to use a logarithmic scale, False for linear.

PlotWidget.isYAxisLogarithmic()

Return True if Y axis scale is logarithmic, False if linear.

PlotWidget.setYAxisLogarithmic(flag)

Set the Y axes scale (either linear or logarithmic).

Parameters:flag (bool) – True to use a logarithmic scale, False for linear.

PlotWidget.isYAxisInverted()

Return True if Y axis goes from top to bottom, False otherwise.

PlotWidget.setYAxisInverted(flag=True)

Set the Y axis orientation.

Parameters:flag (bool) – True for Y axis going from top to bottom, False for Y axis going from bottom to top

PlotWidget.isKeepDataAspectRatio()

Returns whether the plot is keeping data aspect ratio or not.

PlotWidget.setKeepDataAspectRatio(flag=True)

Set whether the plot keeps data aspect ratio or not.

Parameters:flag (bool) – True to respect data aspect ratio

PlotWidget.getGraphGrid()

Return the current grid mode, either None, ‘major’ or ‘both’.

See setGraphGrid().

PlotWidget.setGraphGrid(which=True)

Set the type of grid to display.

Parameters:which (str of bool) – None or False to disable the grid, ‘major’ or True for grid on major ticks (the default), ‘both’ for grid on both major and minor ticks.

Reset zoom settings

Those methods change the behavior of PlotWidget.resetZoom().

PlotWidget.getDataMargins()

Get the default data margin ratios, see setDataMargins().

Returns:The margin ratios for each side (xMin, xMax, yMin, yMax). Return type:A 4-tuple of floats.

PlotWidget.setDataMargins(xMinMargin=0.0, xMaxMargin=0.0, yMinMargin=0.0, yMaxMargin=0.0)

Set the default data margins to use in resetZoom().

Set the default ratios of margins (as floats) to add around the data inside the plot area for each side.

PlotWidget.isXAxisAutoScale()

Return True if X axis is automatically adjusting its limits.

PlotWidget.setXAxisAutoScale(flag=True)

Set the X axis limits adjusting behavior of resetZoom().

Parameters:flag (bool) – True to resize limits automatically, False to disable it.

PlotWidget.isYAxisAutoScale()

Return True if Y axes are automatically adjusting its limits.

PlotWidget.setYAxisAutoScale(flag=True)

Set the Y axis limits adjusting behavior of resetZoom().

Parameters:flag (bool) – True to resize limits automatically, False to disable it.

Defaults

Those methods set-up default values for PlotWidget.addCurve() and PlotWidget.addImage().

PlotWidget.getDefaultColormap()

Return the default colormap used by addImage() as a dict.

See Plot for the documentation of the colormap dict.

PlotWidget.setDefaultColormap(colormap=None)

Set the default colormap used by addImage().

Parameters:colormap (dict) – The description of the default colormap, or None to set the colormap to a linear autoscale gray colormap. See Plot for the documentation of the colormap dict.

PlotWidget.getSupportedColormaps()

Get the supported colormap names as a tuple of str.

The list should at least contain and start by: (‘gray’, ‘reversed gray’, ‘temperature’, ‘red’, ‘green’, ‘blue’)

PlotWidget.setDefaultPlotPoints(flag)

Set the default symbol of all curves.

When called, this reset the symbol of all existing curves.

Parameters:flag (bool) – True to use ‘o’ as the default curve symbol, False to use no symbol.

PlotWidget.setDefaultPlotLines(flag)

Toggle the use of lines as the default curve line style.

Parameters:flag (bool) – True to use a line as the default line style, False to use no line as the default line style.

Interaction

Those methods allow to change the interaction mode (e.g., drawing mode) of the plot and to toggle the use of a crosshair cursor.

PlotWidget.getInteractiveMode()

Returns the current interactive mode as a dict.

The returned dict contains at least the key ‘mode’. Mode can be: ‘draw’, ‘pan’, ‘select’, ‘zoom’. It can also contains extra keys (e.g., ‘color’) specific to a mode as provided to setInteractiveMode().

PlotWidget.setInteractiveMode(mode, color='black', shape='polygon', label=None, zoomOnWheel=True)

Switch the interactive mode.

Parameters:

• mode (str) – The name of the interactive mode. In ‘draw’, ‘pan’, ‘select’, ‘zoom’.
• color (Color description: The name as a str or a tuple of 4 floats.) – Only for ‘draw’ and ‘zoom’ modes. Color to use for drawing selection area. Default black.
• shape (str) – Only for ‘draw’ mode. The kind of shape to draw. In ‘polygon’, ‘rectangle’, ‘line’, ‘vline’, ‘hline’. Default is ‘polygon’.
• label (str) – Only for ‘draw’ mode, sent in drawing events.
• zoomOnWheel (bool) – Toggle zoom on wheel support

PlotWidget.getGraphCursor()

Returns the state of the crosshair cursor.

See setGraphCursor().

Returns:None if the crosshair cursor is not active, else a tuple (color, linewidth, linestyle).

PlotWidget.setGraphCursor(flag=False, color='black', linewidth=1, linestyle='-')

Toggle the display of a crosshair cursor and set its attributes.

Parameters:

• flag (bool) – Toggle the display of a crosshair cursor. The crosshair cursor is hidden by default.
• color (A string (either a predefined color name in Colors.py or “#RRGGBB”)) or a 4 columns unsigned byte array (Default: black).) – The color to use for the crosshair.
• linewidth (int) – The width of the lines of the crosshair (Default: 1).
• linestyle (str) –

  Type of line:

  - ' ' no line
  - '-' solid line (the default)
  - '--' dashed line
  - '-.' dash-dot line
  - ':' dotted line