class pyqtgraph.PlotCurveItem(*args, **kargs)[source]

Class representing a single plot curve. Instances of this class are created automatically as part of PlotDataItem; these rarely need to be instantiated directly.


  • Fast data update
  • Fill under curve
  • Mouse interaction
sigPlotChanged(self) Emitted when the data being plotted has changed
sigClicked(self, ev) Emitted when the curve is clicked
__init__(*args, **kargs)[source]

Forwards all arguments to setData.

Some extra arguments are accepted as well:

parent The parent GraphicsObject (optional)
clickable If True, the item will emit sigClicked when it is clicked on. Defaults to False.

Return a QPainterPath representing the clickable shape of the curve

setBrush(*args, **kargs)[source]

Set the brush used when filling the area under the curve

setClickable(s, width=None)[source]

Sets whether the item responds to mouse clicks.

The width argument specifies the width in pixels orthogonal to the curve that will respond to a mouse click.


Change the composition mode of the item (see QPainter::CompositionMode in the Qt documentation). This is useful when overlaying multiple items.

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.
setData(*args, **kargs)[source]
x, y (numpy arrays) Data to show
pen Pen to use when drawing. Any single argument accepted by mkPen is allowed.
shadowPen Pen for drawing behind the primary pen. Usually this is used to emphasize the curve by providing a high-contrast border. Any single argument accepted by mkPen is allowed.
fillLevel (float or None) Fill the area ‘under’ the curve to fillLevel
fillOutline (bool) If True, an outline surrounding the fillLevel area is drawn.
brush QBrush to use when filling. Any single argument accepted by mkBrush is allowed.
antialias (bool) Whether to use antialiasing when drawing. This is disabled by default because it decreases performance.
stepMode (str or None) If “center”, a step is drawn using the x values as boundaries and the given y values are associated to the mid-points between the boundaries of each step. This is commonly used when drawing histograms. Note that in this case, len(x) == len(y) + 1 If “left” or “right”, the step is drawn assuming that the y value is associated to the left or right boundary, respectively. In this case len(x) == len(y) If not passed or an empty string or None is passed, the step mode is not enabled. Passing True is a deprecated equivalent to “center”.
connect Argument specifying how vertexes should be connected by line segments. Default is “all”, indicating full connection. “pairs” causes only even-numbered segments to be drawn. “finite” causes segments to be omitted if they are attached to nan or inf values. For any other connectivity, specify an array of boolean values.
compositionMode See setCompositionMode.

If non-keyword arguments are used, they will be interpreted as setData(y) for a single argument and setData(x, y) for two arguments.


Set the level filled to when filling under the curve

setPen(*args, **kargs)[source]

Set the pen used to draw the curve.

setShadowPen(*args, **kargs)[source]

Set the shadow pen used to draw behind the primary pen. This pen must have a larger width than the primary pen to be visible.