PyDMSlider

class pydm.widgets.slider.PyDMSlider(parent=None, init_channel=None)

A QSlider with support for Channels and more from PyDM.

Parameters

• parent (QWidget) – The parent widget for the Label

• init_channel (str, optional) – The channel to be used by the widget.

connection_changed(connected)

Callback invoked when the connection state of the Channel is changed. This callback acts on the connection state to enable/disable the widget and also trigger the change on alarm severity to ALARM_DISCONNECTED.

Parameters

connected (int) – When this value is 0 the channel is disconnected, 1 otherwise.

ctrl_limit_changed(which, new_limit)

Callback invoked when the Channel receives new control limit values.

Parameters

• which (str) – Which control limit was changed. “UPPER” or “LOWER”

• new_limit (float) – New value for the control limit

find_closest_slider_position_to_value(val)

Find and returns the index for the closest position on the slider for a given value.

Parameters

val (float) –

Returns

Return type

int

hasTracking()

An alternative function to get the tracking property, to match what Qt provides for QSlider.

ignoreMouseWheel

If true, the mouse wheel will not change the value of the slider. This is useful if you want to put sliders inside a scroll view, and don’t want to accidentally change the slider as you are scrolling.

init_for_designer()

Method called after the constructor to tweak configurations for when using the widget with the Qt Designer

internal_slider_moved(val)

Method invoked when the slider is moved.

Parameters

val (float) –

internal_slider_pressed()

Method invoked when the slider is pressed

internal_slider_released()

Method invoked when the slider is released

internal_slider_value_changed(val)

Method invoked when a new value is selected on the slider. This will cause the new value to be emitted to the signal unless mute_internal_slider_changes is True.

Parameters

val (int) –

property maximum

The current value being used for the upper limit

Returns

Return type

float

property minimum

The current value being used for the lower limit

Returns

Return type

float

num_steps

The number of steps on the slider

Returns

Return type

int

orientation

The slider orientation (Horizontal or Vertical)

Returns

Qt.Horizontal or Qt.Vertical

Return type

int

reset_slider_limits()

Reset the limits and adjust the labels properly for the slider.

setTracking(checked)

An alternative function to set the tracking property, to match what Qt provides for QSlider.

set_enable_state()

Determines wether or not the widget must be enabled or not depending on the write access, connection state and presence of limits information

set_slider_to_closest_value(val)

Set the value for the slider according to a given value.

Parameters

val (float) –

setup_widgets_for_orientation(new_orientation)

Reconstruct the widget given the orientation.

Parameters

new_orientation (int) – Qt.Horizontal or Qt.Vertical

showLimitLabels

Whether or not the high and low limits should be displayed on the slider.

Returns

Return type

bool

showValueLabel

Whether or not the current value should be displayed on the slider.

Returns

Return type

bool

tickPosition

Where to draw tick marks for the slider.

Returns

Return type

QSlider.TickPosition

tracking

If tracking is enabled (the default), the slider emits new values while the slider is being dragged. If tracking is disabled, it will only emit new values when the user releases the slider. Tracking can cause PyDM to rapidly send new values to the channel. If you are using the slider to control physical hardware, consider whether the device you want to control can handle large amounts of changes in a short timespan.

update_format_string()

Reconstruct the format string to be used when representing the output value.

Returns

format_string – The format string to be used including or not the precision and unit

Return type

str

update_labels()

Update the limits and value labels with the correct values.

userDefinedLimits

Wether or not to use limits defined by the user and not from the channel

Returns

Return type

bool

userMaximum

Upper user defined limit value

Returns

Return type

float

userMinimum

Lower user defined limit value

Returns

Return type

float

value_changed(new_val)

Callback invoked when the Channel value is changed.

Parameters

new_val (int or float) – The new value from the channel.

wheelEvent(self, QWheelEvent)

write_access_changed(new_write_access)

Callback invoked when the Channel has new write access value. This callback calls check_enable_state so it can act on the widget enabling or disabling it accordingly

Parameters

new_write_access (bool) – True if write operations to the channel are allowed.