The zplane~ object provides a way to graph filter poles and zeros in the Z-plane for display. Use the zplane~ object in conjunction with the filtergraph~ object, or provide it with a list of biquad~ coefficients.
Like the filtergraph~ object, it does not process audio signals by itself, but it does react internally to the current MSP sampling rate. The zplane~ object is designed to help in digital filter design and visualization for MSP, and to provide a basic pedagogical tool which may be used to help explain digital filter theory.
You can change the filter parameters by clicking and dragging on the zplane~ object’s display. Clicking and dragging on any of the poles (shown as an x in the display) or zeros (shown as an o in the display) will modify the filter coefficients and output the new filter coefficient values.
bgcolor [4 floats]
Sets the background color of the zplane~ object in RGBA format.
gridlinecolor [4 floats]
Sets the colors for the grids and lines in RGBA format. The style color.attribute is mapped to the
order [int] (default: 2)
The word, followed by an even number between 2 and 24, sets the number of poles and zeros.
pconstrain [int] (default: 0)
When set to 1, poles will be constrained inside the unit circle, and thus yield a stable filter. An argument of zero will turn this feature off (the default).
polezerocolor [4 floats]
Sets the pole zero color in RGBA format. The style color.attribute is mapped to the
style [symbol] (default: )7.0.0
Common Box Attributes
Sets the text that will be displayed in the Clue window when the user moves the mouse over the object.
background [int] (default: 0)
Adds or removes the object from the patcher's background layer.adds the object to the background layer, removes it. Objects in the background layer are shown behind all objects in the default foreground layer.
color [4 floats]
Sets the color for the object box outline.
Sets the type style used by the object. The options are:
0 = 'regular'
1 = 'bold'
2 = 'italic'
3 = 'bold italic'
Sets the object's font.
Sets the object's font size (in points).
hidden [int] (default: 0)
Toggles whether an object is hidden when the patcher is locked.
Sets the text that will be displayed in as a pop-up hint when the user moves the mouse over the object in a locked patcher.
ignoreclick [int] (default: 0)
Toggles whether an object ignores mouse clicks in a locked patcher.
patching_rect [4 floats] (default: 0. 0. 100. 0.)
Sets the position and size of the object in the patcher window.
position [2 floats]
Sets the object's x and y position in both patching and presentation modes (if the object belongs to its patcher's presentation), leaving its size unchanged.
presentation [int] (default: 0)
Sets whether an object belongs to the patcher's presentation.
presentation_rect [4 floats] (default: 0. 0. 0. 0.)
Sets the x and y position and width and height of the object in the patcher's presentation, leaving its patching position unchanged.
rect [4 floats]
Sets the x and y position and width and height of the object in both patching and presentation modes (if the object belongs to its patcher's presentation).
size [2 floats]
Sets the object's width and height in both patching and presentation modes (if the object belongs to its patcher's presentation), leaving its position unchanged.
Sets the color for the object's text in RGBA format.
0 = 'left'
1 = 'center'
2 = 'right'
If more than five values are sent, they are interpreted as sets of cascaded biquad coefficients. The zplane~ object will display a composite pole-zero graph which shows the multiplication of a group of biquad filters in cascade. Up to 24 groups of five float values may be cascaded.
Out left outlet: a list of 5 floating-point filter coefficients for the biquad~ object. Coefficients output in response to mouse clicks and changes in the coefficient inlets.
Out second outlet: a list of "zero" location values expressed as complex numbers (real, imaginary). These correspond to the "a" coefficients of the filter. A 2nd order (biquad) filter will have 2 zeros, a 4th order filter will have four, etc...
Out third outlet: a list of "pole" location values expressed as complex numbers (real, imaginary). These correspond to the "b" coefficients of the filter. A 2nd order (biquad) filter will have 2 zeros, a 4th order filter will have four, etc...
Out fourth outlet: a list of floating-point values representing the overall gain of each cascaded filter.
|biquad~||Two-pole, two-zero filter|
|cascade~||Cascaded series of biquad filters|
|filtercoeff~||Signal-rate filter coefficient generator|
|Audio Filtering||Audio Filtering|