File Button

fileButton creates a button that opens a native file browser dialog. When clicked, it allows users to select files from their system. The selected file path is sent as a string value through the widget’s channel, enabling dynamic audio file loading and other file-based operations in Csound.

fileButton.csd

Download .csd

Properties

Active

"active": true

Will deactivate a control if false is set (use 0/1 to update from Csound). Controls which are deactivated can still be updated from Csound. Any widget that has its active property set to false will allow all mouse-clicks to pass through it.

Automatable

"automatable": true

Defaults to true. Determines if a widget is automatable by a host DAW. Automatable widgets show up as plug-in parameters in the host. Non-automatable widgets can still communicate with Csound but are not accessible by the host. Note that hosts don't allow this parameter to change dynamically. If you change this setting, the plugin will need to be reloaded.

Bounds

"bounds": {"left":0, "top":0, "width":100, "height":100}

Integer values that set position and size on screen(in pixels).

Channel

"channels": [
    {
        "id": "channelName",
        "label": { "name": "Channel Name", "prefix": "", "suffix": "" },
        "event": "valueChanged",
        "type": "number",
        "range": {"min":0, "max":100, "defaultValue":0, "skew":1, "increment":0.1}
    }
]

In Cabbage 3, widgets use an array of channels instead of a single channel string. Each channel object includes an id that defines a unique channel name. Widgets in Cabbage 3 can have any number of channels attached to them. An optional label object controls how the parameter appears in DAW parameter editors and automation lanes; if omitted, the id is used. An optional event property specifies the type of interaction. A range object can define the minimum, maximum, and default values, along with the skew and step increment. The type is set to number by default. Each widget sets its own type, number or string. A "string" channel carries text (readable with the string variant of cabbageGetValue), persists through session saves, and is excluded from DAW automation. See Persisting Custom UI State.

Two different labels

The label object inside channels[] only sets the name shown in DAW parameter lists and automation lanes. It never changes any on-screen text. The text a widget displays on screen is set with the widget's top-level Label property (see below):

"label": {"text": "Cutoff"},
"channels": [{"id": "cutoff", "label": {"name": "Filter Cutoff"}}]

Csound code always uses the channel id, never either label.

Channel label: DAW display name

The label object separates the internal channel identifier from the display name shown in DAWs, and allows a prefix and suffix to be appended to the parameter's value string in the DAW. This is useful when you want short, code-friendly channel IDs (e.g., hrm1, hrm2) while showing descriptive names in the DAW (e.g., Harmonic 1, Harmonic 2). Csound code always uses the id for channel access via cabbageGetValue and cabbageSetValue.

Field	Description
name	Human-readable parameter name shown in the DAW (required if using label)
prefix	String prepended to the value in the DAW's value display (optional)
suffix	String appended to the value in the DAW's value display (optional)

Caution

During runtime, range objects will be appended with the current value. You should never set this value explicitly as it will override any state recall.

If range is omitted, it defaults to a range from 0 to 1, with increments of 0.001 for widgets that use drag events (e.g., sliders, XY pads) and 1 for widgets that use click or toggle events (e.g., buttons, checkboxes).

Note on increment parameter behavior:

The increment parameter quantizes all values sent to Csound channels, ensuring they snap to the specified step size. For example, with increment: 0.1, values will be rounded to 0.0, 0.1, 0.2, etc. before reaching Csound.

The DAW host automation has additional constraints:

• increment >= 1.0: The host will display discrete integer steps (e.g., move from 1 to 2 to 3, etc.) in its native controls, and enforce these steps during automation.
• increment < 1.0: The host displays a continuous slider.

Cabbage always quantizes values internally before sending to Csound.

Note

A widget's top-level id property defines the general communication channel for updating attributes, while the channels specified in the channels array are used for value and parameter updates. If no top level id is specified, the first channel.id will be used as the general communication channel.

Supported event types:

Event	Description
valueChanged (default)	Tracks simple value changes
mousePressLeft	Tracks presses of left mouse button
mousePressRight	Tracks presses of right mouse button
mousePressMiddle	Tracks presses of middle mouse button
mouseMoveX	Tracks movement along X axis.
mouseMoveY	Tracks movement along Y axis.
mouseDragX	Tracks movement along X axis with mouse pressed
mouseDragY	Tracks movement along Y axis with mouse pressed
mouseInside	Returns max when any mouse button is within the bounds of the widget, min if outside.

Note

In Cabbage 3, channels don't need to start with a letter and white spaces are permitted.

The fileButton channel returns a string value containing the full path to the selected file. Use cabbageGetValue in Csound to retrieve both the file path and a trigger value (1 when a new file is selected, 0 otherwise).

Directory

Type: String Default: ""

Sets the initial directory that the file browser will open in. If empty, the browser opens in the system’s default location or the last known location (depending on openAtLastKnownLocation).

"directory": "/Users/username/audio_files"

Filters

Type: String Default: "*"

Specifies file type filters for the file browser. Use wildcards to filter by extension. Multiple filters can be separated by semicolons.

"filters": "*.wav;*.aif;*.mp3"

For all files, use "*" or "*.*".

Id

"id": "widgetId"

This optional channel can be used to define a top-level line of communication between the instrument’s UI and Csound. It is reserved for UI updates only. If omitted, it defaults to the first id from the channels array. Its primary purpose is to help produce clearer code, especially for widgets with multiple channels.

Label

"label": {
  "text": {
    "off": "Start",
    "on": "Stop"
  },
  "align": "center"
}

Configures the label shown inside widgets that switch between off/on states, such as button and fileButton.

• text.off: string — the text shown when the widget value is 0.
• text.on: string — the text shown when the widget value is 1.
• align: string — optional text alignment for widgets that support it, such as button.

Typography and colors are configured via style.*, including style.on.textColor, style.off.textColor, and related state styles.

Mode

Type: String Default: "file"

Determines whether the file browser selects files or directories.

• "file": Select a single file (default)
• "directory": Select a directory/folder

"mode": "directory"

Open At Last Known Location

Type: Boolean Default: true

When true, the file browser will open at the location of the last selected file. When false, it opens at the location specified by directory (or the system default if directory is empty).

"openAtLastKnownLocation": false

Persistence

"persistence": {
  "preset": true,
  "session": true
}

Controls whether a widget's state is saved in DAW presets and Csound session files. Both properties default to true.

• preset: When true, the widget's current value/state is included when using Csound's cabbageSaveState opcode to save preset data. Set to false for widgets that should not persist in Csound preset files (e.g., widgets that load presets).
• session: When true, the widget's state is included when the DAW saves a preset. Set to false for widgets that should not have their values loaded/saved when a DAW session loads (e.g., widgets that load presets).

Auto-cascade behavior: If you set preset to false without explicitly setting session, the system automatically sets session to false as well. This prevents state from being saved anywhere unless explicitly requested.

Visible

"visible": true

A value of true will cause the widget to become invisible (use 0/1 to update from Csound). Widgets have their visibility set to true by default.

ZIndex

"zIndex": 1

Sets the stacking order of the widget. Widgets with higher zIndex values will appear in front of widgets with lower values. Default is 1.

Style

"style": {
  "opacity": 1,
  "borderRadius": 4,
  "borderWidth": 0,
  "borderColor": "#dddddd",

  "on": {
    "backgroundColor": "#3d800a",
    "textColor": "#dddddd"
  },
  "off": {
    "backgroundColor": "#3d800a",
    "textColor": "#dddddd"
  },
  "hover": {
    "backgroundColor": "#4ca10c",
    "textColor": "#dddddd"
  },
  "active": {
    "backgroundColor": "#2d6008",
    "textColor": "#dddddd"
  }
},

• Colors accept named CSS colors, hex (e.g., #RRGGBB or #RRGGBBAA), or rgb/rgba strings.
• The label text is configured under label.text.on and label.text.off.
• Border radius/width/color control the button outline.

Csound Usage

The fileButton returns a string containing the file path and a k-rate trigger value. The trigger value will be 1 for one k-cycle when a new file is selected, then return to 0. Read it with the CabbageStrTrig struct form of cabbageGetValue:

file:CabbageStrTrig = cabbageGetValue("audioFile")
if file.trig == 1 then
    cabbageSet("infoText", "text", file.val)
endif

Example

fileButton.csd

<Cabbage>
{
    "pluginId"      : "def1",
    "enableDevTools": true,
    "channelConfig" : [ {"name": "0 in 2 out", "ins": "0", "outs": "2"} ],
    "widgets"       : [
        {
            "type"   : "form",
            "caption": "File Button Example",
            "size"   : {"width": 400, "height": 300},
            "guiMode": "queue"
        },
        {
            "type"    : "fileButton",
            "bounds"  : {"left": 20, "top": 20, "width": 120, "height": 30},
            "channels": [ {"id": "audioFile"} ],
            "label"   : { "text": {"off": "Choose File", "on": "Choose File"} },
            "filters" : "*.wav;*.aif;*.mp3",
            "mode"    : "file"
        },
        {
            "type"    : "textEditor",
            "bounds"  : {"left": 20, "top": 62, "width": 360, "height": 80},
            "channels": [ {"id": "infoText"} ],
            "label"   : {"text": "No file selected"},
            "readOnly": 1,
            "wrap"    : 1
        }
    ]
}

</Cabbage>
<CsoundSynthesizer>
<CsOptions>
-n -d -+rtmidi=NULL -M0
</CsOptions>
<CsInstruments>
; Initialize the global variables.
ksmps = 32
nchnls = 2
0dbfs = 1

; Rory Walsh 2021
;
; License: CC0 1.0 Universal
; You can copy, modify, and distribute this file,
; even for commercial purposes, all without asking permission.

instr Loader
    file:CabbageStrTrig = cabbageGetValue("audioFile")

    if file.trig == 1 then
        if active:k(nstrnum("Player")) > 0 then
            turnoff2(nstrnum("Player"), 0, 0)
        endif
        event("i", "Player", 0, 3600)
    endif
endin

instr Player
    path:S = cabbageGetValue("audioFile")
    cabbageSet("infoText", "label.text", path)
    if filevalid(path) == 1 then
        if filenchnls(path) == 2 then
            sigL:a, sigR:a = diskin2(path, 1, 0, 1)
            outs(sigL, sigR)
        else
            sig:a = diskin2(path, 1, 0, 1)
            outs(sig, sig)
        endif
    else
        prints("File not found: %s\n", path)
        turnoff()
    endif
endin

</CsInstruments>
<CsScore>
;starts the loader and runs it for a week
i"Loader" 0 z
</CsScore>
</CsoundSynthesizer>