webaudio-controls

WebAudioControls is GUI parts Custom Elements library for Web application using WebComponents.
Especially suitable for audio-applications like VST plugins.

webaudio-controls is consist of following components

Component	Description
webaudio-knob	Rotating or some other frame-by-frame animation knob
webaudio-slider	Vertical or Horizontal slider
webaudio-switch	Toggle/Kick/Radio switches
webaudio-param	Editable value display field
webaudio-keyboard	Mouse/Touch playable keyboard. multi-touch support.

• Also available 'webaudio-pianoroll' at : https://github.com/g200kg/webaudio-pianoroll/

Difference from old version

There are some difference from old [Polymer 1.4] version.

• Current webaudio-controls uses the Custom Elements V1 API directly. In Chrome / Safari / Firefox (59 and later) it works without polyfill. Please install webcomponentsjs on Firefox (58 or less), Edge etc Custom Elements non-compatible browsers.

• Event firing. Knobs/Sliders fires 'input' event instead of 'change' during drag. This is same behavior as input type=range tags.

• Value post conversion function conv attribute is available. It will help for implement, for example, exponential curve parameters. Also Tooltip and Valuetip is integrated. It is now acceptable C-like formatting string for current value display.

Chrome / Firefox / Safari / Opera compatible
iOS and Android touch devices compatible

Live Demo (with external image-files)
Live Demo (with code example)
Live Demo (Knob/Slider/Switch/Param/Keyboard default style)
Live Demo (Various Knob Images)
Live Demo (Multi-Touch Fader)
Live Demo (webaudio-keyboard to Web MIDI API)
(need Web MIDI API support)
Renoid : Practical application using webaudio-controls
webaudio-controls Resize Test
webaudio-controls NonLinear values Test

Using with external image-files.

Default style with no external image-files.

To Operate

Following user actions are supported.

Operation	Component	Description
Click	Switch/Param	toggle / activate the switch or focus the param
Drag	Knob/Slider	up/right to increase value / down/left to decrease value
Shift+Drag	Knob/Slider	fine control
Ctrl+Click / Command+Click(Mac)	Knob/Slider/Switch	set to default value
Keyboard	Param/Keyboard	edit the param value directly / [ZSXDCV...for lowest visible 'C' octave] and [Q2W3E... one octave higher] as a music keyboard
MouseWheel	Knob/Slider	rotate upward to increase value / downward to decrease value
Shift+MouseWheel	Knob/Slider	fine control
Mouse Button Press / Touch	Keyboard	play keyboard. multi-touch is supported

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How to use

• Install

  • The main file is webaudio-controls.js. If you want to support non-WebComponents ready browsers, webcomponents.js is also needed.
  • Use command bower install --save g200kg/webaudio-controls, if you use bower. Or download zipped file and deploy appropriately.
  • If you want to load webaudio-controls.js directly from this GitHub page, installation is not necessary.

• [for WebComponents polyfill] load webcomponents.js

  • <script src="bower_components/webcomponentsjs/webcomponents-lite.js"></script>

• load webaudio-contols
  • <script src="bower_components/webaudio-controls/webaudio-controls.js"></script>
  • Or, if you want to load webaudio-controls.js directly from this GitHub page as CDN:
    <script src="https://g200kg.github.io/webaudio-controls/webaudio-controls.js" ></script>

• insert webaudio-knob/slider/switch/param/keyboard elements. for example...
  • <webaudio-knob src="img/LittlePhatty.png" sprites="100" min="0" max="100"></webaudio-knob>
  • <webaudio-slider src="img/hsliderbody.png"></webaudio-slider>
  • <webaudio-switch src="img/switch_toggle.png" width="32" height="32"></webaudio-switch>
  • <webaudio-param src="" link="knob-1"></webaudio-param>
  • <webaudio-keyboard keys="25" ></webaudio-keyboard>

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Attributes

webaudio-knob

Attribute	Options	Default	Description
src	string	null	url of the knob image, Single frame or vertical stitched. Internal embedded resource is used if not specified.
value	float	0	The current value. Also used as initial value if specified
defvalue	float	Initial 'value' is used if not specified	The default value that will be used when ctrl+click
min	float	0	Minimum value of the knob
max	float	100	Maximum value of the knob
step	float	1	Value step of the control. The 'value' is always rounded to multiple of 'step'
width	int	0	Knob width in px. diameter value is used if this value is 0.
height	int	0	Knob height in px. diameter value is used if this value is 0.
diameter	int	64	Knob diameter in px. This attribute can be used instead of width / height if the display image is square.
sprites	int	0	if 0, the src image should be single frame image that indicate middle position. the image will be rotated -135deg to +135deg. If sprirites is not 0, the src image should be vertically stitched multi-framed image. sprites specify the max frame number in the stitched knob image. Note that this is (number of frames) - 1
sensitivity	float	1	Pointing device sensitivity. min-max range correspond to (128 / sensitivity) px
valuetip	0,1	1	Enable the overlaid value-tip display.
tooltip	string	null	Tooltip text that will be shown when mouse hover a while. If the text include a C-printf style value formatter like %8.2f, it will be replaced by current value. This formatter should be %[n][.][m]{d,f,x,X,s}. Here the 'n' is total columns, 'm' is after the decimal point columns. If the conv function is specified, the converted value convValue is used for display.
conv	string	null	Value conversion function. If this function is specified, the function is called with current value as argument and be stored as convValue. That will be used as tooltip display. For example, conv="(x)=>{return Math.pow(10,x)*20}" is specified, for range of value between 0 and 3, the range of convValue corresponds to 20 to 20000.
enable	0,1	1	Enable control with the pointing device.
colors	string	"#e00;#000;#000"	Semicolon separated 3 colors for 'indicator', 'body' and 'highlight'. These colors are used in default knob (when src is not provided).
outline	0,1	1	Border display when focused.
midilearn	0,1	0	If 1, MIDI learn function with right-click menu is enabled.
midicc	string	null	Assign MIDI control change to this knob, with format ch.cn, here the ch is channel (1-16, ignore channel if 0) and cn is control number (0-119).

webaudio-slider

Attribute	Options	Default	Description
src	string	null	url of the slider background image. Solid background color if not specified.
knobsrc	string	null	url of the slider knob part image. Internal embedded resouce is used if not specified
value	float	0	The current value. Also used as initial value if specified
defvalue	float	Initial 'value' is used if not specified	The default value that will be used when ctrl+click
min	float	0	Minimum value of the slider
max	float	100	Maximum value of the slider
step	float	1	Value step of the control. The 'value' is always rounded to multiple of 'step'
width	int	24	Slider display width in px
height	int	128	Slider display height in px
knobwidth	int	same as 'width' if 'direction' is vert, or same as 'height' if 'direction' is horz	Slider knob part width in px
knobheight	int	same as 'width' if 'direction' is vert, or same as 'height' if 'direction' is horz	Slider knob part height in px
ditchlength	int	('height'-'knobheight') or ('width'-'knobwidth') depends on 'direction'	Knob movable length
direction	"vert","horz"	"vert"	Slider direction. vertical or horizontal
sensitivity	float	1	Pointing device sensitivity. min-max range correspond to (128 / 'sensitivity') px
valuetip	0,1	1	Enable the overlaid value-tip display.
tooltip	string	null	Tooltip text that will be shown when mouse hover a while. If the text include a C-printf style value formatter like %8.2f, it will be replaced by current value. This formatter should be %[n][.][m]{d,f,x,X,s}. Here the 'n' is total columns, 'm' is after the decimal point columns. If the conv function is specified, the converted value convValue is used for display.
conv	string	null	Value conversion function. If this function is specified, the function is called with current value as argument and be stored as convValue. That will be used as tooltip display. For example, conv="(x)=>{return Math.pow(10,x)*20}" is specified, for range of value between 0 and 3, the range of convValue corresponds to 20 to 20000.
enable	0, 1	1	Enable control with the pointing device.
colors	string	"#e00;#000;#fff"	Semicolon separated 3 colors for 'knob', 'background' and 'highlight'. These colors are used in default knob (when src or knobsrc is not provided).
outline	0,1	1	Border display when focused.
midilearn	0,1	0	If 1, MIDI learn function with right-click menu is enabled.
midicc	string	null	Assign MIDI control change to this slider. with format ch.cn, here the ch is channel (1-16, ignore channel if 0) and cn is control number (0-119).

webaudio-switch

Attribute	Options	Default	Description
src	string	Internal embedded resource is used if not specified	url of the vertical stitched switch image
value	0,1	0	The current value (0 or 1). Also used as initial value of the switch if specified
defvalue	0,1	Initial 'value' is used if not specified	The default value that will be used when ctrl+click
width	int	32	Switch display width in px
height	int	32	Switch display height in px
type	"toggle","kick","radio"	"toggle"	Switch type. "toggle" switch has so-called 'checkbox' function. "radio" switch is a radio-button and the "kick" switch is a general command button
group	string	null	Group id string used if the 'type' is "radio". Only one switch will be set to "1" in same group
invert	0,1	0	exchange on and off image
tooltip	string	null	Tooltip text that will be shown when mouse hover a while
enable	0,1	1	Enable control with the pointing device.
colors	string	"#e00;#000;#fff"	Semicolon separated 3 colors for 'knob', 'background' and 'highlight'. These colors are used in default switch (when src is not provided).
outline	0,1	1	Border display when focused.
midilearn	string	null	If true, MIDI learn function with right-click menu is enabled.
midicc	string	null	Assign MIDI control change to this switch. with format ch.cn, here the ch is channel (1-16, ignore channel if 0) and cn is control number (0-119).

webaudio-param

Attribute	Options	Default	Description
src	string	Black rectangle if not specified	Background image or color. Transparent if set to "", or url to background image.
value	float	0	The current value. Usually same as linked control
width	int	32	Parameter display width in px
height	int	16	Parameter display height in px
fontsize	int	9	Font-size of the parameter display
colors	string	"#e00;#000"	Semicolon separated 2 colors for text and background. background color is used when src is not defined.
outline	0,1	1	Border display when focused.
link	string	null	Specify the linked webaudio-knob/slider/switch by Id

webaudio-keyboard

Attribute	Options	Default	Description
values	int array	[]	The array of current pressed key numbers. "values" may has more than one element in multi-touch environment.
width	int	480	Keyboard display width in px
height	int	128	Keyboard display height in px
min	int	0	Lowest Key number. Each key is numbered incrementally from this number. If the "min" is not 0 and the modulo 12 is not zero, the keyboard is started from corresponding position (not-C). Note that the specified key should be a 'white-key'.
keys	int	25	Number of keys. 25 means 25 keys keyboard.
colors	string	'#222; #eee;#ccc; #333;#000; #e88;#c44; #c33;#800'	semicolon separated 9 keyboard colors. 'border; whitekey-grad-from;whitekey-grad-to; blackkey-grad-from;blackkey-grad-to; active-whitekey-grad-from;active-whitekey-grad-to; active-blackkey-grad-from;active-blackkey-grad-to'. Each key surface can has garadient left to right with 'from' and 'to'.
outline	0,1	1	Border display when focused.
enable	0,1	1	Enable control with the pointing device.

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Functions

setValue(value, fire)

webaudio-knob | webaudio-slider | webaudio-switch
description: Each control can be setup and redraw by calling this function from JavaScript. If the fire parameter is undefined or false, this function will not fire 'change' event. Or the change event will be fired.

setNote(state,note)

webaudio-keyboard
description: webaudio-keyboard can be setup pressing state with this function from JavaScript. corresponding key specified by the note is pressed if the state is non-zero otherwise the key is released. This function will NOT fire the 'change' event.

---

Events

'input'

webaudio-knob | webaudio-slider
description: 'input' event is fired when knob / slider value changes while dragging.

'change'

webaudio-knob | webaudio-slider | webaudio-switch | webaudio-keyboard
description: 'change' event is fired when value changes is decided. It means mouse button release for knobs and sliders, or switch / keyboard state changes. Also issued when setValue() function call with fire flag is nonzero. In the event handler of webaudio-knob,webaudio-slider or webaudio-switch, current value can be get with referring event.target.value.

var knobs = document.getElementsByTagName('webaudio-knob');
for (var i = 0; i < knobs.length; i++) {
  var knob = knobs[i];
  knob.addEventListener('change', function(e) {
    console.log(e.target.value);
  });
}

For the webaudio-keyboard, each 'change' event has the property '.note' that contain a array [key-state, key-number]. For example event.note = [1, 60] if the key#60 is on, or event.note = [0, 60] if the key#60 is off.

var keyboard = document.getElementsById('keyboard');
keyboard.addEventListener('change', function(e) {
	if(e.note[0])
		console.log("Note-On:"+e.note[1]);
	else
		console.log("Note-Off:"+e.note[1]);
});

'click'

webaudio-switch (kick)
description: 'click' event is emitted if the 'kick' type webaudio-switch has clicked.

---

WebAudioControlsOptions

By setting the global object, WebAudioControlsOptions, you can specify default values such as the knob size or colors etc when attribute setting on each tag is omitted. This declaration should be prior to the webaduio-controls.js loading.

<script>
WebAudioControlsOptions={
  useMidi:1,
  knobDiameter:80,
  switchWidth:40,
  switchHeight:20,
};
</script>
<script src="webaudio-controls.js"></script>

The items that can be set are as follows

name	default	description
useMidi	0	enable control from midi devices
midilearn	0	enable midilearn function for each knobs/sliders/switches
outline	1	border display when focused
knobWidth	0	width for knobs
knobHeight	0	height for knobs
knobDiameter	64	diameter for knobs
knobSrc	null	knob image source
knobSprites	0	knob image number of frames
knobColors	"#e00;#000;#000"	color setting for knobs
sliderWidth	24	width for sliders
sliderHeight	128	height for sliders
sliderColors	"#e00;#000;#fcc"	color setting for sliders
switchWidth	0	width for switches
switchHeight	0	height for switches
switchDiameter	24	diameter for switches
switchColors	"#e00;#000;#fcc"	color setting for switches
paramWidth	32	width for param
paramHeight	16	height for param
paramColors	"#fff;#000"	color setting for param

---

Creating knob images

webaudio-knob (with sprites is 0 (default)) use a single frame knob image that indicate center position. For example,

This image will be rotated from -135deg to +135deg. This approach will works well if the image is flat designed, but more complex animation (for example, drop-shadowed, highlighted or something elastic) will need pre-rendered frame-by-frame animation as below.

webaudio-knob (with non zero "sprites") use a vertical 'stitched' multi-frames animation image, and webaudio-switch use a vertical 'stitched' two-frames animation image. For example,

This knob example has only 5 frames but it should has more frames for smooth animation. I recommend to use JKnobMan/WebKnobMan for making these stitched images,

• JKnobMan -- Java based Knob image creation tool.
• WebKnobMan -- WebApp version of the JknobMan
• KnobGallery -- knob data sharing space

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Here is a brief instruction to export knob-image from KnobGallery

• Go to KnobGallery
• Find your favorite knob design and click 'Open with WebKnobMan'
• Click on 'Export' to download png file
• Of course, you can create your own!

Note: comply with license requirements

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MIDI support: knobs, sliders and switches have midilearn/midicc support built-in

To enable MIDI related functions, add the following line before the <link> tag that loads webaudio-controls.html

<script>WebAudioControlsOptions={useMidi:1}</script>

Midilearn right click menu: add a midilearn=1 attribute to the <webaudio-knob>, <webaudio-slider> and <webaudio-switch> elements. Then right click on the element in the GUI, a midi learn menu should appear. Then, operate one of your midi controller and it should start actionning the webaudio-controls widget in the HTML page. You can hot plug/unplug midi devices, they will be detected.

Declarative association between a midi controller and a GUI webaudiocontrol: There is also an HTML midicc="channel.cc#" attribute that works like this: midicc="3.2" means "listen to a cc event on channel 3, cc number 2". If you don't know the channel/cc number of your controller: 1) add a midilearn=1 attribute so that a right click on the GUI widget will display the midilearn menu, 2) select "learn" in the menu, 3) operate your knob/slider/switch, normally the midi controller and the GUI object are in sync. 4) look at the devtool console, there is a message indicating the channel and cc number, for example "channel 0, cc 28". Then if you add the attribute midicc="0.28" to the HTML of your knob/slider/switch, the midi mapping between your GUI webaudiocontrol and your midi controller will be automatic. Follow the links at the end of this section and look at the HTML source code to see some examples.

Example: associate a knob with a controller on channel 7, cc number 7:

<webaudio-knob midilearn=true midicc="7.7" ...></webaudio-knob>

External midi event listener (hook): you can also declare in your HTML file your own midi event listener (for example for listening to program changes events): use the webAudioControlsMidiManager object, that comes with an addMidiListener method. Like that you will benefit from the MIDI code included in the webaudiocontrols. Here is an example (also, look at the source code of the Sample1.html demo, and open the devtool console to see midi messages received by the hook at the end of the HTML file).

<script>
// add this to your html page that uses webaudiocontrols
webAudioControlsMidiManager.addMidiListener(function(event) {
    var data = event.data;
    var channel = data[0] & 0xf;
    var controlNumber = data[1];

    console.log("Midi event hook: data:[" + data + "] channel:" + channel + " cc:"+controlNumber);

    // do whatever you want with the event
    // ...
});
</script>

Demo at: https://wasabi.i3s.unice.fr/AmpSimFA/ and at https://wasabi.i3s.unice.fr/AmpSimFA/sample1.html

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License

WebAudio-Controls is developped based on:

• WebAudio-Knob by Eiji Kitamura
• WebAudio-Slider by Ryoya KAWAI
• WebAudio-Switch by Keisuke Ai
  Integrated and enhanced by g200kg

Copyright (c) 2013 Eiji Kitamura / Ryoya KAWAI / Keisuke Ai / g200kg / @micbuffa / @CellouBalde
Licensed under the Apache License, Version 2.0

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Knob/Switch images in samples are from Knob Gallery
switch_toggle.knob by az (c) 2011 CC-BY