P5Beholder

Constructor

(private) new P5Beholder()

Creates an instance of P5Beholder. It is automatically called during p5 loading. Initialization of the library is only compelte after prepare() is called on sketch setup (see P5Beholder#prepare).

Source: p5.beholder.js, line 4

Members

(static) _defaultConfig

An object holding camera, detection, feed and overlay default options for the Beholder detection system.

Source: p5.beholder.js, line 257

Example

// Structure of the default configuration object
{
  camera_params: {
    videoSize: 0, // The video size values map to the following [320 x 240, 640 x 480, 1280 x 720, 1920 x 1080]
    rearCamera: false, // Boolean value for defaulting to the rear facing camera. Only works on mobile
    torch: false, // Boolean value for if torch/flashlight is on. Only works for rear facing mobile cameras. Can only be set from init
  },
  detection_params: {
    minMarkerDistance: 10,
    minMarkerPerimeter: 0.2,
    maxMarkerPerimeter: 0.8,
    sizeAfterPerspectiveRemoval: 49,
  },
  feed_params: {
    contrast: 0,
    brightness: 0,
    grayscale: 0,
    flip: false,
  },
  overlay_params: {
    present: true, // Determines if the Beholder overlay will display or be invisible entirely via display: none
    hide: true, // Determines if the overlay should be hidden on the left of the screen or visible
  },
}

Methods

angleInRange(currentAngle, detectionTargetAngle, angleRange) → {true|false}

Checks if the current angle is within a defined range from a target angle. All angles are in radians.

Parameters:

Name	Type	Description
`currentAngle`	number	Value to be checked.
`detectionTargetAngle`	number	The target angle.
`angleRange`	number	The range centers around the target angle. Should be less than PI.

Source: p5.beholder.js, line 212

Returns:

Type:: true | false

cameraToCanvasVector(coord) → {p5.Vector}

Converts a position from camera to canvas using a p5.Vector.

Parameters:

Name	Type	Description
`coord`	p5.Vector	p5.Vector with camera position.

Source: p5.beholder.js, line 171

Returns:

p5.Vector with canvas position.

Type:: p5.Vector

cameraToCanvasX(x) → {number}

Converts X position from camera to canvas.

Parameters:

Name	Type	Description
`x`	number	Camera X position.

Source: p5.beholder.js, line 151

Returns:

Canvas X position.

Type:: number

cameraToCanvasXY(pX, pY) → {p5.Vector}

Converts a position from camera to canvas positions using 2 numbers.

Parameters:

Name	Type	Description
`pX`	number	Camera-relative X value.
`pY`	number	Camera-relative Y value.

Source: p5.beholder.js, line 185

Returns:

p5.Vector with canvas position.

Type:: p5.Vector

cameraToCanvasY(y) → {number}

Converts Y position from camera to canvas.

Parameters:

Name	Type	Description
`y`	number	Camera Y position.

Source: p5.beholder.js, line 161

Returns:

Canvas Y position.

Type:: number

debugDrawMarker(markerIdopt)

Debug functionality for drawing a marker on the canvas.

Parameters:

Name	Type	Attributes	Default	Description
`markerId`	number	<optional>	0	The id of the marker to draw.

Source: p5.beholder.js, line 113

markerPresenceToKey(markerIdopt, pKeyCodeopt)

Quick converter between marker presence and keyboard input. When a marker is detected, fires the keydown event. Whe the marker is undetected, fires the keyup event.

Parameters:

Name	Type	Attributes	Default	Description
`markerId`	number	<optional>	0	The id of the marker to check.
`pKeyCode`	number	<optional>	32	The number with the keyboard code (from `event.key`).

Source: p5.beholder.js, line 77

markerPresenceToMouseClick(markerIdopt, non-null, clickXopt, clickYopt)

If a marker is present, the mouse button 0 goes down and, when undetected, goes up. The position of the resulting click can be defined, in pixels.

Parameters:

Name	Type	Attributes	Description
`markerId`	number	<optional>	The id of the marker to check presence.
`clickX`	number	<optional>	The X position where of the resulting click.
`clickY`	number	<optional>	The Y position where of the resulting click.

Source: p5.beholder.js, line 48

markerRotationInRange(markerId, detectionTargetAngle, angleRange) → {true|false}

Checks if a marker's rotation is within a specified range from a target angle. Useful for detecting things like a crank or spinner with a marker at its center. All angles are in radians.

Parameters:

Name	Type	Description
`markerId`	number	The id of the marker to be checked.
`detectionTargetAngle`	number	The target angle.
`angleRange`	number	The range centers around the target angle. Should be less than PI.

Source: p5.beholder.js, line 198

Returns:

Type:: true | false

prepare(configopt, querySelectoropt)

Sets-up the p5beholder and sketch integration. Adds Beholder to the HTML page at the and initializes it with proper config file. Important: must be called once on setup(). The config file must use P5Beholder._defaultConfig as a base.

Parameters:

Name	Type	Attributes	Default	Description
`config`	*	<optional>	P5Beholder._defaultConfig	Controls how Beholder detection will run.
`querySelector`	string	<optional>	"#beholder_root"	Picks an HTML element to be the parent of the Beholder system elements (GUI, etc).

Source: p5.beholder.js, line 24

setMarkersTimeout(timeoutopt)

Changes the timeout value for all markers.

Parameters:

Name	Type	Attributes	Default	Description
`timeout`	number	<optional>	50	New time in milliseconds.

Source: p5.beholder.js, line 101