ImageCapture
Image capture
ImageCapture grabs frames from a static source (image). It implements source initialization, setup, start/stop of capture, and frame grabbing. Internally, ImageCapture utilizes ImageBuffer as storage and fast resizer.
Extends
Constructors
new ImageCapture()
new ImageCapture():
ImageCapture
Constructor
Returns
Inherited from
Properties
buffer
buffer:
ImageBuffer
Context of original stream
Inherited from
captureTime
captureTime:
number=0
Timestamp of the last captured frame
Inherited from
clipRect?
protectedoptionalclipRect:ClipRect
Clipping rectangle
Inherited from
imageRef?
protectedoptionalimageRef:ImageBitmap
Image bitmap
sizeMax?
protectedoptionalsizeMax:number
Maximum capture resolutions
Inherited from
transpose?
protectedoptionaltranspose:boolean
Transpose frames
Inherited from
Methods
addListener()
addListener<
E>(event,listener):this
Adds the listener function to the end of the listeners array
Type Parameters
• E extends "resize"
Parameters
• event: E
The name of the event
• listener: CaptureEvents[E]
The callback function
Returns
this
This EventEmitter
Inherited from
capture()
capture():
boolean
Grab the next video frame
VideoCapture grabs the next frame from an image and stores it in embedded ImageBuffer.
Returns
boolean
True if next frame was available and grabbed
Overrides
dispose()
dispose():
void
Dispose video capture object
Returns
void
Overrides
emit()
emit<
E>(event, …args):boolean
Synchronously calls each of the listeners registered for the event
Type Parameters
• E extends "resize"
Parameters
• event: E
The name of the event
• …args: Args<CaptureEvents[E]>
Arguments passed to the listeners
Returns
boolean
True if the event had listeners, False otherwise
Inherited from
eventNames()
eventNames(): (
string|symbol)[]
List of emitter’s events
Returns
(string | symbol)[]
List of emitter’s events
Inherited from
getMaxListeners()
getMaxListeners():
number
Maximum number of listeners per event
Returns
number
Maximum number of listeners per event
Inherited from
listenerCount()
listenerCount<
E>(event):number
The number of listeners listening to the event
Type Parameters
• E extends "resize"
Parameters
• event: E
The name of the event
Returns
number
Number of listeners
Inherited from
listeners()
listeners<
E>(event):Function[]
Copy of the array of listeners for the event
Type Parameters
• E extends "resize"
Parameters
• event: E
The name of the event
Returns
Function[]
Copy of the listeners array
Inherited from
off()
off<
E>(event,listener):this
Removes the listener from the listener array for the event
Type Parameters
• E extends "resize"
Parameters
• event: E
The name of the event
• listener: CaptureEvents[E]
The callback function
Returns
this
This EventEmitter
Inherited from
on()
on<
E>(event,listener):this
Adds the listener function to the event
Type Parameters
• E extends "resize"
Parameters
• event: E
The name of the event
• listener: CaptureEvents[E]
The callback function
Returns
this
This EventEmitter
Inherited from
once()
once<
E>(event,listener):this
Adds a one-time listener function for the event
Type Parameters
• E extends "resize"
Parameters
• event: E
The name of the event
• listener: CaptureEvents[E]
The callback function
Returns
this
This EventEmitter
Inherited from
pause()
pause():
void
Pause video capture
Returns
void
Overrides
prependListener()
prependListener<
E>(event,listener):this
Adds the listener function to the beginning of the listeners array
Type Parameters
• E extends "resize"
Parameters
• event: E
The name of the event
• listener: CaptureEvents[E]
The callback function
Returns
this
This EventEmitter
Inherited from
prependOnceListener()
prependOnceListener<
E>(event,listener):this
Adds a one-time listener function to the beginning of the listeners array
Type Parameters
• E extends "resize"
Parameters
• event: E
The name of the event
• listener: CaptureEvents[E]
The callback function
Returns
this
Inherited from
VideoSource.prependOnceListener
ratio()
ratio():
number
Aspect ratio of the video stream
Returns
number
Aspect ratio of the video stream
Inherited from
rawListeners()
rawListeners<
E>(event):Function[]
Copy of the array of listeners for the event including wrappers
Type Parameters
• E extends "resize"
Parameters
• event: E
The name of the event
Returns
Function[]
Copy of the listeners array
Inherited from
removeAllListeners()
removeAllListeners<
E>(event?):this
Removes all listeners, or those of the specified event
Type Parameters
• E extends "resize"
Parameters
• event?: E
The name of the event
Returns
this
This EventEmitter
Inherited from
VideoSource.removeAllListeners
removeListener()
removeListener<
E>(event,listener):this
Removes the specified listener from the listener array
Type Parameters
• E extends "resize"
Parameters
• event: E
The name of the event
• listener: CaptureEvents[E]
The callback function
Returns
this
This EventEmitter
Inherited from
reset()
reset():
void
Reset video capture
After reset() capture may be started again only after setup().
Returns
void
Overrides
setMaxListeners()
setMaxListeners(
n):this
Sets maximum number of listeners per event
Parameters
• n: number
Maximum number of listeners
Returns
this
This EventEmitter
Inherited from
setup()
setup(
params?):Promise<boolean>
Setup video capture
Loads image specified by a url and sets up a video capture.
Parameters
• params?: VideoSourceParams
Parameters of video capture
Returns
Promise<boolean>
Promise resolved to the status of setup when finished
Overrides
size()
size():
Size
Resolution of the video stream
Returns
Resolution of the video stream
Inherited from
start()
start():
Promise<void>
Start video capture
Video capture can be started only after successful setup().
Returns
Promise<void>
Promise resolved when capture is started
Overrides
updateSize()
protectedupdateSize(size):void
Update callback on video resize
Parameters
• size: Size
New size of the video stream
Returns
void