Interface CanvasAdapter

Hierarchy

CanvasAdapter

Implemented by

Index

Methods

create createImage createImageData disposeCanvas disposeImage drawText getImageData initialize isInitialized measureText mergeCanvas scaleImage scaleImageToDimensions toBytes toDataURL writeImageToBytes

Methods

create

create(width: number, height: number): any
Creates a canvas object
Parameters
- width: number
- height: number
Returns any
- Defined in lib/canvas/canvasAdapter.ts:20

createImage

createImage(data: string | Buffer | Uint8Array | Blob, contentType: string): Promise<GeoPackageImage>
Creates an Image object to be used in the context.drawImage function
Parameters
- data: string | Buffer | Uint8Array | Blob
- contentType: string
Returns Promise<GeoPackageImage>
- Defined in lib/canvas/canvasAdapter.ts:27

createImageData

createImageData(width: any, height: any): ImageData
Creates an ImageData object
Parameters
- width: any
- height: any
Returns ImageData
- Defined in lib/canvas/canvasAdapter.ts:49

disposeCanvas

disposeCanvas(canvas: any): any
Performs any cleanup needed for the specified canvas. The canvas should not be used after calling this function.
Parameters
- canvas: any
Returns any
- Defined in lib/canvas/canvasAdapter.ts:55

disposeImage

disposeImage(image: GeoPackageImage): void
Performs any cleanup needed for the specified image
Parameters
- image: GeoPackageImage
Returns void
- Defined in lib/canvas/canvasAdapter.ts:89

drawText

drawText(context: any, text: string, location: number[], fontFace: string, fontSize: number, fontColor: string): void
Draws text centered at the location specified in the canvas rendering context
Parameters
- context: any
- text: string
- location: number[]
- fontFace: string
- fontSize: number
- fontColor: string
Returns void
- Defined in lib/canvas/canvasAdapter.ts:75

getImageData

getImageData(image: GeoPackageImage): ImageData
Gets the image as ImageData
Parameters
- image: GeoPackageImage
Returns ImageData
- Defined in lib/canvas/canvasAdapter.ts:104

initialize

initialize(): Promise<void>
Initializes the adapter for use.

Returns Promise<void>
- Defined in lib/canvas/canvasAdapter.ts:8

isInitialized

isInitialized(): boolean
Returns if the Adapter has been initialized.

Returns boolean
- Defined in lib/canvas/canvasAdapter.ts:13

measureText

measureText(context: any, fontFace: string, fontSize: number, text: string): number
Returns the width of the text in the given font face and font size
Parameters
- context: any
- fontFace: string
- fontSize: number
- text: string
Returns number
- Defined in lib/canvas/canvasAdapter.ts:64

mergeCanvas

mergeCanvas(fromCanvas: any, toContext: any): void
Draw content of fromCanvas into the toContext
Parameters
- fromCanvas: any
- toContext: any
Returns void
- Defined in lib/canvas/canvasAdapter.ts:111

scaleImage

scaleImage(image: GeoPackageImage, scale: number): Promise<GeoPackageImage>
Scales an image created using this adapter.
Parameters
- image: GeoPackageImage
- scale: number
Returns Promise<GeoPackageImage>
- Defined in lib/canvas/canvasAdapter.ts:34

scaleImageToDimensions

scaleImageToDimensions(image: GeoPackageImage, scaledWidth: number, scaledHeight: number): Promise<GeoPackageImage>
Scales an image created using this adapter.
Parameters
- image: GeoPackageImage
- scaledWidth: number
- scaledHeight: number
Returns Promise<GeoPackageImage>
- Defined in lib/canvas/canvasAdapter.ts:42

toBytes

toBytes(canvas: any, imageFormat: ImageType, compressionQuality?: number): Promise<Uint8Array>
Converts the contents drawn in a canvas to a byte array
Parameters
- canvas: any
- imageFormat: ImageType
- Optional compressionQuality: number
Returns Promise<Uint8Array>
- Defined in lib/canvas/canvasAdapter.ts:119

toDataURL

toDataURL(canvas: any, format: string, quality?: number): Promise<string>
Converts the canvas to a base64 data url in the format specified
Parameters
- canvas: any
- format: string
- Optional quality: number
  
  0 to 1
Returns Promise<string>
- Defined in lib/canvas/canvasAdapter.ts:83

writeImageToBytes

writeImageToBytes(image: GeoPackageImage, imageFormat: ImageType, compressionQuality: number): Promise<Uint8Array>
Writes the image to a buffer
Parameters
- image: GeoPackageImage
- imageFormat: ImageType
- compressionQuality: number
  
  a Number between 0 and 1 indicating the image quality to be used when creating images using file formats that support lossy compression (such as jpg)
Returns Promise<Uint8Array>
- Defined in lib/canvas/canvasAdapter.ts:98

Interface CanvasAdapter

Hierarchy

Implemented by

Index

Methods

Methods

create

Parameters

width: number

height: number

Returns any

createImage

Parameters

data: string | Buffer | Uint8Array | Blob

contentType: string

Returns Promise<GeoPackageImage>

createImageData

Parameters

width: any

height: any

Returns ImageData

disposeCanvas

Parameters

canvas: any

Returns any

disposeImage

Parameters

image: GeoPackageImage

Returns void

drawText

Parameters

context: any

text: string

location: number[]

fontFace: string

fontSize: number

fontColor: string

Returns void

getImageData

Parameters

image: GeoPackageImage

Returns ImageData

initialize

Returns Promise<void>

isInitialized

Returns boolean

measureText

Parameters

context: any

fontFace: string

fontSize: number

text: string

Returns number

mergeCanvas

Parameters

fromCanvas: any

toContext: any

Returns void

scaleImage

Parameters

image: GeoPackageImage

scale: number

Returns Promise<GeoPackageImage>

scaleImageToDimensions

Parameters

image: GeoPackageImage

scaledWidth: number

scaledHeight: number

Returns Promise<GeoPackageImage>

toBytes

Parameters

canvas: any

imageFormat: ImageType

Optional compressionQuality: number

Returns Promise<Uint8Array>

toDataURL

Parameters

canvas: any

format: string

Optional quality: number

`Optional` compressionQuality: number

`Optional` quality: number