nativeImage and NativeImage
A small image class with no native dependencies: a full PNG codec (using Node's zlib), bilinear resize, and crop. Identical on Linux and Windows.
import { nativeImage, NativeImage } from '@owear/core'
Factory
nativeImage.createFromPath(path: string): NativeImage
nativeImage.createFromBuffer(buf: Buffer): NativeImage
nativeImage.createFromDataURL(dataURL: string): NativeImage
All three are synchronous, like Electron.
NativeImage
img.isEmpty(): boolean
img.getSize(): { width: number; height: number }
img.toPNG(): Buffer
img.toJPEG(quality?: number): Buffer
img.toDataURL(): string
img.resize(options: { width?; height?; quality?: 'good' | 'better' | 'best' }): NativeImage
img.crop(rect: { x; y; width; height }): NativeImage
resize preserves aspect ratio if only one of width/height is given.
Format support
| Format | Range |
|---|---|
| PNG | color types 0/2/3/4/6, bit depths 1/2/4/8/16, non-interlaced; decode to RGBA and encode from RGBA |
| JPEG | getSize (SOF header) and toJPEG (returns the original bytes when the source is already JPEG); resizing JPEG is not supported |
Methods that require decoded pixels (toPNG when the source is not PNG,
resize, crop) throw if the image was not decodable.
Example
const shot = await win.webContents.capturePage() // NativeImage
const thumb = shot.resize({ width: 128 })
const icon = thumb.crop({ x: 0, y: 0, width: 16, height: 16 })
fs.writeFileSync('thumb.png', thumb.toPNG())
tray.setImage(icon)
Types
interface Size { width: number; height: number }
interface Rectangle { x: number; y: number; width: number; height: number }
interface ResizeOptions { width?; height?; quality? }