nestjs-img-resize

Description

NestJS module for simple and flexible image resizing. Uses the gm library and implements a user-friendly interface for resizing and converting images.

Features

• Format support: jpg, jpeg, png, tif, tiff (other formats were not tested)
• Resize images while maintaining aspect ratio
• Automatic image rotation by exif metadata
• Converting images to supported formats
• Additional settings for resizing images

Installation

Install this library

npm install nestjs-img-resize

The library depends on gm, so the graphicsmagick and imagemagick libraries need to be installed

apt-get install -y graphicsmagick imagemagick

or

brew install imagemagick
brew install graphicsmagick

Usage

Connect the module to your project

@Module({
  imports: [
    NestjsImgResizeModule,
  ],
})
export class AppModule {
}

Inject ImgResizeService into controller or your service

@Injectable()
export class Myservice {
  constructor(protected imgResizeService: ImgResizeService) {
  }
}

Image conversion method

Converting an image to a specific format

convert(image: Buffer, convertConfig: ImgConvertConfig):Promise<Buffer>;

Image resize method

Resize image by configuration

resize(image: Buffer, resizeConfig: ImgResizeConfig): Promise<ImgResizeResponse>;

Image bulk resize method

Resize image by bulk configuration, and the result is images in several sizes.

resizeBulk(image: Buffer, resizeConfig: ImgResizeConfig[]): Promise<ImgResizeResponse[]>

Get image dimension

getImgDimension(buffer: Buffer): Promise<ImgDimension>

Interfaces

ImgConvertConfig

Prop	Type	Description
autoExifRotate	boolean	Allow to automatically rotate the image based on exif metadata, default - false
outType	ImageTypes	Output Image Format, default jpeg
fillAlpha	string	Fill the alpha channel with a specific color, useful when converting a format with an alpha channel to a format without it

ImgResizeConfig

extends ImgConvertConfig

Prop	Type	Description
width	number	Resized image width, required
height	number	Resized image height, required
exact	boolean	If true then the output image size will have the exact size specified in the configuration, by default false - resizing takes into account the aspect ratio of the image
allowStretch	allowStretch	Stretch the image if it is smaller than the specified size, only works if exact = false, default false
sizeName	string	Size name, for identify resized result, optional
autoExifRotate	boolean	Allow to automatically rotate the image based on exif metadata, default - false
outType	ImageTypes	Output Image Format, default jpeg
fillAlpha	string	Fill the alpha channel with a specific color, useful when converting a format with an alpha channel to a format without it

Benchmark

npm run benchmark

Benchmark results

The results depend on the characteristics of the machine on which the test is performed.
My results on Intel Core i5-10300H CPU @ 2.50GHz × 8, 15,5 GiB, Ubuntu 20.04.2 LTS

v1.0.0

Resize jpg 1920x1080 to 500x281 --> 9.81338447508557 ops/sec | Samples: 49
Resize png 1920x1080 to 500x281 --> 4.821842038356058 ops/sec | Samples: 27
Convert 650x434 png to jpg --> 28.200684305778598 ops/sec | Samples: 68
Convert 650x434 tiff to jpg --> 25.820336860905076 ops/sec | Samples: 45

Tests

npm run test:e2e

License

MIT