Function lanczos

lanczos(
    source: ImageData,
    dest: ImageData,
    sx?: number,
    sy?: number,
    sw?: number,
    sh?: number,
    dx?: number,
    dy?: number,
    dw?: number,
    dh?: number,
    use2?: boolean,
): void
Lanczos Resampling
Description
Perform a 2D Lanczos filter on an image. the Lanczos resampler creates some regions that are darker than any in the original and others that are lighter than any in the original. This Fourier transform method is useful in spatial/GIS applications, especially downscaling raster data.

Usage
```
import sharp from 'sharp';
import { lanczos, createImage } from 'gis-tools-ts';
// pull in the image you want to downscale
const pattern = await sharp('./pattern.png')
.raw()
.toBuffer({ resolveWithObject: true });
// setup the destianation image
const patternHalf = createImage(4, 4);
// resize down into patternHalf
lanczos(pattern, patternHalf);
```
Links
Parameters
- source: ImageData
  the source image
- dest: ImageData
  the destination image
- sx: number = 0
  source starting x point [Default: 0]
- sy: number = 0
  source starting y point [Default: 0]
- sw: number = ...
  source width to use [Default: source width - sx]
- sh: number = ...
  source height to use [Default: source height - sy]
- dx: number = 0
  destination starting x point [Default: 0]
- dy: number = 0
  destination starting y point [Default: 0]
- dw: number = ...
  destination width to use [Default: destination width - dx]
- dh: number = ...
  destination height to use [Default: destination height - dy]
- use2: boolean = false
  use 2nd lanczos filter instead of 3rd [Default: false]
Returns void

Function lanczos

Lanczos Resampling

Description

Usage

Links

Parameters

Returns void

Settings

On This Page