https://github.com/swnb/dct-ts
dct and idct algorithm implement with typescript
https://github.com/swnb/dct-ts
algorithm dct idct typescript
Last synced: 9 months ago
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dct and idct algorithm implement with typescript
- Host: GitHub
- URL: https://github.com/swnb/dct-ts
- Owner: swnb
- License: mit
- Created: 2022-01-26T07:55:34.000Z (almost 4 years ago)
- Default Branch: master
- Last Pushed: 2022-01-27T15:22:19.000Z (almost 4 years ago)
- Last Synced: 2025-02-16T21:33:21.933Z (10 months ago)
- Topics: algorithm, dct, idct, typescript
- Language: TypeScript
- Homepage: https://github.com/swnb/dct-ts#readme
- Size: 969 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# @swnb/dct
> dct and idct algorithm implement in typescript
## for example
luma image before dct
after dct, you can use idct to recovery origin image
## install
use pnpm
```shell
pnpm i @swnb/dct
```
use npm
```shell
npm i @swnb/dct
```
## usage
prepare example data
```typescript
const example = [
[65, 76, 82, 66, 18, 32],
[12, 87, 9, 2, 54, 78],
[74, 45, 18, 48, 60, 72],
[65, 2, 54, 404, 800, 905],
]
```
discrete cosine transform
```typescript
import { dct } from '@swnb/dct'
const result = dct(example)
console.log(result)
// [
// [
// 638.5003262854817, -416.9193200063309, 154.99999999999983, 42.4578222082416, -43.01259505462728,
// -17.244243642209376,
// ],
// [
// -512.6170218697843, 578.6135814300578, -184.03403633138637, -109.98075816639899,
// 29.645534009728465, -12.201804240974509,
// ],
// [
// 410.2895319161823, -385.13955429855645, 75.4999999999998, 66.54447134560958, 8.660254037844224,
// 12.49428061324591,
// ],
// [
// -188.89844420398651, 249.46420106733234, -75.84671035435811, 2.2508146252807193,
// 52.71203828296457, 1.9283180367658657,
// ],
// ]
```
inverse discrete cosine transform
```typescript
import { idct } from '@swnb/dct'
const result = dct(example)
const originData = idct(result)
console.log(originData)
// [
// [
// 64.99999999999993,
// 75.99999999999999,
// 81.99999999999997,
// 65.99999999999996,
// 17.999999999999897,
// 31.999999999999893
// ],
// [
// 11.99999999999998,
// 87.00000000000003,
// 8.999999999999943,
// 1.9999999999999762,
// 53.99999999999998,
// 78.00000000000009
// ],
// [
// 73.99999999999994,
// 45.000000000000036,
// 17.999999999999922,
// 47.99999999999986,
// 59.99999999999982,
// 71.99999999999982
// ],
// [
// 64.99999999999974,
// 2.00000000000048,
// 53.99999999999999,
// 404.0000000000001,
// 799.9999999999999,
// 904.9999999999995
// ]
// ]
```
## use interface
```typescript
// if you implement Matrix or MatrixPromise
interface Matrix {
getValue: (x: number, y: number) => number
}
interface MatrixPromise {
getValue: (x: number, y: number) => Promise
}
```
you can use dctMatrix, dctMatrixPromise, idctMatrix, idctMatrixPromise to process matrix
```typescript
import { dctMatrix, idctMatrix, dctMatrixPromise, idctMatrixPromise, Matrix, MatrixPromise } from '@swnb/dct'
declare const m: number // matrix's width
declare const n: number // matrix's height
declare const matrix: Matrix // matrix implement { getValue: ( x, y ) => number } 0 <= x < m , 0 <= y < n
declare const matrixPromise: MatrixPromise
const result1 = dctMatrix(matrix, m, n)
const result2 = await dctMatrixPromise(matrixPromise, m, n)
```