converted @cwasm/webp to typescript

.eslintrc.js

@@ -20,5 +20,6 @@ module.exports = {
     'plugin:@typescript-eslint/recommended-requiring-type-checking',
   ],
   rules: {
+    "@typescript-eslint/ban-ts-comment": "off"
   },
 };

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@watergis/terrain-rgb",
-  "version": "1.1.0",
+  "version": "1.1.1",
   "description": "This module is to get elevation from terrain RGB tilesets by longitude and latitude.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
@@ -44,8 +44,10 @@
     "typescript": "^3.9.6"
   },
   "dependencies": {
-    "@cwasm/webp": "^0.1.5",
+    "@canvas/image-data": "^1.0.0",
     "axios": "^0.21.0",
+    "fs": "0.0.1-security",
+    "path": "^0.12.7",
     "png-ts": "0.0.3"
   },
   "jest": {
@@ -58,7 +60,7 @@
     },
     "globals": {
       "ts-jest": {
-        "tsConfig": "tsconfig.json"
+        "tsconfig": "tsconfig.json"
       }
     },
     "testMatch": [

src/terrainrgb.ts

@@ -1,7 +1,7 @@
 import * as tilebelt from './tilebelt';
 import axios from 'axios';
 import PNG from 'png-ts';
-import webp from '@cwasm/webp';
+import { decode } from './webp';
 
 
 class TerrainRGB {
@@ -85,7 +85,7 @@ class TerrainRGB {
   }
 
   getElevationFromWEBP(binary: Uint8Array, tile: number[], lng: number, lat: number, tileSize: number): number{
-    const image = webp.decode(binary);
+    const image = decode(binary);
     const pixels = image.data;
 
     const data = [];

src/webp.ts

@@ -0,0 +1,80 @@
+/* global WebAssembly */
+
+/**
+ * This module was inpired from the below repository.
+ * https://github.com/LinusU/cwasm-webp
+ * I converted the module to typescript.
+ * Thanks a lot!
+ */
+
+import fs from 'fs'
+import path from 'path'
+
+import ImageData from '@canvas/image-data'
+
+const stubs = {
+  fd_close () { throw new Error('Syscall fd_close not implemented') },
+  fd_seek () { throw new Error('Syscall fd_seek not implemented') },
+  fd_write () { throw new Error('Syscall fd_write not implemented') }
+}
+
+const code = fs.readFileSync(path.join(__dirname, 'webp.wasm'))
+const wasmModule = new WebAssembly.Module(code)
+const instance = new WebAssembly.Instance(wasmModule, { wasi_snapshot_preview1: stubs })
+
+export const decode = (input: Uint8Array): ImageData => {
+  // Allocate memory to hand over the input data to WASM
+  // @ts-ignore
+  // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
+  const inputPointer = instance.exports.malloc(input.byteLength)
+  // @ts-ignore
+  const targetView = new Uint8Array(instance.exports.memory.buffer, inputPointer, input.byteLength)
+
+  // Copy input data into WASM readable memory
+  targetView.set(input)
+
+  // Allocate metadata (width & height)
+  // @ts-ignore
+  // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
+  const metadataPointer : number = instance.exports.malloc(8)
+
+  // Decode input data
+  // @ts-ignore
+  // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
+  const outputPointer = instance.exports.WebPDecodeRGBA(inputPointer, input.byteLength, metadataPointer, metadataPointer + 4)
+
+  // Free the input data in WASM land
+  // @ts-ignore
+  instance.exports.free(inputPointer)
+
+  // Guard return value for NULL pointer
+  if (outputPointer === 0) {
+    // @ts-ignore
+    instance.exports.free(metadataPointer)
+    throw new Error('Failed to decode WebP image')
+  }
+
+  // Read returned metadata
+  // @ts-ignore
+  const metadata = new Uint32Array(instance.exports.memory.buffer, metadataPointer, 2)
+  const [width, height] = metadata
+
+  // Free the metadata in WASM land
+  // @ts-ignore
+  instance.exports.free(metadataPointer)
+
+  // Create an empty buffer for the resulting data
+  const outputSize = (width * height * 4)
+  const output = new Uint8ClampedArray(outputSize)
+
+  // Copy decoded data from WASM memory to JS
+  // @ts-ignore
+  output.set(new Uint8Array(instance.exports.memory.buffer, outputPointer, outputSize))
+
+  // Free WASM copy of decoded data
+  // @ts-ignore
+  instance.exports.free(outputPointer)
+
+  // Return decoded image as raw data
+  return new ImageData(output, width, height)
+}