imagescript
Version:
zero-dependency javascript image manipulation
56 lines (45 loc) • 1.84 kB
JavaScript
const wasm_name = 'svg';
const { join } = require('path');
const { promises: { readFile } } = require('fs');
const wasm_path = process.env.IMAGESCRIPT_WASM_SIMD ? 'simd' : 'any';
let mod = null;
module.exports = {
async init() {
if (!mod) mod = new WebAssembly.Module(await readFile(join(__dirname, `../${wasm_path}/${wasm_name}.wasm`)));
return this.new();
},
new() {
const wasm = new WebAssembly.Instance(mod).exports;
class mem {
static length() { return wasm.wlen(); }
static alloc(size) { return wasm.walloc(size); }
static free(ptr, size) { return wasm.wfree(ptr, size); }
static u8(ptr, size) { return new Uint8Array(wasm.memory.buffer, ptr, size); }
static u32(ptr, size) { return new Uint32Array(wasm.memory.buffer, ptr, size); }
static copy_and_free(ptr, size) {
let slice = mem.u8(ptr, size).slice();
return (wasm.wfree(ptr, size), slice);
}
}
function load(buffer, fit) {
if (!fit) return rasterize(buffer, 0, 0);
if (fit.zoom) return rasterize(buffer, 1, fit.zoom);
if (fit.width) return rasterize(buffer, 2, fit.width);
if (fit.height) return rasterize(buffer, 3, fit.height);
}
function rasterize(buffer, fit, scale) {
const bptr = mem.alloc(buffer.length);
mem.u8(bptr, buffer.length).set(buffer);
const ptr = wasm.rasterize(bptr, buffer.length, fit, scale);
if (0 === ptr) throw new Error('svg: failed to parse');
if (1 === ptr) throw new Error('svg: failed to rasterize');
const framebuffer = {
width: wasm.rasterize_width(ptr),
height: wasm.rasterize_height(ptr),
buffer: mem.u8(wasm.rasterize_buffer(ptr), mem.length()).slice(),
}
return (wasm.rasterize_free(ptr), framebuffer);
}
return { load, rasterize };
}
}