53 lines
2.1 KiB
JavaScript
53 lines
2.1 KiB
JavaScript
'use strict';
|
|
|
|
const assert = require('node:assert/strict');
|
|
const { encode } = require('../js/animated-webp-encoder');
|
|
|
|
function chunk(type, payload) {
|
|
const output = Buffer.alloc(8 + payload.length + (payload.length & 1));
|
|
output.write(type, 0, 4, 'ascii');
|
|
output.writeUInt32LE(payload.length, 4);
|
|
payload.copy(output, 8);
|
|
return output;
|
|
}
|
|
|
|
function stillWebp() {
|
|
const body = Buffer.concat([Buffer.from('WEBP'), chunk('VP8 ', Buffer.from([1, 2, 3, 4]))]);
|
|
const output = Buffer.alloc(8 + body.length);
|
|
output.write('RIFF', 0, 4, 'ascii');
|
|
output.writeUInt32LE(body.length, 4);
|
|
body.copy(output, 8);
|
|
return output;
|
|
}
|
|
|
|
function chunks(buffer) {
|
|
const result = [];
|
|
for (let offset = 12; offset + 8 <= buffer.length;) {
|
|
const size = buffer.readUInt32LE(offset + 4);
|
|
result.push({ type: buffer.toString('ascii', offset, offset + 4), payload: buffer.subarray(offset + 8, offset + 8 + size) });
|
|
offset += 8 + size + (size & 1);
|
|
}
|
|
return result;
|
|
}
|
|
|
|
const output = encode({
|
|
width: 400,
|
|
height: 300,
|
|
frames: [{ webp: stillWebp(), duration: 50 }, { webp: stillWebp(), duration: 75 }],
|
|
});
|
|
assert.equal(output.toString('ascii', 0, 4), 'RIFF');
|
|
assert.equal(output.readUInt32LE(4), output.length - 8);
|
|
assert.equal(output.toString('ascii', 8, 12), 'WEBP');
|
|
const parsed = chunks(output);
|
|
assert.deepEqual(parsed.map((entry) => entry.type), ['VP8X', 'ANIM', 'ANMF', 'ANMF']);
|
|
assert.equal(parsed[0].payload[0], 0x02, 'VP8X must declare animation without alpha');
|
|
assert.deepEqual([...parsed[0].payload.subarray(4, 7)], [143, 1, 0]);
|
|
assert.deepEqual([...parsed[0].payload.subarray(7, 10)], [43, 1, 0]);
|
|
assert.equal(parsed[1].payload[3], 255, 'animation background must be opaque');
|
|
assert.deepEqual([...parsed[2].payload.subarray(12, 15)], [50, 0, 0]);
|
|
assert.equal(parsed[2].payload[15], 0x02, 'full frames must replace without blending');
|
|
assert.equal(parsed[2].payload.toString('ascii', 16, 20), 'VP8 ');
|
|
assert.throws(() => encode({ width: 1, height: 1, frames: [{ webp: Buffer.alloc(0), duration: 50 }] }), /at least two frames/);
|
|
|
|
console.log('PASS: animated WebP RIFF structure, timing and opaque full-frame mode');
|