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您没有指定您的API服务器正在运行的软件，所以我为您的客户端水印需求编写了此内容。它仅适用于没有透明度的图像。它是 LSB（最低有效位）编码的实现。索引.html<!DOCTYPE html><script src="index.js"></script><body></body><script> (async () => { const base64 = `data:image/png;base64,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`; const watermark = await createWatermark(base64, 'John Doe'); const image = new Image(); image.src = watermark; document.body.appendChild(image); // displays watermarked image on screen const hiddenText = await readWatermark(watermark, 8); console.log(hiddenText); // John Doe })();</script></html>索引.jsfunction stringToBits(string) { return string.split('') .map(char => char.charCodeAt(0)) .map(int => (int).toString(2).padStart(8, '0').split('')) .flat() .map(n => +n);}function bitsToString(bits) { bits = [...bits.map(n => getBit(n, 0))]; return String.fromCharCode(...Array(Math.ceil(bits.length / 8)) .fill() .map(() => bits.splice(0, 8)) .map(arr => parseInt(arr.join(''), 2)));}function setBit(number, bitPosition, sign) { if (sign) return number | (1 << bitPosition); const mask = ~(1 << bitPosition); return number & mask;}function getBit(number, bitPosition) { return (number & (1 << bitPosition)) === 0 ? 0 : 1;}function createWatermark(imageAsBase64, text) { return new Promise(resolve => { const image = new Image(); image.src = imageAsBase64; image.onload = () => { const canvas = document.createElement('canvas'); canvas.width = image.width; canvas.height = image.height; const context = canvas.getContext('2d'); context.drawImage(image, 0, 0); const imageData = context.getImageData(0, 0, canvas.width, canvas.height); const bits = stringToBits(text); for (let i = 0; i < text.length * 8; i += 4) { imageData.data[i] = setBit(imageData.data[i], 0, bits[i]); imageData.data[i + 1] = setBit(imageData.data[i + 1], 0, bits[i + 1]); imageData.data[i + 2] = setBit(imageData.data[i + 2], 0, bits[i + 2]); imageData.data[i + 3] = setBit(imageData.data[i + 3], 0, bits[i + 3]); } context.putImageData(imageData, 0, 0); resolve(canvas.toDataURL()); } });}function readWatermark(base64, textLength) { return new Promise(resolve => { const image = new Image(); image.src = base64; image.onload = () => { const canvas = document.createElement('canvas'); canvas.width = image.width; canvas.height = image.height; const context = canvas.getContext('2d'); context.drawImage(image, 0, 0); const imageData = context.getImageData(0, 0, canvas.width, canvas.height); const bits = imageData.data.slice(0, textLength * 8); resolve(bitsToString(bits)); } });}