JS实现ascii字符画

function imageToAscii(imageUrl, outputWidth = 100) {
    const asciiChars = ['@', '#', 'S', '%', '?', '*', '+', ';', ':', ',', '.'];
    const img = new Image();
    img.src = imageUrl;
    img.onload = () => {
        const canvas = document.createElement('canvas');
        const ctx = canvas.getContext('2d');
        const aspectRatio = img.height / img.width;
        canvas.width = outputWidth;
        canvas.height = outputWidth * aspectRatio;
        ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
        const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
        let ascii = '';
        for (let y = 0; y < imageData.height; y += 2) {
            for (let x = 0; x < imageData.width; x++) {
                const index = (y * imageData.width + x) * 4;
                const r = imageData.data[index];
                const g = imageData.data[index + 1];
                const b = imageData.data[index + 2];
                const gray = 0.2126 * r + 0.7152 * g + 0.0722 * b;
                const charIndex = Math.floor((gray / 255) * (asciiChars.length - 1));
                ascii += asciiChars[charIndex];
            }
            ascii += '
';
        }
        console.log(ascii);
    };
}

// 使用示例
imageToAscii('path/to/image.jpg');