在设置背景的时候，有时需要先选颜色值，然后再调整透明度，但却又不能影响文字透明度(功能类似简单封面EasyCover (jiandan.link))，此时可以将颜色值（线性颜色或者十六进制颜色）和透明度作为参数，然后处理成rgba的格式。

function convertGradientsToRgba(gradients, opacity) {// 修改后的正则表达式以匹配多重渐变和多个色标const gradientRegex = /(linear-gradient\(([^,]+?)(?:,(?:\s*rgba?\([^)]+\)|\s*#(?:[0-9A-Fa-f]{3}){1,2})\s*(?:[0-9]{1,3}%?)?)*\))/g;let match;let outputGradient = [];// 匹配每个渐变，并分别处理while ((match = gradientRegex.exec(gradients)) !== null) {const gradientDeclaration = match[0];// 分离渐变类型和颜色并将每个颜色转换为rgbaconst colorsRegex = /(rgba?\([^)]+\)|#(?:[0-9A-Fa-f]{3}){1,2})\s*(?:[0-9]{1,3}%?)?/g;let colorMatch;let gradientColors = [];while ((colorMatch = colorsRegex.exec(gradientDeclaration)) !== null) {let color = colorMatch[0];if (!/^rgba/.test(color)) {// 只转换非rgba颜色color = convertHexToRgba(color, opacity);} else {// 更新存在的rgba颜色的透明度color = updateRgbaOpacity(color, opacity);}gradientColors.push(color);}// 用转换后的颜色值替换原有颜色const newGradient = gradientDeclaration.replace(colorsRegex, () => gradientColors.shift());outputGradient.push(newGradient);}// 将所有的渐变合并return outputGradient.join(', ');
}function convertHexToRgba(hex, alpha) {if (!/#/.test(hex)) { return hex; }const hexColor = hex.trim().replace('#', '');const r = parseInt(hexColor.substring(0, 2), 16);const g = parseInt(hexColor.substring(2, 4), 16);const b = parseInt(hexColor.substring(4, 6), 16);return `rgba(${r}, ${g}, ${b}, ${alpha})`;
}function updateRgbaOpacity(rgba, alpha) {return rgba.replace(/rgba?\(([^,]+), ([^,]+), ([^,]+),?[^)]*\)/, `rgba($1, $2, $3, ${alpha})`);
}