wxapp/uview-ui/libs/function/colorGradient.js
2024-08-03 19:57:17 +08:00

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/**
* 求两个颜色之间的渐变值
* @param {string} startColor 开始的颜色
* @param {string} endColor 结束的颜色
* @param {number} step 颜色等分的份额
* */
function colorGradient(startColor = 'rgb(0, 0, 0)', endColor = 'rgb(255, 255, 255)', step = 10) {
let startRGB = hexToRgb(startColor, false); //转换为rgb数组模式
let startR = startRGB[0];
let startG = startRGB[1];
let startB = startRGB[2];
let endRGB = hexToRgb(endColor, false);
let endR = endRGB[0];
let endG = endRGB[1];
let endB = endRGB[2];
let sR = (endR - startR) / step; //总差值
let sG = (endG - startG) / step;
let sB = (endB - startB) / step;
let colorArr = [];
for (let i = 0; i < step; i++) {
//计算每一步的hex值
let hex = rgbToHex('rgb(' + Math.round((sR * i + startR)) + ',' + Math.round((sG * i + startG)) + ',' + Math.round((sB *
i + startB)) + ')');
colorArr.push(hex);
}
return colorArr;
}
// 将hex表示方式转换为rgb表示方式(这里返回rgb数组模式)
function hexToRgb(sColor, str = true) {
let reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/;
sColor = sColor.toLowerCase();
if (sColor && reg.test(sColor)) {
if (sColor.length === 4) {
let sColorNew = "#";
for (let i = 1; i < 4; i += 1) {
sColorNew += sColor.slice(i, i + 1).concat(sColor.slice(i, i + 1));
}
sColor = sColorNew;
}
//处理六位的颜色值
let sColorChange = [];
for (let i = 1; i < 7; i += 2) {
sColorChange.push(parseInt("0x" + sColor.slice(i, i + 2)));
}
if(!str) {
return sColorChange;
} else {
return `rgb(${sColorChange[0]},${sColorChange[1]},${sColorChange[2]})`;
}
} else if (/^(rgb|RGB)/.test(sColor)) {
let arr = sColor.replace(/(?:\(|\)|rgb|RGB)*/g, "").split(",")
return arr.map(val => Number(val));
} else {
return sColor;
}
};
// 将rgb表示方式转换为hex表示方式
function rgbToHex(rgb) {
let _this = rgb;
let reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/;
if (/^(rgb|RGB)/.test(_this)) {
let aColor = _this.replace(/(?:\(|\)|rgb|RGB)*/g, "").split(",");
let strHex = "#";
for (let i = 0; i < aColor.length; i++) {
let hex = Number(aColor[i]).toString(16);
hex = String(hex).length == 1 ? 0 + '' + hex : hex; // 保证每个rgb的值为2位
if (hex === "0") {
hex += hex;
}
strHex += hex;
}
if (strHex.length !== 7) {
strHex = _this;
}
return strHex;
} else if (reg.test(_this)) {
let aNum = _this.replace(/#/, "").split("");
if (aNum.length === 6) {
return _this;
} else if (aNum.length === 3) {
let numHex = "#";
for (let i = 0; i < aNum.length; i += 1) {
numHex += (aNum[i] + aNum[i]);
}
return numHex;
}
} else {
return _this;
}
}
/**
* JS颜色十六进制转换为rgb或rgba,返回的格式为 rgba2552552550.5)字符串
* sHex为传入的十六进制的色值
* alpha为rgba的透明度
*/
function colorToRgba(color, alpha = 0.3) {
color = rgbToHex(color)
// 十六进制颜色值的正则表达式
var reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/
/* 16进制颜色转为RGB格式 */
let sColor = color.toLowerCase()
if (sColor && reg.test(sColor)) {
if (sColor.length === 4) {
var sColorNew = '#'
for (let i = 1; i < 4; i += 1) {
sColorNew += sColor.slice(i, i + 1).concat(sColor.slice(i, i + 1))
}
sColor = sColorNew
}
// 处理六位的颜色值
var sColorChange = []
for (let i = 1; i < 7; i += 2) {
sColorChange.push(parseInt('0x' + sColor.slice(i, i + 2)))
}
// return sColorChange.join(',')
return 'rgba(' + sColorChange.join(',') + ',' + alpha + ')'
}
else {
return sColor
}
}
export default {
colorGradient,
hexToRgb,
rgbToHex,
colorToRgba
}