init

uview-ui/libs/function/colorGradient.js

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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 rgba（255，255，255，0.5）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
+}