如何将颜色在RGB格式转换为十六进制格式,反之亦然?
例如,将'#0080C0'转换为(0,128,192)。
如何将颜色在RGB格式转换为十六进制格式,反之亦然?
例如,将'#0080C0'转换为(0,128,192)。
当前回答
这可以用于从计算样式属性中获取颜色:
function rgbToHex(color) {
color = ""+ color;
if (!color || color.indexOf("rgb") < 0) {
return;
}
if (color.charAt(0) == "#") {
return color;
}
var nums = /(.*?)rgb\((\d+),\s*(\d+),\s*(\d+)\)/i.exec(color),
r = parseInt(nums[2], 10).toString(16),
g = parseInt(nums[3], 10).toString(16),
b = parseInt(nums[4], 10).toString(16);
return "#"+ (
(r.length == 1 ? "0"+ r : r) +
(g.length == 1 ? "0"+ g : g) +
(b.length == 1 ? "0"+ b : b)
);
}
// not computed
<div style="color: #4d93bc; border: 1px solid red;">...</div>
// computed
<div style="color: rgb(77, 147, 188); border: 1px solid rgb(255, 0, 0);">...</div>
console.log( rgbToHex(color) ) // #4d93bc
console.log( rgbToHex(borderTopColor) ) // #ff0000
裁判:https://github.com/k-gun/so/blob/master/so_util.js
其他回答
@ Tim,补充一下你的答案(把这个放进评论里有点尴尬)。
正如所写的,我发现rgbToHex函数返回一个包含元素的字符串,它要求r, g, b值落在0-255的范围内。
我相信这对大多数人来说是显而易见的,但我花了两个小时才弄明白,到那时,原来的方法已经膨胀到7行,直到我意识到我的问题在其他地方。因此,为了节省其他人的时间和麻烦,下面是我稍微修改过的代码,它检查了先决条件,并删除了字符串中无关的部分。
function rgbToHex(r, g, b) {
if(r < 0 || r > 255) alert("r is out of bounds; "+r);
if(g < 0 || g > 255) alert("g is out of bounds; "+g);
if(b < 0 || b > 255) alert("b is out of bounds; "+b);
return "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1,7);
}
HEX转RGB (ES6) +测试[2022]
convertHexToRgb.ts:
/**
* RGB color regexp
*/
export const RGB_REG_EXP = /rgb\((\d{1,3}), (\d{1,3}), (\d{1,3})\)/;
/**
* HEX color regexp
*/
export const HEX_REG_EXP = /^#?(([\da-f]){3}|([\da-f]){6})$/i;
/**
* Converts HEX to RGB.
*
* Color must be only HEX string and must be:
* - 7-characters starts with "#" symbol ('#ffffff')
* - or 6-characters without "#" symbol ('ffffff')
* - or 4-characters starts with "#" symbol ('#fff')
* - or 3-characters without "#" symbol ('fff')
*
* @function { color: string => string } convertHexToRgb
* @return { string } returns RGB color string or empty string
*/
export const convertHexToRgb = (color: string): string => {
const errMessage = `
Something went wrong while working with colors...
Make sure the colors provided to the "PieDonutChart" meet the following requirements:
Color must be only HEX string and must be
7-characters starts with "#" symbol ('#ffffff')
or 6-characters without "#" symbol ('ffffff')
or 4-characters starts with "#" symbol ('#fff')
or 3-characters without "#" symbol ('fff')
- - - - - - - - -
Error in: "convertHexToRgb" function
Received value: ${color}
`;
if (
!color
|| typeof color !== 'string'
|| color.length < 3
|| color.length > 7
) {
console.error(errMessage);
return '';
}
const replacer = (...args: string[]) => {
const [
_,
r,
g,
b,
] = args;
return '' + r + r + g + g + b + b;
};
const rgbHexArr = color
?.replace(HEX_REG_EXP, replacer)
.match(/.{2}/g)
?.map(x => parseInt(x, 16));
/**
* "HEX_REG_EXP.test" is here to create more strong tests
*/
if (rgbHexArr && Array.isArray(rgbHexArr) && HEX_REG_EXP.test(color)) {
return `rgb(${rgbHexArr[0]}, ${rgbHexArr[1]}, ${rgbHexArr[2]})`;
}
console.error(errMessage);
return '';
};
我正在使用Jest进行测试
color.spec.ts
describe('function "convertHexToRgb"', () => {
it('returns a valid RGB with the provided 3-digit HEX color: [color = \'fff\']', () => {
expect.assertions(2);
const { consoleErrorMocked } = mockConsole();
const rgb = convertHexToRgb('fff');
expect(RGB_REG_EXP.test(rgb)).toBeTruthy();
expect(consoleErrorMocked).not.toHaveBeenCalled();
});
it('returns a valid RGB with the provided 3-digit HEX color with hash symbol: [color = \'#fff\']', () => {
expect.assertions(2);
const { consoleErrorMocked } = mockConsole();
const rgb = convertHexToRgb('#fff');
expect(RGB_REG_EXP.test(rgb)).toBeTruthy();
expect(consoleErrorMocked).not.toHaveBeenCalled();
});
it('returns a valid RGB with the provided 6-digit HEX color: [color = \'ffffff\']', () => {
expect.assertions(2);
const { consoleErrorMocked } = mockConsole();
const rgb = convertHexToRgb('ffffff');
expect(RGB_REG_EXP.test(rgb)).toBeTruthy();
expect(consoleErrorMocked).not.toHaveBeenCalled();
});
it('returns a valid RGB with the provided 6-digit HEX color with the hash symbol: [color = \'#ffffff\']', () => {
expect.assertions(2);
const { consoleErrorMocked } = mockConsole();
const rgb = convertHexToRgb(TEST_COLOR);
expect(RGB_REG_EXP.test(rgb)).toBeTruthy();
expect(consoleErrorMocked).not.toHaveBeenCalled();
});
it('returns an empty string when the provided value is not a string: [color = 1234]', () => {
expect.assertions(2);
const { consoleErrorMocked } = mockConsole();
// @ts-ignore
const rgb = convertHexToRgb(1234);
expect(rgb).toBe('');
expect(consoleErrorMocked).toHaveBeenCalledTimes(1);
});
it('returns an empty string when the provided color is too short: [color = \'FF\']', () => {
expect.assertions(2);
const { consoleErrorMocked } = mockConsole();
const rgb = convertHexToRgb('FF');
expect(rgb).toBe('');
expect(consoleErrorMocked).toHaveBeenCalledTimes(1);
});
it('returns an empty string when the provided color is too long: [color = \'#fffffff\']', () => {
expect.assertions(2);
const { consoleErrorMocked } = mockConsole();
const rgb = convertHexToRgb('#fffffff');
expect(rgb).toBe('');
expect(consoleErrorMocked).toHaveBeenCalledTimes(1);
});
it('returns an empty string when the provided value is looks like HEX color string but has invalid symbols: [color = \'#fffffp\']', () => {
expect.assertions(2);
const { consoleErrorMocked } = mockConsole();
const rgb = convertHexToRgb('#fffffp');
expect(rgb).toBe('');
expect(consoleErrorMocked).toHaveBeenCalledTimes(1);
});
it('returns an empty string when the provided value is invalid: [color = \'*\']', () => {
expect.assertions(2);
const { consoleErrorMocked } = mockConsole();
const rgb = convertHexToRgb('*');
expect(rgb).toBe('');
expect(consoleErrorMocked).toHaveBeenCalledTimes(1);
});
it('returns an empty string when the provided value is undefined: [color = undefined]', () => {
expect.assertions(2);
const { consoleErrorMocked } = mockConsole();
// @ts-ignore
const rgb = convertHexToRgb(undefined);
expect(rgb).toBe('');
expect(consoleErrorMocked).toHaveBeenCalledTimes(1);
});
});
测试结果:
function "convertHexToRgb"
√ returns a valid RGB with the provided 3-digit HEX color: [color = 'fff']
√ returns a valid RGB with the provided 3-digit HEX color with hash symbol: [color = '#fff']
√ returns a valid RGB with the provided 6-digit HEX color: [color = 'ffffff']
√ returns a valid RGB with the provided 6-digit HEX color with the hash symbol: [color = '#ffffff']
√ returns an empty string when the provided value is not a string: [color = 1234]
√ returns an empty string when the provided color is too short: [color = 'FF']
√ returns an empty string when the provided color is too long: [color = '#fffffff']
√ returns an empty string when the provided value is looks like HEX color string but has invalid symbols: [color = '#fffffp']
√ returns an empty string when the provided value is invalid: [color = '*']
√ returns an empty string when the provided value is undefined: [color = undefined]
和mockConsole:
export const mockConsole = () => {
const consoleError = jest.spyOn(console, 'error').mockImplementationOnce(() => undefined);
return { consoleError };
};
很惊讶这个答案没有出现。
不使用任何库#使用平台✔️ 3行,并处理任何颜色的浏览器支持。
const toRGB = (color) => {
const { style } = new Option();
style.color = color;
return style.color;
}
// handles any color the browser supports and converts it.
console.log(toRGB("#333")) // rgb(51, 51, 51);
console.log(toRGB("hsl(30, 30%, 30%)"))
我的hex2rbg版本:
接受短十六进制,如#fff 算法容量为o(n),应该比使用正则表达式快。如字符串。替换字符串。分裂,字符串。匹配等。 使用固定空间。 支持rgb和rgba。
如果你使用的是IE8,你可能需要删除hex.trim()。
如。
hex2rgb('#fff') //rgb(255,255,255)
hex2rgb('#fff', 1) //rgba(255,255,255,1)
hex2rgb('#ffffff') //rgb(255,255,255)
hex2rgb('#ffffff', 1) //rgba(255,255,255,1)
代码:
function hex2rgb (hex, opacity) {
hex = hex.trim();
hex = hex[0] === '#' ? hex.substr(1) : hex;
var bigint = parseInt(hex, 16), h = [];
if (hex.length === 3) {
h.push((bigint >> 4) & 255);
h.push((bigint >> 2) & 255);
} else {
h.push((bigint >> 16) & 255);
h.push((bigint >> 8) & 255);
}
h.push(bigint & 255);
if (arguments.length === 2) {
h.push(opacity);
return 'rgba('+h.join()+')';
} else {
return 'rgb('+h.join()+')';
}
}
我假设您指的是html风格的十六进制符号,即#rrggbb。你的代码几乎是正确的,只是顺序颠倒了。它应该是:
var decColor = red * 65536 + green * 256 + blue;
此外,使用位移位可能会让它更容易阅读:
var decColor = (red << 16) + (green << 8) + blue;