Support to parse color from rgb[a] string format

README.md

@@ -30,15 +30,23 @@ const invert = require('invert-color');
 // ES2015, JSNext
 import invert from 'invert-color';
 // TypeScript
-import invert, { RGB, RgbArray, HexColor, BlackWhite } from 'invert-color';
+import invert, { RGB, RgbArray, RgbString, HexColor, BlackWhite } from 'invert-color';
 ```
 For UMD in browser, use `lib/invert.min.js`.
 See [other exports](https://github.com/onury/invert-color/tree/master/lib).
 
 ### `invert(color[, bw])`
 
 - **`color`** : `String|Array|Object`  
-Color in HEX string, RGB array or RGB object to be inverted.  
+    Color to be inverted in following formats:
+
+    * HEX string: '#ff0'
+    * RGB string with alpha channel supported: 'rgb(100,100,100)' or 'rgba(255, 255, 0, 0.2)'
+    * RGB array
+    * RGB object
+
+  See the example bellow for more detail.
+
 - **`bw`** : `Boolean|Object`  
 Optional. A boolean value indicating whether the output should be amplified to black (`#000000`) or white (`#ffffff`), according to the luminance of the original color. You can set custom black/white values (and/or luminance threshold) by passing an object.  
 
@@ -47,6 +55,10 @@ Optional. A boolean value indicating whether the output should be amplified to b
 invert('#000')              // —> #ffffff
 invert('#282b35')           // —> #d7d4ca
 
+// as rgb string
+invert('rgb(0,0,0)')              // —> 'rgb(255,255,255)'
+invert('rgba(0,0,0,0.3)')              // —> 'rgba(255,255,255,0.3)'
+
 // input color as RGB array or object
 invert([69, 191, 189])              // —> #ba4042
 invert({ r: 249, g: 119, b: 121 })  // —> #068886

lib/cjs/invert.js

@@ -75,10 +75,57 @@ function invertToBW(color, bw, asArr) {
  */
 function invert(color, bw) {
     if (bw === void 0) { bw = false; }
-    color = toRgbArray(color);
-    if (bw)
-        return invertToBW(color, bw);
-    return '#' + color.map(function (c) { return padz((255 - c).toString(16)); }).join('');
+    var isRgbString = false;
+    var isRgbaString = false;
+    if (typeof color === 'string' && color.startsWith('rgb')) {
+        if (color.startsWith('rgba')) {
+            isRgbaString = true;
+        }
+        else {
+            isRgbString = true;
+        }
+    }
+    if (isRgbString) {
+        var matches = color.match(/rgb\(([0-9 ]+),([0-9 ]+),([0-9 ]+)\)/);
+        if (matches) {
+            var rgbArr = [
+                parseInt(matches[1]),
+                parseInt(matches[2]),
+                parseInt(matches[3]),
+            ];
+            rgbArr = bw
+                ? invertToBW(rgbArr, bw, true)
+                : rgbArr.map(function (c) { return 255 - c; });
+            return "rgb(" + rgbArr.join(',') + ")";
+        }
+        else {
+            throw new Error('Invalid rgb color string: ' + color);
+        }
+    }
+    else if (isRgbaString) {
+        var matches = color.match(/rgba\(([0-9 ]+),([0-9 ]+),([0-9 ]+),([0-9. ]+)\)/);
+        if (matches) {
+            var rgbArr = [
+                parseInt(matches[1]),
+                parseInt(matches[2]),
+                parseInt(matches[3]),
+            ];
+            var alphaChannel = matches[4].replace(/\s/g, '');
+            rgbArr = bw
+                ? invertToBW(rgbArr, bw, true)
+                : rgbArr.map(function (c) { return 255 - c; });
+            return "rgba(" + rgbArr.join(',') + "," + alphaChannel + ")";
+        }
+        else {
+            throw new Error('Invalid rgba color string: ' + color);
+        }
+    }
+    else {
+        color = toRgbArray(color);
+        if (bw)
+            return invertToBW(color, bw);
+        return '#' + color.map(function (c) { return padz((255 - c).toString(16)); }).join('');
+    }
 }
 /**
  *  Utility methods to generate inverted version of a color.

lib/esm/invert.js

@@ -71,10 +71,57 @@ function invertToBW(color, bw, asArr) {
  *  @returns {HexColor} - Hexadecimal representation of the inverted color.
  */
 function invert(color, bw = false) {
-    color = toRgbArray(color);
-    if (bw)
-        return invertToBW(color, bw);
-    return '#' + color.map(c => padz((255 - c).toString(16))).join('');
+    let isRgbString = false;
+    let isRgbaString = false;
+    if (typeof color === 'string' && color.startsWith('rgb')) {
+        if (color.startsWith('rgba')) {
+            isRgbaString = true;
+        }
+        else {
+            isRgbString = true;
+        }
+    }
+    if (isRgbString) {
+        const matches = color.match(/rgb\(([0-9 ]+),([0-9 ]+),([0-9 ]+)\)/);
+        if (matches) {
+            let rgbArr = [
+                parseInt(matches[1]),
+                parseInt(matches[2]),
+                parseInt(matches[3]),
+            ];
+            rgbArr = bw
+                ? invertToBW(rgbArr, bw, true)
+                : rgbArr.map(c => 255 - c);
+            return `rgb(${rgbArr.join(',')})`;
+        }
+        else {
+            throw new Error('Invalid rgb color string: ' + color);
+        }
+    }
+    else if (isRgbaString) {
+        const matches = color.match(/rgba\(([0-9 ]+),([0-9 ]+),([0-9 ]+),([0-9. ]+)\)/);
+        if (matches) {
+            let rgbArr = [
+                parseInt(matches[1]),
+                parseInt(matches[2]),
+                parseInt(matches[3]),
+            ];
+            const alphaChannel = matches[4].replace(/\s/g, '');
+            rgbArr = bw
+                ? invertToBW(rgbArr, bw, true)
+                : rgbArr.map(c => 255 - c);
+            return `rgba(${rgbArr.join(',')},${alphaChannel})`;
+        }
+        else {
+            throw new Error('Invalid rgba color string: ' + color);
+        }
+    }
+    else {
+        color = toRgbArray(color);
+        if (bw)
+            return invertToBW(color, bw);
+        return '#' + color.map(c => padz((255 - c).toString(16))).join('');
+    }
 }
 /**
  *  Utility methods to generate inverted version of a color.

lib/invert.d.ts

@@ -14,10 +14,11 @@ export declare type RgbArray = [number, number, number];
  *  Hexadecimal representation of a color.
  */
 export declare type HexColor = string;
+export declare type RgbString = string;
 /**
  *  Color represented as hexadecimal value or as RGB object or list.
  */
-export declare type Color = RGB | RgbArray | HexColor;
+export declare type Color = RGB | RgbArray | RgbString | HexColor;
 /**
  *  Interface for defining black and white colors; used to amplify the contrast
  *  of the color inversion.