luci-base: generalize random color generation

Generation of pseudo random hex color from a string can be useful also for other task. Generalize it to make it available also for other purpose.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/modules/luci-base/htdocs/luci-static/resources/tools/prng.js b/modules/luci-base/htdocs/luci-static/resources/tools/prng.js
index 752dc75ce8..b916cc7792 100644
--- a/modules/luci-base/htdocs/luci-static/resources/tools/prng.js
+++ b/modules/luci-base/htdocs/luci-static/resources/tools/prng.js
@@ -89,5 +89,23 @@ return L.Class.extend({
 		}
 
 		return Math.floor(r * (u - l + 1)) + l;
+	},
+
+	derive_color: function(string) {
+		this.seed(parseInt(sfh(string), 16));
+
+		var r = this.get(128),
+		    g = this.get(128),
+		    min = 0,
+		    max = 128;
+
+		if ((r + g) < 128)
+			min = 128 - r - g;
+		else
+			max = 255 - r - g;
+
+		var b = min + Math.floor(this.get() * (max - min));
+
+		return '#%02x%02x%02x'.format(0xff - r, 0xff - g, 0xff - b);
 	}
 });