cli_tool: Add CLI options to configure lightness range.

Earlier, the CLI options offered doesn't include option
to configure lightness range of colored and grayscale shapes.

The npm package itself has options to configure these, but
was not exposed via CLI tool.

This commit makes changes to add the following two options:
* --lightness-color
* --lightness-grayscale

Signed-off-by: Prakhar Pratyush <prakhar1144@gmail.com>

Author: prakhar1144

bin/jdenticon.js

@@ -50,6 +50,8 @@ function writeHelp() {
     console.log("  -f, --format <svg|png>    Format of generated icon. Otherwise detected from output path. (default: png)");
     console.log("  -b, --back-color <value>  Background color on format #rgb, #rgba, #rrggbb or #rrggbbaa. (default: transparent)");
     console.log("  -p, --padding <value>     Padding in percent in range 0 to 0.5. (default: 0.08)");
+    console.log("  --lightness-color <min,max>      Lightness range of colored shapes in [0,1]. (default: 0.4,0.8)");
+    console.log("  --lightness-grayscale <min,max>  Lightness range of grayscale shapes in [0,1]. (default: 0.3,0.9)");
     console.log("  -v, --version             Gets the version of Jdenticon.");
     console.log("  -h, --help                Show this help information.");
     console.log("");
@@ -117,10 +119,33 @@ function parseArgs(args) {
         format: consume(["-f", "--format"], true),
         padding: consume(["-p", "--padding"], true),
         backColor: consume(["-b", "--back-color"], true),
+        lightnessColor: consume(["--lightness-color"], true),
+        lightnessGrayscale: consume(["--lightness-grayscale"], true),
         value: args
     };
 }
 
+function parseLightnessRange(value) {
+    var parts = value.split(",");
+    if (parts.length !== 2) {
+        return;
+    }
+
+    var min = Number(parts[0]);
+    var max = Number(parts[1]);
+
+    if (
+        isNaN(min) || isNaN(max) ||
+        min < 0 || min > 1 ||
+        max < 0 || max > 1 ||
+        min > max
+    ) {
+        return;
+    }
+
+    return [min, max];
+}
+
 function validateArgs(args) {
     if (args.value.length) {
 
@@ -153,7 +178,34 @@ function validateArgs(args) {
                 console.warn("WARN Invalid background color specified. Defaults to transparent.");
             }
         }
-        
+
+        // Lightness
+        var lightnessColor;
+        if (args.lightnessColor != null) {
+            lightnessColor =  parseLightnessRange(args.lightnessColor);
+            if (!lightnessColor) {
+                lightnessColor = [0.4, 0.8];
+                console.warn("WARN Invalid lightness range of colored shapes specified. Defaults to 0.4,0.8.");
+            }
+        }
+
+        var lightnessGrayscale;
+        if (args.lightnessGrayscale != null) {
+            lightnessGrayscale = parseLightnessRange(args.lightnessGrayscale);
+            if (!lightnessGrayscale) {
+                lightnessGrayscale = [0.3, 0.9];
+                console.warn("WARN Invalid lightness range of grayscale shapes specified. Defaults to 0.3,0.9.");
+            }
+        }
+
+        var lightness;
+        if (lightnessColor || lightnessGrayscale) {
+            lightness = {
+                color: lightnessColor,
+                grayscale: lightnessGrayscale
+            };
+        }
+
         // Format
         var generateSvg = 
             args.format ? /^svg$/i.test(args.format) :
@@ -166,7 +218,8 @@ function validateArgs(args) {
         return {
             config: {
                 padding: padding,
-                backColor: backColor
+                backColor: backColor,
+                lightness: lightness
             },
             output: args.output,
             size: size,