From 921c7dbd5fdd69cf22da3cfc74797ec1478a1675 Mon Sep 17 00:00:00 2001
From: kkapsner <github@mail.kkapsner.de>
Date: Mon, 7 Aug 2017 08:49:49 +0200
Subject: [PATCH] Changed rng interface to use colors instead of separate
 channels.

---
 lib/modifiedAPI.js    | 34 ++++++++++++++++++++++++++++------
 lib/randomSupplies.js | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+), 6 deletions(-)

diff --git a/lib/modifiedAPI.js b/lib/modifiedAPI.js
index ec246c8..494e3e1 100644
--- a/lib/modifiedAPI.js
+++ b/lib/modifiedAPI.js
@@ -59,10 +59,22 @@
 			var {imageData, source} = getImageData(window, context);
 			var desc = imageData.data;
 			var l = desc.length;
-			var rng = randomSupply.getRng(l, window);
 			
-			for (var i = 0; i < l; i += 1){
-				desc[i] = rng(source[i], i);
+			var ignoredColors = {};
+			var rng = randomSupply.getPixelRng(l, window, ignoredColors);
+			
+			for (var i = 0; i < l; i += 4){
+				var [r, g, b, a] = rng(
+					source[i + 0], 
+					source[i + 1], 
+					source[i + 2], 
+					source[i + 3],
+					i / 4
+				);
+				desc[i + 0] = r;
+				desc[i + 1] = g;
+				desc[i + 2] = b;
+				desc[i + 3] = a;
 			}
 			var canvas = original.cloneNode(true);
 			context = window.HTMLCanvasElement.prototype.getContext.call(canvas, "2d");
@@ -337,10 +349,20 @@
 						var xPixels = pixels;
 						var ret = original.apply(this, window.Array.from(arguments));
 						var l = xPixels.length;
-						var rng = randomSupply.getRng(l, window);
+						var rng = randomSupply.getPixelRng(l, window, {});
 						
-						for (var i = 0; i < l; i += 1){
-							xPixels[i] = rng(xPixels[i], i);
+						for (var i = 0; i < l; i += 4){
+							var [r, g, b, a] = rng(
+								xPixels[i + 0],
+								xPixels[i + 1],
+								xPixels[i + 2],
+								xPixels[i + 3],
+								i / 4
+							);
+							xPixels[i + 0] = r;
+							xPixels[i + 1] = g;
+							xPixels[i + 2] = b;
+							xPixels[i + 3] = a;
 						}
 						
 						return ret;
diff --git a/lib/randomSupplies.js b/lib/randomSupplies.js
index ba27ae5..eabef49 100644
--- a/lib/randomSupplies.js
+++ b/lib/randomSupplies.js
@@ -68,6 +68,22 @@
 				// XOR the bit and the value to alter the last bit of it... or not
 				return value ^ bit;
 			};
+		},
+		getPixelRng: function(length, window, ignoredColors){
+			var rng = this.getRng(length, window);
+			return function(r, g, b, a, i){
+				var index = String.fromCharCode(r, g, b, a);
+				if (ignoredColors[index]){
+					return [r, g, b, a];
+		}
+				var baseIndex = i * 4;
+				return [
+					rng(r, baseIndex + 0),
+					rng(g, baseIndex + 1),
+					rng(b, baseIndex + 2),
+					rng(a, baseIndex + 3)
+				];
+			}
 		}
 	};
 	
@@ -92,6 +108,22 @@
 				// XOR the last bit to alter it... or not
 				return value ^ (rnd & 0x01);
 			};
+		},
+		getPixelRng: function(length, window, ignoredColors){
+			var rng = this.getRng(length, window);
+			return function(r, g, b, a, i){
+				var index = String.fromCharCode(r, g, b, a);
+				if (ignoredColors[index]){
+					return [r, g, b, a];
+				}
+				var baseIndex = i * 4;
+				return [
+					rng(r, baseIndex + 0),
+					rng(g, baseIndex + 1),
+					rng(b, baseIndex + 2),
+					rng(a, baseIndex + 3)
+				];
+			}
 		}
 	};
 }());	
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