From 253d3f68b1048f6e15e37687fd3d6c436787431c Mon Sep 17 00:00:00 2001
From: kkapsner <github@mail.kkapsner.de>
Date: Sun, 24 May 2020 23:39:44 +0200
Subject: [PATCH] Added canvas cache to isPointInPath and isPointInStroke

---
 lib/modifiedCanvasAPI.js | 52 ++++++++++++++++++++++++++++++++--------
 releaseNotes.txt         |  2 +-
 test/test.html           |  3 +--
 3 files changed, 44 insertions(+), 13 deletions(-)

diff --git a/lib/modifiedCanvasAPI.js b/lib/modifiedCanvasAPI.js
index b8c59e2..8242938 100644
--- a/lib/modifiedCanvasAPI.js
+++ b/lib/modifiedCanvasAPI.js
@@ -244,6 +244,31 @@
 		}
 	}
 	
+	const isPointCache = Object.create(null);
+	function getIsPointCacheIndex(x, y, values){
+		return String.fromCodePoint(...values, x, y);
+	}
+	function getIsPointValue({func, x, y, index, originalValue, window, prefs}){
+		const useCanvasCache = prefs("useCanvasCache");
+		let cacheIndex;
+		const values = [originalValue, func(x^1, y), func(x, y^1), func(x^1, y^1)];
+		if (useCanvasCache){
+			cacheIndex = getIsPointCacheIndex(x, y, values);
+			const cached = isPointCache[cacheIndex];
+			if ((typeof cached) === "boolean"){
+				return cached;
+			}
+		}
+		
+		const rng = randomSupply.getIndexRng(1, 4, window);
+		const res = values[rng(index)];
+		
+		if (useCanvasCache){
+			isPointCache[cacheIndex] = res;
+		}
+		return res;
+	}
+	
 	// changed functions and their fakes
 	scope.changedFunctions = {
 		getContext: {
@@ -348,13 +373,16 @@
 			fakeGenerator: function(checker){
 				return function isPointInPath(x, y){
 					return checkerWrapper(checker, this, arguments, function(args, check){
-						const {notify, window, original} = check;
-						const rng = randomSupply.getValueRng(1, window);
+						const {prefs, notify, window, original} = check;
 						const originalValue = original.call(this, ...args);
 						if ((typeof originalValue) === "boolean"){
 							notify("fakedReadout");
-							const index = x + this.width * y;
-							return original.call(this, rng(x, index), rng(y, index), args[2]);
+							return getIsPointValue({
+								func: (x, y) => original.call(this, x, y, args[2]),
+								x, y,
+								index: x + this.width * y,
+								originalValue, window, prefs
+							});
 						}
 						else {
 							return originalValue;
@@ -370,22 +398,26 @@
 			fakeGenerator: function(checker){
 				return function isPointInStroke(x, y){
 					return checkerWrapper(checker, this, arguments, function(args, check){
-						const {notify, window, original} = check;
-						const rng = randomSupply.getValueRng(1, window);
+						const {prefs, notify, window, original} = check;
 						const originalValue = original.call(this, ...args);
 						if ((typeof originalValue) === "boolean"){
 							notify("fakedReadout");
+							let func;
 							if (x instanceof window.Path2D){
 								let path = x;
 								x = y;
 								y = args[2];
-								let index = x + this.width * y;
-								return original.call(this, path, rng(x, index), rng(y, index));
+								func = (x, y) => original.call(this, path, x, y);
 							}
 							else {
-								let index = x + this.width * y;
-								return original.call(this, rng(x, index), rng(y, index));
+								func = (x, y) => original.call(this, x, y);
 							}
+							return getIsPointValue({
+								func,
+								x, y,
+								index: x + this.width * y,
+								originalValue, window, prefs
+							});
 						}
 						else {
 							return originalValue;
diff --git a/releaseNotes.txt b/releaseNotes.txt
index 101182b..26820c1 100644
--- a/releaseNotes.txt
+++ b/releaseNotes.txt
@@ -1,6 +1,6 @@
 Version 1.3:
 	changes:
-		- 
+		- added canvas cache to isPointInPath and isPointInStroke
 	
 	new features:
 		- added link to FAQ
diff --git a/test/test.html b/test/test.html
index 4c51cb3..e17f0f6 100644
--- a/test/test.html
+++ b/test/test.html
@@ -13,8 +13,7 @@
 <ul>
 	<li>all the hashes should be equal for each test</li>
 	<li>the hash before and after the "/" do not have to match</li>
-	<li>"isPointInPath" may vary between tests</li>
-	<li>if "refresh" is clicked the hash must not change (but "isPointInPath" may)</li>
+	<li>if "refresh" is clicked the hash must not change</li>
 	<li>upon page reload the hash changes (depending on CanvasBlocker settings - e.g. not in the stealth preset)</li>
 </ul>
 <h2>Tests</h2>