Added support for pixel fractions

Pixel fractions can be controlled by CSS. These fractions must not be
faked.

For #236.

_locales/en/messages.json

@@ -898,6 +898,15 @@
 		"description": ""
 	},
 	
+	"domRectIntegerFactor_title": {
+		"message": "DOMRect integer factor",
+		"description": ""
+	},
+	"domRectIntegerFactor_description": {
+		"message": "Some fraction of a pixel can be controlled by CSS. To prevent detection values of a DOMRect that multiplied with this factor are integers will not be altered.",
+		"description": ""
+	},
+	
 	"theme_title": {
 		"message": "Theme",
 		"description": ""

lib/intercept.js

@@ -337,7 +337,7 @@
 								descriptor.get = exportFunction(getter, window);
 								
 								if (descriptor.hasOwnProperty("set") && changedGetter.setterGenerator){
-									const setter = changedGetter.setterGenerator(window, descriptor.set);
+									const setter = changedGetter.setterGenerator(window, descriptor.set, prefs);
 									descriptor.set = exportFunction(setter, window);
 								}
 								

lib/modifiedDOMRectAPI.js

@@ -45,11 +45,11 @@
 	function getDOMRectRegistration(domRect){
 		return registeredRects.get(getWrapped(domRect));
 	}
-	function getFakeDomRect(window, domRect, notify){
+	function getFakeDomRect(window, domRect, prefs, notify){
 		
 		var rng = randomSupply.getRng(4, window);
 		function getFakeValue(value, i){
-			if (value % 1 === 0){
+			if ((value * prefs("domRectIntegerFactor", window.location)) % 1 === 0){
 				return value;
 			}
 			else {
@@ -159,17 +159,17 @@
 			if (prefs("protectDOMRect", window.location)){
 				const registration = getDOMRectRegistration(this);
 				if (registration){
-					return getFakeDomRect(window, this, registration.notify)[property];
+					return getFakeDomRect(window, this, prefs, registration.notify)[property];
 				}
 			}
 			
 			return originalValue;
 		};
 	}
-	function setProperty(domRect, window, original, newValue, property){ // eslint-disable-line max-params
+	function setProperty(domRect, window, original, newValue, property, prefs){ // eslint-disable-line max-params
 		const registration = getDOMRectRegistration(domRect);
 		if (registration){
-			const fakeDomRect = getFakeDomRect(window, domRect, registration.notify);
+			const fakeDomRect = getFakeDomRect(window, domRect, prefs, registration.notify);
 			registeredRects.delete(getWrapped(domRect));
 			["x", "y", "width", "height"].forEach(function(prop){
 				if (prop === property){
@@ -200,10 +200,10 @@
 				};
 				return Object.getOwnPropertyDescriptor(temp, "x").get;
 			},
-			setterGenerator: function(window, original){
+			setterGenerator: function(window, original, prefs){
 				const temp = {
 					set x(x){
-						setProperty(this, window, original, x, "x");
+						setProperty(this, window, original, x, "x", prefs);
 					}
 				};
 				return Object.getOwnPropertyDescriptor(temp, "x").set;
@@ -223,10 +223,10 @@
 				};
 				return Object.getOwnPropertyDescriptor(temp, "y").get;
 			},
-			setterGenerator: function(window, original){
+			setterGenerator: function(window, original, prefs){
 				const temp = {
 					set y(y){
-						setProperty(this, window, original, y, "y");
+						setProperty(this, window, original, y, "y", prefs);
 					}
 				};
 				return Object.getOwnPropertyDescriptor(temp, "y").set;
@@ -246,10 +246,10 @@
 				};
 				return Object.getOwnPropertyDescriptor(temp, "width").get;
 			},
-			setterGenerator: function(window, original){
+			setterGenerator: function(window, original, prefs){
 				const temp = {
 					set width(width){
-						setProperty(this, window, original, width, "width");
+						setProperty(this, window, original, width, "width", prefs);
 					}
 				};
 				return Object.getOwnPropertyDescriptor(temp, "width").set;
@@ -269,10 +269,10 @@
 				};
 				return Object.getOwnPropertyDescriptor(temp, "height").get;
 			},
-			setterGenerator: function(window, original){
+			setterGenerator: function(window, original, prefs){
 				const temp = {
 					set height(height){
-						setProperty(this, window, original, height, "height");
+						setProperty(this, window, original, height, "height", prefs);
 					}
 				};
 				return Object.getOwnPropertyDescriptor(temp, "height").set;

lib/settingDefinitions.js

@@ -267,6 +267,10 @@
 			defaultValue: true,
 			urlSpecific: true
 		},
+		{
+			name: "domRectIntegerFactor",
+			defaultValue: 4
+		},
 		{
 			name: "blockDataURLs",
 			defaultValue: true

options/settingsDisplay.js

@@ -411,6 +411,13 @@
 				"displayAdvancedSettings": [true]
 			}
 		},
+		{
+			"name": "domRectIntegerFactor",
+			"displayDependencies": {
+				"protectDOMRect": [true],
+				"displayAdvancedSettings": [true]
+			}
+		},
 		"misc",
 		{
 			"name": "theme"