Update: Cluster image quality on iOS
(Probably solved)
MODIFY
plugin.xml
plugin.xml
<?xml version='1.0' encoding='utf-8'?>
-<plugin id="cordova-plugin-googlemaps" version="2.0.0-beta3-20170830-1907" xmlns="http://apache.org/cordova/ns/plugins/1.0" xmlns:android="http://schemas.android.com/apk/res/android">
+<plugin id="cordova-plugin-googlemaps" version="2.0.0-beta3-20170831-1528" xmlns="http://apache.org/cordova/ns/plugins/1.0" xmlns:android="http://schemas.android.com/apk/res/android">
<name>cordova-plugin-googlemaps</name>
<js-module name="BaseClass" src="www/BaseClass.js">
<runs />

MODIFY
src/ios/GoogleMaps/PluginMarker.m
src/ios/GoogleMaps/PluginMarker.m
NSParagraphStyleAttributeName : style
};
- UIGraphicsBeginImageContext(image.size);
+ UIGraphicsBeginImageContextWithOptions(image.size, NO, 0.0);
[image drawInRect:CGRectMake(0,0, image.size.width, image.size.height)];
[text drawInRect:CGRectMake((image.size.width - rect.size.width) /2 , (image.size.height - rect.size.height) /2, rect.size.width, rect.size.height) withAttributes:attributes];
+ UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
/*
//(debug)
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetRGBFillColor(context, 1.0, 1.0, 1.0, 0.5);
CGContextFillRect(context, rect);
*/
-
- UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
image = nil;

Update: Cluster image quality on iOS #1679
(Probably solved)