Add support for new system built-in indicator with medium and large style. Fallback on OS version which does not support dark mode

SDWebImage/SDWebImageIndicator.h

@@ -74,6 +74,10 @@
 @property (nonatomic, class, nonnull, readonly) SDWebImageActivityIndicator *whiteIndicator;
 /// large white-style activity indicator
 @property (nonatomic, class, nonnull, readonly) SDWebImageActivityIndicator *whiteLargeIndicator;
+/// large activity indicator, supports dark mode if available
+@property (nonatomic, class, nonnull, readonly) SDWebImageActivityIndicator *largeIndicator;
+/// medium activity indicator, supports dark mode if available
+@property (nonatomic, class, nonnull, readonly) SDWebImageActivityIndicator *mediumIndicator;
 
 @end
 

SDWebImage/SDWebImageIndicator.m

@@ -124,6 +124,36 @@
     return indicator;
 }
 
++ (SDWebImageActivityIndicator *)largeIndicator {
+    SDWebImageActivityIndicator *indicator = [SDWebImageActivityIndicator new];
+#if SD_UIKIT
+    if (@available(iOS 13.0, tvOS 13.0, *)) {
+        indicator.indicatorView.activityIndicatorViewStyle = UIActivityIndicatorViewStyleLarge;
+    } else {
+        indicator.indicatorView.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhiteLarge;
+    }
+#else
+    indicator.indicatorView.controlSize = NSControlSizeRegular;
+    [indicator.indicatorView sizeToFit];
+#endif
+    return indicator;
+}
+
++ (SDWebImageActivityIndicator *)mediumIndicator {
+    SDWebImageActivityIndicator *indicator = [SDWebImageActivityIndicator new];
+#if SD_UIKIT
+    if (@available(iOS 13.0, tvOS 13.0, *)) {
+        indicator.indicatorView.activityIndicatorViewStyle = UIActivityIndicatorViewStyleMedium;
+    } else {
+        indicator.indicatorView.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhite;
+    }
+#else
+    indicator.indicatorView.controlSize = NSControlSizeSmall;
+    [indicator.indicatorView sizeToFit];
+#endif
+    return indicator;
+}
+
 @end
 
 #pragma mark - Progress Indicator