refactor: autogenerate the macOS client's Message Log dots (#3224)

* Replaces DotFlat png with generated icons

* code review: udating popup item icons

* code review: increasing inset

macosx/NSImageAdditions.mm

@@ -5,9 +5,35 @@
 #import "CocoaCompatibility.h"
 
 #import "NSImageAdditions.h"
+#import "NSApplicationAdditions.h"
 
 @implementation NSImage (NSImageAdditions)
 
+#define ICON_WIDTH 16.0
+#define BORDER_WIDTH 1.25
+
++ (NSImage*)discIconWithColor:(NSColor*)color insetFactor:(CGFloat)insetFactor
+{
+    return [NSImage imageWithSize:NSMakeSize(ICON_WIDTH, ICON_WIDTH) flipped:NO drawingHandler:^BOOL(NSRect rect) {
+        //shape
+        rect = NSInsetRect(rect, BORDER_WIDTH / 2 + rect.size.width * insetFactor / 2, BORDER_WIDTH / 2 + rect.size.height * insetFactor / 2);
+        NSBezierPath* bp = [NSBezierPath bezierPathWithOvalInRect:rect];
+        bp.lineWidth = BORDER_WIDTH;
+
+        //border
+        CGFloat fractionOfBlendedColor = [NSApp isDarkMode] ? 0.15 : 0.3;
+        NSColor* borderColor = [color blendedColorWithFraction:fractionOfBlendedColor ofColor:NSColor.controlTextColor];
+        [borderColor setStroke];
+        [bp stroke];
+
+        //inside
+        [color setFill];
+        [bp fill];
+
+        return YES;
+    }];
+}
+
 - (NSImage*)imageWithColor:(NSColor*)color
 {
     NSImage* coloredImage = [self copy];