A chat round rect bubble with triangle on top left or top right.

BubbleView1.m

//
//  BubbleView1.m
//  ChatBubbleGuiPrototype
//
//  Created by Alexander Dodatko on 4/5/17.
//  Copyright © 2017 monspace. All rights reserved.
//

#import "BubbleView1.h"

@implementation BubbleView1

- (void)drawRect:(CGRect)rect
{
    // copy-pasted from SO. Replaced some code to make compiler happy.
    // http://stackoverflow.com/questions/11196112/speech-bubble-in-ios-sdk-using-objective-c
    
    static const CGFloat LINE_WIDTH = 2.f;
    
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetLineWidth(context, 2.f);
    
    UIColor* strokeColor = [UIColor colorWithRed: 0xFD / 255.f
                                           green: 0xD6 / 255.f
                                            blue: 0xCC / 255.f
                                           alpha: 1.f];
    CGContextSetStrokeColorWithColor(context, strokeColor.CGColor);
    CGContextSetRGBFillColor(context, 1, 1, 1, 1);
    
    rect.origin.y += LINE_WIDTH;
    rect.size.width -= LINE_WIDTH * 2;
    rect.size.height -= LINE_WIDTH * 2;
    
    CGFloat radius = self.cornerRadius;
    
    CGFloat minx = CGRectGetMinX(rect),
            midx = CGRectGetMidX(rect),
            maxx = CGRectGetMaxX(rect);
    
    CGFloat miny = CGRectGetMinY(rect),
            midy = CGRectGetMidY(rect),
            maxy = CGRectGetMaxY(rect);
    
    CGMutablePathRef outlinePath = CGPathCreateMutable();
    
    static const CGFloat TRIANGLE_HEIGHT = 16;
    const CGFloat TRIANGLE_MID_Y = miny + 2 * TRIANGLE_HEIGHT;
    
    if (self.isTriangleLeft)
    {
        minx += TRIANGLE_HEIGHT;
        
        // top mid
        CGPathMoveToPoint(outlinePath, nil, midx, miny);
        // top mid ==> top right ==> mid right ==> ...
        CGPathAddArcToPoint (outlinePath, nil, maxx    , miny, maxx, midy, radius);
        // mid right ==> bottom right ==> bottom mid ==> ...
        CGPathAddArcToPoint (outlinePath, nil, maxx    , maxy, midx, maxy, radius);
        // bottom mid ==> bottom left ==> mid left ==> ...
        CGPathAddArcToPoint (outlinePath, nil, minx    , maxy, minx, midy, radius);
        
        
        // draw left triangle
        //
        CGPathAddLineToPoint(outlinePath, nil, minx                  , TRIANGLE_MID_Y + TRIANGLE_HEIGHT);
        CGPathAddLineToPoint(outlinePath, nil, minx - TRIANGLE_HEIGHT, TRIANGLE_MID_Y                  );
        CGPathAddLineToPoint(outlinePath, nil, minx                  , TRIANGLE_MID_Y - TRIANGLE_HEIGHT);
        
        // mid left (after triangle) ==> top left ==> top mid
        CGPathAddArcToPoint (outlinePath, nil, minx, miny, midx, miny, radius);
    }
    else
    {
        minx += TRIANGLE_HEIGHT;
        maxx -= TRIANGLE_HEIGHT;
        
        // top mid
        CGPathMoveToPoint(outlinePath, nil, midx, miny);
        
        // top mid ==> top left ==> mid left ==> ...
        CGPathAddArcToPoint (outlinePath, nil, minx, miny, minx, midy, radius);
        // mid left ==> bottom left ==> bottom mid ==> ...
        CGPathAddArcToPoint (outlinePath, nil, minx, maxy, midx, maxy, radius);
        
        // bottom mid ==> bottom right ==> mid right ==> ...
        CGPathAddArcToPoint (outlinePath, nil, maxx, maxy, maxx, midy, radius);
        
        // draw right triangle
        //
        CGPathAddLineToPoint(outlinePath, nil, maxx, miny + TRIANGLE_MID_Y + TRIANGLE_HEIGHT);
        CGPathAddLineToPoint(outlinePath, nil, maxx + TRIANGLE_HEIGHT, miny + TRIANGLE_MID_Y);
        CGPathAddLineToPoint(outlinePath, nil, maxx, miny + TRIANGLE_MID_Y - TRIANGLE_HEIGHT);
        
        // mid right ==> top right ==> tom mid
        CGPathAddArcToPoint (outlinePath, nil, maxx, miny, midx, miny, radius);
     
    }
    

    CGPathCloseSubpath(outlinePath);
    CGContextAddPath(context, outlinePath);
    
    
    static const CGFloat SHADOW_BLUR = 8;

    // http://stackoverflow.com/questions/10024543/draw-lines-with-glow-effect-in-ipad-app
    //
    //Set the shadow in your graphics context to have a zero size offset, a blur of around 6-10 (change according to taste) and the same colour as your stroke colour. This will give all subsequent drawing a glow effect. The command is
    //
    //
    CGContextSetShadowWithColor(context, CGSizeMake(0, 0), SHADOW_BLUR, strokeColor.CGColor);
    CGContextFillPath(context);
    
    CGContextStrokePath(context);

    
    CGContextAddPath(context, outlinePath);
    CGContextClip(context);
    
    
    CGContextDrawPath(context, kCGPathFillStroke);
    
}

@end

Credits to the SO topic