bezier_heart.js

function drawShape(ctx, xoff, yoff) {
  ctx.beginPath();
  ctx.moveTo(206 + xoff, 86 + yoff);
  ctx.bezierCurveTo(263 + xoff, 33 + yoff, 381 + xoff, 65 + yoff, 348 + xoff, 160 + yoff);
  ctx.bezierCurveTo(328 + xoff, 218 + yoff, 251 + xoff, 194 + yoff, 206 + xoff, 279 + yoff);
  ctx.bezierCurveTo(161 + xoff, 194 + yoff, 84 + xoff, 218 + yoff, 64 + xoff, 160 + yoff);
  ctx.bezierCurveTo(31 + xoff, 65 + yoff, 149 + xoff, 33 + yoff, 206 + xoff, 86 + yoff);
  ctx.stroke();
}

bezier_heart.swift

import UIKit

UIGraphicsBeginImageContext(CGSize(width: 450, height: 300))
UIColor.whiteColor().setFill()
UIBezierPath(rect: CGRectMake(0, 0, 450, 300)).fill()

// ennek a valtozonak az allitasaval tudod valtoztatni a kitoltes merteket
let ratio = 0.5 as CGFloat

var bp = UIBezierPath()
bp.moveToPoint(CGPoint(x: 206, y: 86))

// jobb oldal
bp.addCurveToPoint(CGPoint(x: 348, y: 160), controlPoint1: CGPoint(x: 263, y: 33), controlPoint2: CGPoint(x: 381, y: 65))
bp.addCurveToPoint(CGPoint(x: 206, y: 279), controlPoint1: CGPoint(x: 328, y: 218), controlPoint2: CGPoint(x: 251, y: 194))

// bal oldal
bp.addCurveToPoint(CGPoint(x: 64, y: 160), controlPoint1: CGPoint(x: 161, y: 194), controlPoint2: CGPoint(x: 84, y: 218))
bp.addCurveToPoint(CGPoint(x: 206, y: 86), controlPoint1: CGPoint(x: 31, y: 65), controlPoint2: CGPoint(x: 149, y: 33))

var bp_filled = bp.copy() as UIBezierPath

UIColor.redColor().setFill()
bp_filled.fill()

UIColor.whiteColor().setFill()
UIBezierPath(rect: CGRectMake(0, 0, 450, 300.0 * ratio)).fill()

UIColor.blueColor().setStroke()
bp.lineWidth = 2
bp.stroke()

let img = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()