用Quartz 2D画小黄人

第一步：

先创建一个OneView类，并在storyboard里边拖拽一个UIview,将这个UIview的类改成OneView。如图所示:

第二步：

在新创建的Oneview里，补齐下列代码：

 //
 //  OneView.m
 //  03-drawImage
 //
 //  Created by jerry on 15/7/20.
 //  Copyright (c) 2015年 jerry. All rights reserved.
 //

 #import "OneView.h"

 @implementation OneView

 -(void)drawRect:(CGRect)rect
 {
     // [self drawImage];
     [self drawYellowPop:rect];
 }
 //
 -(void)drawYellowPop:(CGRect)rect
 {
     // 先获取图片上下文对象
     CGContextRef ctx = UIGraphicsGetCurrentContext();
     // 设置头及颜色
     [self setHeaderWithCGContextRef:ctx andRect:rect];

     [self setMouthWith:ctx andRect:rect];

     [self setGlassesWith:ctx andRect:rect];

     [self setHairWith:ctx andRect:rect];

 }
 /**
  *   画嘴
  *
  *  @param ctx  <#ctx description#>
  *  @param rect <#rect description#>
  */
 -(void)setMouthWith:(CGContextRef)ctx andRect:(CGRect)rect
 {
     // 设置中间点
     CGFloat CenterX = rect.size.width * 0.5;
     CGFloat CenterY = rect.size.width * 0.5;

     // 设置当前点
     CGFloat marginX = ;
     CGFloat marginY = ;
     CGFloat currenX = CenterX - marginX;
     CGFloat currenY = CenterY - marginY;
     CGContextMoveToPoint(ctx, currenX, currenY);

     // 结束点
     CGFloat endX = CenterX + marginX;
     CGFloat endY = currenY;
     // 贝塞尔曲线
     CGContextAddQuadCurveToPoint(ctx, CenterX, CenterY, endX, endY);

     // 设置颜色
     [[UIColor blackColor]set];
     // 渲染
     CGContextStrokePath(ctx);
 }
 // 设置眼镜
 -(void)setGlassesWith:(CGContextRef)ctx andRect:(CGRect)rect
 {
     CGFloat LineX = rect.size.width * 0.5 - ;  // 减半径
     CGFloat LineY = ;
     // 画一条黑线
     CGContextMoveToPoint(ctx,LineX , LineY);
     // 结束点
     CGFloat EndLineX = LineX +  * ;
     CGFloat EndLineY = LineY;
     CGContextAddLineToPoint(ctx,EndLineX, EndLineY);
     CGContextSetLineWidth(ctx, );
     [[UIColor blackColor]set];
     CGContextStrokePath(ctx);

     // 2.画眼
     // 注释：画眼就是画圆
     CGFloat leftEyesY = LineY;
     CGFloat leftEyesRadius = ;
     CGFloat leftEyesX = rect.size.width *0.5 - leftEyesRadius;
     CGFloat leftEyesStartAngle = ;
     CGFloat leftEyesEndAngle = M_PI * ;
     [[UIColor redColor]set];
     CGContextAddArc(ctx, leftEyesX, leftEyesY, leftEyesRadius, leftEyesStartAngle, leftEyesEndAngle, );
     CGContextFillPath(ctx);

     CGFloat rightEyesX = leftEyesX + leftEyesRadius * ;
     CGFloat rightEyesY = leftEyesY;
     CGFloat rightEyesSstartAngle = ;
     CGFloat rightEyesRadius = leftEyesRadius;
     CGFloat rightEyesEndAngle = leftEyesEndAngle;
     CGContextAddArc(ctx, rightEyesX, rightEyesY, rightEyesRadius, rightEyesSstartAngle, rightEyesEndAngle, );
     [[UIColor redColor]set];
     CGContextFillPath(ctx);

     // 镜片
     CGFloat leftGlassesRadius = ;
     CGFloat leftGlassesX = leftEyesX;
     CGFloat leftGlassesY = LineY;
     CGContextAddArc(ctx, leftGlassesX, leftGlassesY, leftGlassesRadius, , M_PI * , );

     CGFloat rightGlassesRadius = leftGlassesRadius;
     CGFloat rightGlassesX = rightEyesX;
     CGFloat rightGlassesY = LineY;
     CGContextAddArc(ctx, rightGlassesX, rightGlassesY, rightGlassesRadius,, M_PI *  , );
     [[UIColor whiteColor]set];
     CGContextFillPath(ctx);

     // 眼睛珠
     CGFloat leftZhuRadius = ;
     CGFloat leftZhuY = LineY;
     CGFloat leftZhuX = leftGlassesX +;
     CGContextAddArc(ctx, leftZhuX, leftZhuY, leftZhuRadius, , M_PI * , );

     CGFloat rightZhuRadius = leftZhuRadius;
     CGFloat rightZhuY = LineY;
     CGFloat rightZhuX = rightGlassesX - ;
     CGContextAddArc(ctx, rightZhuX, rightZhuY, rightZhuRadius, , M_PI * , );

     [[UIColor colorWithRed:/255.0 green:/255.0 blue:/255.0 alpha:]set];
     CGContextFillPath(ctx);

     // 左瞳孔
     CGFloat  leftTongRadius = ;
     CGFloat  leftTongY = leftZhuY;
     CGFloat  leftTontX = leftZhuX;
     CGContextAddArc(ctx, leftTontX, leftTongY, leftTongRadius, , M_PI * , );

     // 右瞳孔
     CGFloat rightTongRadius = leftTongRadius;
     CGFloat rightTongX = rightZhuX;
     CGFloat rightTongY = rightZhuY;
     CGContextAddArc(ctx, rightTongX, rightTongY, rightTongRadius, , M_PI *, );
     [[UIColor colorWithRed:/255.0 green:/255.0 blue:/255.0 alpha:]set];
     CGContextFillPath(ctx);

     // 左聚光
     CGFloat leftJuRadius = ;
     CGFloat leftJuX = leftTontX - ;
     CGFloat leftJuY =leftTongY - ;
     CGContextAddArc(ctx, leftJuX, leftJuY, leftJuRadius, , M_PI * , );

     // 右聚光
     CGFloat rightJuRadius = leftJuRadius;
     CGFloat rightJuX = rightTongX - ;
     CGFloat rightJuY = rightTongY - ;
     CGContextAddArc(ctx, rightJuX, rightJuY, rightJuRadius, , M_PI *, );
     [[UIColor whiteColor]set];
     CGContextFillPath(ctx);
 }

 -(void)setHeaderWithCGContextRef:(CGContextRef)ctx andRect:(CGRect)rect
 {
     // 画图片
     CGFloat topX = rect.size.width * 0.5; // 确定x 轴的点
     CGFloat topY = ;
     CGFloat topRadius = ; // 半径
     CGFloat topStartAngle = ; // 起点
     CGFloat topEndAngle = M_PI;
     // 0 是顺时针  1 是逆时针
     CGContextAddArc(ctx, topX, topY, topRadius, topStartAngle, topEndAngle, );
     // 以上一个终点为起点画直线
     CGFloat leftLineX = topX - topRadius;
     CGFloat leftLineY = topY + ;
     CGContextAddLineToPoint(ctx, leftLineX, leftLineY);

     CGFloat downX = topX;
     CGFloat downY = leftLineY;
     CGContextAddArc(ctx, downX, downY, topRadius,topEndAngle , topStartAngle, );
     // 关闭路径
     CGContextClosePath(ctx);
     // 填充背景颜色
     [[UIColor yellowColor]set];
     //显示在view
     CGContextFillPath(ctx);
 }
 /**
  *  设置头发
  *
  */
 - (void)setHairWith:(CGContextRef)ctx andRect:(CGRect)rect
 {
     // 第一根头发
     CGFloat hairStartX = rect.size.width *0.5;
     CGFloat hairStartY = ;
     CGContextMoveToPoint(ctx, hairStartX, hairStartY);
     CGFloat hairEndX = rect.size.width * 0.5 + ;
     CGFloat hairEndY = ;
     CGContextAddLineToPoint(ctx, hairEndX, hairEndY);

     // 第二根头发
     CGFloat hairTwoStartX = rect.size.width * 0.5 + ;
     CGFloat hairTwoStartY = ;
     CGContextMoveToPoint(ctx, hairTwoStartX, hairTwoStartY);
     CGFloat hairTowEndX = rect.size.width * 0.5 + ;
     CGFloat hairTowEndY = ;
     CGContextAddLineToPoint(ctx, hairTowEndX, hairTowEndY);

     // 第三根头发
     CGFloat hairThreeStartX = rect.size.width * 0.5 - ;
     CGFloat hairThreeStartY = ;
     CGContextMoveToPoint(ctx, hairThreeStartX, hairThreeStartY);
     CGFloat hairThreeEndX = rect.size.width * 0.5 - ;
     CGFloat hairThreeEndY = ;
     CGContextAddLineToPoint(ctx, hairThreeEndX, hairThreeEndY);

     // 第四个头发
     CGFloat hairFourStartX = rect.size.width * 0.5 - ;
     CGFloat hairFourStartY = ;
     CGContextMoveToPoint(ctx, hairFourStartX, hairFourStartY);
     CGFloat hairFourEndX = rect.size.width *0.5 - ;
     CGFloat hairFourEndY = ;
     CGContextAddLineToPoint(ctx, hairFourEndX, hairFourEndY);

     // 第五根头发
     CGFloat hairFiveStartX = rect.size.width * 0.5 + ;
     CGFloat hairFiveStartY = ;
     CGContextMoveToPoint(ctx, hairFiveStartX, hairFiveStartY);
     CGFloat hairFiveEndX = rect.size.width * 0.5 + ;
     CGFloat hairFiveEndY = ;
     CGContextAddLineToPoint(ctx, hairFiveEndX, hairFiveEndY);

     [[UIColor blackColor]set];
     CGContextSetLineWidth(ctx, );
     CGContextStrokePath(ctx);

 }
 /**
  *  画图片
  */
 -(void)drawImage
 {
     // 用oc代码 可以不用获取图形上下文对象
     UIImage *img = [UIImage imageNamed:@""];
     [img drawAsPatternInRect:CGRectMake(, , , )];

 }
 @end

最后运行显示的结果如下：