源码下载地址：http://download.csdn.net/detail/liu537192/8546469

效果图：

核心代码：

////  JLViewController.m//  02-涂鸦////  Created by XinYou on 15-3-30.//  Copyright (c) 2015年 vxinyou. All rights reserved.//#import "JLViewController.h"#import "JLPaintView.h"#import "UIImage+Extension.h"#import "MBProgressHUD+MJ.h"@interface JLViewController ()- (IBAction)clear;- (IBAction)back;- (IBAction)save;@property (weak, nonatomic) IBOutlet JLPaintView *paintView;@end@implementation JLViewController- (void)viewDidLoad{    [super viewDidLoad];        }- (IBAction)clear {        [self.paintView clear];}- (IBAction)back {        [self.paintView back];}- (IBAction)save {        // 1,截图    UIImage *image = [UIImage captureWithView:self.paintView];        // 2,保存到相册    UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);}- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo{        if (error) {// 内存不足等情况会导致失败                [MBProgressHUD showError:@"保存失败"];    }else{            [MBProgressHUD showSuccess:@"保存成功"];    }}@end////  JLPaintView.h//  02-涂鸦////  Created by XinYou on 15-3-30.//  Copyright (c) 2015年 vxinyou. All rights reserved.//#import @interface JLPaintView : UIView/** *  清空 */- (void)clear;/** *  后退 */- (void)back;@end////  JLPaintView.m//  02-涂鸦////  Created by XinYou on 15-3-30.//  Copyright (c) 2015年 vxinyou. All rights reserved.//#import "JLPaintView.h"@interface JLPaintView()/** *  可变数组，用于存储所有的路径(每一条线表示一个路径) */@property (nonatomic, strong)NSMutableArray *allPaths;@end@implementation JLPaintView- (void)clear{    // 清空存储所有路径的数组    [self.allPaths removeAllObjects];        // 重绘(刷新)    [self setNeedsDisplay];}- (void)back{        // 删除最后条路径    [self.allPaths removeLastObject];        // 重绘(刷新)    [self setNeedsDisplay];}- (NSMutableArray *)allPaths{    if (_allPaths == nil) {        _allPaths = [NSMutableArray array];    }        return _allPaths;}/** *  手指刚接触屏幕时调用 */- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{    UITouch *touch = [touches anyObject];        // 确定起点    CGPoint startPoint = [touch locationInView:touch.view];        // 每一次开始触摸, 就新建一个数组来存放这次触摸过程的所有点(这次触摸过程的路径)    NSMutableArray *path = [NSMutableArray array];        // 把起点添加到path这个数组中    [path addObject:[NSValue valueWithCGPoint:startPoint]];        // 把本次的路径(path)添加到allPaths中    [self.allPaths addObject:path];        // 重绘(刷新)    [self setNeedsDisplay];}/** *  手指在屏幕上移动时会调用 */- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{    UITouch *touch = [touches anyObject];        // 当前移动到了哪个点(当前点)    CGPoint currentPoint = [touch locationInView:touch.view];        // 取出本次路径对应的数组    NSMutableArray *path = [self.allPaths lastObject];        // 把当前点添加到path数组中    [path addObject:[NSValue valueWithCGPoint:currentPoint]];        // 重绘(刷新)    [self setNeedsDisplay];}/** *  手指离开屏幕时会调用 */- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{    [self touchesMoved:touches withEvent:event];}- (void)drawRect:(CGRect)rect{    // 1,获得上下文    CGContextRef ctx = UIGraphicsGetCurrentContext();        // 2,画线    for (NSMutableArray *path in self.allPaths) {                for (int i = 0; i  path.count; i++) {            CGPoint point = [path[i] CGPointValue];                        if (i == 0) {                // 2.1,画一条线的起点                CGContextMoveToPoint(ctx, point.x, point.y);            }else {                // 2.2,连线                CGContextAddLineToPoint(ctx, point.x, point.y);            }        }    }        // 3,设置样式    // 3.1,设置线宽    CGContextSetLineWidth(ctx, 5);    // 3.2,设置线段头尾的样式    CGContextSetLineCap(ctx, kCGLineCapRound);    // 3.3,设置线段转折点的样式    CGContextSetLineJoin(ctx, kCGLineJoinRound);        // 4,渲染(显示到view上)    CGContextStrokePath(ctx);}@end