iOS最简单绘图实现

来源：互联网发布：淘宝客服问题总结编辑：程序博客网时间：2024/06/05 00:32

drawView.h:

#import <UIKit/UIKit.h>@interface drawView : UIView@property (nonatomic,retain) NSMutableArray *array; //全局变量，存储所有绘图线条@end

drawView.m:

#import "drawView.h"@implementation drawView@synthesize array;- (id)initWithFrame:(CGRect)frame{    self=[super initWithFrame:frame];    array=[NSMutableArray arrayWithCapacity:1];//可变数组也必须先分配1个存储空间，否则无法使用。    self.backgroundColor=[UIColor whiteColor];    UIButton *backButton=[[UIButton alloc]initWithFrame:CGRectMake(0, 0,(self.frame.size.width-40)/3, 30)];    UIButton *cleanButton=[[UIButton alloc]initWithFrame:CGRectMake((self.frame.size.width-40)/3+20, 0,(self.frame.size.width-40)/3, 30)];    UIButton *saveButton=[[UIButton alloc]initWithFrame:CGRectMake((self.frame.size.width-40)/3*2+40, 0, (self.frame.size.width-40)/3, 30)];    backButton.backgroundColor=[UIColor redColor];    backButton.tag=1;    [backButton setTitle:@"撤销" forState:UIControlStateNormal];    [backButton addTarget:self action:@selector(click:) forControlEvents:UIControlEventTouchUpInside];    cleanButton.backgroundColor=[UIColor redColor];    cleanButton.tag=2;    [cleanButton setTitle:@"清空" forState:UIControlStateNormal];    [cleanButton addTarget:self action:@selector(click:) forControlEvents:UIControlEventTouchUpInside];    saveButton.backgroundColor=[UIColor redColor];    saveButton.tag=3;    [saveButton setTitle:@"保存" forState:UIControlStateNormal];    [saveButton addTarget:self action:@selector(click:) forControlEvents:UIControlEventTouchUpInside];    [self addSubview:backButton];    [self addSubview:cleanButton];    [self addSubview:saveButton];    return self;}- (void)click:(UIButton *)sender{    if (sender.tag==1) {        [array removeLastObject];        [self setNeedsDisplay];    }    else if(sender.tag==2)    {        [array removeAllObjects];        [self setNeedsDisplay];    }    else if(sender.tag==3)//保存图像    {        UIGraphicsBeginImageContext(self.frame.size);//创建bitmap上下文        [self.layer renderInContext:UIGraphicsGetCurrentContext()];//保存当前的层到bitmap        UIImage *image=UIGraphicsGetImageFromCurrentImageContext();//获取保存后的图像指针        UIGraphicsEndImageContext();//保存图像（至内存）结束        UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);//保存图像至相册。    }}- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{    UITouch *touch=[touches anyObject];//获得触摸对象    CGPoint startPoint=[touch locationInView:self];    UIBezierPath *path=[UIBezierPath bezierPath];    [path moveToPoint:startPoint];//用贝塞尔曲线对象存储一笔的起点，起点需用moveToPiont方法    [array addObject:path];//将贝塞尔曲线对象存储到全局数组中}- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{    UITouch *touch=touches.anyObject;    CGPoint currentPoint=[touch locationInView:self];    UIBezierPath *path=array.lastObject;//从全局数组中取出最后一个贝塞尔曲线对象，肯定是当前在画的起点    [path addLineToPoint:currentPoint];//贝塞尔曲线对象存储接下来的所有触摸过的点，添加剩下的点需用addLineToPoint方法。    [self setNeedsDisplay];//重绘过程调用了drawRect方法。}- (void)drawRect:(CGRect)rect{//设置绘图的上下文    [[UIColor redColor]setStroke];//画笔颜色    for (UIBezierPath *path in array) {        path.lineWidth=3;//画笔宽度        [path stroke];//绘制贝塞尔曲线对象中的两个点（直线）    }}- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo  //<span style="font-family: Arial, Helvetica, sans-serif;">保存成功与否的官方回调函数</span>{    if (error==nil) {        NSLog(@"保存成功!");    }    else{        NSLog(@"保存失败!");    }}@end

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