1.建一个view
.h文件复制以下代码
/**
* 画布
*/
@interface SKGraphicView : UIView
{
CGPoint _start;
CGPoint _move;
CGMutablePathRef _path;
NSMutableArray *_pathArray;
CGFloat _lineWidth;
UIColor *_color;
}
@property (nonatomic,assign)CGFloat lineWidth;/**< 线宽 */
@property (nonatomic,strong)UIColor *color;/**< 线的颜色 */
@property (nonatomic,strong)NSMutableArray *pathArray;
-(UIImage*)getDrawingImg;
2 .m文件
复制以下代码
- (instancetype)initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]) {
_move = CGPointMake(0, 0);
_start = CGPointMake(0, 0);
_lineWidth = 2;
_color = [UIColor redColor];
_pathArray = [NSMutableArray array];
//创建保存功能
UIButton *but = [UIButton buttonWithType:UIButtonTypeSystem];
but.frame = CGRectMake(0, self.bounds.size.height-60, 100, 60);
[but setTitle:@"保存至相册" forState:UIControlStateNormal];
[but addTarget:self action:@selector(savePhoto) forControlEvents:UIControlEventTouchUpInside];
[self addSubview:but];
UIButton *undoBtn = [UIButton buttonWithType:UIButtonTypeSystem];
undoBtn.frame = CGRectMake(110, self.bounds.size.height-60, 100, 60);
[undoBtn setTitle:@"撤销" forState:UIControlStateNormal];
[undoBtn addTarget:self action:@selector(undoBtnEvent) forControlEvents:UIControlEventTouchUpInside];
[self addSubview:undoBtn];
UIButton *clearBtn = [UIButton buttonWithType:UIButtonTypeSystem];
clearBtn.frame = CGRectMake(220, self.bounds.size.height-60, 100, 60);
[clearBtn setTitle:@"清除" forState:UIControlStateNormal];
[clearBtn addTarget:self action:@selector(clearBtnEvent) forControlEvents:UIControlEventTouchUpInside];
[self addSubview:clearBtn];
}
return self;
}
- (void)drawRect:(CGRect)rect {
// 获取图形上下文
CGContextRef context = UIGraphicsGetCurrentContext();
[self drawPicture:context]; //画图
}
- (void)drawPicture:(CGContextRef)context {
for (NSArray * attribute in _pathArray) {
//将路径添加到上下文中
CGPathRef pathRef = (__bridge CGPathRef)(attribute[0]);
CGContextAddPath(context, pathRef);
//设置上下文属性
[attribute[1] setStroke];
CGContextSetLineWidth(context, [attribute[2] floatValue]);
//绘制线条
CGContextDrawPath(context, kCGPathStroke);
}
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
_path = CGPathCreateMutable(); //创建路径
NSArray *attributeArry = @[(__bridge id)(_path),_color,[NSNumber numberWithFloat:_lineWidth]];
[_pathArray addObject:attributeArry]; //路径及属性数组数组
_start = [touch locationInView:self]; //起始点
CGPathMoveToPoint(_path, NULL,_start.x, _start.y);
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
// 释放路径
CGPathRelease(_path);
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
_move = [touch locationInView:self];
//将点添加到路径上
CGPathAddLineToPoint(_path, NULL, _move.x, _move.y);
[self setNeedsDisplay];
}
#pragma mark --点击事件--
- (void)savePhoto {
if (_pathArray.count) {
UIGraphicsBeginImageContext(self.frame.size);
CGContextRef context = UIGraphicsGetCurrentContext();
UIRectClip(CGRectMake(0, 0, self.frame.size.width, self.frame.size.height));
[self.layer renderInContext:context];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIImageWriteToSavedPhotosAlbum(image, self, nil, NULL);
}
else{
UIAlertView* alert = [[UIAlertView alloc]initWithTitle:@"alert" message:@"请您先绘制图形" delegate:nil cancelButtonTitle:nil otherButtonTitles:@"确定", nil];
[alert show];
}
}
-(UIImage *)getDrawingImg{
if (_pathArray.count) {
UIGraphicsBeginImageContext(self.frame.size);
CGContextRef context = UIGraphicsGetCurrentContext();
UIRectClip(CGRectMake(0, 0, self.frame.size.width, self.frame.size.height));
[self.layer renderInContext:context];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
return image;
}
UIAlertView* alert = [[UIAlertView alloc]initWithTitle:@"alert" message:@"请您先绘制图形" delegate:nil cancelButtonTitle:nil otherButtonTitles:@"确定", nil];
[alert show];
return nil;
}
-(void)undoBtnEvent
{
[_pathArray removeLastObject];
[self setNeedsDisplay];
}
-(void)clearBtnEvent
{
[_pathArray removeAllObjects];
[self setNeedsDisplay];
}
3在控制器中包含你建立的那个view
调用以下代码就OK 了
SKGraphicView *view = [[SKGraphicView alloc] initWithFrame:CGRectMake(0, 130, kwidth, [UIScreen mainScreen].bounds.size.height - 130)];
view.backgroundColor = [UIColor whiteColor];
view.color = [UIColor blackColor];
view.lineWidth = 10;
[self.view addSubview:view];
4. 大功告成
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