多个彩色贝塞尔曲线路径

这是我的免费手绘图代码。 但是当我绘制路径时，之前的路径就消失了。 我无法弄清楚为什么会这样。 有谁能够帮助我。 这是我的代码。

- (void)drawRect:(CGRect)rect { for (NSMutableDictionary *dictionary in pathArray) { UIBezierPath *_path = [dict objectForKey:@"Path"]; UIColor *_colors = [dict objectForKey:@"Colors"]; [_colors setStroke]; _path.lineCapStyle = kCGLineCapRound; [_path stroke]; } } -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { isEdited=YES; myPath=[[UIBezierPath alloc]init]; myPath.lineWidth=lineWidths; CGPoint touchPoint = [[touches anyObject] locationInView:self]; UITouch *mytouch=[[touches allObjects] objectAtIndex:0]; [myPath moveToPoint:[mytouch locationInView:self]]; [myPath addLineToPoint:CGPointMake(touchPoint.x+1, touchPoint.y+1)]; [dict setObject:myPath forKey:@"Path"]; [dict setObject:brushPattern forKey:@"Colors"]; [pathArray addObject:dict]; [self setNeedsDisplay]; } -(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *mytouch=[[touches allObjects] objectAtIndex:0]; [myPath addLineToPoint:[mytouch locationInView:self]]; [self setNeedsDisplay]; } 

Answer 1

你应该在touchesBegan:创建myPath和dict localy touchesBegan:每次触发它。 放弃他们的全class定义。

为了更简单（更快）的性能，您仍然可以在touchesMoved:使用类范围的currentPath和currentDict ivars touchesMoved:

编辑：代码看起来像这样：

 //currentPath declared as an iVar of UIBezierPath* type //currentDict declared as an iVar of NSMutableDictionary* type -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { isEdited=YES; UIBezierPath *myPath=[[UIBezierPath alloc]init]; //locally created myPath.lineWidth=lineWidths; CGPoint touchPoint = [[touches anyObject] locationInView:self]; UITouch *mytouch=[[touches allObjects] objectAtIndex:0]; [myPath moveToPoint:[mytouch locationInView:self]]; [myPath addLineToPoint:CGPointMake(touchPoint.x+1, touchPoint.y+1)]; NSMutableDictionary *dict=[[NSMutableDictionary alloc]init]; //locally created [dict setObject:myPath forKey:@"Path"]; [dict setObject:brushPattern forKey:@"Colors"]; [pathArray addObject:dict]; [self setNeedsDisplay]; currentPath = myPath; currentDict = dict; } -(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *mytouch=[[touches allObjects] objectAtIndex:0]; [currentPath addLineToPoint:[mytouch locationInView:self]]; [self setNeedsDisplay]; } 

Answer 2

1）在图纸视图中创建UIImage *currentImage实例变量。

2）在你的view的drawRect方法中放入以下行：

 [currentImage drawInRect:self.bounds]; 

3）在touchesEnded方法中输入以下代码：

  CGRect rect = self.bounds; UIGraphicsBeginImageContext(rect.size); [self.layer renderInContext:UIGraphicsGetCurrentContext()]; UIImage *tempImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); currentImage = tempImage;