开发绘图、手势综合App注意点

2020-07-26 02:30:21

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手势的一些注意事项

对于 UITapGestureRecognizer 来说我们一般需要知道该点击手势在屏幕中的位置（locationInView:self）

对于 UIPanGestureRecognizer 来说我们一般需要知道我们的滑动手势移动了多少距离（translationInView:pan）

-(void) pan: (UIPanGestureRecognizer * ) pan {  CGPoint transP = [pan translationInView: pan.view]; //$1 = (x = 0.73990527317289434, y = 0)  CGPoint pont1 = [pan locationInView: self]; //$2 = (x = 198.16665649414063, y = 342.33332824707031)  CGPoint pont2 = [pan locationInView: self.imageV]; //$3 = (x = 198.12057060663793, y = 342.61609831987914)  pan.view.transform = CGAffineTransformTranslate(pan.view.transform, transP.x, transP.y);  //复位  [pan setTranslation: CGPointZero inView: pan.view];}

[UIView animateWithDuration: 0.25 animations: ^ {    self.imageView.alpha = 0;  }completion: ^ (BOOL finished){    self.imageView.alpha = 1;    UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, 0);    CGContextRef ctx = UIGraphicsGetCurrentContext();    [self.layer renderInContext: ctx];    UIImage * imageGot = UIGraphicsGetImageFromCurrentImageContext();    UIGraphicsEndImageContext();    [self.imageView removeFromSuperview];    if (self.delegate && [self.delegate respondsToSelector: @selector(handleImageView: didOperatedImage: )]){      [self.delegate handleImageView: self didOperatedImage: imageGot];    }  }];

接下来来一个iOS图形绘制、旋转、长按、缩放、滑动等综合手势的一个画图项目