开发绘图、手势综合App注意点

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

源码地址：https://github.com/FantasticLBP/BlogDemos/tree/master/

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