iOS-实现图片的捏合放大与缩小

来源：互联网发布：相片制作软件下载编辑：程序博客网时间：2024/05/26 19:16

第一步设置代理

[m_zoomScrollView setDelegate:self];

第二步重写代理方法

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{

return m_coverImg;

}

第三步设置放大缩小倍数

float minScale = CGRectGetWidth(m_zoomScrollView.bounds) / CGRectGetWidth(m_coverImg.frame);

float maxScale = CGRectGetWidth(m_coverImg.frame) / CGRectGetWidth(m_zoomScrollView.bounds);

m_zoomScrollView.minimumZoomScale = minScale;

m_zoomScrollView.maximumZoomScale = maxScale;

[m_zoomScrollView setZoomScale:minScale animated:YES];

设置图片始终居中显示:

- (void)scrollViewDidZoom:(UIScrollView *)scrollView

{

CGFloat offsetX = (m_zoomScrollView.bounds.size.width > m_zoomScrollView.contentSize.width)?

(m_zoomScrollView.bounds.size.width - m_zoomScrollView.contentSize.width) * 0.5 : 0.0;

CGFloat offsetY = (m_zoomScrollView.bounds.size.height > m_zoomScrollView.contentSize.height)?

(m_zoomScrollView.bounds.size.height - m_zoomScrollView.contentSize.height) * 0.5 : 0.0;

m_coverImg.center = CGPointMake(m_zoomScrollView.contentSize.width * 0.5 + offsetX,

m_zoomScrollView.contentSize.height * 0.5 + offsetY);

}

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