iOS截图那些事

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字数统计: 464

普通view截图

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+ (UIImage *)gjj_viewScreenShot:(UIView *)view {
UIGraphicsBeginImageContextWithOptions(CGSizeMake(view.frame.size.width, view.frame.size.height ), NO, 0.0);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
/// 返回一个基于当前图形上下文的图片
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();

/// 移除栈顶的基于当前位图的图形上下文
UIGraphicsEndImageContext();
return viewImage;
}

tableView、collectionView等scrollView生成长截图

实现步骤

  1. 保存scrollView截取前的偏移量及Frame
  2. 计算出你要截取的长图的高度及宽度，即scrollView的contentSize，将scrollView.frame设成scrollView.contentSize
  3. 渲染出scrollView整体（上下文），截取当前scrollView生成Image
  4. 恢复scrollView的偏移量及Frame
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+ (UIImage *)gjj_scrollViewScreenShot:(UIScrollView *)scrollView {
UIImage *image = nil;

UIGraphicsBeginImageContextWithOptions(scrollView.contentSize, YES, [UIScreen mainScreen].scale);
CGPoint saveContentOffset = scrollView.contentOffset;
CGRect savedFrame = scrollView.frame;
scrollView.contentOffset = CGPointZero;
scrollView.frame = CGRectMake(0, 0, scrollView.contentSize.width, scrollView.contentSize.height);
[scrollView.layer renderInContext:UIGraphicsGetCurrentContext()];
scrollView.layer.contents = nil;
image = UIGraphicsGetImageFromCurrentImageContext();
scrollView.contentOffset = saveContentOffset;
scrollView.frame = savedFrame;
UIGraphicsEndImageContext();
return image;
}

webView生成长截图

webView和scrollView的截图大同小异

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+ (UIImage *)gjj_webViewScreenShot:(UIWebView *)webView {
UIImage *image = nil;

UIGraphicsBeginImageContextWithOptions(webView.scrollView.contentSize, YES, [UIScreen mainScreen].scale);
CGPoint saveContentOffset = webView.scrollView.contentOffset;
CGRect savedFrame = webView.frame;
webView.scrollView.contentOffset = CGPointZero;
webView.frame = CGRectMake(0, 0, webView.scrollView.contentSize.width, webView.scrollView.contentSize.height);
[webView.layer renderInContext:UIGraphicsGetCurrentContext()];
webView.layer.contents = nil;
image = UIGraphicsGetImageFromCurrentImageContext();
webView.scrollView.contentOffset = saveContentOffset;
webView.frame = savedFrame;
UIGraphicsEndImageContext();
return image;
}

图片拼接

很多需求是截图附带二维码等进行分享。

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+ (UIImage *)gjj_addHeadImage:(UIImage *)headImage footImage:(UIImage *)footImage toMasterImage:(UIImage *)masterImage {
CGSize size;
size.width = masterImage.size.width;

CGFloat headProportion = !headImage?0:(headImage.size.width / headImage.size.height);
CGFloat footProportion = !footImage?0:(footImage.size.width / footImage.size.height);

CGFloat headHeight = !headImage? 0:masterImage.size.width/headProportion;
CGFloat footHeight = !footImage? 0:footImage.size.width/footProportion;

size.height = masterImage.size.height + headHeight + footHeight;

UIGraphicsBeginImageContextWithOptions(size, YES, 0.0);

if (headImage) {
[headImage drawInRect:CGRectMake(0, 0, masterImage.size.width, headHeight)];
}
[masterImage drawInRect:CGRectMake(0, headHeight, masterImage.size.width, masterImage.size.height)];
if (footImage) {
[footImage drawInRect:CGRectMake(0, masterImage.size.height + headHeight, masterImage.size.width, footHeight)];
}
UIImage *resultImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext();
return resultImage;
}

添加水印

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+ (UIImage *)gjj_addWaterImage:(UIImage *)waterImage toMasterImage:(UIImage *)masterImage waterImageRect:(CGRect)rect {
UIGraphicsBeginImageContextWithOptions(masterImage.size, NO, 0);
[masterImage drawInRect:CGRectMake(0, 0, masterImage.size.width, masterImage.size.height)];
/// 绘制水印图片到当前上下文
[waterImage drawInRect:rect];

UIImage * newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
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