如何从 UIWebView 获取整个图像，包括屏幕外内容

How to get ENTIRE image from UIWebView including offscreen content(如何从 UIWebView 获取整个图像，包括屏幕外内容)

问题描述

我有一种方法可以从我的 iOS 应用程序中的各种视图中获取图像，以便让用户通过电子邮件发送屏幕.我绘制的大多数屏幕都可以正常工作，但是当我将这种技术与 UIWebView 一起使用时，我只能得到屏幕的可见部分.屏幕外的任何内容都不包含在渲染图像中.一直在 Stack 上挖掘，但到目前为止我还没有找到工作?！

I have a method I use to get images from a various views in my iOS application for letting users email screens. Most of the screens where I draw are working ok, but when I use this technique with a UIWebView I only get the visible portion of the Screen. Anything off screen is not included in the rendered image. Been digging around here on Stack, but so far nothing I have found works?!

这是我目前使用的方法:

Here is the method I currently use:

-(NSData *)getImageFromView:(UIView *)view
{
    NSData *pngImg;
    CGFloat max, scale = 1.0;
    CGSize size = [view bounds].size;

    // Scale down larger images else we run into mem issues with mail widget
    max = (size.width > size.height) ? size.width : size.height;
    if( max > 960 )
        scale = 960/max;

    UIGraphicsBeginImageContextWithOptions( size, YES, scale );

    CGContextRef context = UIGraphicsGetCurrentContext();
    [view.layer renderInContext:context];    
    pngImg = UIImagePNGRepresentation( UIGraphicsGetImageFromCurrentImageContext() );

    UIGraphicsEndImageContext();    
    return pngImg;
}

推荐答案

哇，答案简直太简单了……正在到处寻找各种与打印/PDF相关的东西……然后我突然想到，为什么不只是将上下文中的视图设置为 sizeThatFits.成功了！

Wow the answer was stupidly simple... was digging all over the place looking at various Printing/PDF related stuff... then it occurred to me, why not just set the view IN THE CONTEXT to a sizeThatFits. It worked!

警告:不能保证您不会遇到内存问题，我建议您在 @autoreleasepool 池中执行此操作，并考虑像我在示例中所做的那样进行一些缩放，但这有效并且是我决定的:

WARNING: No guarantee you don't run into mem issues with this and I DO suggest you do this inside an @autoreleasepool pool and consider doing some scaling as I do in the example, but THIS WORKS and is what I settled on:

-(NSData *)getImageFromView:(UIView *)view  // Mine is UIWebView but should work for any
{
    NSData *pngImg;
    CGFloat max, scale = 1.0;
    CGSize viewSize = [view bounds].size;

    // Get the size of the the FULL Content, not just the bit that is visible
    CGSize size = [view sizeThatFits:CGSizeZero];

    // Scale down if on iPad to something more reasonable
    max = (viewSize.width > viewSize.height) ? viewSize.width : viewSize.height;
    if( max > 960 )
        scale = 960/max;

    UIGraphicsBeginImageContextWithOptions( size, YES, scale );

    // Set the view to the FULL size of the content.
    [view setFrame: CGRectMake(0, 0, size.width, size.height)];

    CGContextRef context = UIGraphicsGetCurrentContext();
    [view.layer renderInContext:context];    
    pngImg = UIImagePNGRepresentation( UIGraphicsGetImageFromCurrentImageContext() );

    UIGraphicsEndImageContext();
    return pngImg;    // Voila an image of the ENTIRE CONTENT, not just visible bit
}

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