将带有添加的叠加层的照片保存到照片库 [英] Saving photo with added overlay to photo library

问题描述

我正在制作一个应用程序，用户在其中拍摄照片，图片上放置了重叠式广告，然后用户可以保存图片或将其上传到Facebook或其他网站。

I'm making an app where the user takes a photo, an overlay is placed over the image, and the user can then save the image or upload it to Facebook or other sites.

我已经设法让应用程序拍摄照片，并使覆盖我使用 UIImageView ，它被放置在

I have managed to get the app to take the photo, and to make the overlay I am using a UIImageView, which is placed over the top of the photo.

我不知道如何将图像以叠加层形式导出到一个文件，照片库或Facebook。

I'm not sure how exactly I can export the image, with the overlay, as one file, to the photo library, or to Facebook.

推荐答案

这应该给你的想法。这段代码可能需要一两个，但是。 （我承认我还没有运行它。）

This should give you the idea. This code may need a tweak or two, though. (I admit that I haven't run it.)

您的 UIImageView 一个CoreGraphics位图上下文（当然包括所有的子图层），然后可以为您提供一个新的 UIImage 。

Your UIImageView's base layer can render itself into a CoreGraphics bitmap context (this will include all the sublayers, of course), which can then provide you with a new UIImage.

UIImage *finalImage;
// Get the layer
CALayer *layer = [myImageView layer];
// Create a bitmap context and make it the current context
UIGraphicsBeginImageContext(layer.bounds.size);
// Get a reference to the context
CGContextRef ctx = UIGraphicsGetCurrentContext();
// Ask the layer to draw itself
[layer drawInContext:ctx];
// Then ask the context itself for the image
finalImage = UIGraphicsGetImageFromCurrentImageContext();
// Finally, pop the context off the stack
UIGraphicsEndImageContext();

这些函数都在 UIKit函数参考。

也是一个稍微更复杂的方法，让你更多的控制像颜色，这涉及到创建一个 CGBitmapContext 并获得一个 CGImageRef ，从中可以再次生成 UIImage 。这在Quartz 2D编程指南的创建位图图形上下文。

There's also a slightly more complicated way that gives you more control over things like color, which involves creating a CGBitmapContext and getting a CGImageRef, from which you can again produce a UIImage. That is described in the Quartz 2D Programming Guide, section "Creating a Bitmap Graphics Context".

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